Clin Exp Nephrol DOI 10.1007/s10157-014-1009-7
ORIGINAL ARTICLE
Serum galectin-3 levels were associated with proteinuria in patients with Familial Mediterranean Fever Hakki Yilmaz • Osman Inan • Tahir Darcin Mukadder Ayse Bilgic • Ali Akcay
•
Received: 14 May 2014 / Accepted: 28 June 2014 Ó Japanese Society of Nephrology 2014
Abstract Background The most common and pernicious complication of Familial Mediterranean fever (FMF) is renal amyloidosis, usually affecting the kidneys, leading to endstage renal failure. FMF-related renal amyloidosis needed to be diagnosed early. Optimal colchicine dose is effective in preventing and reversing renal amyloidosis. Galectin-3, profibrotic mediator, has regulatory functions in inflammation, fibrosis and tumorigenesis. Galectin-3 is a strong prognostic marker for heart failure. Galectin-3 plays role in diabetic nephropathy and chronic kidney disease. The aim of the study is to investigate whether galectin-3 is related to proteinuria and amyloidosis in FMF. Methods Seventy-five FMF patients who have no exclusion criteria and healthy controls (n = 36) were included. Serum galectin-3 was measured and morning spot urine was collected for determination of the protein/creatinine ratio (PCR). Results Serum Galectin-3 levels were significantly higher in FMF patients than the control group [969.66 (3825) pg/ mL vs. 238 (921) pg/mL, respectively; P\0.001]. We classified into two groups: Group1 (n = 48) had FMF patients with proteniuria, Group2 (n = 27) had FMF H. Yilmaz (&) M. A. Bilgic A. Akcay Department of Internal Medicine, Section of Nephrology, School of Medicine, Turgut Ozal University, Alparslan Tu¨rkes Cad. No: 57, Emek, 06510 Ankara, Turkey e-mail: [email protected] O. Inan Department of Internal Medicine, Yenimahalle State Hospital, Ankara, Turkey T. Darcin Department of Internal Medicine, Agri State Hospital, Agri, Turkey
patients without proteinuria. Group1 had higher levels of galectin-3 than Group2 [1106(3812) pg/mL vs. 867.3(1433) pg/mL, P \ 0.001]. Galectin-3 levels were correlated with PCR in whole group and FMF group (r = 0.785, P \ 0.001 and r = 0.803, P \ 0.001). In ROC curve, best cutoff value = 581.50 pg/mL was used to detect proteinuria (sensitivity = 91.7 %, specificity = 71.4 %, AUC = 0.879) and optimal cutoff value = 1458.00 pg/mL was an indicator of nephroticrange proteinuric (sensitivity = 100 %, specificity = 92.1 %, AUC = 0.983). Conclusion Galectin-3 is associated with proteinuria and renal amyloidosis in FMF. Galectin-3 may play role in pathogenesis of amyloidosis. Keywords FMF
Galectin-3 Proteinuria Renal amyloidosis
Introduction Familial Mediterranean fever (FMF), the most frequent of the periodic fever syndromes, is a hereditary autosomal recessive autoinflammatory disease characterized by recurrent spontaneous self-limited febrile attacks and serositis, predominantly affecting people of Mediterranean descent [1, 2]. The most important and devastating complication is reactive AA amyloidosis in FMF [3]. Proteinuria is the most common presenting feature of renal involvement due to FMF-related AA amyloidosis, which may gradually progress a nephrotic stage into end-stage renal failure necessitating kidney transplantation or hemodialysis [4, 5]. Ethnicity, genotype, and gender affect the prevalence of amyloidosis [1–5]. FMF-related amyloidosis was reported to occur in 60–75 % of FMF patients among various ethnicities [6, 7]
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and 12.9–60 % among Turkish patients [8, 9] without colchicine therapy. Incidence of FMF-related amyloidosis has gradually declined since the widespread use of colchicine for FMF patients [10]. We should keep renal amyloidosis in mind if FMF patients have varying levels of proteinuria. If early stage of renal amyloidosis is diagnosed, the colchicine dose should be increased to 2–3 mg/day [3]. This modification prevents progressing into nephrotic syndrome and/or renal dysfunction [3]. Galectin-3 is a b-galactoside-binding lectin highly expressed in activated macrophages, which may be involved in inflammation, fibrosis, immunity, and cancer [11, 12]. Some evidence showed that accelerated diabetic glomerulopathy in galectin-3 knockout mice, galectin-3, had a protective role toward AGE-induced renal injury [13, 14]. Conversely, Galectin-3 was found to play regulatory role in the development of renal fibrosis in mouse models and humans [15–17]. Galectin-3 is emerging as a novel mediator of kidney fibrosis and progressive CKD [17]. Elevated galectin-3 levels were present in patients with cardiac amyloidosis when compared with patients with left ventricular hypertrophy (LVH) or systolic heart failure (HF) [18]. In FMF patients, the relationship between galectin-3 and renal amyloidosis remains unknown still and is an interesting subject. The aim of the study is to investigate whether galectin-3 are related to proteinuria and renal amyloidosis in patients with FMF.
Materials and methods Seventy-five patients with FMF, who were diagnosed based on Tel-Hashomer criteria [19] at the Internal Medicine Clinics between January 2012 and December 2013, were recruited to this cross-sectional study. Thirty-six age- and sex-matched control participants were included in the study. This study was approved by local Ethics Committee (IRB number: 99950669/190). All patients provided written informed consent prior to participating in the study. The patients (n = 102) with acute FMF attack, heart failure, diabetes mellitus, hypertension, coronary heart diseases, metabolic syndrome, anemia, acute/chronic infection, autoimmune disorders, chronic obstructive pulmonary disease, cancer and history of smoking were excluded. Also, the patients were on medication (oral contraceptives, oral antidiabetic agents, antihypertensive drugs, antihyperlipidemic agents and glucocorticoids) except colchicine, were not included in the study. The MEFV gene mutations were achieved from our database. Assessment of the disease severity was performed using the modified scoring systems of Pras et al. [20]. All patients were in attack-free period; At least 2 weeks from the end of
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an FMF attack period was defined as attack-free period according to the physical examination, clinical symptoms, and CRP. The healthy control group was composed to be similar to age, gender ratio and BMI of patients group. The control group had no smoker, acute infection and chronic disease such as heart failure, diabetes mellitus, hypertension, coronary heart diseases, metabolic syndrome, anemia, acute/chronic infection, autoimmune disorders, chronic inflammation, chronic obstructive pulmonary disease and cancer. A single-void morning urine sample was collected for evaluation of the protein/creatinine ratio (PCR) in spot urine during attack-free period. The concentration of total protein in urine was measured by a biuret colorimetric assay (Cobas c501, Roche Diagnostics, Mannheim, Germany), and the urine creatinine level was measured by a modified Jaffe test (Cobas c501, Roche Diagnostics, Mannheim, Germany). The urine PCR was obtained by dividing the urinary protein concentration (g/dl) by the urine creatinine concentration (g/dl). The normal urine PCR is less than 0.2 g/gCr and PCR greater than 3.5 g/gCr is in the nephrotic range for proteinuria [21, 22]. Blood samples were drawn during attack-free period and serum separated in a centrifuge for 15 min at 1000 rpm and immediately transferred into 1-ml cryotubes and stored at -80 °C until analysis. Serum urea nitrogen, creatinine, albumin and C-reactive protein (CRP, Normal values 0–10 mg/L) were measured by standard laboratory techniques using an autoanalyzer (Roche Diagnostics, COBAS INTEGRA 800, Indianapolis, Indiana, USA). Serum levels of Gal3 were measured with enzyme-linked inmunosorbent assay, ELISA, (Catalog No: SK00199-01, Human Galectin-3 ELISA, AVISCERA BIOSCIENCE INC., Santa Clara, CA, USA). Calibration of the assay was performed according to the manufacturer’s recommendations and values were normalized to a standard curve. Descriptive statistics were presented as arithmetic mean ± standard deviation. Results which did not follow normal distribution are expressed as median (range) values. For the tests of normality, we used the Shapiro–Wilk test. Categorical variables were given as percentages. The independent sample unpaired Student’s t test or the Mann– Whitney U test was used for the continuous variables and categorical data were compared with the Chi square test. Relationships between variables were tested using Spearman’s test. Receiver-operating characteristic (ROC) curves were constructed to determine the optimum cutoff for Gal3 levels that could discriminate proteinuria from healthy subjects or non-proteinuric FMF patients, as well as nephrotic-range proteinuric FMF patients from the other FMF patients and healthy subjects. The area under the curve (AUC) was calculated to quantify sensitivity and specificity. The optimal cutoff point was the point on the
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ROC curve closest to the upper-left corner with maximum sensitivity and specificity, namely, the maximum Youden’s index [Youden’s index = sensitivity ? specificity-1] [23]. In all analyses, a two-sided P value of \0.05 was considered to indicate statistical significance. All statistical analyses were performed with the Statistical Package for the Social Sciences (SPSS) 17.0 Package (SPSS Inc., Chicago, IL, USA).
