Pancreatic Enzyme Levels in Bile of Patients with Extrahepatic Biliary Tract Disease Marion C. Anderson, MD, Charleston, South Carolina Robert L. Hauman, MD, Toledo, Ohio Chinda Suriyapa, MD, Toledo, Ohio William R. Schiller, MD, Toledo, Ohio
Substantial progress has been achieved over the past ten years in the identification of factors which contribute to gallstone formation. Contributing mechanisms include reduced bile salt secretion and/or increased cholesterol secretion by the liver [1,2], reduction of the bile salt pool through excessive loss secondary to inadequate intestinal absorption [3], abnormal absorption of bile salts by the inflamed gallbladder [4], and drugs such as estrogen which affect bile secretion and saturation [5]. Another less common factor is increased bile pigment production associated with hemolytic disease. The present study calls attention to another potential factor in the pathogenesis of biliary inflammation and gallstone formation, namely the regurgitation of pancreatic enzymes into the biliary system. Anatomic and radiographic studies have shown that a common terminal ampulla is present at the outlet of the bile and pancreatic ducts in 60 to 90 per cent of cases [6]. Opie [7] implicated this “common channel” as a factor in the initiation of pancreatitis. In 1901 he reported two autopsy cases of acute hemorrhagic pancreatitis in which a stone was found occluding the papilla of Vater [7]. He postulated that the stone produced obstruction and converted the bile and pancreatic ducts to a closed continuous system which permitted bile to pass into the pancreatic duct. Subsequent studies supported this contention, and the “bile reflux” explanation for
From the Department of Surgery, Medical College of Ohio, Toledo, Ohio; and the Medical Universityof South Carolina and the Veterans Administration Hospital, Charleston, South Carolina. Reprint requests should be addressed to Marion C. Anderson, MD, Department of Surgery, Medical University of South Carolina, 171 Ashley Avenue, Charleston,. South Carolina 29403.
Volums 137. March 1979
acute pancreatitis has continued to stimulate inquiry to the present time. Considerable evidence also has accumulated over the past twenty-five years which indicates that pressure generated in the pancreatic duct is usually greater than that observed in the biliary tract, both in animals [8] and in man [9]. This suggests that flow in a closed continuous pancreatobiliary passage would favor pancreatic enzymes entering the biliary tract, and prompted Wolfer [IO] to propose that biliary inflammation might result from the action of pancreatic enzymes regurgitated into the biliary system through a common channel. More recent studies have shown that certain purified pancreatic enzymes are capable of initiating inflammation in the obstructed canine gallbladder [I 11. Trypsin, lipase, and phospholipase-A caused acute cholecystitis, while saline, amylase, trypsinogen, or obstruction alone had little or no effect. The present study was undertaken to determine the level of amylase and lipase in the bile of patients undergoing operations to correct biliary tract disease. Material and Methods A total of ninety-three patients were included in the study. Seventy underwent cholecystectomy without common bile duct exploration to correct acute or chronic cholecystitis with cholelithiasis. In fourteen patients both cholecystectomy and common duct exploration were performed, and in nine patients samples were obtained only from a T tube introduced at the time of choledochostomy. Gallbladder bile was obtained at operation by insertion of a large bore needle into the lumen and aspiration of the contents prior to manipulation of the organ. Gallbladders
301
Anderson et al
600.
Fioure 3. Muftiole bile samoies obtained from a T tube fofF igure 1. Comparative values of amylase in bile and serum in twenty-six patienfs. Bile levels exceeded serum levels in twenty-one cases (81 percent).
Figure 2. Comparative values of lipase in bile and serum in twenty-six patients. Bile levels exceeded serum levels in thirteen cases (50 per cent).
which contained only mucoid material or were involved by empyema were excluded. Only those samples that clearly contained bile-colored fluid were included. Multiple samples of bile were obtained from patients with T tubes following choledochostomy. In several patients a communication between the bile and pancreatic ducts was confirmed either by cholangiography or at the time of transduodenal sphincteroplasty; however, in most cases the presence of a functional communication between the bile and pancreatic ducts was not confirmed. In forty patients serum samples were drawn either at the time of cholecystectomy or in conjunction with bile collection from a T tube. Amylase levels in serum and bile were measured according to the ultramicromodification of Caraway [12]. Lipase levels were determined by the method of Vogel and Zieve [13]. In twenty-six patients both serum and gallbladder bile levels of amylase and lipase were measured. In five the concentrations of amylase in gallbladder bile and serum were similar, whereas in thirteen the gallbladder levels exceeded the serum concentrations by 1 to 3 times, and in
cholecysiitis and choleliihiasis. Over time amilase and lipase levels Increased fo approximately 2,000 U/d1 and 20 U/d& respectively, in common ducf bile.
