APMIS 122: 818–823
© 2014 APMIS. Published by John Wiley & Sons Ltd. DOI 10.1111/apm.12223
Serum concentrations of cytokines in infants with retinopathy of prematurity HONGHUA YU,1,2,# LING YUAN,3,# YUPING ZOU,1,# LIANGHONG PENG,1 YONG WANG,1 TAO LI2 and SHIBO TANG2 1
Department of Ophthalmology, General Hospital of Guangzhou Military Command of PLA, Guangzhou; 2 State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou; 3Department of Ophthalmology, The First Affiliated Hospital of Kunming Medical College, Kunming, China
Yu H, Yuan L, Zou Y, Peng L, Wang Y, Li T, Tang S. Serum concentrations of cytokines in infants with retinopathy of prematurity. APMIS 2014; 122: 818–823. Retinopathy of prematurity (ROP) is the leading cause of blindness in preterm infants. In this study, we investigated the cytokine levels in cord blood of normal preterm neonates and preterm infants developed ROP. Serum levels of 10 cytokines in umbilical cord blood were measured by multiplex protein arrays from 62 healthy preterm neonates and 30 preterm neonate cases who developed ROP at later stage. Results showed that serum levels of cytokines including interleukin 7 (IL-7), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1a), and macrophage inflammatory protein 1 beta (MIP-1b) were significantly increased in cases who developed ROP than in healthy preterm neonates (3.5-fold, 3.2-fold, 3.4-fold, and 2.1-fold, respectively), whereas levels of these four cytokines did not reveal any significant differences between healthy preterm infants and normal infants. When comparing the expression of cytokines in ROP patients with different clinical parameters, ROP cases whose gestational age at delivery earlier than 29.0 weeks demonstrated increased levels of MCP-1 and MIP-1b than those later than 29.0 weeks (p < 0.05). Also, ROP cases with birth weight less than 1.28 kg revealed significantly higher level of MIP-1b than those who were heavier than 1.28 kg (p < 0.05). These data indicated that levels of IL-7, MCP-1, MIP-1a, and MIP-1b were associated with increased risk of ROP, in which MIP-1b may be further correlated with the severity of ROP. Key words: Cytokine; retinopathy of prematurity. Tao Li and Shibo Tang, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, South, Guangzhou 510060, China. e-mail: [email protected]; [email protected] #
These authors contributed equally to this study.
Retinopathy of prematurity (ROP) is a retinal vascular disorder that occurs in eyes with an incomplete development of the vascular system (1). In severe cases, pathologic neovascularization leads to fibrovascular proliferation, vitreoretinal traction, and tractional retinal detachment, which often leads to severe visual reduction (2, 3). ROP is still the leading cause of blindness in infants, especially in developed countries, although more than half a century has passed since the first report of ROP by Terry (4). To improve the results of treating ROP, a better understanding of the molecular mechanisms involved in the pathologic condition of ROP must be obtained. Received 2 September 2013. Accepted 4 November 2013
818
Evidence has shown that inflammation may play critical roles in the pathogenesis of ROP. Studies investigating histologic chorioamnionitis as a risk factor for ROP have been inconclusive; an association with ROP is present only in univariate analyses (5). Other studies reveal higher rates of ROP in infants born to mothers with evidence of histologic chorioamnionitis compared with those born to mothers without signs of inflammation (6, 7). Infants born to mothers with clinical chorioamnionitis as well as maternal leukocytosis have also been reported to be at increased risk of ROP. Maternal systemic inflammation might also contribute to the development of ROP in preterm infants by decreasing levels of IGF-1 (7, 8). Low levels of IGF-1 have been associated with an increased risk of ROP and
CYTOKINES AND RETINOPATHY OF PREMATURITY
IGF-1 levels vary inversely with the severity of ROP (7, 8). At least part of the sepsis-associated risk increase for ROP might be due to circulating products of inflammation. In preterm infants with early onset sepsis, studies suggest that there is a relationship between high plasma levels of cytokines IL-6, IL-8, and TNF-a in the first days of life with the later development of ROP requiring treatment (9). Findings from a very large cohort study suggest that levels of circulating pro-inflammatory cytokines are elevated at multiple time-points after birth in preterm infants who later develop ROP when compared with controls (10). The purpose of this study was to explore potential biomarkers among cytokines and growth factors in cord blood at birth and to identify clinical parameters predictive of the development of ROP in preterm newborns through a case–control study with a high degree of matching for gestational age and birth weight. MATERIALS AND METHODS Study population The study population consisted of 30 preterm infants who developed ROP at later stage. The inclusion criteria for case subjects were as follows: (i) live, singleton infants born earlier than 32.0 weeks of gestation with survival until 38 weeks postmenstrual age; (ii) infants undergoing ROP screening examinations; and (iii) the absence of a major congenital anomaly. A total of 62 healthy preterm infants were selected as a control group, which matched the case group by gestational age (difference, 0.05 Gestational age 29.0 1.5 at delivery (week) Neonatal birth 1.28 0.36 1.26 0.38 >0.05 weight (kg) Results are presented as mean SD or as absolute numbers of patients (percentage).