Results Out of 75 patients which were included to the present study, thirty-one were newly diagnosed patients and fortyfour were patients having the appropriate criteria and who had been using colchicine. Control group consist of 36 individuals who had no known disease and who were not using cigarette and any drug. There were no statistical differences between patients with FMF and healthy individuals in terms of age (32.6 ± 11.2 vs. 31.3 ± 12.4 years, respectively). And also, we did find male/female ratio between patients with FMF and controls (M/F = 36/39 vs. M/F = 17/19, P = 0.678, respectively) (Table 1). There was no statistical significance in levels of CRP between FMF patients and healthy controls (4.72 ± 1.75 mg/L vs. 2.61 ± 1.68 mg/L, P = 0.258) (Table 1). Serum Galectin-3 levels were significantly higher in FMF patients than the control group [969.66 (3825) pg/ml vs. 238 (921) pg/ml, respecttively; P \ 0.001, Table 1]. FMF patients were classified according to whether they have proteinuria (PCR [ 0.2). Group1 (n = 48) was composed of proteinuric patients, Group2 (n = 27) had FMF patients without proteinuria. PCR and serum galectin3 levels were detected significantly higher in Group1 when compared with Group2 [0.84 (16.02) vs. 0.10 (0.17), P \ 0.001 for PCR; 1106 (3812) pg/mL vs. 867.3 (1433) pg/mL, P \ 0.001 for Galectin-3]. No significant differences were found in terms of the ages of patients, gender of patients, recurrent attacks, duration of attacks, duration of the illness, severity of the disease, CRP and MEFV gene mutations between Group1 and Group2 (P [ 0.05) (Table 2). Serum level of Galectin-3 was found to be directly correlated with PCR in whole group (Fig. 1) and FMF group (Fig. 2) (r = 0.785, P \ 0.001 and r = 0.803, P \ 0.001). There was no association of galectin-3 with age, BMI, gender, colchicine dose, duration of the illness, severity of the disease, CRP, albumin and creatinine in patients with FMF. There was nephrotic-range proteinuria in 10 patients in Group1. Renal biopsy was recommended to all patients who had nephrotic-range proteinuria. The cause of
Table 1 Demographic characteristics and between FMF patients and healthy controls
laboratory
analyses
FMF patients (n = 75)
Healthy control (n = 36)
P value
Gender, male/female
36/39
17/19
0.678
Age, years
32.6 ± 11.2
31.3 ± 12.4
0.719
BMI, kg/m2
25.4 ± 3.2
24.9 ± 3.8
0.832
Age of onset, years
22.8 ± 7.6
–
Disease duration, years
9.8 ± 6.5
–
Number of attacks per month
1.86 ± 1.23
–
Colchicine dose (mg/day)
1.65 ± 0.68
–
CRP, mg/L
4.72 ± 1.75
2.61 ± 1.68
0.285
Albumin, g/dL
3.92 ± 0.72
4.07 ± 0.85
0.196
Urea, mg/dL Creatinine, mg/dL
32.8 ± 8.4 0.91 ± 0.32
31.7 ± 7.9 0.84 ± 0.28
0.546 0.215
Galectin-3, pg/mL
969.66 (3825)
238 (921)
\0.001
nephrotic syndrome in seven patients in which renal biopsy was done was renal amyloidosis. One patient did not accept renal biopsy, and two did not continue polyclinic control following renal biopsy. Thus, renal AA amyloidosis was the most important reason causing nephrotic-range proteinuria in patients with FMF. To evaluate the ability of serum Gal-3 to discriminate proteinuria patients from healthy controls and FMF patients, we performed ROC curve analyses. A cutoff point of 581.50 pg/mL was used to detect proteinuria (sensitivity = 91.7 %, specificity = 71.4 %, AUC = 0.879, Fig. 3). A cutoff point of 1458.00 pg/mL was used to distinguish nephrotic-range proteinuric FMF patients from the other FMF patients and healthy subjects, showing high performance (sensitivity = 100 %, specificity = 92.1 %, AUC = 0.983, Fig. 4).
Discussion The main result of the present study is that there is a strong correlation between galectin-3 level and the level of proteinuria in patients with FMF. Galectin-3 level is a reliable marker that can determine both the proteinuria and the nephrotic-range proteinuria in patients with FMF. Galectin3 levels were not associated with CRP in FMF patients. CRP levels were similar between FMF patients with proteinuria and without proteinuria. The most important reason of nephrotic-range proteinuria in patients with FMF was renal AA amyloidosis.
