Detection of human hepatitis anti-liver kidney microsomes (LKM2) autoantibodies on rat liver sections is predominantly due to reactivity with rat liver P-450 IIC11.

Anti-liver kidney microsomes (anti-LKM2) autoantibodies, appearing in patients treated with tienilic acid and suffering from hepatitis, react with proteins in rat liver sections. The nature of the rat proteins responsible for this recognition and detection of anti-LKM2 has been investigated. Immunoblot testing of the anti-LKM2 with liver microsomes from diversely treated rats and with purified rat liver cytochromes P450 (IA1, IA2, IIB1, IIB2, IIC6, IIC11 and IVA1) showed that these antibodies cross-reacted with cytochrome P450IIC11 and also with phenobarbital-induced cytochromes P450IIB1 and IIB2. Moreover, metabolic activation of tienilic acid and of a tienilic acid isomer by untreated rat liver microsomes was partially inhibited by anti-LKM2. On the other hand, monospecific polyclonal anti-rat P450IIC11 antibodies cross-reacted with human microsomal cytochromes P450 and recognized the same cytochromes P450 as anti-LKM2. This antibody also gave an immunofluorescence pattern on rat and mouse liver and kidney sections very similar to anti-LKM2. The data presented here show that anti-LKM2 recognize epitopes shared by rat P450 IIC11, and a human P450 of the family IIC. All the results indicate rat P450 IIC11, the major isoenzyme present in normal adult male rat liver, as the main antigen recognized by human anti-LKM2 autoantibodies; this is the basis of the immunofluorescence test for detection of these antibodies.

Diuretics physiology pharmacology and clinical use

Uricosuric diuretics have been developed to counteract renal urate retention accompanying diuretic-induced extracellular volume contraction. Their intrinsic uricosuric activity would prevent diuretic-induced hyperuricemia. Ticrynafen, a prototype uricosuric diuretic, has largely fallen into disuse because of hepatic toxicity. However, one lesson learned during the short period that ticrynafen was available in the US is that the administration of a potent uricosuric agent to a patient previously trated with diuretics can precipitate acute renal failure, possibly as a consequence of uric acid nephropathy. Another novel uricosuric diuretic, indacrinone, is composed of two enantiomorphic isomers exhibiting predominantly either a uricosuric or a natriuretic action. Manipulation of the isomer ratio currently is being attempted with a view toward obtaining a combination that produces little change in the serum urate during chronic diuretic therapy. Uricosuric diuretics have the therapeutic potential to treat hypertension and edematous states without increasing the serum urate. Although current information suggests that chronic asymptomatic hyperuricemia poses very little health hazard, future data could indicate that it may be desirable to maintain the serum urate near the normal range

Diuretics. Clinical pharmacology and therapeutic use (Part II).

25 years have elapsed since the introduction of the first effective oral diuretic, chlorothiazide. Diuretics are now amongst the most widely prescribed drugs in clinical practice worldwide. Availability of these drugs has not only brought therapeutic benefit to countless numbers of patients but it has at the same time provided valuable research tools with which to investigate the functional behaviour of the kidney and other electrolyte-transporting tissues. Despite many remaining gaps in our knowledge of the biochemical processes involved in diuretic drug action, available compounds can be divided into 5 groups on the basis of their preferential effects on different segments of the nephron involved in tubular reabsorption of sodium chloride and water. Firstly, there is a heterogeneous group of chemicals that share the common property of powerful, short-lived diuretic effects that are complete within 4 to 6 hours. These agents act on the thick ascending limb of Henle's loop and are known as 'high ceiling' or 'loop' diuretics. The second group are the benzothiadiazines and their many related heterocyclic variants, all of which localise their effects to the early portion of the distal tubule. The third group comprises the potassium-sparing diuretics which act exclusively on the Na+-K+/H+ exchange mechanisms in the late distal tubule and cortical collecting duct. The action of drugs in groups 2 and 3 is prolonged to between 12 and 24 hours. The fourth group consists of diuretics that are chemically related to ethacrynic acid but have the unusual property of combining within the same molecule the property of saluresis and uricosuria. These compounds have actions, to different individual extents, in the proximal tubule, thick ascending limb, and early distal tubule and are known as 'polyvalent' diuretics. Finally, there is a mixed group of weak or adjunctive diuretics which includes the vasodilator xanthines such as aminophylline, and the osmotically active compounds such as mannitol. The metabolic consequences of continued diuretic usage are considered along with non-metabolic sequelae such as ototoxicity or interactions with other concurrent treatments. The relationships between the clinical benefits conferred and the potential harms generated by long term diuretic therapy are also discussed.