Figure 4. Muftiple bile samples obtained from a T tube follo wing common duct expiora tion. A If ftough the gallbladder contained neither amylase nor Iipase, the levels In the common duct varied widely and almost without exception were greater than the serum value. The findings suggest fhat pancreatic enzymes were infermfttent/y ref/ux/ng into the biliary system through a common channel at the ampullary level.
eight the gallbladder concentration was more than 3 times that recorded for serum. Lipase levels in gallbladder bile were similar to those in serum in thirteen patients, whereas in three the gallbladder level exceeded the serum values by 1 to 3 times, and in ten the gallbladder level was more than 3 times the serum value. In 81 per cent of patients bile amylase levels exceeded serum amylase levels, whereas the bile lipase level was more than the serum lipase levels in 50 per cent of cases. (Figures 1 and 2.) In forty-four patients only gallbladder bile amylase and lipase levels were measured. Utilizing the mean serum enzyme concentrations of the twenty-six patients described above, the results were comparable. In four, the gallbladder bile amylase level was similar to the mean serum amylase level, while in seventeen bile concentrations exceeded mean serum values by 1 to 3 times, and in twenty-three the bile values exceeded the mean serum concentrations by more than 3 times. Lipase levels in gallbladder bile were similar
The American Journal of Surgery
j-g
Pancreatic Enzyme Levels in Bile
Serum
0
Figure 5. Multiple bile samples obtained from a T tube lo/lowing cholecystectomy and common duct exploration. Although the amylase level in gallbladder bile was similar Both to that in serum, the lipase level was elevated. amylase and lipase bile levels were consistently markedly elevated compared to the serum values.
while gallbladder lipase concentrations exceeded mean serum lipase levels by 1 to 3 times in seven and were greater than 3 times mean serum levels in twenty-seven. For the group, the gallbladder amylase level was higher than the mean serum amylase level in 90 per cent of cases, and lipase levels exceeded mean serum levels in 77 per cent of cases. When the above groups, involving seventy samples of gallbladder bile, were combined, the bile amylase levels exceeded real or predicted serum values in 87 per cent of cases and bile lipase levels exceeded serum values in 66 per cent of cases. In twenty-three patients with T tubes multiple samples were assayed for amylase and lipase concentrations. In most patients there was great variability in bile concentrations, ranging from the real or predicted serum range to remarkably high levels. Figures 3, 4, and 5 illustrate these findings.
T-Tube
Figure 6. Comparison Of serum levels in a uatient who had flow if pan&eatlc s&retions into’the du&len;m. Postoperative levets of amylase and lipase were similar serum in and common duct bile, suggesting that reflux from pancreatic to bile duct was eliminated.
to mean lipase levels in serum in ten patients,
mally through the tumor to decompress the intrahepatic ductal system into the lower common duct. (Figure 7.) A postoperative cholangiogram demonstrated a communication between the bile and pancreatic ducts near their termination in the duodenum. (Figure 8.) Figure 9 shows that on several occasions bile enzyme levels were at least 2 times the serum value, while at other times serum and bile levels were similar. These findings suggest that pancreatic enzymes intermittently regurgitated into the biliary system, possibly at times when the intact sphincter of Oddi was closed.
Case Reports Case I. SG, a sixty-four year old black male with sclerosing cholangitis and associated chronic pancreatitis, was treated by cholecystectomy, T tube drainage of the common duct, and transduodenal sphincteroplasty. The duct of Wirsung opened on the inferior lip of the papilla of Vater. The septum between the bile and pancreatic ducts was excised (septectomy), which provided a widely patent exit directly into the duodenum, making the possibility of reflux from pancreas to bile duct remote. Figure 6 shows the comparative levels of serum and bile enzyme. None of eight bile amylase values exceeded serum levels, which were measured on four separate occasions. Case II. LC, a fifty-four year old white male, was operated on for obstructive jaundice secondary to a cholangiocarcinoma located at the level of the common hepatic duct in the hilum of the liver. A T tube was passed proxi-
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137, March 1979
Figure 7. postoperative cholangiogram show&g a T tube passed through a carcinoma of the common hepatic duct to relieve proximal intrahepatic biliary obstruction.
303
Anderson et al
a
Serum
cl
T-Tube
300;
200-
,. -
000
z 0Q. .-I
0
-
00
-
I.O2.0-
9. Figure Comparison of postoperative serum enzyme levels wilh levels obtained from fube T bile in the patient shown in Figures 7 and 8. Aithough several bile sampie ieveis were Similar to serum /eve/s, on other occasions bile enzymes exceeded those in serum, suggesting refiux from panfhe creatic fo th& biiiary system.