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Clin Exp Nephrol Table 2 Baseline and laboratory characteristics among Group1 and Group2
Group 1 is consisted of FMF patients with proteinuria. Group 2 is consisted of FMF patients without proteinuria
Group1 (n = 48)
P value
Gender, male/female
23/25
13/14
0.609
Age, years
33.2 ± 12.3
31.9 ± 10.8
0.341
BMI, kg/m2
25.3 ± 3.4
25.5 ± 3.9
0.842
Age of onset, years
22.7 ± 8.1
22.9 ± 7.5
0.703
Disease duration, years
10.1 ± 6.8
9.6 ± 7.0
0.471 0.782
Number of attacks per month
1.88 ± 1.29
1.81 ± 1.32
Disease severity score
6.10 ± 1.95
5.94 ± 2.04
0.531
Colchicine dose (mg/day)
1.72 ± 0.62
1. 60 ± 0.71
0.237
CRP, mg/L
2.93 ± 1.80
2.62 ± 1.76
0.328
Albumin, g/dL
3.78 ± 0.76
4.03 ± 0.82
0.102
Urea, mg/dL
33.5 ± 9.1
32.0 ± 7.3
0.736
Creatinine, mg/dL
0.93 ± 0.28
0.88 ± 0.25
Galectin-3, pg/mL
1106 (3812)
867.3 (1433)
\0.001
PCR, mg/mg
0.84 (16.02)
0.10 (0.17)
\0.001
MEFV gene mutations, % (n) Homozygous M694V
20.8 (10)
22.2 (6)
0.651
0.407
Heterozygous M694V
16.6 (8)
14.8 (4)
0.572
Heterozygous M680I
6.25 (3)
3.7 (1)
0.058
Heterozygous E148Q
8.4 (4)
7.4 (2)
0.617
Heterozygous V726A
2 (1)
3.7 (1)
0.283
Heterozygous M694V/M680I
8.4 (4)
11.1 (3)
0.346
Heterozygous M694V/E148Q
8.4 (4)
11.1 (3)
0.346
Others
27 (13)
25.9 (7)
0.683
Fig. 1 Galectin-3 levels were associated with PCR in whole group
The most important and unwanted complication in FMF was development of renal amyloidosis [1–4]. Renal amyloidosis presents with persistent or ingravescent proteinuria leading to nephrotic syndrome and progressive nephropathy leading to end-stage renal disease
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Group2 (n = 27)
Fig. 2 Galectin-3 levels were associated with PCR in patients with FMF
[2–4]. Appropriate dose of colchicine prevents renal amyloidosis in most patients and is also effective in arresting and reversing renal amyloidosis. Thus, the
Clin Exp Nephrol
Fig. 3 ROC curve showed that cutoff value 3 = 581.50 pg/mL was an indicator of proteinuria
of
galectin-
Fig. 4 In ROC curve, cutoff value of galectin-3 = 1458.00 pg/mL was used to detect nephrotic-range proteinuria in whole group
diagnosis of renal amyloidosis at early stages has critical importance. According to the results of the current study, it could be assumed that development of renal amyloidosis might be determined at early stages by determination and follow-up of galectin-3 levels.
There is a strong positive correlation between Galectin-3 levels and proteinuria. In addition, galectin-3 level has capacity to determine nephrotic-range proteinuria. Early detection of proteinuria and nephrotic-range proteinuria with the help of galectin-3 level in patients with FMF could enable earlier detection of renal amyloidosis. In this way, it would be possible to prevent progressive renal failure. We tried to explain the relation among galectin-3, proteinuria and renal amyloidosis with the following mechanisms: (1) together with the amyloid which accumulated in glomerules, advanced glycation end products (AGEs) and receptor for advanced glycation end products (RAGE) also accumulate and they are correlated with amyloid deposits [24]. The serum levels of AGE increase [24]. Both development of diabetic nephropathy accelerates and also AGEinduced glomerular damage accelerates in gal-3 knockout mice in which diabetic nephropathy model is produced [13, 14]. These data indicate that in diabetic mice, galectin-3 is upregulated and is operating in vivo as an AGE receptor to afford protection toward AGE-dependent tissue injury and increased expression of gal-3 acts as opposed to RAGE [13, 14]. Galectin-3 level increases to prevent the damage caused by AGE; however, it could be assumed that it could not be protective due to galectin-3 resistance; (2) there is a positive correlation between glomerular amyloid accumulation and interstitial fibrosis in renal amyloidosis caused by FMF [25, 26]. Galectin-3 is profibrotic marker, having a stimulatory effect on macrophage migration, myofibroblast accumulation/activation, and development of fibrosis in renal tissues [15–17]. There is generally interstitial fibrosis on the basis of renal amyloidosis and galectin-3 level might increase depending on this fibrosis [25, 26]; (3) in many FMF patients, chronic inflammation may persist in attackfree periods [27]. Persistent chronic inflammation in FMF may cause renal amyloidosis [27]. In addition, there is a positive correlation between the degree of glomerular amyloid accumulation and inflammation [26]. As a result, chronic inflammation in patients with proteinuric attackfree FMF might be one of possible factors responsible for the increase of galectin-3 levels. Despite FMF patients had higher levels of CRP than healthy control, we found no statistical significance among two groups because of small sample size of this study and no serial measurement of CRP. In the present study we did not find a correlation between Galectin-3 and CRP. When compared with SAA, CRP is an acute phase reactant that has no ability to determine renal amyloidosis caused by FMF and subclinical inflammation in FMF [27–30]. As correlation of galectin-3 was not evaluated with a strong marker such as SAA, we could not say that there is no correlation between galectin-3 and chronic subclinical inflammation in FMF. Perhaps galectin-3 might be a strong
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marker reflecting chronic subclinic inflammation in patients with FMF. One of the most common causes of proteinuria in patients with FMF is renal AA amyloidosis. In the current study there was proteinuria in 64 % of the patients with FMF, nephrotic-range proteinuria in 13.3 % and renal amyloidosis which was definitely diagnosed with biopsy in 9.3 % and the findings of the present study were consistent with the literature [6–9]. Nonamyloid glomerulopathies have been reported and can seldom develop in patients with FMF [3, 8, 31–33]. While there may be rarely other causes in FMF patients with proteinuria, the most important cause which should be absolutely kept in mind is renal amyloidosis. Renal biopsy is the gold standard method in diagnosis of renal amyloidosis [2–5]. The most important noninvasive technique that is helpful in diagnosis of renal amyloidosis is severe proteinuria measured in 24-h urine collection. Two major limitations of measuring protein excretion in a 24-h urine collection are that it is cumbersome for patients and often collected incorrectly. The most important easy alternative in diagnosis of proteinuria is PCR in spot urine sample. According to our results, urine PCR was appeared to be used to evaluate of proteinuria and monitor the degree of proteinuria in patients with FMF. This study had several limitations. First, the cross-sectional study design with the observed associations does not represent causal relationships between galectin-3 and proteinuria. Second, we used spot urinary PCR for evaluation of proteinuria. Although the PCR correlates well with 24-h urine protein excretion, there are two major limitations of using random spot urine samples to quantify proteinuria: (a) the PCR is heavily influenced by the urine creatinine concentration (the denominator of the ratio) so PCR will underestimate and/or overestimate proteinuria, (b) urine protein excretion can vary throughout the day and from day to day. Third, AGE-RAGE and other inflammatory markers (SAA, IL-1) were not measured except CRP. SAA is a better indicator of subclinical inflammation and development of renal amyloidosis than CRP. In conclusion, increased levels of galectin-3 are associated with proteinuria and renal amyloidosis in FMF. Galectin-3 may play role in development of amyloidosis. If further prospective studies validate our results, galectin-3 will be used routinely for development of renal amyloidosis in patients with FMF. The patients with FMF should be regularly followed in terms of proteinuria and the daily dose of colchicine should be increased in FMF patients with proteinuria. Conflict of interest interest.
