The treatment of the hepatorenal syndrome with intra-renal administration of prostaglandin E1

Promising utilization areas of therapeutic plasmapheresis in cardiovascular surgery practice

OBJECTIVE

Apheresis is performed for treatment of numerous diseases by removing auto-antibodies, antigen-antibody complexes, allo-antibodies, paraproteins, non-Ig proteins, toxins, exogenous poisons. In current study, we present our experience of using therapeutic plasma exchange (TPE) in patients with different types of clinical scenarios.

METHODS

Between January 2013 and May 2016, we retrospectively presented the results of 64 patients in whom postoperative TPE was performed in ICU setting after cardiac surgery. Patients were grouped into four as; 1-sepsis (n = 26), 2-hepatorenal syndrome(n = 24), 3-antibody mediated rejection(AMR) following heart transplantation(n = 4) and 4-right heart failure(RHF) after left ventricular asist device(LVAD)(n = 10). Hemodynamic parameters were monitored constantly, pre- and post-procedure peripheral blood tests including renal and liver functions and daily complete blood count (CBC), sedimentation, C-reactive protein and procalcitonin (ng/ml) levels were studied.

RESULTS

The mean age was 61 ± 17.67 years old and 56.25% (n = 36) were male. Mean Pre TPE left ventricular ejection fraction (LVEF) (%), central venous pressure (CVP)(mmHg) pulmonary capillary wedge pressure (PCWP)(mmHg) and pulmonary arterial pressure (PAP)(mmHg) were measured as 41.8 ± 8.1, 15.5 ± 4.4, 17.3 ± 3.24 and 39.9 ± 5.4, respectively. Procalcitonin (ng/ml) level of patients undergoing TPE due to sepsis was significantly reduced from 873 ± 401 ng/ml to 248 ± 132 ng/ml. Seventeen (26.5%) patients died in hospital during treatment, mean length of intensive care unit (ICU) stay(days) was 13.2 ± 5.1.

CONCLUSION

This study shows that TEP is a safe and feasible treatment modality in patients with different types of complications after cardiac surgery and hopefully this study will lead to new utilization areas.

[Kidney function and liver transplantation]

INTRODUCTION

In liver cirrhosis renal function decreases as well. Hepatorenal syndrome is the most frequent cause of the decrease, but primary kidney failure, diabetes mellitus and some diseases underlying endstage liver failure (such as hepatitis C virus infection) can also play an important role. In liver transplantation several further factors (total cross-clamping of vena cava inferior, polytransfusion, immunosuppression) impair the renal function, too.

AIM

The aim of this study was to analyse the changes in kidney function during the first postoperative year after liver transplantation.

METHOD

Retrospective data analysis was performed after primary liver transplantations (n = 319).

RESULTS

impaired preoperative renal function increased the devepolment of postoperative complications and the first year cumulative patient survival was significantly worse (91,7% vs 69,9%; p<0,001) in this group. If renal function of the patients increased above 60 ml/min/1,73 m2 after the first year, patient survival was better. Independently of the preoperative kidney function, 76% of the patients had impaired kidney function at the first postoperative year. In this group, de novo diabetes mellitus was more frequently diagnosed (22,5% vs 9,5%; p = 0,023).

CONCLUSIONS

Selection of personalized immunosuppressive medication has a positive effect on renal function.

PGE2 alleviates kidney and liver damage, decreases plasma renin activity and acute phase response in cirrhotic rats with acute liver damage