Figure 8. Cholangiogram showing lower common bile ducf and communication with the pancreatic ducf proximal to the ampuiia of Vafer.
Comments
The data presented indicate that the enzymes amylase and lipase are present in bile obtained from the gallbladder and/or common bile duct of patients operated on for various forms of biliary tract disease in concentrations which exceed serum values in well over 50 per cent of cases. In a substantial number of patients bile enzymes were intermittently elevated to remarkably high levels. These findings can be criticized on the ground that these enzymes may originate from extrapancreatic sources, including the liver [14]. This question can be answered in future studies by measuring isoenzymes, utilizing one of several methods now available [15]. At the same time it is difficult to ignore the fact that a number of patients had bile and serum enzyme concentrations that were similar. Moreover, when multiple bile samples were tested, the enzyme concentrations often fluctuated in the same patient from values similar to serum values to extremely high levels. The latter findings suggest intermittent reflux
304
of pancreatic enzymes at times when the sphincter of Oddi was closed, thereby permitting flow from pancreas to biliary system in those patients having a common channel at the ampullary level. There was a close co&elation between the percentage of patients with elevated bile enzyme levels and the known incidence of an anatomic communication between pancreatic and biliary ducts in man (60 to 90 per cent). A second question could be raised regarding the pressure relationships which occur in the common duct when it communicates with atmospheric pressure through an open T tube. It is possible that this may facilitate flow of pancreatic juice into the common duct in patients with a common pancreatobiliary outlet, and thereby account for the extremely high values observed in some T tube samples. While this may be true, it also supports the premise that pancreatic enzymes gain entry to bile through a common channel. While levels in the intact biliary system might be less remarkable, available evidence regarding pressures generated in the bile and pancreatic ducts suggests that flow should occur from the pancreas to the biliary system when the sphincter is closed and a continuous channel is present [8,9]. Assuming that the findings presented do in fact represent reflux of pancreatic enzymes into the biliary system, the question of the potential action of enzymes, when permitted to accumulate in the gallbladder, becomes important. We have shown in
The American Journal of Surgery
Pancreatic Enzyme Levels in Bile
earlier animal studies that specific enzyme fractions, notably trypsin, lipase, and phospholipase-A, produced severe inflammatory changes in the obstructed canine gallbladder, whereas saline, amylase, trypsinogen, and obstruction alone had little or no effect [11]. The precise mechanism of these enzyme-induced inflammatory changes is a matter of speculation. Trypsin is known to induce severe alterations of the microcirculation, including vasodilatation, stasis, and increased capillary permeability when introduced into interstitial tissues, such as the pancreatic parenchyma [16]. Similar changes appear to occur following absorption of trypsin across the mucosa of the gallbladder [111. Lipase also has been demonstrated to disrupt cellular integrity when infused into the interstitial tissues of the pancreas, probably as a consequence of its action on the lipid components of cell membranes [17]. A similar effect was observed with phospholipase-A. In addition, phospholipase-A converts lecithin, a major constituent of bile, to lysolecithin, a product with known potent lytic properties [18]. A recent report from Sjiidahl, Tagesson, and Wetterfors [19] suggests that the mediators of inflammation which develop during acute cholecystitis are phospholipase-A, derived from lysosomes of cells damaged at the site of stone impaction in the outlet of the gallbladder, and lysolecithin, which forms in response to the action of phospholipase-A upon lecithin, the major phospholipid constituent of bile. Phospholipase-A, lysolecithin, and bile salts are known to exert lytic effects upon cells. These authors exclude the possibility of pancreatic enzymes playing a role in acute cholecystitis on the basis that pancreatic enzymes should not enter the gallbladder when the cystic duct is occluded by a stone. This premise ignores the fact that acute cholecystitis is initiated when a stone enters the cystic duct and produces an acute obstru_ction. Our findings indicate that bile, trapped in the obstructed gallbladder, may contain very high concent.rations of pancreatic enzymes. The human pancreas represents a rich source of phospholipase-A [20]. Chronic cholecystitis develops more gradually over an extended time interval. Here again one could postulate that pancreatic enzymes would initiate a low grade progressive inflammatory response, particularly during periods of storage and concentration in bile or when gallbladder emptying is less than optimal because of intermittent temporary obstruction by stones or a spastic ampullary sphinct.er. ___.