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All the authors have declared no competing
References 1. Soriano A, Manna R. Familial Mediterranean fever: new phenotypes. Autoimmun Rev. 2012;12:31–7. 2. Portincasa P, Scaccianoce G, Palasciano G. Familial Mediterranean fever: a fascinating model of inherited autoinflammatory disorder. Eur J Clin Invest. 2013;43(12):1314–27. 3. Onen F. Familial Mediterranean fever. Rheumatol Int. 2006;26:489–96. 4. Lidar M, Livneh A. Familial Mediterranean fever: clinical, molecular and management advancements. Neth J Med. 2007;65(9):318–24. 5. Pinney JH, Lachmann HJ. Systemic AA amyloidosis. Subcell Biochem. 2012;65:541–64. 6. Sohar E, Gafni J, Pras M, Heller H. Familial Mediterranean fever. A survey of 470 cases and review of the literature. Am J Med. 1967;43(2):227–53. 7. Pras M, Bronshpigel N, Zemer D, Gafni J. Variable incidence of amyloidosis in familial Mediterranean fever among different ethnic groups. Johns Hopkins Med J. 1982;150:22–6. 8. Tunca M, Akar S, Onen F, Ozdogan H, Kasapcopur O, Yalcinkaya F, Tutar E, Ozen S, Topaloglu R, Yilmaz E, Arici N, Bakkaloglu A, Besbas N, Akpolat T, Dinc A, Erken E, Turkish FMF study group. Familial Mediterranean fever in Turkey. Results of a nationwide multicenter study. Medicine. 2005;84:1–11. 9. Ben-Chetrit E, Levy M. Familial Mediterranean fever. Lancet. 1998;351:659–64. 10. Drenth JP, van der Meer JW. Hereditary periodic fever. N Engl J Med. 2001;345(24):1748–57. 11. de Boer RA, Voors AA, MuntendamP, vanGilstWH, van Veldhuisen DJ. Galectin-3: a novel mediator of heart failure development and progression. Eur J Heart Fail. 2009;11:811–7. 12. Henderson NC, Sethi T. The regulation of inflammation by galectin-3. Immunol Rev. 2009;230(1):160–71. 13. Pugliese G, Pricci F, Iacobini C, Leto G, Amadio L, Barsotti P, Frigeri L, Hsu DK, Vlassara H, Liu F-T, Di Mario U. Accelerated diabetic glomerulopathy in galectin-3/AGE receptor 3 knockout mice. FASEB J. 2001;15(13):2471–9. 14. Iacobini C, Amadio L, Oddi G, Ricci C, Barsotti P, Missori S, Sorcini M, Di Mario U, Pricci F, Pugliese G. Role of galectin-3 in diabetic nephropathy. J Am Soc Nephrol. 2003;14:S264–70. 15. Henderson NC, Mackinnon AC, Farnworth SL, Kipari T, Haslett C, Iredale JP, Liu FT, Hughes J, Sethi T. Galectin-3 expression and secretion links macrophages to the promotion of renal fibrosis. Am J Pathol. 2008;172:288–98. 16. Dang Z, MacKinnon A, Marson LP, Sethi T. Tubular atrophy and interstitial fibrosis after renal transplantation is dependent on galectin-3. Transplantation. 2012;93:477–84. 17. O’Seaghdha CM, Hwang SJ, Ho JE, Vasan RS, Levy D, Fox CS. Elevated galectin-3 precedes the development of CKD. J Am Soc Nephrol. 2013;24:1470–7. 18. Friedman EA, Brittain E, Su YR, LeBoeuf J, Sawyer D, Lenihan D. Markedly elevated galectin-3 levels in cardiac amyloidosis may indicate significant fibrosis. J Cardiac Fail. 2013;19(8):S63. 19. Livneh A, Langevitz P, Zemer D, Zaks N, Kees S, Lidar T, et al. Criteria for the diagnosis of familial Mediterranean fever. Arthr Rheum. 1997;40:1879–85. 20. Pras E, Livneh A, Balow JE, Kastner DL, Pras M, Langevitz P. Clinical differences between North African and Iraqi Jews with familial Mediterranean fever. Am J Med Genet. 1998;75:216–9. 21. Schwab SJ, Christensen RL, Dougherty K, Klahr S. Quantitation of proteinuria by the use of protein-to-creatinine ratios in single urine samples. Arch Intern Med. 1987;147(5):943–4.
Clin Exp Nephrol 22. Ginsberg JM, Chang BS, Matarese RA, Garella S. Use of single voided urine samples to estimate quantitative proteinuria. N Engl J Med. 1983;309(25):1543–6. 23. Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 1982;143:29–36. 24. Matsunaga N, Anan I, Rosenberg P, Nagai R, Lundstro¨m O, Horiuchi S, Ando Y, Suhr OB. Advanced glycation end product is implicated in amyloid-related kidney complications. Scand J Clin Lab Invest. 2005;65(4):263–72. 25. Bohle A, Wehrmann M, Eissele R, von Gise H, Mackensen-Haen S, Muller C. The long-term prognosis of AA and AL renal amyloidosis and the pathogenesis of chronic renal failure in renal amyloidosis. Pathol Res Pract. 1993;189:316–31. 26. Sen S, Sarsik B. A proposed histopathologic classification, scoring, and grading system for renal amyloidosis: standardization of renal amyloid biopsy report. Arch Pathol Lab Med. 2010;134(4):532–44. 27. Ben-Zvi I, Livneh A. Chronic inflammation in FMF: markers, risk factors, outcomes and therapy. Nat Rev Rheumatol. 2011;7(2):105–12. 28. Yalc¸inkaya F, Cakar N, Acar B, Tutar E, Gu¨riz H, Elhan AH, Oztu¨rk S, Kansu A, Ince E, Atalay S, Girgin N, Dog˘ru U, Aysev
29.
30.
31.
32.
33.
D, Ekim M. The value of the levels of acute phase reactants for the prediction of familial Mediterranean fever associated amyloidosis: a case control study. Rheumatol Int. 2007;27(6):517–22. ¨ zen S, Du¨zova A, Bakkalog˘lu A, Bes¸ bas¸ N, Topalog˘lu R, O ¨ zaltin F, Bas¸ soy Y, Yilmaz E. Role of A-SAA in monitoring O subclinical inflammation and in colchicines dosage in familial Mediterranean fever. Clin Exp Rheum. 2003;21:509–14. Gillmore JD, Lovat LB, Persey MR, Pepys MB, Hawkins PN. Amyloid load and clinical outcome in AA amyloidosis in relation to circulating concentration of serum amyloid A protein. Lancet. 2001;358:24–9. Yalcinkaya F, Turner N. Glomerular lesions other than amyloidosis in patients with FMF. Nephrol Dial Transplant. 1999;14:21–3. Akpolat T, Akpolat I, Karagoz F, et al. Familial Mediterranean fever and glomerulonephritis and review of the literature. Rheumatol Int. 2004;24:43–5. Said R, Hamzeh Y, Said S, et al. Spectrum of renal involvement in FMF. Kidney Int. 1992;41:414–9.