cases and 1.26 kg in controls. There were no significant differences in these characteristics between cases and controls, indicating that the two groups matched well. Serum levels of cytokines between ROP patients and healthy preterm infants
Serum levels of IL-7, IL-13, IL-15, IL-17, FGF basic, GM-CSF, IP -10, MCP-1, MIP-1a, and MIP-1b were measured and compared between ROP patients and matched healthy preterm infants (Fig. 1). Data showed that serum level of IL-7 was
3.5-fold higher in patients than in controls (p < 0.001). Actual values of IL-7 were 2.11 0.25 pg/mL in controls and 7.28 1.79 pg/ mL in cases. Level of MCP-1 was 3.2-fold higher in patient than in controls (p < 0.001). Actual values of MCP-1 were 68.2 8.9 pg/mL in controls and 218.2 20.5 pg/mL in cases. Level of MIP-1a was 3.4-fold higher in patients than in controls (p < 0.01). Actual values of MIP-1a were 11.6 2.4 pg/mL in controls and 39.7 16.4 pg/ mL in cases. Similarly, the MIP-1b was 2.1-fold higher in cases than in controls (p < 0.01). Actual values of MIP-1b were 212.5 17.0 pg/mL mL in controls and 446.3 63.8 pg/mL in cases. However, levels of IL-13, IL-15, IL-17, FGF basic, GMCSF, and IP -10 did not show any significant differences between cases and controls (p > 0.05) (Fig. 1). These results suggested that expression of IL-7, MCP-1, MIP-1a, and MIP-1b were associated with increased risk of ROP. Serum levels of cytokines between preterm infants and healthy full-term infants
To understand whether the augmentation of IL-7, MCP-1, MIP-1a, and MIP-1b were specifically associated with ROP or it was just a result of preterm, we compared levels of these four cytokines among ROP cases, healthy preterm infants, and healthy full-term infants (Fig. 2). Results revealed that serum levels of IL-7, MCP-1, MIP-1a, and MIP-1b were significantly elevated in ROP cases than in preterm infants or healthy full-term neonates, whereas difference of these four cytokines was not observed between healthy preterm infants and healthy full-term neonates. These data indicated that that expression of IL-7, MCP-1, MIP-1a, and MIP-1b were specifically associated with the development of ROP. Serum levels of cytokines in ROP cases with different clinical parameters
Fig. 1. Relative cytokine levels of interleukin 7 (IL-7), IL-13, IL-15, IL-17, fibroblast growth factor (FGF) basic, granulocyte macrophage colony-stimulating factor (GM-CSF), interferon c inducible protein (IP) -10, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1a), and macrophage inflammatory protein 1 beta (MIP-1b) in the cord blood of healthy preterm neonates and preterm neonates who developed retinopathy of prematurity (ROP) at later stage. Data were presented as mean SD. Values are normalized to control. **p < 0.01; ***p < 0.001.