Although lysosomal enzymes liberated from damaged cells might represent one mechanism for
Volume 137, March 1979
the entry of potent enzymes such as phospholipase-A into bile, our findings suggest that another important source is the pancreas. Finally, it is interesting to speculate about the possible effects pancreatic enzymes may exert upon the suspension stability of bile, which is dependent on the relative concentrations of bile salts, lecithin, and cholesterol [21]. This balance between the principal constituents of bile permits the maintenance of otherwise insoluble compounds, such as cholesterol, in solution through the formation of micelles. It is possible that phospholipase-A, a major component of pancreatic exocrine secretion, may alter suspension stability of bile by conversion of lecithin to lysolecithin, thereby permitting precipitation of cholesterol and the formation of gallstones. Summary
A total of ninety-three patients with biliary tract disease were studied to determine the concentration of the pancreatic enzymes, amylase and lipase, in bile obtained from the gallbladder and/or common bile duct. Of seventy gallbladder bile samples, amylase levels were higher than actual or predicted serum levels in 87 per cent, while bile lipase levels were higher than serum lipase values in 66 per cent. Bile obtained from the common bile duct had enzyme concentrations which fluctuated from values similar to those in serum to remarkably high levels. This suggests that pancreatic enzymes enter the biliary system through a common terminal ampulla which is known to exist in 60 to 90 per cent of human subjects. The premise is advanced that pancreatic enzymes may initiate inflammatory changes in the gallbladder and could play a role in gallstone formation by altering the constituents which maintain cholesterol in a soluble state. Biliary reflux of pancreatic enzymes could play a role in the pathogenesis of some cases of cholecystitis and cholelithiasis. References 1. Grundy M, Metzger AL, Adler D: Mechanisms of lithogenic bile formation in American Indian women with cholesterol gallstones. J C/in lnvesf 51: 3026, 1972. 2. Bennion LT, Grundy SM: Effects of obesity and caloric intake on biliary lipid metabolism in man. J Clin invest 56: 996, 1975. 3. Heaton KW, Read AE: Gallstones in patients with disorders of the terminal ileum and disturbedbile salt metabolism. Br. A&d J 3: 494, 1969. 4. Andrews E, Harkins H, Schoenheimer R. Hrdina L: Etiology of gallstones; chemical factors and role of gallbladder. Arch &rg 25: 796, 1932. 5. Lynn J, Williams L, O’Brien J. Wittenberg J, Egdahl RH: Effects of estrogen upon bile: implications with respect to gallstone
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formation. Ann Surg 178: 514, 1973. 6. Hjorth E: Contributions to the knowledge of pancreatic reflux as a factor in chronic affections of the gallbladder. Acfa Chir Stand [Suppl 1341 96: 12, 1947. 7. Opie EL: The etiology of acute pancreatitis. BullJohns Hopkins Hasp 12: 182, 1901. 8. Menguy RB, Hallenbeck GA, Bollman JL, Grindlay JH: lntraductal pressures and sphincteric resistance in canine pancreatic and biliary ducts after various stimuli. Surg Gynecol Obstet 106: 306, 1958. 9. Hagstrom WJ Jr, France TD, Anderson MC: A comparison of pancreatic and biliary pressures recorded simultaneously in man. Can J Surg 5: 461, 1962. 10. Wolfer JS: The role of pancreatic juice in the production of gallbladder disease. Surg Gynecol.Obstet 53: 433, 1931. 11. Hauman RL, Gramatica L, Anderson MC: Effect of specific pancreatic enzymes on the gallbladder. Surg forum 21: 388, 1970. 12. Caraway W: A stable starch substrate for the determination of amylase in serum and other body fluids. Am J C/in fatho/ 32: 97, 1959. 13. Vogel WC, Zieve L: A rapid and sensitive turbidimetric method for measurement of lipase in normal and pancreatitis serum.
306
C/in Chem 9: 168, 1963. 14. Hammerton K. Messer M: The origin of serum amylase electrophoretic studies of 150 amylases of the serum, liver and other tissues of adult and infant rats. Biochem Biophys Acta 244: 441, 1971. 15. Warshaw AL, Lee K: Characteristic alterations of serum isoenzymes of amylase in diseases of liver, pancreas, salivary gland, lung and genitalia. J Surg Res 22: 362, 1977. 16. Anderson MC, Bergan JJ: Effect of Proteolytic enzymes upon pancreatic blood vessels. Surg Forum 13: 304, 1962. 17. Anderson MC, Needleman SB, Gramatica L, Toranto IR, Briggs DR: Further inquiry into the role of pancreatic enzymes in the pathogenesis of acute pancreatitis. Arch Surg 99: 185, 1969. 18. Sjodahl R, Tagesson C, Wetterfors J: Lysolecithin mediated inflammatory reaction in rabbit gallbladder. Acfa Chir Stand 141: 403,1975. 19. Sjodahl R, Tagesson C, Wetterfors J: On the pathogenesis of acute cholecystitis. Surg Gynecol Obstet 146: 199. 1978. 20. Zieve L, Vogel WC: Measurement of lecithinase A in serum and other body fluids. J Lab C/in Med 57: 586, 1961. 2 1. Small DM: Etiology and pathogenesis of gallstones. I. Adv Surg 10: 63, 1976.