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ORIGINAL ARTICLE
Serum galectin-3 levels were associated with proteinuria in patients with Familial Mediterranean Fever Hakki Yilmaz • Osman Inan • Tahir Darcin Mukadder Ayse Bilgic • Ali Akcay
•
Received: 14 May 2014 / Accepted: 28 June 2014 Ó Japanese Society of Nephrology 2014
Abstract Background The most common and pernicious complication of Familial Mediterranean fever (FMF) is renal amyloidosis, usually affecting the kidneys, leading to endstage renal failure. FMF-related renal amyloidosis needed to be diagnosed early. Optimal colchicine dose is effective in preventing and reversing renal amyloidosis. Galectin-3, profibrotic mediator, has regulatory functions in inflammation, fibrosis and tumorigenesis. Galectin-3 is a strong prognostic marker for heart failure. Galectin-3 plays role in diabetic nephropathy and chronic kidney disease. The aim of the study is to investigate whether galectin-3 is related to proteinuria and amyloidosis in FMF. Methods Seventy-five FMF patients who have no exclusion criteria and healthy controls (n = 36) were included. Serum galectin-3 was measured and morning spot urine was collected for determination of the protein/creatinine ratio (PCR). Results Serum Galectin-3 levels were significantly higher in FMF patients than the control group [969.66 (3825) pg/ mL vs. 238 (921) pg/mL, respectively; P\0.001]. We classified into two groups: Group1 (n = 48) had FMF patients with proteniuria, Group2 (n = 27) had FMF H. Yilmaz (&) M. A. Bilgic A. Akcay Department of Internal Medicine, Section of Nephrology, School of Medicine, Turgut Ozal University, Alparslan Tu¨rkes Cad. No: 57, Emek, 06510 Ankara, Turkey e-mail: [email protected] O. Inan Department of Internal Medicine, Yenimahalle State Hospital, Ankara, Turkey T. Darcin Department of Internal Medicine, Agri State Hospital, Agri, Turkey
patients without proteinuria. Group1 had higher levels of galectin-3 than Group2 [1106(3812) pg/mL vs. 867.3(1433) pg/mL, P \ 0.001]. Galectin-3 levels were correlated with PCR in whole group and FMF group (r = 0.785, P \ 0.001 and r = 0.803, P \ 0.001). In ROC curve, best cutoff value = 581.50 pg/mL was used to detect proteinuria (sensitivity = 91.7 %, specificity = 71.4 %, AUC = 0.879) and optimal cutoff value = 1458.00 pg/mL was an indicator of nephroticrange proteinuric (sensitivity = 100 %, specificity = 92.1 %, AUC = 0.983). Conclusion Galectin-3 is associated with proteinuria and renal amyloidosis in FMF. Galectin-3 may play role in pathogenesis of amyloidosis. Keywords FMF
Galectin-3 Proteinuria Renal amyloidosis
Introduction Familial Mediterranean fever (FMF), the most frequent of the periodic fever syndromes, is a hereditary autosomal recessive autoinflammatory disease characterized by recurrent spontaneous self-limited febrile attacks and serositis, predominantly affecting people of Mediterranean descent [1, 2]. The most important and devastating complication is reactive AA amyloidosis in FMF [3]. Proteinuria is the most common presenting feature of renal involvement due to FMF-related AA amyloidosis, which may gradually progress a nephrotic stage into end-stage renal failure necessitating kidney transplantation or hemodialysis [4, 5]. Ethnicity, genotype, and gender affect the prevalence of amyloidosis [1–5]. FMF-related amyloidosis was reported to occur in 60–75 % of FMF patients among various ethnicities [6, 7]
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and 12.9–60 % among Turkish patients [8, 9] without colchicine therapy. Incidence of FMF-related amyloidosis has gradually declined since the widespread use of colchicine for FMF patients [10]. We should keep renal amyloidosis in mind if FMF patients have varying levels of proteinuria. If early stage of renal amyloidosis is diagnosed, the colchicine dose should be increased to 2–3 mg/day [3]. This modification prevents progressing into nephrotic syndrome and/or renal dysfunction [3]. Galectin-3 is a b-galactoside-binding lectin highly expressed in activated macrophages, which may be involved in inflammation, fibrosis, immunity, and cancer [11, 12]. Some evidence showed that accelerated diabetic glomerulopathy in galectin-3 knockout mice, galectin-3, had a protective role toward AGE-induced renal injury [13, 14]. Conversely, Galectin-3 was found to play regulatory role in the development of renal fibrosis in mouse models and humans [15–17]. Galectin-3 is emerging as a novel mediator of kidney fibrosis and progressive CKD [17]. Elevated galectin-3 levels were present in patients with cardiac amyloidosis when compared with patients with left ventricular hypertrophy (LVH) or systolic heart failure (HF) [18]. In FMF patients, the relationship between galectin-3 and renal amyloidosis remains unknown still and is an interesting subject. The aim of the study is to investigate whether galectin-3 are related to proteinuria and renal amyloidosis in patients with FMF.
Materials and methods Seventy-five patients with FMF, who were diagnosed based on Tel-Hashomer criteria [19] at the Internal Medicine Clinics between January 2012 and December 2013, were recruited to this cross-sectional study. Thirty-six age- and sex-matched control participants were included in the study. This study was approved by local Ethics Committee (IRB number: 99950669/190). All patients provided written informed consent prior to participating in the study. The patients (n = 102) with acute FMF attack, heart failure, diabetes mellitus, hypertension, coronary heart diseases, metabolic syndrome, anemia, acute/chronic infection, autoimmune disorders, chronic obstructive pulmonary disease, cancer and history of smoking were excluded. Also, the patients were on medication (oral contraceptives, oral antidiabetic agents, antihypertensive drugs, antihyperlipidemic agents and glucocorticoids) except colchicine, were not included in the study. The MEFV gene mutations were achieved from our database. Assessment of the disease severity was performed using the modified scoring systems of Pras et al. [20]. All patients were in attack-free period; At least 2 weeks from the end of
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an FMF attack period was defined as attack-free period according to the physical examination, clinical symptoms, and CRP. The healthy control group was composed to be similar to age, gender ratio and BMI of patients group. The control group had no smoker, acute infection and chronic disease such as heart failure, diabetes mellitus, hypertension, coronary heart diseases, metabolic syndrome, anemia, acute/chronic infection, autoimmune disorders, chronic inflammation, chronic obstructive pulmonary disease and cancer. A single-void morning urine sample was collected for evaluation of the protein/creatinine ratio (PCR) in spot urine during attack-free period. The concentration of total protein in urine was measured by a biuret colorimetric assay (Cobas c501, Roche Diagnostics, Mannheim, Germany), and the urine creatinine level was measured by a modified Jaffe test (Cobas c501, Roche Diagnostics, Mannheim, Germany). The urine PCR was obtained by dividing the urinary protein concentration (g/dl) by the urine creatinine concentration (g/dl). The normal urine PCR is less than 0.2 g/gCr and PCR greater than 3.5 g/gCr is in the nephrotic range for proteinuria [21, 22]. Blood samples were drawn during attack-free period and serum separated in a centrifuge for 15 min at 1000 rpm and immediately transferred into 1-ml cryotubes and stored at -80 °C until analysis. Serum urea nitrogen, creatinine, albumin and C-reactive protein (CRP, Normal values 0–10 mg/L) were measured by standard laboratory techniques using an autoanalyzer (Roche Diagnostics, COBAS INTEGRA 800, Indianapolis, Indiana, USA). Serum levels of Gal3 were measured with enzyme-linked inmunosorbent assay, ELISA, (Catalog No: SK00199-01, Human Galectin-3 ELISA, AVISCERA BIOSCIENCE INC., Santa Clara, CA, USA). Calibration of the assay was performed according to the manufacturer’s recommendations and values were normalized to a standard curve. Descriptive statistics were presented as arithmetic mean ± standard deviation. Results which did not follow normal distribution are expressed as median (range) values. For the tests of normality, we used the Shapiro–Wilk test. Categorical variables were given as percentages. The independent sample unpaired Student’s t test or the Mann– Whitney U test was used for the continuous variables and categorical data were compared with the Chi square test. Relationships between variables were tested using Spearman’s test. Receiver-operating characteristic (ROC) curves were constructed to determine the optimum cutoff for Gal3 levels that could discriminate proteinuria from healthy subjects or non-proteinuric FMF patients, as well as nephrotic-range proteinuric FMF patients from the other FMF patients and healthy subjects. The area under the curve (AUC) was calculated to quantify sensitivity and specificity. The optimal cutoff point was the point on the
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ROC curve closest to the upper-left corner with maximum sensitivity and specificity, namely, the maximum Youden’s index [Youden’s index = sensitivity ? specificity-1] [23]. In all analyses, a two-sided P value of \0.05 was considered to indicate statistical significance. All statistical analyses were performed with the Statistical Package for the Social Sciences (SPSS) 17.0 Package (SPSS Inc., Chicago, IL, USA).