In this study, we evaluated the effect of prostaglandin E2 (PGE2) on renal and hepatic function using an experimental cirrhosis model plus acute liver damage (ALD). Male Wistar rats treated with carbon tetrachloride (CCl4) for 8 weeks were used for the cirrhosis model. Cirrhotic rats were further exposed to an additional acute dose of CCl4 to induce ALD and then treated with PGE2 intramuscularly twice a day for 7 days (200 microg/Kg/day). PGE2 administration started 3 h after the additional dosing of CCl4 and PGE2 effect on hepatorenal function was examined on days 1, 2, 3, and 7. PGE2-treatment ameliorated the decrease in urinary sodium excretion, and normalized serum activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and plasma renin observed in cirrhotic rats with ALD. In addition, PGE2-treatment decreased mean arterial pressure, glomerular hypercellularity and thickening of the kidney capillary wall, and liver steatosis and cellular necrosis. Also, PGE2 increased the number of regenerative nodules. Finally, PGE2-treatment inhibited the increase in Alpha 1-acid glycoprotein (pAGP), fibrinogen, and Apo A-1 mRNA expression by 83%, 59%, and 77%, respectively. These results suggest that PGE2 administration may decrease the expression of acute phase proteins. In conclusion, PGE2-treatment improved hepatic and renal function and may be useful to down-regulate the acute phase response in cirrhotic rats presenting ALD induced by CCl4.

Hepatorenal syndrome in patients with cirrhosis

Type 1 hepatorenal syndrome (HRS) is a severe complication of end-stage cirrhosis. Type 1 HRS is an acute functional renal failure (i.e. glomerular hypofiltration) with no other explanation than the presence of the circulatory and neurohumoral alterations associated with severe chronic liver disease. Plasma volume expansion does not improve renal function. In contrast, administration of the vasopressin analog terlipressin, a splanchnic and systemic vasoconstrictor, may improve renal function and be used while awaiting liver transplantation.

Hepatorenal syndrome

Hepatorenal syndrome is a functional renal failure that occurs in cirrhotic patients with advanced liver disease and ascites. The diagnostic criteria and clinical types of this syndrome have recently been revised. Hepatorenal syndrome is caused by marked hypoperfusion of the kidney as the result of renal vasoconstriction, which is thought to be the extreme manifestation of an underfilling of the arterial circulation. This circulatory dysfunction is the consequence of arterial vasodilation in the splanchnic circulation. Liver transplantation is the best treatment for HRS, but its applicability is low because of the short survival of these patients. New therapies, such as the use of systemic vasoconstrictors or TIPS, seem promising, but prospective investigations are needed to delineate their role in the management of cirrhotic patients with HRS.

Oral misoprostol or intravenous prostaglandin E2 do not improve renal function in patients with cirrhosis and ascites with hyponatremia or renal failure

Prostaglandins play an important role in the maintenance of renal hemodynamics and water excretion in cirrhosis. To investigate whether the administration of prostaglandins improves renal function in cirrhotic patients with ascites, 16 patients with functional renal failure and/or dilutional hyponatremia were given oral misoprostol, a prostaglandin E1 analogue (200 micrograms/6 h for 4 days; n = 9) or intravenous prostaglandin E2 (0.5 microgram/min for 1 h followed by 1 microgram/min for another hour; n = 7). The administration of misoprostol did not induce significant changes in the glomerular filtration rate (59 +/- 11 vs. 54 +/- 11 ml/min), sodium excretion (4.0 +/- 1.3 vs. 4.1 +/- 2.1 microEq/min), and free water clearance (2.4 +/- 0.8 vs. 2.1 +/- 0.9 ml/min), nor did it improve the natriuretic response to an intravenous bolus of 40 mg of furosemide (486 +/- 124 vs. 406 +/- 88 microEq/min). Similarly, an infusion of prostaglandin E2 did not induce significant changes in the glomerular filtration rate (baseline: 33 +/- 6; 0.5 microgram/min: 31 +/- 5; 1 microgram/min: 31 +/- 6 ml/min) and sodium excretion (5.7 +/- 2.7; 3.2 +/- 1.4; and 1.5 +/- 0.7 microEq/min, respectively), whereas free water clearance decreased significantly (1.1 +/- 0.7; 0.5 +/- 0.5; and -0.1 +/- 0.2 ml/min, respectively, p < 0.05). These results indicate that oral misoprostol or the intravenous infusion of prostaglandin E2 do not improve renal function in cirrhosis with ascites.