The Amerlcan Journal of Surgery
Substantial progress has been achieved over the past ten years in the identification of factors which contribute to gallstone formation. Contributing mechanisms include reduced bile salt secretion and/or increased cholesterol secretion by the liver [1,2], reduction of the bile salt pool through excessive loss secondary to inadequate intestinal absorption [3], abnormal absorption of bile salts by the inflamed gallbladder [4], and drugs such as estrogen which affect bile secretion and saturation [5]. Another less common factor is increased bile pigment production associated with hemolytic disease. The present study calls attention to another potential factor in the pathogenesis of biliary inflammation and gallstone formation, namely the regurgitation of pancreatic enzymes into the biliary system. Anatomic and radiographic studies have shown that a common terminal ampulla is present at the outlet of the bile and pancreatic ducts in 60 to 90 per cent of cases [6]. Opie [7] implicated this “common channel” as a factor in the initiation of pancreatitis. In 1901 he reported two autopsy cases of acute hemorrhagic pancreatitis in which a stone was found occluding the papilla of Vater [7]. He postulated that the stone produced obstruction and converted the bile and pancreatic ducts to a closed continuous system which permitted bile to pass into the pancreatic duct. Subsequent studies supported this contention, and the “bile reflux” explanation for
From the Department of Surgery, Medical College of Ohio, Toledo, Ohio; and the Medical Universityof South Carolina and the Veterans Administration Hospital, Charleston, South Carolina. Reprint requests should be addressed to Marion C. Anderson, MD, Department of Surgery, Medical University of South Carolina, 171 Ashley Avenue, Charleston,. South Carolina 29403.
Volums 137. March 1979
acute pancreatitis has continued to stimulate inquiry to the present time. Considerable evidence also has accumulated over the past twenty-five years which indicates that pressure generated in the pancreatic duct is usually greater than that observed in the biliary tract, both in animals [8] and in man [9]. This suggests that flow in a closed continuous pancreatobiliary passage would favor pancreatic enzymes entering the biliary tract, and prompted Wolfer [IO] to propose that biliary inflammation might result from the action of pancreatic enzymes regurgitated into the biliary system through a common channel. More recent studies have shown that certain purified pancreatic enzymes are capable of initiating inflammation in the obstructed canine gallbladder [I 11. Trypsin, lipase, and phospholipase-A caused acute cholecystitis, while saline, amylase, trypsinogen, or obstruction alone had little or no effect. The present study was undertaken to determine the level of amylase and lipase in the bile of patients undergoing operations to correct biliary tract disease. Material and Methods A total of ninety-three patients were included in the study. Seventy underwent cholecystectomy without common bile duct exploration to correct acute or chronic cholecystitis with cholelithiasis. In fourteen patients both cholecystectomy and common duct exploration were performed, and in nine patients samples were obtained only from a T tube introduced at the time of choledochostomy. Gallbladder bile was obtained at operation by insertion of a large bore needle into the lumen and aspiration of the contents prior to manipulation of the organ. Gallbladders
301
Anderson et al
600.
Fioure 3. Muftiole bile samoies obtained from a T tube fofF igure 1. Comparative values of amylase in bile and serum in twenty-six patienfs. Bile levels exceeded serum levels in twenty-one cases (81 percent).
Figure 2. Comparative values of lipase in bile and serum in twenty-six patients. Bile levels exceeded serum levels in thirteen cases (50 per cent).
which contained only mucoid material or were involved by empyema were excluded. Only those samples that clearly contained bile-colored fluid were included. Multiple samples of bile were obtained from patients with T tubes following choledochostomy. In several patients a communication between the bile and pancreatic ducts was confirmed either by cholangiography or at the time of transduodenal sphincteroplasty; however, in most cases the presence of a functional communication between the bile and pancreatic ducts was not confirmed. In forty patients serum samples were drawn either at the time of cholecystectomy or in conjunction with bile collection from a T tube. Amylase levels in serum and bile were measured according to the ultramicromodification of Caraway [12]. Lipase levels were determined by the method of Vogel and Zieve [13]. In twenty-six patients both serum and gallbladder bile levels of amylase and lipase were measured. In five the concentrations of amylase in gallbladder bile and serum were similar, whereas in thirteen the gallbladder levels exceeded the serum concentrations by 1 to 3 times, and in
cholecysiitis and choleliihiasis. Over time amilase and lipase levels Increased fo approximately 2,000 U/d1 and 20 U/d& respectively, in common ducf bile.