Results Out of 75 patients which were included to the present study, thirty-one were newly diagnosed patients and fortyfour were patients having the appropriate criteria and who had been using colchicine. Control group consist of 36 individuals who had no known disease and who were not using cigarette and any drug. There were no statistical differences between patients with FMF and healthy individuals in terms of age (32.6 ± 11.2 vs. 31.3 ± 12.4 years, respectively). And also, we did find male/female ratio between patients with FMF and controls (M/F = 36/39 vs. M/F = 17/19, P = 0.678, respectively) (Table 1). There was no statistical significance in levels of CRP between FMF patients and healthy controls (4.72 ± 1.75 mg/L vs. 2.61 ± 1.68 mg/L, P = 0.258) (Table 1). Serum Galectin-3 levels were significantly higher in FMF patients than the control group [969.66 (3825) pg/ml vs. 238 (921) pg/ml, respecttively; P \ 0.001, Table 1]. FMF patients were classified according to whether they have proteinuria (PCR [ 0.2). Group1 (n = 48) was composed of proteinuric patients, Group2 (n = 27) had FMF patients without proteinuria. PCR and serum galectin3 levels were detected significantly higher in Group1 when compared with Group2 [0.84 (16.02) vs. 0.10 (0.17), P \ 0.001 for PCR; 1106 (3812) pg/mL vs. 867.3 (1433) pg/mL, P \ 0.001 for Galectin-3]. No significant differences were found in terms of the ages of patients, gender of patients, recurrent attacks, duration of attacks, duration of the illness, severity of the disease, CRP and MEFV gene mutations between Group1 and Group2 (P [ 0.05) (Table 2). Serum level of Galectin-3 was found to be directly correlated with PCR in whole group (Fig. 1) and FMF group (Fig. 2) (r = 0.785, P \ 0.001 and r = 0.803, P \ 0.001). There was no association of galectin-3 with age, BMI, gender, colchicine dose, duration of the illness, severity of the disease, CRP, albumin and creatinine in patients with FMF. There was nephrotic-range proteinuria in 10 patients in Group1. Renal biopsy was recommended to all patients who had nephrotic-range proteinuria. The cause of
Table 1 Demographic characteristics and between FMF patients and healthy controls
laboratory
analyses
FMF patients (n = 75)
Healthy control (n = 36)
P value
Gender, male/female
36/39
17/19
0.678
Age, years
32.6 ± 11.2
31.3 ± 12.4
0.719
BMI, kg/m2
25.4 ± 3.2
24.9 ± 3.8
0.832
Age of onset, years
22.8 ± 7.6
–
Disease duration, years
9.8 ± 6.5
–
Number of attacks per month
1.86 ± 1.23
–
Colchicine dose (mg/day)
1.65 ± 0.68
–
CRP, mg/L
4.72 ± 1.75
2.61 ± 1.68
0.285
Albumin, g/dL
3.92 ± 0.72
4.07 ± 0.85
0.196
Urea, mg/dL Creatinine, mg/dL
32.8 ± 8.4 0.91 ± 0.32
31.7 ± 7.9 0.84 ± 0.28
0.546 0.215
Galectin-3, pg/mL
969.66 (3825)
238 (921)
\0.001
nephrotic syndrome in seven patients in which renal biopsy was done was renal amyloidosis. One patient did not accept renal biopsy, and two did not continue polyclinic control following renal biopsy. Thus, renal AA amyloidosis was the most important reason causing nephrotic-range proteinuria in patients with FMF. To evaluate the ability of serum Gal-3 to discriminate proteinuria patients from healthy controls and FMF patients, we performed ROC curve analyses. A cutoff point of 581.50 pg/mL was used to detect proteinuria (sensitivity = 91.7 %, specificity = 71.4 %, AUC = 0.879, Fig. 3). A cutoff point of 1458.00 pg/mL was used to distinguish nephrotic-range proteinuric FMF patients from the other FMF patients and healthy subjects, showing high performance (sensitivity = 100 %, specificity = 92.1 %, AUC = 0.983, Fig. 4).
Discussion The main result of the present study is that there is a strong correlation between galectin-3 level and the level of proteinuria in patients with FMF. Galectin-3 level is a reliable marker that can determine both the proteinuria and the nephrotic-range proteinuria in patients with FMF. Galectin3 levels were not associated with CRP in FMF patients. CRP levels were similar between FMF patients with proteinuria and without proteinuria. The most important reason of nephrotic-range proteinuria in patients with FMF was renal AA amyloidosis.