820
Gestational age at delivery and neonatal birth weight are two risk factors for ROP. We first analyzed expression of IL-7, MCP-1, MIP-1a, and MIP-1b in ROP cases with different gestational age at delivery (Fig. 3). The mean gestational age at delivery of our case group was 29.0 weeks. Cases were then divided into two groups, >29.0 weeks and
© 2014 APMIS. Published by John Wiley & Sons Ltd. DOI 10.1111/apm.12223
Serum concentrations of cytokines in infants with retinopathy of prematurity HONGHUA YU,1,2,# LING YUAN,3,# YUPING ZOU,1,# LIANGHONG PENG,1 YONG WANG,1 TAO LI2 and SHIBO TANG2 1
Department of Ophthalmology, General Hospital of Guangzhou Military Command of PLA, Guangzhou; 2 State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou; 3Department of Ophthalmology, The First Affiliated Hospital of Kunming Medical College, Kunming, China
Yu H, Yuan L, Zou Y, Peng L, Wang Y, Li T, Tang S. Serum concentrations of cytokines in infants with retinopathy of prematurity. APMIS 2014; 122: 818–823. Retinopathy of prematurity (ROP) is the leading cause of blindness in preterm infants. In this study, we investigated the cytokine levels in cord blood of normal preterm neonates and preterm infants developed ROP. Serum levels of 10 cytokines in umbilical cord blood were measured by multiplex protein arrays from 62 healthy preterm neonates and 30 preterm neonate cases who developed ROP at later stage. Results showed that serum levels of cytokines including interleukin 7 (IL-7), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1a), and macrophage inflammatory protein 1 beta (MIP-1b) were significantly increased in cases who developed ROP than in healthy preterm neonates (3.5-fold, 3.2-fold, 3.4-fold, and 2.1-fold, respectively), whereas levels of these four cytokines did not reveal any significant differences between healthy preterm infants and normal infants. When comparing the expression of cytokines in ROP patients with different clinical parameters, ROP cases whose gestational age at delivery earlier than 29.0 weeks demonstrated increased levels of MCP-1 and MIP-1b than those later than 29.0 weeks (p < 0.05). Also, ROP cases with birth weight less than 1.28 kg revealed significantly higher level of MIP-1b than those who were heavier than 1.28 kg (p < 0.05). These data indicated that levels of IL-7, MCP-1, MIP-1a, and MIP-1b were associated with increased risk of ROP, in which MIP-1b may be further correlated with the severity of ROP. Key words: Cytokine; retinopathy of prematurity. Tao Li and Shibo Tang, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, South, Guangzhou 510060, China. e-mail: [email protected]; [email protected] #
These authors contributed equally to this study.
Retinopathy of prematurity (ROP) is a retinal vascular disorder that occurs in eyes with an incomplete development of the vascular system (1). In severe cases, pathologic neovascularization leads to fibrovascular proliferation, vitreoretinal traction, and tractional retinal detachment, which often leads to severe visual reduction (2, 3). ROP is still the leading cause of blindness in infants, especially in developed countries, although more than half a century has passed since the first report of ROP by Terry (4). To improve the results of treating ROP, a better understanding of the molecular mechanisms involved in the pathologic condition of ROP must be obtained. Received 2 September 2013. Accepted 4 November 2013
818
Evidence has shown that inflammation may play critical roles in the pathogenesis of ROP. Studies investigating histologic chorioamnionitis as a risk factor for ROP have been inconclusive; an association with ROP is present only in univariate analyses (5). Other studies reveal higher rates of ROP in infants born to mothers with evidence of histologic chorioamnionitis compared with those born to mothers without signs of inflammation (6, 7). Infants born to mothers with clinical chorioamnionitis as well as maternal leukocytosis have also been reported to be at increased risk of ROP. Maternal systemic inflammation might also contribute to the development of ROP in preterm infants by decreasing levels of IGF-1 (7, 8). Low levels of IGF-1 have been associated with an increased risk of ROP and
CYTOKINES AND RETINOPATHY OF PREMATURITY
IGF-1 levels vary inversely with the severity of ROP (7, 8). At least part of the sepsis-associated risk increase for ROP might be due to circulating products of inflammation. In preterm infants with early onset sepsis, studies suggest that there is a relationship between high plasma levels of cytokines IL-6, IL-8, and TNF-a in the first days of life with the later development of ROP requiring treatment (9). Findings from a very large cohort study suggest that levels of circulating pro-inflammatory cytokines are elevated at multiple time-points after birth in preterm infants who later develop ROP when compared with controls (10). The purpose of this study was to explore potential biomarkers among cytokines and growth factors in cord blood at birth and to identify clinical parameters predictive of the development of ROP in preterm newborns through a case–control study with a high degree of matching for gestational age and birth weight. MATERIALS AND METHODS Study population The study population consisted of 30 preterm infants who developed ROP at later stage. The inclusion criteria for case subjects were as follows: (i) live, singleton infants born earlier than 32.0 weeks of gestation with survival until 38 weeks postmenstrual age; (ii) infants undergoing ROP screening examinations; and (iii) the absence of a major congenital anomaly. A total of 62 healthy preterm infants were selected as a control group, which matched the case group by gestational age (difference, 0.05 Gestational age 29.0 1.5 at delivery (week) Neonatal birth 1.28 0.36 1.26 0.38 >0.05 weight (kg) Results are presented as mean SD or as absolute numbers of patients (percentage).