Figure 4. Muftiple bile samples obtained from a T tube follo wing common duct expiora tion. A If ftough the gallbladder contained neither amylase nor Iipase, the levels In the common duct varied widely and almost without exception were greater than the serum value. The findings suggest fhat pancreatic enzymes were infermfttent/y ref/ux/ng into the biliary system through a common channel at the ampullary level.
eight the gallbladder concentration was more than 3 times that recorded for serum. Lipase levels in gallbladder bile were similar to those in serum in thirteen patients, whereas in three the gallbladder level exceeded the serum values by 1 to 3 times, and in ten the gallbladder level was more than 3 times the serum value. In 81 per cent of patients bile amylase levels exceeded serum amylase levels, whereas the bile lipase level was more than the serum lipase levels in 50 per cent of cases. (Figures 1 and 2.) In forty-four patients only gallbladder bile amylase and lipase levels were measured. Utilizing the mean serum enzyme concentrations of the twenty-six patients described above, the results were comparable. In four, the gallbladder bile amylase level was similar to the mean serum amylase level, while in seventeen bile concentrations exceeded mean serum values by 1 to 3 times, and in twenty-three the bile values exceeded the mean serum concentrations by more than 3 times. Lipase levels in gallbladder bile were similar
The American Journal of Surgery
j-g
Pancreatic Enzyme Levels in Bile
Serum
0
Figure 5. Multiple bile samples obtained from a T tube lo/lowing cholecystectomy and common duct exploration. Although the amylase level in gallbladder bile was similar Both to that in serum, the lipase level was elevated. amylase and lipase bile levels were consistently markedly elevated compared to the serum values.
while gallbladder lipase concentrations exceeded mean serum lipase levels by 1 to 3 times in seven and were greater than 3 times mean serum levels in twenty-seven. For the group, the gallbladder amylase level was higher than the mean serum amylase level in 90 per cent of cases, and lipase levels exceeded mean serum levels in 77 per cent of cases. When the above groups, involving seventy samples of gallbladder bile, were combined, the bile amylase levels exceeded real or predicted serum values in 87 per cent of cases and bile lipase levels exceeded serum values in 66 per cent of cases. In twenty-three patients with T tubes multiple samples were assayed for amylase and lipase concentrations. In most patients there was great variability in bile concentrations, ranging from the real or predicted serum range to remarkably high levels. Figures 3, 4, and 5 illustrate these findings.
T-Tube
Figure 6. Comparison Of serum levels in a uatient who had flow if pan&eatlc s&retions into’the du&len;m. Postoperative levets of amylase and lipase were similar serum in and common duct bile, suggesting that reflux from pancreatic to bile duct was eliminated.
to mean lipase levels in serum in ten patients,
mally through the tumor to decompress the intrahepatic ductal system into the lower common duct. (Figure 7.) A postoperative cholangiogram demonstrated a communication between the bile and pancreatic ducts near their termination in the duodenum. (Figure 8.) Figure 9 shows that on several occasions bile enzyme levels were at least 2 times the serum value, while at other times serum and bile levels were similar. These findings suggest that pancreatic enzymes intermittently regurgitated into the biliary system, possibly at times when the intact sphincter of Oddi was closed.
Case Reports Case I. SG, a sixty-four year old black male with sclerosing cholangitis and associated chronic pancreatitis, was treated by cholecystectomy, T tube drainage of the common duct, and transduodenal sphincteroplasty. The duct of Wirsung opened on the inferior lip of the papilla of Vater. The septum between the bile and pancreatic ducts was excised (septectomy), which provided a widely patent exit directly into the duodenum, making the possibility of reflux from pancreas to bile duct remote. Figure 6 shows the comparative levels of serum and bile enzyme. None of eight bile amylase values exceeded serum levels, which were measured on four separate occasions. Case II. LC, a fifty-four year old white male, was operated on for obstructive jaundice secondary to a cholangiocarcinoma located at the level of the common hepatic duct in the hilum of the liver. A T tube was passed proxi-
Vclume
137, March 1979
Figure 7. postoperative cholangiogram show&g a T tube passed through a carcinoma of the common hepatic duct to relieve proximal intrahepatic biliary obstruction.
303
Anderson et al
a
Serum
cl
T-Tube
300;
200-
,. -
000
z 0Q. .-I
0
-
00
-
I.O2.0-
9. Figure Comparison of postoperative serum enzyme levels wilh levels obtained from fube T bile in the patient shown in Figures 7 and 8. Aithough several bile sampie ieveis were Similar to serum /eve/s, on other occasions bile enzymes exceeded those in serum, suggesting refiux from panfhe creatic fo th& biiiary system.
Figure 8. Cholangiogram showing lower common bile ducf and communication with the pancreatic ducf proximal to the ampuiia of Vafer.