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Clin Exp Nephrol Table 2 Baseline and laboratory characteristics among Group1 and Group2
Group 1 is consisted of FMF patients with proteinuria. Group 2 is consisted of FMF patients without proteinuria
Group1 (n = 48)
P value
Gender, male/female
23/25
13/14
0.609
Age, years
33.2 ± 12.3
31.9 ± 10.8
0.341
BMI, kg/m2
25.3 ± 3.4
25.5 ± 3.9
0.842
Age of onset, years
22.7 ± 8.1
22.9 ± 7.5
0.703
Disease duration, years
10.1 ± 6.8
9.6 ± 7.0
0.471 0.782
Number of attacks per month
1.88 ± 1.29
1.81 ± 1.32
Disease severity score
6.10 ± 1.95
5.94 ± 2.04
0.531
Colchicine dose (mg/day)
1.72 ± 0.62
1. 60 ± 0.71
0.237
CRP, mg/L
2.93 ± 1.80
2.62 ± 1.76
0.328
Albumin, g/dL
3.78 ± 0.76
4.03 ± 0.82
0.102
Urea, mg/dL
33.5 ± 9.1
32.0 ± 7.3
0.736
Creatinine, mg/dL
0.93 ± 0.28
0.88 ± 0.25
Galectin-3, pg/mL
1106 (3812)
867.3 (1433)
\0.001
PCR, mg/mg
0.84 (16.02)
0.10 (0.17)
\0.001
MEFV gene mutations, % (n) Homozygous M694V
20.8 (10)
22.2 (6)
0.651
0.407
Heterozygous M694V
16.6 (8)
14.8 (4)
0.572
Heterozygous M680I
6.25 (3)
3.7 (1)
0.058
Heterozygous E148Q
8.4 (4)
7.4 (2)
0.617
Heterozygous V726A
2 (1)
3.7 (1)
0.283
Heterozygous M694V/M680I
8.4 (4)
11.1 (3)
0.346
Heterozygous M694V/E148Q
8.4 (4)
11.1 (3)
0.346
Others
27 (13)
25.9 (7)
0.683
Fig. 1 Galectin-3 levels were associated with PCR in whole group
The most important and unwanted complication in FMF was development of renal amyloidosis [1–4]. Renal amyloidosis presents with persistent or ingravescent proteinuria leading to nephrotic syndrome and progressive nephropathy leading to end-stage renal disease
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Group2 (n = 27)
Fig. 2 Galectin-3 levels were associated with PCR in patients with FMF
[2–4]. Appropriate dose of colchicine prevents renal amyloidosis in most patients and is also effective in arresting and reversing renal amyloidosis. Thus, the
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Fig. 3 ROC curve showed that cutoff value 3 = 581.50 pg/mL was an indicator of proteinuria
of
galectin-
Fig. 4 In ROC curve, cutoff value of galectin-3 = 1458.00 pg/mL was used to detect nephrotic-range proteinuria in whole group
diagnosis of renal amyloidosis at early stages has critical importance. According to the results of the current study, it could be assumed that development of renal amyloidosis might be determined at early stages by determination and follow-up of galectin-3 levels.
There is a strong positive correlation between Galectin-3 levels and proteinuria. In addition, galectin-3 level has capacity to determine nephrotic-range proteinuria. Early detection of proteinuria and nephrotic-range proteinuria with the help of galectin-3 level in patients with FMF could enable earlier detection of renal amyloidosis. In this way, it would be possible to prevent progressive renal failure. We tried to explain the relation among galectin-3, proteinuria and renal amyloidosis with the following mechanisms: (1) together with the amyloid which accumulated in glomerules, advanced glycation end products (AGEs) and receptor for advanced glycation end products (RAGE) also accumulate and they are correlated with amyloid deposits [24]. The serum levels of AGE increase [24]. Both development of diabetic nephropathy accelerates and also AGEinduced glomerular damage accelerates in gal-3 knockout mice in which diabetic nephropathy model is produced [13, 14]. These data indicate that in diabetic mice, galectin-3 is upregulated and is operating in vivo as an AGE receptor to afford protection toward AGE-dependent tissue injury and increased expression of gal-3 acts as opposed to RAGE [13, 14]. Galectin-3 level increases to prevent the damage caused by AGE; however, it could be assumed that it could not be protective due to galectin-3 resistance; (2) there is a positive correlation between glomerular amyloid accumulation and interstitial fibrosis in renal amyloidosis caused by FMF [25, 26]. Galectin-3 is profibrotic marker, having a stimulatory effect on macrophage migration, myofibroblast accumulation/activation, and development of fibrosis in renal tissues [15–17]. There is generally interstitial fibrosis on the basis of renal amyloidosis and galectin-3 level might increase depending on this fibrosis [25, 26]; (3) in many FMF patients, chronic inflammation may persist in attackfree periods [27]. Persistent chronic inflammation in FMF may cause renal amyloidosis [27]. In addition, there is a positive correlation between the degree of glomerular amyloid accumulation and inflammation [26]. As a result, chronic inflammation in patients with proteinuric attackfree FMF might be one of possible factors responsible for the increase of galectin-3 levels. Despite FMF patients had higher levels of CRP than healthy control, we found no statistical significance among two groups because of small sample size of this study and no serial measurement of CRP. In the present study we did not find a correlation between Galectin-3 and CRP. When compared with SAA, CRP is an acute phase reactant that has no ability to determine renal amyloidosis caused by FMF and subclinical inflammation in FMF [27–30]. As correlation of galectin-3 was not evaluated with a strong marker such as SAA, we could not say that there is no correlation between galectin-3 and chronic subclinical inflammation in FMF. Perhaps galectin-3 might be a strong
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marker reflecting chronic subclinic inflammation in patients with FMF. One of the most common causes of proteinuria in patients with FMF is renal AA amyloidosis. In the current study there was proteinuria in 64 % of the patients with FMF, nephrotic-range proteinuria in 13.3 % and renal amyloidosis which was definitely diagnosed with biopsy in 9.3 % and the findings of the present study were consistent with the literature [6–9]. Nonamyloid glomerulopathies have been reported and can seldom develop in patients with FMF [3, 8, 31–33]. While there may be rarely other causes in FMF patients with proteinuria, the most important cause which should be absolutely kept in mind is renal amyloidosis. Renal biopsy is the gold standard method in diagnosis of renal amyloidosis [2–5]. The most important noninvasive technique that is helpful in diagnosis of renal amyloidosis is severe proteinuria measured in 24-h urine collection. Two major limitations of measuring protein excretion in a 24-h urine collection are that it is cumbersome for patients and often collected incorrectly. The most important easy alternative in diagnosis of proteinuria is PCR in spot urine sample. According to our results, urine PCR was appeared to be used to evaluate of proteinuria and monitor the degree of proteinuria in patients with FMF. This study had several limitations. First, the cross-sectional study design with the observed associations does not represent causal relationships between galectin-3 and proteinuria. Second, we used spot urinary PCR for evaluation of proteinuria. Although the PCR correlates well with 24-h urine protein excretion, there are two major limitations of using random spot urine samples to quantify proteinuria: (a) the PCR is heavily influenced by the urine creatinine concentration (the denominator of the ratio) so PCR will underestimate and/or overestimate proteinuria, (b) urine protein excretion can vary throughout the day and from day to day. Third, AGE-RAGE and other inflammatory markers (SAA, IL-1) were not measured except CRP. SAA is a better indicator of subclinical inflammation and development of renal amyloidosis than CRP. In conclusion, increased levels of galectin-3 are associated with proteinuria and renal amyloidosis in FMF. Galectin-3 may play role in development of amyloidosis. If further prospective studies validate our results, galectin-3 will be used routinely for development of renal amyloidosis in patients with FMF. The patients with FMF should be regularly followed in terms of proteinuria and the daily dose of colchicine should be increased in FMF patients with proteinuria. Conflict of interest interest.
