Koev, D.

Nenov, D.

Taushanova, G.

English

Varna Medical University Press: Journals

PLASMA RENIN ACTIVITY IN PATIENTS WITH CHRONIC R E N A L F A I L U R E B E F O R E AND A F T E R HEMODIALYSIS D . K o e v , D . Nenov, G . Taushanova Data about plasma renin act iv i ty ( P R A ) in chronic renal disease are rath-er controversial ( 1 , 4, 5, 10, 11). A n increase in plasma renin ac t iv i ty is re-corded in isolated cases only. The deterioration of renal functions, leading to chronic renal failure and uremia, does not change significantly P R A le-ve l . Most frequently, P R A in chronic renal failure is normal (2) or decreased, and only in 15 per cent increased (3, 7) wi th no relation to blood pressure what-soever. Hemodialysis in this condition may change P R A level because of the electrolyte variations in the blood and removal of body fluids. I t is of in-terest to study the interrelation between P R A alterations and blood pressure in such patients. I n the present preliminary report we would l ike to outline some of our observations in connection wi th this problem. Material and methods Seventeen patients wi th chronic renal failure, treated wi th chronic hemo-dialysis three times weekly for 8 hours, were investigated. Chronic glomeru-lonephritis was found in 14 patients, and chronic pyelonephritis — in three ( in one associated wi th polycystosis renum, and in one — wi th gout). Renal hypertension was present in eight cases, and secondary anemia — in four-teen. Blood for determination of P R A , blood urea, creatinin, serum electro-lytes and acid-base equil ibrium was taken just prior to the beginning of he-modialysis, and for a second time after its end. P R A was determined radioim-munologically using the test k i t obtained from the firm B Y K - M a l i n k r o d t , based on the generation of Angiotensin I . I n four patients P R A was estimated using the biological method of Pickens as modified by Serebrovskaja et al> simultaneously wi th the radioimmunoassay. Results The in i t ia l P R A level was normal in nine patients, decreased in s ix , and increased only in two (F ig . 1). There was no correlation between P R A level, on one hand, and blood pressure and serum electrolytes level , on the other. I t is now accepted that normal renin act ivi ty takes place in controllable hy-pertension, while high P R A occurs in incontrollable renal hypertension. How-ever, not a l l patients could be str ict ly assigned to either of the two groups (9). Some of our patients have a high P R A showing an appreciable increase after hemodialysis, but they are wi th a normal blood pressure. 74 D. Koen , D. Nenov, G . Taushanova Following hemodialysis (F ig . 2) , in a l l the patients there was a decrease in blood urea from 223^72 mg% to 88^=28 mg%, as wel l as in creatinin from 14.02:5.1 mg% to 7 .7^2 .8 mg%. Blood p H increased from 7 .35^0 .08 to 7.46^:0.05. Serum sodium decreased slightly from 139 + 3.8 mEq/1 to 1 3 4 ± F i g . 1: P l a s m a r en in a c t i v i t y F i g . 2: Mean p lasma r en in a c t i v i t y l eve l l e v e l i n the patients under before and after hemodia lys i s , s tudy . + 2 . 9 m E q / 1 , while serum potassium showed a marked fall in a l l patients from 6.01+0.80 to 3.26 + 0.51 mEq/1 . Before hemodialysis, P R A was 168^124 ng/100 ml /h , and after that — 229=±=172 ng/100 ml /h , but the difference was insignificant (Table 1), because of the substantial individual values' scatter. T a b l e 1 Before hemodialysis After hemodialysis Blood urea mg % Creatinin mg % pH Serum sodium mEq/1 Serum potassium mEq/1 2 2 3 ± 7 2 14.0=!=5.1 7.35^=0.08 1 3 9 ^ 3 . 8 6.01=^0.80 88 ± 2 8 7.7=£2.8 7.46=t0.05 134 =£2.9 3 . 2 6 ^ 0 . 5 1 On the basis of P R A reaction, the patients were divided up in two groups as follows: 9 cases wi th an increase in P R A after hemodialysis, and 8 cases where P R A after hemodialysis remained unchanged or decreased. The electrolyte changes in either group were identical — a marked decrease in serum potas-s ium, and a slight decrease in serum sodium (Table 2 and 3). However, the Plasma renin ac t iv i ty in patients w i t h chronic renal failure before. 