Comments
The data presented indicate that the enzymes amylase and lipase are present in bile obtained from the gallbladder and/or common bile duct of patients operated on for various forms of biliary tract disease in concentrations which exceed serum values in well over 50 per cent of cases. In a substantial number of patients bile enzymes were intermittently elevated to remarkably high levels. These findings can be criticized on the ground that these enzymes may originate from extrapancreatic sources, including the liver [14]. This question can be answered in future studies by measuring isoenzymes, utilizing one of several methods now available [15]. At the same time it is difficult to ignore the fact that a number of patients had bile and serum enzyme concentrations that were similar. Moreover, when multiple bile samples were tested, the enzyme concentrations often fluctuated in the same patient from values similar to serum values to extremely high levels. The latter findings suggest intermittent reflux
304
of pancreatic enzymes at times when the sphincter of Oddi was closed, thereby permitting flow from pancreas to biliary system in those patients having a common channel at the ampullary level. There was a close co&elation between the percentage of patients with elevated bile enzyme levels and the known incidence of an anatomic communication between pancreatic and biliary ducts in man (60 to 90 per cent). A second question could be raised regarding the pressure relationships which occur in the common duct when it communicates with atmospheric pressure through an open T tube. It is possible that this may facilitate flow of pancreatic juice into the common duct in patients with a common pancreatobiliary outlet, and thereby account for the extremely high values observed in some T tube samples. While this may be true, it also supports the premise that pancreatic enzymes gain entry to bile through a common channel. While levels in the intact biliary system might be less remarkable, available evidence regarding pressures generated in the bile and pancreatic ducts suggests that flow should occur from the pancreas to the biliary system when the sphincter is closed and a continuous channel is present [8,9]. Assuming that the findings presented do in fact represent reflux of pancreatic enzymes into the biliary system, the question of the potential action of enzymes, when permitted to accumulate in the gallbladder, becomes important. We have shown in
The American Journal of Surgery
Pancreatic Enzyme Levels in Bile
earlier animal studies that specific enzyme fractions, notably trypsin, lipase, and phospholipase-A, produced severe inflammatory changes in the obstructed canine gallbladder, whereas saline, amylase, trypsinogen, and obstruction alone had little or no effect [11]. The precise mechanism of these enzyme-induced inflammatory changes is a matter of speculation. Trypsin is known to induce severe alterations of the microcirculation, including vasodilatation, stasis, and increased capillary permeability when introduced into interstitial tissues, such as the pancreatic parenchyma [16]. Similar changes appear to occur following absorption of trypsin across the mucosa of the gallbladder [111. Lipase also has been demonstrated to disrupt cellular integrity when infused into the interstitial tissues of the pancreas, probably as a consequence of its action on the lipid components of cell membranes [17]. A similar effect was observed with phospholipase-A. In addition, phospholipase-A converts lecithin, a major constituent of bile, to lysolecithin, a product with known potent lytic properties [18]. A recent report from Sjiidahl, Tagesson, and Wetterfors [19] suggests that the mediators of inflammation which develop during acute cholecystitis are phospholipase-A, derived from lysosomes of cells damaged at the site of stone impaction in the outlet of the gallbladder, and lysolecithin, which forms in response to the action of phospholipase-A upon lecithin, the major phospholipid constituent of bile. Phospholipase-A, lysolecithin, and bile salts are known to exert lytic effects upon cells. These authors exclude the possibility of pancreatic enzymes playing a role in acute cholecystitis on the basis that pancreatic enzymes should not enter the gallbladder when the cystic duct is occluded by a stone. This premise ignores the fact that acute cholecystitis is initiated when a stone enters the cystic duct and produces an acute obstru_ction. Our findings indicate that bile, trapped in the obstructed gallbladder, may contain very high concent.rations of pancreatic enzymes. The human pancreas represents a rich source of phospholipase-A [20]. Chronic cholecystitis develops more gradually over an extended time interval. Here again one could postulate that pancreatic enzymes would initiate a low grade progressive inflammatory response, particularly during periods of storage and concentration in bile or when gallbladder emptying is less than optimal because of intermittent temporary obstruction by stones or a spastic ampullary sphinct.er. ___.
