A CLINICAL OBSERVATION OF RENAL MEDULLARY FUNCTION IN RENAL ALLOTRANSPLANTATION

Abstract

Recently, to evaluate the transplanted renal function, creatinine clearance and serum creatinine, which show cortical function, have been preferred. But medullary function is also important for proper evaluation.
For this purpose, urinary concentration tests, response of urinary volume and osmolarity by pitressin loading under water dieresis were performed. Concerning with these tests, cystoscopic examinations for new ureteral orifice, excretory urography for the transplanted kidney and ureter, and voiding cystography for vesicoureteral reflux were also made.
Twenty-five patients had renal transplantation (living related) in Kanazawa Medical University Hospital during the period of March 1975 through December 1978. One of them died due to duodenal perforation and sepsis, and the graft of one patient was removed due to hyperacute rejection two days after the operation. Therefore, twenty-three cases were studied, but the same set of examinations could not be performed in all cases.
In donors, examinations were made before nephrectomy and two weeks after nephrectomy, and in recipients, 40-80 days after transplantation (discharged from the hospital), as well as one year, two years and three years thereafter. Concentration tests were made by the Fishberg's method and pitressin loading tests were done by a modification of Massry's method. About 500-600ml of water was given orally, 5% glucose solution was infused intravenously, and urinary volume was stable at 10ml per one minute. Then, as the first loading one miliunit of pitressin (water soluble) per 1kg (body weight) was injected intravenously, urinary volume and osmolarity were measured four times every 15 minutes, and then 10.0 miliunits of pitressin was given as the second loading. In normal cases (such as donors), urinary volume decreased, and osmolarity increased more than 400mOsm/kg by the first loading of pitressin. By the second loading, urinary volume decreased, and osmolarity was more than 600-700mOsm/kg.
As for the results of examinations, concentration tests which were evaluated by specific gravity showed a few differences between before and after nephrectomy of donors. But, when they were evaluated by osmolarity, no statistic difference was noticed. In recipients, whose histocompatibilty was HLA-identical and showed no rejection, specific gravity (osmolarity) of urine was normal. But, in recipients of HLA-haloidentical and showing rejection crisis, specific gravity (osmolarity) fixed in the lower border of the normal range or in the abnormal range.
Response for pitressin loading showed almost the same pattern in donors and recipients of HLA-identical. It is supposed that renal response has its individual character. When a removed kidney is transplanted to recipient's iliac fossa or, in other words, “new circumstance”, its character is handed down. On the other hand, when the rejection crisis occurs, the pattern of response changes and the maximum point of osmolarity decreases. These data may mean that rejection crisis gives damages to the renal medulla which is also the target area of pitressin.
By calculation of osmolar clearance per GFR of the kidney, when rejection crisis occurs, it was higher than in normal cases. It means that the kidney is in an overworking state per nephron. In donors, who are over 50 years old, osmolar clearance has a tendency to show a higher increase than in preoperative condition.
By observing the appearance of the new ureteral orifice, thee cases of HLA-identical showed a smooth extention of ureteral and vesical mucosa each other and a good normal vascularity. But the cases of HLA-haploidentical showed an edematous orifice and an unnatural state in recipient's vesical mucosa.
Excretory urography revealed a normal renal function and no dilatation of ureter. Voiding cystography revealed that vesicoureteral reflux did not exist in the transplanted ureter but in the bilateral own ureters of two cases.
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