Multicentre controlled trial of tienilic acid in hyperuricaemic, hypertensive subjects, with intensive monitoring of liver function.

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.

Long term treatment with tienilic acid or thiazides: comparison of antihypertensive and metabolic effects.

A comparison has been made of arterial pressure and major metabolic parameters during long term treatment with tienilic acid and a hydrochlorothiazide-amiloride combination, using a randomized single-blind study without cross-over. A significant fall in systolic and diastolic blood pressure and no change in most biochemical parameters was observed with both drugs. Serum uric acid concentration was decreased during tienilic acid and was slightly increased whilst subjects took the hydrochlorothiazide-amiloride combination; serum potassium was slightly decreased on tienilic acid. No sign of hepatotoxicity was detected.

Tienilic acid in patients with impaired renal function.

Diuretic therapy is usually accompanied by biochemical changes, such as hypokalemia, impaired glucose tolerance and hyperuricaemia. Tienilic acid is a new long-acting diuretic with antihypertensive effect, combined with uricosuric property. For the purpose of evaluating the effect of tienilic acid in patients with impaired renal function, eleven patients with hypertension and slight to moderate renal impairment were randomized to either hydrochlorothiazide or tienilic acid therapy. During eight weeks of treatment no changes occurred in serum-creatinine, creatinine-clearance, serum-sodium, or urea. Despite renal impairment, serum uric acid decreased during tienilic acid treatment. Compared with placebo, a significant decrease in uric acid was seen as early as after one week of treatment (p less than 0.01) and after 8 weeks the difference was still of the same order (p less than 0.01). During hydrochlorothiazide therapy, serum uric acid increased progressively. The difference was p less than 0.002 at 4 weeks and p less than 0.0005 at 8 weeks of treatment, compared with placebo. The results of this study show that the uricosuric effect of tienilic acid is maintained in patients with mild to moderate renal impairment.

Effects of prostaglandins inhibition on changes in active and inactive renin induced by antihypertensive drugs.

The behaviour of active (AR) and inactive (IR) renin was studied in 48 hypertensive patients (37 with uncomplicated essential hypertension and 11 with reno-vascular hypertension) treated with indomethacin alone or with AR stimulating (bumetanide, tienilic acid, captopril) and inhibiting (atenolol) drugs before and after indomethacin addition. In 10 pts indomethacin (50mg q.i.d./3 days) reduced (p less than 0.05) AR and to a lesser extent IR. In 6 pts bumetanide (1 mg) increased (p less than 0.05) only AR and this effect was abolished by indomethacin. In 6 pts tienilic acid (250 mg) increased (p less than 0.05) only AR and this action was unchanged by indomethacin. In 11 renovascular pts captopril (100mg) increased AR (p less than 0.01) and lesser IR and both these effects were uninfluenced by indomethacin. In 11 essential hypertensive pts captopril (25mg b.i.d./3 days) increased only AR (p less than 0.02), but after 1 year both AR and IR were increased (p less than 0.05) and these effects were abolished by indomethacin. In all the above reported protocols we did never find any inverse correlation between either AR and IR values or their induced changes. These data suggest that prostaglandins stimulate, even if not to a similar extent, both AR and IR and that drugs, which stimulate renin either through or independently of PGs, did not cause any apparent interconversion of plasma IR into AR. In 6 pts atenolol (100 mg daily/6 days) reduced AR (p less than 0.05) and tended to increase IR. Indomethacin addition further decreased AR and reduced IR (both p less than 0.05 vs atenolol alone): however the proportion (% of total) of IR was still reduced. These findings suggest that beta 1-adrenoreceptors blockade exerts a divergent effect on active and inactive renin and that this action is not influenced by PGs synthesis inhibition.

Ticrynafen and hydrochlorothiazide. A comparison in hypertensive patients with renal impairment.