Although lysosomal enzymes liberated from damaged cells might represent one mechanism for
Volume 137, March 1979
the entry of potent enzymes such as phospholipase-A into bile, our findings suggest that another important source is the pancreas. Finally, it is interesting to speculate about the possible effects pancreatic enzymes may exert upon the suspension stability of bile, which is dependent on the relative concentrations of bile salts, lecithin, and cholesterol [21]. This balance between the principal constituents of bile permits the maintenance of otherwise insoluble compounds, such as cholesterol, in solution through the formation of micelles. It is possible that phospholipase-A, a major component of pancreatic exocrine secretion, may alter suspension stability of bile by conversion of lecithin to lysolecithin, thereby permitting precipitation of cholesterol and the formation of gallstones. Summary
A total of ninety-three patients with biliary tract disease were studied to determine the concentration of the pancreatic enzymes, amylase and lipase, in bile obtained from the gallbladder and/or common bile duct. Of seventy gallbladder bile samples, amylase levels were higher than actual or predicted serum levels in 87 per cent, while bile lipase levels were higher than serum lipase values in 66 per cent. Bile obtained from the common bile duct had enzyme concentrations which fluctuated from values similar to those in serum to remarkably high levels. This suggests that pancreatic enzymes enter the biliary system through a common terminal ampulla which is known to exist in 60 to 90 per cent of human subjects. The premise is advanced that pancreatic enzymes may initiate inflammatory changes in the gallbladder and could play a role in gallstone formation by altering the constituents which maintain cholesterol in a soluble state. Biliary reflux of pancreatic enzymes could play a role in the pathogenesis of some cases of cholecystitis and cholelithiasis. References 1. Grundy M, Metzger AL, Adler D: Mechanisms of lithogenic bile formation in American Indian women with cholesterol gallstones. J C/in lnvesf 51: 3026, 1972. 2. Bennion LT, Grundy SM: Effects of obesity and caloric intake on biliary lipid metabolism in man. J Clin invest 56: 996, 1975. 3. Heaton KW, Read AE: Gallstones in patients with disorders of the terminal ileum and disturbedbile salt metabolism. Br. A&d J 3: 494, 1969. 4. Andrews E, Harkins H, Schoenheimer R. Hrdina L: Etiology of gallstones; chemical factors and role of gallbladder. Arch &rg 25: 796, 1932. 5. Lynn J, Williams L, O’Brien J. Wittenberg J, Egdahl RH: Effects of estrogen upon bile: implications with respect to gallstone
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formation. Ann Surg 178: 514, 1973. 6. Hjorth E: Contributions to the knowledge of pancreatic reflux as a factor in chronic affections of the gallbladder. Acfa Chir Stand [Suppl 1341 96: 12, 1947. 7. Opie EL: The etiology of acute pancreatitis. BullJohns Hopkins Hasp 12: 182, 1901. 8. Menguy RB, Hallenbeck GA, Bollman JL, Grindlay JH: lntraductal pressures and sphincteric resistance in canine pancreatic and biliary ducts after various stimuli. Surg Gynecol Obstet 106: 306, 1958. 9. Hagstrom WJ Jr, France TD, Anderson MC: A comparison of pancreatic and biliary pressures recorded simultaneously in man. Can J Surg 5: 461, 1962. 10. Wolfer JS: The role of pancreatic juice in the production of gallbladder disease. Surg Gynecol.Obstet 53: 433, 1931. 11. Hauman RL, Gramatica L, Anderson MC: Effect of specific pancreatic enzymes on the gallbladder. Surg forum 21: 388, 1970. 12. Caraway W: A stable starch substrate for the determination of amylase in serum and other body fluids. Am J C/in fatho/ 32: 97, 1959. 13. Vogel WC, Zieve L: A rapid and sensitive turbidimetric method for measurement of lipase in normal and pancreatitis serum.
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C/in Chem 9: 168, 1963. 14. Hammerton K. Messer M: The origin of serum amylase electrophoretic studies of 150 amylases of the serum, liver and other tissues of adult and infant rats. Biochem Biophys Acta 244: 441, 1971. 15. Warshaw AL, Lee K: Characteristic alterations of serum isoenzymes of amylase in diseases of liver, pancreas, salivary gland, lung and genitalia. J Surg Res 22: 362, 1977. 16. Anderson MC, Bergan JJ: Effect of Proteolytic enzymes upon pancreatic blood vessels. Surg Forum 13: 304, 1962. 17. Anderson MC, Needleman SB, Gramatica L, Toranto IR, Briggs DR: Further inquiry into the role of pancreatic enzymes in the pathogenesis of acute pancreatitis. Arch Surg 99: 185, 1969. 18. Sjodahl R, Tagesson C, Wetterfors J: Lysolecithin mediated inflammatory reaction in rabbit gallbladder. Acfa Chir Stand 141: 403,1975. 19. Sjodahl R, Tagesson C, Wetterfors J: On the pathogenesis of acute cholecystitis. Surg Gynecol Obstet 146: 199. 1978. 20. Zieve L, Vogel WC: Measurement of lecithinase A in serum and other body fluids. J Lab C/in Med 57: 586, 1961. 2 1. Small DM: Etiology and pathogenesis of gallstones. I. Adv Surg 10: 63, 1976.
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