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All the authors have declared no competing
References 1. Soriano A, Manna R. Familial Mediterranean fever: new phenotypes. Autoimmun Rev. 2012;12:31–7. 2. Portincasa P, Scaccianoce G, Palasciano G. Familial Mediterranean fever: a fascinating model of inherited autoinflammatory disorder. Eur J Clin Invest. 2013;43(12):1314–27. 3. Onen F. Familial Mediterranean fever. Rheumatol Int. 2006;26:489–96. 4. Lidar M, Livneh A. Familial Mediterranean fever: clinical, molecular and management advancements. Neth J Med. 2007;65(9):318–24. 5. Pinney JH, Lachmann HJ. Systemic AA amyloidosis. Subcell Biochem. 2012;65:541–64. 6. Sohar E, Gafni J, Pras M, Heller H. Familial Mediterranean fever. A survey of 470 cases and review of the literature. Am J Med. 1967;43(2):227–53. 7. Pras M, Bronshpigel N, Zemer D, Gafni J. Variable incidence of amyloidosis in familial Mediterranean fever among different ethnic groups. Johns Hopkins Med J. 1982;150:22–6. 8. Tunca M, Akar S, Onen F, Ozdogan H, Kasapcopur O, Yalcinkaya F, Tutar E, Ozen S, Topaloglu R, Yilmaz E, Arici N, Bakkaloglu A, Besbas N, Akpolat T, Dinc A, Erken E, Turkish FMF study group. Familial Mediterranean fever in Turkey. Results of a nationwide multicenter study. Medicine. 2005;84:1–11. 9. Ben-Chetrit E, Levy M. Familial Mediterranean fever. Lancet. 1998;351:659–64. 10. Drenth JP, van der Meer JW. Hereditary periodic fever. N Engl J Med. 2001;345(24):1748–57. 11. de Boer RA, Voors AA, MuntendamP, vanGilstWH, van Veldhuisen DJ. Galectin-3: a novel mediator of heart failure development and progression. Eur J Heart Fail. 2009;11:811–7. 12. Henderson NC, Sethi T. The regulation of inflammation by galectin-3. Immunol Rev. 2009;230(1):160–71. 13. Pugliese G, Pricci F, Iacobini C, Leto G, Amadio L, Barsotti P, Frigeri L, Hsu DK, Vlassara H, Liu F-T, Di Mario U. Accelerated diabetic glomerulopathy in galectin-3/AGE receptor 3 knockout mice. FASEB J. 2001;15(13):2471–9. 14. Iacobini C, Amadio L, Oddi G, Ricci C, Barsotti P, Missori S, Sorcini M, Di Mario U, Pricci F, Pugliese G. Role of galectin-3 in diabetic nephropathy. J Am Soc Nephrol. 2003;14:S264–70. 15. Henderson NC, Mackinnon AC, Farnworth SL, Kipari T, Haslett C, Iredale JP, Liu FT, Hughes J, Sethi T. Galectin-3 expression and secretion links macrophages to the promotion of renal fibrosis. Am J Pathol. 2008;172:288–98. 16. Dang Z, MacKinnon A, Marson LP, Sethi T. Tubular atrophy and interstitial fibrosis after renal transplantation is dependent on galectin-3. Transplantation. 2012;93:477–84. 17. O’Seaghdha CM, Hwang SJ, Ho JE, Vasan RS, Levy D, Fox CS. Elevated galectin-3 precedes the development of CKD. J Am Soc Nephrol. 2013;24:1470–7. 18. Friedman EA, Brittain E, Su YR, LeBoeuf J, Sawyer D, Lenihan D. Markedly elevated galectin-3 levels in cardiac amyloidosis may indicate significant fibrosis. J Cardiac Fail. 2013;19(8):S63. 19. Livneh A, Langevitz P, Zemer D, Zaks N, Kees S, Lidar T, et al. Criteria for the diagnosis of familial Mediterranean fever. Arthr Rheum. 1997;40:1879–85. 20. Pras E, Livneh A, Balow JE, Kastner DL, Pras M, Langevitz P. Clinical differences between North African and Iraqi Jews with familial Mediterranean fever. Am J Med Genet. 1998;75:216–9. 21. Schwab SJ, Christensen RL, Dougherty K, Klahr S. Quantitation of proteinuria by the use of protein-to-creatinine ratios in single urine samples. Arch Intern Med. 1987;147(5):943–4.
Clin Exp Nephrol 22. Ginsberg JM, Chang BS, Matarese RA, Garella S. Use of single voided urine samples to estimate quantitative proteinuria. N Engl J Med. 1983;309(25):1543–6. 23. Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology. 1982;143:29–36. 24. Matsunaga N, Anan I, Rosenberg P, Nagai R, Lundstro¨m O, Horiuchi S, Ando Y, Suhr OB. Advanced glycation end product is implicated in amyloid-related kidney complications. Scand J Clin Lab Invest. 2005;65(4):263–72. 25. Bohle A, Wehrmann M, Eissele R, von Gise H, Mackensen-Haen S, Muller C. The long-term prognosis of AA and AL renal amyloidosis and the pathogenesis of chronic renal failure in renal amyloidosis. Pathol Res Pract. 1993;189:316–31. 26. Sen S, Sarsik B. A proposed histopathologic classification, scoring, and grading system for renal amyloidosis: standardization of renal amyloid biopsy report. Arch Pathol Lab Med. 2010;134(4):532–44. 27. Ben-Zvi I, Livneh A. Chronic inflammation in FMF: markers, risk factors, outcomes and therapy. Nat Rev Rheumatol. 2011;7(2):105–12. 28. Yalc¸inkaya F, Cakar N, Acar B, Tutar E, Gu¨riz H, Elhan AH, Oztu¨rk S, Kansu A, Ince E, Atalay S, Girgin N, Dog˘ru U, Aysev
29.
30.
31.
32.
33.
D, Ekim M. The value of the levels of acute phase reactants for the prediction of familial Mediterranean fever associated amyloidosis: a case control study. Rheumatol Int. 2007;27(6):517–22. ¨ zen S, Du¨zova A, Bakkalog˘lu A, Bes¸ bas¸ N, Topalog˘lu R, O ¨ zaltin F, Bas¸ soy Y, Yilmaz E. Role of A-SAA in monitoring O subclinical inflammation and in colchicines dosage in familial Mediterranean fever. Clin Exp Rheum. 2003;21:509–14. Gillmore JD, Lovat LB, Persey MR, Pepys MB, Hawkins PN. Amyloid load and clinical outcome in AA amyloidosis in relation to circulating concentration of serum amyloid A protein. Lancet. 2001;358:24–9. Yalcinkaya F, Turner N. Glomerular lesions other than amyloidosis in patients with FMF. Nephrol Dial Transplant. 1999;14:21–3. Akpolat T, Akpolat I, Karagoz F, et al. Familial Mediterranean fever and glomerulonephritis and review of the literature. Rheumatol Int. 2004;24:43–5. Said R, Hamzeh Y, Said S, et al. Spectrum of renal involvement in FMF. Kidney Int. 1992;41:414–9.
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