Pathophysiology and treatment of ascites and the hepatorenal syndrome

Ascites indicates the accumulation of fluid in the peritoneal cavity, due to a wide range of causes. These causes can be classified according to the presence of portal hypertension, severe blood dyscrasia and peritoneal disease. Cirrhosis is the most frequent cause of ascites. The occurrence of ascites in cirrhosis is due to portal hypertension, which is responsible for the increase in hydrostatic pressure at the sinusoidal level and the alterations of splanchnic and systemic haemodynamics. These latter include increased splanchnic inflow, reduced systemic resistance and increased plasma volume and cardiac output. Portal hypertension also plays a major role in determining sodium retention, which occurs in the setting of increased RAA system and SNS activity. The mechanisms by which portal hypertension leads to the activation of antinatriuretic factors and sodium retention are not completely understood; three main hypotheses have been proposed to explain this relationship, namely the underfilling, the overflow and the peripheral arterial vasodilatation theories. In patients with cirrhosis and ascites, there is an overall activation of the renal prostaglandin system, which probably acts to maintain renal haemodynamics and GFR by counteracting the vasoconstricting effects of AII and noradrenaline on renal circulation. In advanced stages, ascites may become refractory to medical treatment and renal function shows a progressive impairment and eventually acute renal failure, the so-called HRS, due to a marked vasoconstriction of the renal arteries and the opening of the intrarenal-arteriovenous (A-V) shunts. In this condition, the reduced renal synthesis of vasodilating prostaglandins is probably of pathogenic importance. Treatment of ascites is usually based on bed rest, low-sodium diet and administration of aldosterone antagonists and loop diuretics. A sequential treatment of ascites based on the progressive addition of more potent drugs is the best way to relieve ascites while avoiding potentially dangerous side-effects. Patients who fail to respond to the above manoeuvres are said to have refractory ascites. Current treatment of this latter condition is mainly based on therapeutic paracentesis and the application of the LeVeen shunt, but long-term results are unsatisfactory.

Analysis of cysteinyl leukotrienes in human urine: enhanced excretion in patients with liver cirrhosis and hepatorenal syndrome

The cysteinyl leukotrienes, comprising leukotriene C4 and its metabolites, are biologically most active mediators, eliminated from the blood circulation by the liver and the kidneys. The urine of normal subjects and of patients with hepatic and/or renal failure was analysed for endogenous cysteinyl leukotrienes. The leukotriene metabolites were separated by reversed-phase high-performance liquid chromatography and subsequently quantified by radioimmunoassay. Leukotriene E4 was detected in all urine samples analysed. Its mean concentration increased from 0.3 nmol l-1 in healthy subjects to 0.8 nmol l-1 in patients with liver cirrhosis. In patients with hepatorenal syndrome leukotriene E4 averaged 7.8 nmol l-1; in addition, N-acetyl-leukotriene E4 was detected in an average amount of 1.5 nmol l-1. The mean leukotriene E4/creatinine ratio in urine increased from 0.02 in healthy subjects to 0.11 in patients with liver cirrhosis and to 1.2 mumol leukotriene E4 mol-1 creatinine in patients with hepatorenal syndrome. These results indicate that cysteinyl leukotrienes may play an important role in the mediator network responsible for the development of the hepatorenal syndrome in patients with severe liver disease.

Pathophysiology of the hepatorenal syndrome and potential for therapy

Acute renal failure is frequently observed in patients with ascites and alcoholic cirrhosis of the liver. In the absence of any discernible anatomic or clinical cause for the renal failure, the decrease in renal perfusion is usually associated with significant arterial hypovolemia. If there is no contraction of the effective blood volume, then the functional renal failure is entitled to be labeled "hepatorenal syndrome." This implies that there is some unique cause for intrarenal vasoconstriction independent of a contracted effective arterial blood volume. A possible cause for such vasoconstriction may be abnormal intrarenal production of prostaglandins. Therapy is ineffective, but calcium antagonists may have some therapeutic potential.