75 T a b l e 2 Pat ients wi th an increase i n P R A after hemodialys is Name Blood pressure P R A ng/ЮО. ml/h before after hemodialysis Serum potassium m E q / l before after hemodialysis Serum sodium m E q / l before after hemodialysis D . G . L . M . G . A . M . M . 3. G . C. A . K . V . T . M . D . V . normal normal normal normal normai normal 160/100 170/110 200/100 180 410 61 267 23 417 71 150 29 330 545 172 564 145 528 240 286 86 5.5 4.8 7.2 5.1 6.7 4.8 6.5 6.9 7.4 3.1 3.0 3.1 2.7 3.8 3.0 3.6 2.8 3.4 144 140 142 134 138 144 143 142 146 134 136 133 137 134 140 136 133 144 Pat ients wi thout an increase i n P R A after hemodialys is T a b l e 3 Name Blood pressure P R A ng/100 ml /h before after hemodialysis Serum potassium m E q / l before after hemodialysis Serum sodium m E q / l before after hemodialysis P . c. I . P . S . A , G . B . V . S. M . M . V . S . E . P . normal" normal 200/120 200/100 180/100 170/100 190/105 170/110 58 46 181 212 111 266 120 272 44 47 170 222 85 191 40 202 6.0 6.2 5.1 4.8 7.8 4.5 6.2 6.5 3,0 3.4 3.2 3.1 3.8 3.1 3.5 3.9 140 135 132 142 140 130 147 139 130 133 112 135 138 132 139 137 two groups differed by blood pressure indicators. I n group one (nine patients wi th post-hemodialysis P R A increase) only 3 cases had hypertension; in group two (eight patients without P R A increase) 6 were with hypertension and only two had normal values. The results in four patients from the former group, investigated w i t h the biological method, were analogical. No parallelism was established between the rate of serum potassium de­crease and P R A increase. I n patients without any change in P R A a decrease in potassium under the effect of hemodialysis was also established. After hemodialysis, a l l patients lost weight ranging from 2V 2 to 3 kg, attributed to the removal of body fluids mainly . The blood pressure of patients in the course of hemodialysis did not show noteworthy changes. 76 D . Koen , D. Nenov, G . Taushanova Discussion Our study confirms already established data about P R A level variations in chronic renal failure. We failed to find any correlation between blood pressure and plasma renin ac t iv i ty level , claimed by other authors ( 1 , 3 , 4, 7, 10, 11). The good renin secretion in Cholesterol chronic renal failure despite the advanc-I ed nephrosclerosis and destruction of I the juxtaglomerular apparatus, is ex-plained by hyperplasia of epitheloid cells t in the media of the preafferent and Deoxycorticosterone interlobular arteries, containing granu-ft- I les which, according to Faarup (6), Cortccosterone Vrem la" 18-hydroxycortLcosterone F i g . 3: Aldosterone Presumed influence of u r e m i a on aldosterone synthes is . most l ikely secrete renin. I t is possible that an extrarenal secretion of renin exists (13), as wel l as a decrease in na-tural renin inhibitors (7). The results of this study, pointing to a normal P R A in most of the patients wi th chronic renal failure, are in agree-ment with the data published by Can-giano et al (2). P R A increase in almost half of the patients after hemodialysis is pro-bably due to two main reasons. The first one is the marked decrease in serum potassium, associated wi th slight chan-ges in serum sodium and a decrease in N a / K ratio. As wel l known potas-sium deficit leads to P R A increase (12). The second cause is the reduction of body fluids during hemodialysis, and diminution of extracellular fluid. The question posed is why half of the patients do not show a P R A in-crease in spite of the stimulating influences referred to above. One has to bear in mind the possibility of destruction of a great part of the juxtaglomerular apparatus, and the secretion of renin from extrarenal sources wi th limited secretory capacity. Besides, secondary hyperaldosteronism in chronic renal failure may also take part in the blunted P R A reaction after hemodialysis. Secondary hyperaldosteronism in this condition is not so closely related to the renin-angiotensin system. The high serum potassium level suppresses renin secretion but exerts direct stimulation on aldosterone secretion. Along wi th that, high blood urea stimulates the enzyme 18-hydroxylase, and thus facilitates aldosterone synthesis even in the lack of other stimulators (8) (F ig . 