The efficacy of ticrynafen in the treatment of hypertension in patients with moderate renal impairment was compared with that of hydrochlorothiazide in a randomised, double-blind crossover trial in eleven subjects with renal insufficiency. Significant reductions in blood pressure occurred with both treatments, with the maximum responses occurring at different time intervals and to different degrees in individual patients. Thus, although ticrynafen caused a significant reduction in blood pressure in this group of hypertensive patients with renal insufficiency, it was not consistently different from that which could be achieved with hydrochlorothiazide. Ticrynafen also significantly reduced the serum uric acid concentration, compared with a significant rise with hydrochlorothiazide. No major biochemical abnormalities or side-effects were encountered in any subject. Thus, in these patients with renal insufficiency, ticrynafen still demonstrated a uricosuric effect as well as a useful anti-hypertensive action.

[Hypertensive patients treated with tielinic acid. A retrospective study of 298 cases (author's transl)]. / Hypertendus traités par l'acide tiénilique. Etude rétrospective de 298 observations.

Two-hundred and ninety-eight hypertensive patients received tielinic acid for a period of 4 to 42 months; in 295 cases the drug was combined with a potassium-sparing diuretic. No significant changes in mean serum creatinine levels were observed in the whole group. The slight rise in serum creatinine which occurred in 17 patients cannot be ascribed with certainty to the combined treatment. Two patients developed cytolytic hepatitis, and of the 253 patients whose serum transaminase levels were systematically measured, 18 had moderately increased levels; here again, the responsibility of the drug could not be fully established. These data suggest that combining tielinic acid with a potassium-sparing diuretic carries little risk of renal impairment and that this treatment can safely be used. The risk of liver damage is unquestionable but probably small no greater than that of other commonly used hepatotoxic drugs, notably allopurinol.

Comparison of the metabolic and antihypertensive properties of tienilic acid and hydrochlorothiazide.

Tienilic acid (2,3-dichloro-4-(2-thienylcarbonyl) phenoxyacetic acid) is a new diuretic with uricosuric properties. Eighteen patients, aged between 37 and 67 years, with moderate arterial hypertension underwent a double-blind, within-patient, crossover study to compare the effects of tienilic acid (TNCF) and hydrochlorothiazide (HCTZ) on blood pressure, renal function, serum levels of uric acid and electrolytes, and liver function. Blood pressure was lowered similarly by TNCF and HCTZ. The prime advantage of TCNF over HCTZ was its profound hypouricaemic effect. Despite the possibility of hepatotoxicity of TNCF, it may still have a place in the treatment of hypertensive hyperuricaemic patients when the mechanism of hepatotoxicity of TNCF is elucidated.

[Tienilic acid, hyperuricemia and kidney function]. / Acide tiénilique, hyperuricémie et fonction rénale.

Tienilic acid (Diflurex) was given to 10 patients with secondary hyperuricemia following hydrochlorothiazide or furosemide administration. Eight of these 10 patients suffered acute worsening of renal function reflected in a significant increase in plasma creatinine. Plasma urates fell in all patients. Plasma creatinine returned to pretreatment levels in all patients within 4 to 15 days. Extreme caution should be exercised in prescribing tienilic acid to hyperuricemic patients, in view of the significant risk of reversible renal impairment.

[Diuretics and vascular risk factors. Comparison between tienilic acid and chlorothiazide (author's transl)]. / Diurétiques et facteurs de risque vasculaire. Comparaison entre les effets de l'acide tiénilique et du chlorothiazide sur la pression artérielle et les métabolismes lipidique, glucidique et urique.

Tienilic acid (250 mg/day) was compared with chlorothiazide (500 mg/day) in 25 hypertensive patients in a randomized cross-over study (2 periods of 2 months). Mean supine arterial pressure was lower with tienilic acid than with chlorothiazide (106 +/- 3 vs 111 +/- 3 mm Hg, p less than 0.05) whereas no difference could be noted in body weight, natriuresis and plasma renin activity. Glucose tolerance tests were altered in the same fashion. Serum cholesterol (234 with tienilic acid and 239 mg/dl with chlorothiazide) and serum triglyceride levels (178 with tienilic acid and 179 mg/dl with chlorothiazide) were not different. Serum urate concentrations were lower with tienilic acid (4.8 mg/dl) than with chlorothiazide (7.8 mg/dl) whereas fractional excretion of urate was much higher with tienilic acid (17 +/- 2%) than with chlorothiazide (7 +/- 2%). Thus, the only metabolic advantage of tienilic acid over chlorothiazide is its hypouricemic effect which warrants long term studies to evaluate its vascular prognostic significance.