Renal eicosanoids as determinants of renal function in liver disease

The available data suggest that alterations in renal prostaglandin metabolism participate in the pathogenesis of at least two prominent renal complications of liver disease: (a) sodium retention and (b) HRS. Although the data are highly suggestive, additional studies, including experimental manipulations that augment vasodilatory prostaglandins while diminishing vasoconstrictor metabolites of arachidonic acid, will be required to establish the role of prostaglandins or other arachidonic acid metabolites in mediating these renal abnormalities. The clinical caveat emerging from these observations is that every attempt should be made to avoid prescribing drugs which possess cyclooxygenase inhibitory activity to patients with decompensated liver disease who are sodium-avid.

Immunohistochemical distribution of renal prostaglandin endoperoxide synthase and prostacyclin synthase: diminished endoperoxide synthase in the hepatorenal syndrome

To evaluate possible causes of the diminished prostaglandin production in advanced hepatorenal syndrome, prostaglandin endoperoxide synthase and prostacyclin synthase were localized and semiquantitated by immunofluorescence in postmortem, biopsy and nephrectomy renal tissues. In normal kidneys, antiprostacyclin synthase serum caused intense staining in peritubular capillaries, in the adjacent renal interstitial cells and in glomerular mesangial regions. Antiprostaglandin endoperoxide synthase serum caused staining of collecting duct epithelial cells, cells of the thin ascending limb and possibly glomerular mesangial cells. Prostacyclin synthase-positive staining was graded 5+ (scale of 0+ to 5+) in all kidney samples. Medullary collecting tubule prostaglandin endoperoxide synthase-positive staining was graded 4+ or 5+ in kidney samples from patients with acute tubular necrosis or acute tubulointerstitial nephritis and from patients with liver failure without the hepatorenal syndrome. However, prostaglandin endoperoxide synthase-positive staining was markedly diminished or absent (average 1+) in patients with the hepatorenal syndrome. These data suggest that loss of the medullary prostaglandin endoperoxide synthase is the cause of diminished urinary prostaglandin E2 excretion in the hepatorenal syndrome.

Role of renal prostaglandins and the effects of nonsteroidal anti-inflammatory drugs in patients with liver disease

Renal prostaglandins have several key functions in patients with severe liver disease and ascites. Increased activity of vasodilatory prostaglandins counters the underlying impairment in renal perfusion and the effects of vasoactive hormones. Prostaglandins also participate in renin secretion, renal diluting ability, sodium excretion, the action of diuretics, and, possibly, the development of the hepatorenal syndrome. Nonsteroidal anti-inflammatory drugs inhibit these compensatory actions of prostaglandins and cause a functional reduction in glomerular filtration rate and an impairment in sodium and fluid excretion. The severity of these nephrotoxic effects depends on the potency of the drug in inhibiting renal prostaglandins and on patient susceptibility. Patients with ascites and avid sodium retention, sodium-restricted diets, or concurrent diuretic use are most at risk. If nonsteroidal anti-inflammatory drugs must be administered to these patients, the type of drug should be carefully selected and renal function should be closely monitored.

Renal prostaglandins and the control of renal function in liver disease

Recent evidence suggests that renal prostaglandins play a major role in the control of renal hemodynamics and function in patients with advanced liver disease. The available data suggest that alterations in renal prostaglandin metabolism participate in the pathogenesis of at least three prominent renal complications of liver disease: sodium retention, impaired renal diluting ability, and the hepatorenal syndrome. Nonsteroidal anti-inflammatory agents that inhibit cyclooxygenase activity favor sodium retention and diminish renal plasma flow and glomerular filtration rate in patients with decompensated cirrhosis. The clinical caveat emerging from these observations is that nonsteroidal anti-inflammatory agents, which inhibit cyclooxygenase activity, should not be prescribed for sodium-retaining patients with decompensated liver disease.

