Immune mechanisms in tienilic acid associated hepatotoxicity.
(9/20)
In order to investigate the mechanisms underlying the hepatotoxicity associated with tienilic acid (Ticrynafen) ingestion we have looked for evidence of sensitisation to drug altered liver cell determinants using an indirect antibody dependent, cell mediated cytotoxicity assay (ADCC). As targets, hepatocytes were isolated from rabbits pretreated with either tienilic acid or its isomer with or without previous enzyme induction with either phenobarbitone or B-naphthoflavone (BNF). Sera from 16 of 36 patients with presumed tienilic acid hepatotoxicity induced significant cytotoxicity to hepatocytes isolated from rabbits pretreated with BNF and subsequently tienilic acid. Three of 10 sera from patients receiving tienilic acid but without overt liver damage also induced significant cytotoxicity to these hepatocytes, however, although none of 20 normal controls or of 16 patients with other liver diseases did so. Non-organ specific autoantibodies, classified as anti-LKM2, were also detectable. These were present in association with tienilic acid associated antibodies: of the 36 patients with presumed tienilic acid hepatotoxicity, 38% had both antibodies, 18% had only anti-LKM2 antibodies and 9% only tienilic acid associated antibodies. These results suggest that this drug reaction is associated with sensitisation to drug altered liver cell antigens and autoantigens. If ticrynafen associated hepatotoxicity is immune mediated, then one possible mechanism is that the drug induced antigens break tolerance, leading to an immune attack on normal liver cell components. (+info)
Human anti-endoplasmic reticulum autoantibodies appearing in a drug-induced hepatitis are directed against a human liver cytochrome P-450 that hydroxylates the drug.
(10/20)
"Anti-liver/kidney microsome" (anti-LKM) autoantibodies have been found in the serum of patients with cryptogenic chronic hepatitis and with immunoallergic drug-induced hepatitis, such as those induced by halothane or by tienilic acid (called anti-LKM2 in this case). So far the nature of the human microsomal macromolecules recognized by these antibodies has not been determined. Here we show, by using immunoblot techniques, that among the macromolecules present in human adult liver microsomes, one protein called cytochrome P-450-8 is specifically recognized by most sera of patients containing anti-LKM2 antibodies but not by control serum. Human fetal liver microsomes that do not contain cytochrome P-450-8 are not recognized by the anti-LKM2 antibodies. It is also shown that anti-cytochrome P-450-8 antibodies as well as human serum containing anti-LKM2 antibodies specifically inhibit the hydroxylation of tienilic acid by human liver microsomes. These results indicate that anti-LKM2 antibodies appearing in patients with hepatitis and concomitant administration of tienilic acid are directed against a cytochrome P-450 isoenzyme that catalyzes the metabolic oxidation of this drug. This suggests a possible mechanism for the appearance of anti-organelle antibodies in a drug-induced hepatitis. (+info)
Multicentre controlled trial of tienilic acid in hyperuricaemic, hypertensive subjects, with intensive monitoring of liver function.
(11/20)
1 Tienilic acid, a diuretic with potent uricosuric properties, has been compared with conventional diuretic therapy, mainly thiazide, in a parallel group (random allocation) multicentre study in hyperuricaemic hypertensives (n = 96). 2 The study was designed to last 1 year but tienilic acid was withdrawn for suspected hepatotoxicity before the study was complete. Mean follow-up was 8.5 (range 1-12) months and the mean daily dose of tienilic acid was 278 (range 125-500 mg). 3 Blood pressure levels on tienilic acid and on conventional diuretics were similar. 4 Serum potassium and sodium levels were also similar in the two groups, but serum urea and creatinine rose somewhat more in the tienilic acid group. 5 Serum uric acid fell dramatically in the patients on tienilic acid from 0.56 to 0.32 mmol/l, but did not alter significantly in the control group. 6 There were no problems with renal failure or urate deposition probably because patients were instructed to drink plenty of fluid when tienilic acid was started, because initial dose was low and because all previous diuretics were stopped for 3 days before tienilic acid was started. 7 Mean liver function indices did not rise in either group. Mild elevation in liver enzymes occurred in one control patient and one patient on tienilic acid; the latter drug was stopped and the values returned to normal. 8 The general incidence of side-effects was low. 9 Our impression was that tienilic acid was a useful drug. Whether it could have been used safely with monitoring of liver function will not now be known. (+info)
A new anti-liver-kidney microsome antibody (anti-LKM2) in tienilic acid-induced hepatitis.