cases and 1.26 kg in controls. There were no significant differences in these characteristics between cases and controls, indicating that the two groups matched well. Serum levels of cytokines between ROP patients and healthy preterm infants
Serum levels of IL-7, IL-13, IL-15, IL-17, FGF basic, GM-CSF, IP -10, MCP-1, MIP-1a, and MIP-1b were measured and compared between ROP patients and matched healthy preterm infants (Fig. 1). Data showed that serum level of IL-7 was
3.5-fold higher in patients than in controls (p < 0.001). Actual values of IL-7 were 2.11 0.25 pg/mL in controls and 7.28 1.79 pg/ mL in cases. Level of MCP-1 was 3.2-fold higher in patient than in controls (p < 0.001). Actual values of MCP-1 were 68.2 8.9 pg/mL in controls and 218.2 20.5 pg/mL in cases. Level of MIP-1a was 3.4-fold higher in patients than in controls (p < 0.01). Actual values of MIP-1a were 11.6 2.4 pg/mL in controls and 39.7 16.4 pg/ mL in cases. Similarly, the MIP-1b was 2.1-fold higher in cases than in controls (p < 0.01). Actual values of MIP-1b were 212.5 17.0 pg/mL mL in controls and 446.3 63.8 pg/mL in cases. However, levels of IL-13, IL-15, IL-17, FGF basic, GMCSF, and IP -10 did not show any significant differences between cases and controls (p > 0.05) (Fig. 1). These results suggested that expression of IL-7, MCP-1, MIP-1a, and MIP-1b were associated with increased risk of ROP. Serum levels of cytokines between preterm infants and healthy full-term infants
To understand whether the augmentation of IL-7, MCP-1, MIP-1a, and MIP-1b were specifically associated with ROP or it was just a result of preterm, we compared levels of these four cytokines among ROP cases, healthy preterm infants, and healthy full-term infants (Fig. 2). Results revealed that serum levels of IL-7, MCP-1, MIP-1a, and MIP-1b were significantly elevated in ROP cases than in preterm infants or healthy full-term neonates, whereas difference of these four cytokines was not observed between healthy preterm infants and healthy full-term neonates. These data indicated that that expression of IL-7, MCP-1, MIP-1a, and MIP-1b were specifically associated with the development of ROP. Serum levels of cytokines in ROP cases with different clinical parameters
Fig. 1. Relative cytokine levels of interleukin 7 (IL-7), IL-13, IL-15, IL-17, fibroblast growth factor (FGF) basic, granulocyte macrophage colony-stimulating factor (GM-CSF), interferon c inducible protein (IP) -10, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1a), and macrophage inflammatory protein 1 beta (MIP-1b) in the cord blood of healthy preterm neonates and preterm neonates who developed retinopathy of prematurity (ROP) at later stage. Data were presented as mean SD. Values are normalized to control. **p < 0.01; ***p < 0.001.
820
Gestational age at delivery and neonatal birth weight are two risk factors for ROP. We first analyzed expression of IL-7, MCP-1, MIP-1a, and MIP-1b in ROP cases with different gestational age at delivery (Fig. 3). The mean gestational age at delivery of our case group was 29.0 weeks. Cases were then divided into two groups, >29.0 weeks and