The pathogenesis of renal sodium retention and ascites formation in Laennec's cirrhosis

This chapter critically reviews our current understanding of the pathogenesis, clinical syndrome, and therapy of the disturbances of renal sodium handling, renal perfusion, and glomerular filtration rate that occur in patients with Laennec's cirrhosis. Avid renal sodium reabsorption, a characteristic feature of cirrhosis, occurs independent of moderate changes in renal function and precedes the onset of ascites. The initiation of sodium retention may be a direct consequence of the hepatic disease process and may also result from defective intravascular filling. In the presence of ascites the most important sodium retaining signal is a defective intravascular volume. The principal effectors of renal sodium retention and vasoconstriction are stimulation of the renin-angiotensin-aldosterone axis and augmentation of renal sympathetic nerve activity. Deficient production of natriuretic hormone(s) and endogenous renal vasodilators, such as prostaglandins and kinins, also contributes to the sodium retention and renal hypoperfusion seen in cirrhosis. The hepatorenal syndrome is an extreme imbalance in these renal vasoconstrictor and vasodilator forces. In the therapy of ascites in Laennec's cirrhosis, abstention from alcohol, sodium restriction, and cautious diuresis are the principal therapeutic measures. A grave prognosis accompanies the diagnosis of the hepatorenal syndrome although recoveries have been reported.

Determination of prostaglandin E1 in plasma with picogram per millilitre sensitivity by double antibody extraction and column switching high-performance liquid chromatography

Prostaglandin E(1) (PGE(1)) is a vaso- and arteriodilator that is used for the experimental treatment of a variety of vascular diseases. A high-performance liquid chromatography (HPLC) method was developed for the purpose of quantifying PGE(1) in the plasma of patients undergoing constant infusion therapy. Plasma (0.5 ml) was extracted with a double antibody precipitation technique and the PGE(1)-immunoprecipitate was isolated and washed by repeated resuspension and centrifugation. PGE(1) was recovered from the precipitate by extraction with acetonitrile and derivatized with panacyl bromide for determination on a heteromodel column switching HPLC system with fluorescence detection. The content of PGE(1) in immunoextracts was determined by HPLC peak height comparison against a standard curve of PGE(1) peak height vs amount derivatized. The result was corrected for the plasma extraction efficiency (determined with radiolabelled PGE(1)) to obtain the plasma concentration. Standard curves were linear from 25 to 400 pg (r > 0.99) and the y-intercepts were not significantly different from zero (p < 0.05). The immunoextraction recovery from six human donors was 63.5 +/- 2.0% (S.D., n = 18). The quantification limit of the method was 50 pg ml(-1) (signal-to-noise ratio 3:1), at which the estimated assay relative standard deviation was 18%. The utility of the method for the measurement of PGE(1) plasma levels during constant intravenous infusion was demonstrated in a dog study.

Redistribution of renal blood flow in patients with liver cirrhosis. The role of renal PGE2

Cirrhotic patients frequently show a decrease in renal blood flow and redistribution of the flow from the outer cortex to the juxtamedullary cortex. The cause of the maintenance of juxtamedullary perfusion is not presently known. Prostaglandin E2 (PGE2) has its vasodilating effect on medullary and juxtamedullary vessels where it is synthesized. Therefore, its increased production, frequently shown in cirrhotics, could be responsible for the relative preservation of juxtamedullary blood flow. To verify this hypothesis we examined 13 cirrhotic patients. In these patients we determined mean renal blood flow (MRBF), blood flow in the 1st compartment (ICBF) and in the 2nd compartment (IICBF) with the 133-Xenon washout technique and PGE2 plasma levels in the renal veins (PGE2V). MRBF and ICBF were significantly reduced as compared to control subjects (P less than 0.01); IICBF resulted unaltered. Significant correlation was found between IICBF and PGE2V (P less than 0.01). Our data confirm the decrease in renal blood flow and the redistribution of intrarenal blood flow in cirrhotic patients. The maintenance of IICBF is likely to be a consequence of PGE2 renal production.