3) . Therefore, it is possible that secondary hyperaldosteronism, which is relat ively independent from the renin-angiotensin system and is fixed in some patients, may lead to suppression of the renin reaction in hemodialysis. Perhaps for this reason a lack of P R A increase is more frequent in patients wi th hypertension. Certainly, the number of patients in our series is too small to justify such a conclusion. Moreover, it is necessary to investigate simul-taneously the aldosterone secretion which w i l l be the subject of further stu-dies along this line. Plasma renin act ivi ty in patients wi th chronic renal failure before. 77 Conclusion . P R A in patients wi th chronic renal failure is usually normal although high or low values may occur, which are by no means related to blood pressure. 2. After hemodialysis in patients wi th chronic renal failure, P R A increases in almost half of the cases, most l ikely due to serum potassium decrease, and reduction of body fluids. 3. I n part of the patients P R A does not show an increase after hemodialysis regardless of the stimulating effect exerted by low potassium level and loss of fluids. I n this category of patients hypertension is more frequently recorded. R E F E R E N C E S U B r o w n , J . J . , D . L . D a v i е s, A . F . L e v e r , J . I . S. R o b e r t s o n , Brit. med. 1965, 2, 1215. — 2. C a n g i a n o , J . L . , O . R a m i r e z - M u x o , R . R a m i r e z — G o n z a l e z , A . T r e v i n o , J . A . C a m p e s . Arch. Intern. Med., 1976, 136, 17—23. — 3. C a r l o s R o m e r o , J . , S. W . H о о b 1 е r . Amer. Heart J., 1970, 80, 701—708. — 4. D e l G r e c o , F . , N . M . S i m o n , S . G o o d ­m a n е t a 1. Medicine, 1967, 46, 425. — 5. Е r m о 1 е n к о, V . M . Ch ron i c hemo­d i a l y s i s , i n F u n d a m e n t a l s cf Nephro lcgy ( i n R u s s i a n ) , Moscow, 1972, 8 9 1 — 9 1 1 . — 6. F a-a r u p, P . , I . N i e l s e n , G . J e n s e n . Acta Path. Microbiol. Scand., Sect . A , 1970, 78a , 674—684. — 7. К о t с h е n , Т . A . Nephron, 1970, 7, 317—330. — 8. M u 1 1 е r , J . R e g u l a t i o n of Aldos terone B i o s y n t h e s i s , Spr inger V e r l a g — B e r l i n , 1971, 109. — 9. S t o ­k e s , G . S . , M . K . M a n i , J . H . S t e w a r t . Brit. med. J., 1970, 3, 126—129. — 10. T u , W . H . Clin. Res., 1965, 13, 116. — 11 . T u , W . H . Circulation, 1965, 3 1 , 686. — 12. V е у r a t, R . , H . R . B r u n n e r e t a 1. Acta endocrinol., S u p p l . 119, 1967, 86. — 13. Y u , R . , J . A n d e r s o n , S . L . S k i n n e r , J . B . B e s t . J.Med., 1972, 52, 7 0 7 — 7 1 1 . Р Е Н И Н О В А Я А К Т И В Н О С Т Ь П Л А З М Ы Б О Л Ь Н Ы Х С Х Р О Н И Ч Е С К О Й П О Ч Е Ч Н О Й Н Е Д О С Т А Т О Ч Н О С Т Ь Ю — ДО И ПОСЛЕ Г Е М О Д И А Л И З А Д. Коев, Д. Ненов, Г. Таушанова Р Е З Ю М Е И с с л е д о в а н а р е н и н о в а я а к т и в н о с т ь в п л а з м е к р о в и п р и п о м о щ и р а д и о и м м у н о л о ­г и ч е с к о г о и б и о л о г и ч е с к о г о м е т о д а в г р у п п е б о л ь н ы х с х р о н и ч е с к о й п о ч е ч н о й н е д о с т а ­т о ч н о с т ь ю , п о д в е р г н у т ы х х р о н и о д и а л и з н о м у л е ч е н и ю . И с с л е д о в а н и е п р о в е д е н о д о и п о с л е г е м о д и а л и з а . О б н а р у ж е н о у в е л и ч е н и е р е н и н о в о й а к т и в н о с т и в п л а з м е к р о в и п о с л е п р о в е д е н и я г е м о д и а л и з а . О б с у ж д а ю т с я в о з м о ж н ы е п а т о г е н е т и ч е с к и е м е х а н и з м ы у в е ­л и ч е н и я р е н и н о в о й а к т и в н о с т и в п л а з м е к р о в и п о д в л и я н и е м г е м о д и а л и з а . 

PLASMA RENIN ACTIVITY IN PATIENTS WITH CHRONIC RENAL FAILURE BEFORE AND AFTER HEMODIALYSIS

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PLASMA RENIN ACTIVITY IN PATIENTS WITH CHRONIC RENAL FAILURE BEFORE AND AFTER HEMODIALYSIS

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