(12/20)
The sera of 131 patients with anti-liver-kidney microsome antibodies (anti-LKM) detected between 1973 and 1979 in two different laboratories were re-examined. (1) Eighty-six anti-LKM corresponded to the description given by Rizzetto, Swana & Doniach (1973), with a pattern of fluorescence predominating on the 3rd portion of the proximal tubules (P3). This group comprised 45 cases of idiopathic chronic hepatitis or idiopathic cirrhosis and one case of halothane-induced hepatitis. (2) Forty-five anti-LKM gave a different pattern on male mouse liver and male rat kidney: (a) fluorescence was greater on centrolobular than on periportal hepatocytes; (b) the first and second portions of proximal tubules (P1 and P2) predominated over P3; (c) P1 fluorescence was equally intense as P2 and (d) P3 cells were heterogeneous with one cell out of 20 more positive than the rest. Absorption tests confirmed that the corresponding antigen was also present in the liver microsomal fraction. A retrospective clinical study discovered tienilic acid-induced hepatitis in all cases. We suggest naming this new antibody 'anti-LKM2'. (+info)
Effect of chronic diuretic treatment on the plasma renin-angiotensin-aldosterone system in essential hypertension.
(13/20)
1 Chronic treatment with a constant dose of hydrochlorothiazide or tienilic acid increases plasma renin activity (PRA) acutely to reach a maximum within the first week. 2 During chronic diuretic therapy from 1 month to 1 year, PRA remained elevated at a rather constant level, though this was somewhat lower than the maximum level reached after 1 week. 3 A significant (P less than 0.01) correlation (r = 0.74) between changes in plasma angiotensin II and renin activity provoked by chronic treatment for 3 months with hydrochlorothiazide and tienilic acid was found. 4 The increase in plasma aldosterone during chronic treatment with hydrochlorothiazide and tienilic acid (1000 mg) is related (r = 0.68; P less than 0.01) to the rise in plasma angiotensin II. (+info)
Controlled inpatient study of tienilic acid in treatment of gout and hypertension.
(14/20)
Under inpatient controlled conditions 4 patients with gout and hypertension were treated with varying doses of tienilic acid, a new uricosuric diuretic. Plasma urate levels were reduced by an average of 50% in association with significantly increased urinary urate excretion. A twice-daily regimen was considerably more effective than a single morning dosage in reduction of plasma urate, though both regimens were equally effective in antihypertensive potency. The single daily regimen produced greater diurnal fluctuations in plasma urate and was more frequently associated with the development of acute gout attacks. (+info)
Tienilic acid: a single treatment for hyperuricaemia and hypertension?
(15/20)
Tienilic acid is a drug with established uricosuric and hypotensive properties. We have examined its potential role as a single treatment for hyperuricaemia and hypertension, 2 disorders which are commonly associated. In 17 subjects with gout, blood uric acid levels were reduced by approximately 50%. Eleven of these patients also had hypertension which was improved by tienilic acid. However, a statistically significant effect was observed only with standing diastolic blood pressure. Side effects included acute episodes of gout in 4 patients and transient loin pain and dysuria in 1 patient. The precipitation of gouty arthritis is an acknowledged risk of all potent hypouricaemic drugs. The hazard of urate deposition in the renal tract implicit in the history of loin pain is a more serious complication. Thus, it would appear that tienilic acid is a potentially valuable drug which may have a special role in patients with hyperuricaemia and hypertension. Further study is necessary to determine how it may be best administered without the risk of renal damage. (+info)
Human-liver cytochromes P-450 expressed in yeast as tools for reactive-metabolite formation studies. Oxidative activation of tienilic acid by cytochromes P-450 2C9 and 2C10.
(16/20)
Human liver cytochromes P-450 (P450) 2C9 and 2C10 expressed in yeast reproduce all the metabolic features of the oxidation of tienilic acid (2-aryloxo-thiophene) and its isomer (3-aroylthiophene) by human liver microsomes. Microsomes of yeast expressing either P450 2C9 or P450 2C10 catalyze (a) the 5-hydroxylation of tienilic acid by NADPH and O2 (Km = 6 microM, Vmax = 2.5 turnover/min), (b) the activation of tienilic acid and its isomer into electrophilic metabolites which covalently bind to proteins, and (c) the formation of a mercaptoethanol adduct which results from the trapping of the tienilic acid isomer sulfoxide by this thiol. Microsomes of yeast expressing human liver P450 3A4, 1A1 and 1A2 are unable to catalyze these reactions. There is a striking similarity between the quantitative characteristics of the oxidation of tienilic acid (and its isomer) by yeast-expressed P450 2C9 (or 2C10) and by human liver microsomes: (a) analogous Km values (around 10 microM) for tienilic acid 5-hydroxylation, (b) a strong inhibition of tienilic acid oxidation by human sera containing anti-(liver kidney microsomes type 2) (anti-LKM2) antibodies, and (c) almost identical relative ratios of tienilic acid metabolic activation/5-hydroxylation and of tienilic acid activation/the activation of its isomer with both systems. Rates of oxidation of tienilic acid (and its isomer) by yeast microsomes are 6-8 fold higher than those found in human liver microsomes, which would be in agreement with the previously reported amount of P450 2C9 in human liver. These results not only suggest the important role of P450 2C9 in the oxidative metabolism of tienilic acid in human liver, but also indicate that the 5-hydroxylation reaction could be a useful marker for P450 2C9 activity and underline the interest of human liver P450s expressed in yeast as tools for studying the formation of reactive metabolites. (+info)