[Eicosanoids and phospholipases]

Prostaglandins, thromboxanes, and leukotrienes have been implicated to play an important role in physiology as well as in a growing list of pathophysiologic conditions. These oxidation products of 8.11.14-eicosatrienoic-, 5.8.11.14.-eicosatetraenoic-, and 5.8.11.14.17.-pentaenoic acids have been collectively designated eicosanoids. Many clinically important diseases are associated with altered eicosanoid biosynthesis. Furthermore, a series of hormones are known to induce acutely formation of eicosanoids, suggesting a crucial role in a multitude of tissue responses including phenomena such as secretion, platelet aggregation, chemotaxis, and smooth muscle contraction. The major precursor for the eicosanoids seems to be 5.8.11.14.-eicosatetraenoic acid or arachidonic acid. Virtually all of arachidonic acid however is present in esterified form in complex glycerolipids. Since cyclooxygenase and the lipoxygenases utilize arachidonic acid in its free form, a set of acylhydrolases is required to liberate arachidonic acid from membrane lipids before eicosanoid formation can occur. It became only recently apparent that a minor acidic phospholipid, phosphatidylinositol, comprising only 5%-10% of the phospholipid mass in mammalian cells, plays an important role in arachidonic acid metabolism. Phosphatidylinositol--after phosphorylation to phosphatidylinositolphosphate and phosphatidylinositolbisphosphate--appears to be hydrolyzed by specific phospholipases C generating 1-stearoyl-2-arachidonoyl-diglyceride. Diglyceride serves as substrate for diglyceride lipase to form monoglyceride and free fatty acid. Alternatively diglyceride is phosphorylated by diglyceride kinase yielding phosphatidic acid, which is believed to be reincorporated into phosphatidylinositol. In addition to phosphatidylinositol phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid may contribute to arachidonic acid release. These phospholipids are substrates for phospholipases A2 generating free arachidonic acid and the respective lysophospholipid. Understanding of the biochemistry of arachidonic acid liberation may be critical in developing strategies of pharmacological intervention in a variety of pathological conditions.

Effect of prostaglandin inhibition by indomethacin on renal function in alcoholic versus non-alcoholic cirrhotic patients

The purpose of this study was to compare the effect of inhibition of renal prostaglandin synthesis on renal function in 11 patients with alcoholic cirrhosis and 11 with non-alcoholic cirrhosis. After indomethacin administration to the 11 alcoholic patients, the glomerular filtration rate (GFR) and effective renal plasma flow (RPF) decreased significantly (p less than 0.05), but were found to decrease more significantly in the non-alcoholic cirrhosis group. The plasma disappearance rate of indocyanine green was lower in the non-alcoholic group than the alcoholic group, and correlated inversely with the percent decrease in GFR and RPF after indomethacin. These results suggest that the augmented effect of indomethacin is greater in the non-alcoholic group than the alcoholic group, which may be related to the decrease in hepatic blood flow.

Raised plasma thromboxane B2 levels in alcoholic liver disease

In experimental animals endotoxin administration causes increased levels of thromboxane B2 and prostaglandins. Liver cirrhosis is often complicated by endotoxemia. In sixteen patients with alcoholic liver cirrhosis, we measured plasma thromboxane B2 levels. In twelve patients we found on one or more occasions raised plasma thromboxane B2 levels. Raised plasma thromboxane B2 levels were associated with significantly higher serum levels of urea, alkaline phosphatase, gamma glutamyl transpeptidase and lower antiplasmin and antithrombin III levels. It is possible that some of the complications in patients with alcoholic liver cirrhosis are mediated by thromboxanes.

Combined use of dopamine and prostaglandin A1 in patients with acute renal failure and hepatorenal syndrome

Dopamine and prostaglandin A1 were infused intravenously in 4 patients with the hepatorenal syndrome, in 1 patient with acute tubular necrosis, and 1 patient with cortical necrosis. Large doses of prostaglandin A1 decreased arterial blood pressure preventing increase in dosage; in contrast, high doses of dopamine elevated blood pressure. When the two drugs were administered conjointly, much larger doses of each agent could be administered without change in arterial blood pressure. Significant improvement of renal function was not observed in any of these critically ill patients during or within 24 hours after dopamine and prostaglandin A1 administration. This study demonstrated that extremely large doses of these vasodilating agents can be safely administered conjointly.