STUDIES ON GLOMERULONEPHRITIS WITH RESPECT TO CHANGES IN THE BASEMENT MEMBRANE OF GLOMERULUS "THICKNESS OF GLOMERULAR BASEMENT MEMBRANE

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1 SYMPOSIUM ( T) STUDIES ON GLOMERULONEPHRITIS WITH RESPECT TO CHANGES IN THE BASEMENT MEMBRANE OF GLOMERULUS Chairman : Kenzo Oshima, Tadashi Takeuchi "THICKNESS OF GLOMERULAR BASEMENT MEMBRANE IN HEALTH AND DISEASES" Gengo Osawa, M.D. The 2nd Department Internal Medice, Niigata University School Medice, Niigata Alterations thickness glomerular capillary basement membrane (BM) various diseases have been histopathologically controversial. The auther tried electron Inicroscopicall) to evaluate the thickness healthy subjects analyzed the changes seen some pathological conditions. The width BM was measured 49 glomeruli 21 dividuals. In 7 them, with 26 glomeruli studied, detailed renal function tests showed normal values. The measurements were taken between the endothelial cytoplasmic membrane, as it is attached to the BM, the outer lg the lama rara externa underneath the cytoplasmic membrane epithelial foot processes. The width was measured only the peripheral portions, at tervals 1ƒÊ To avoid tangential plane sections, portions the capillary wall were not measured which the attached epithelial endothelial cytoplasmic membranes were not clearly visible or where

2 Gengo Osawa, M. D. the endothelial pores were seen circularly. Calculatg from the total number 7670 sites measurements, the mean width was 3146 A, with the sterd deviation 983 A. The range mean width all glomeruli varied from 2248 A to 5000 A, dicatg differences the BM thickness healthy subjects. plus twice the stard deviation is accepted as the upper limit "normal ", only a mean width exceedg 5112 A must be regarded as significantly "abnormal" thickness. The results also showed that a mimum 125 measurements was necessary to estimate a mean width with a 95 per cent confidence limit. 1) In diabetics the relation between the thickeng glomerular BM the thickeng tercapillary tissue is still controversy. Renal biopsies 30 diabetics sections from 2 autopsies were used for study 45 glomeruli from them were examed the same manner as healthy controls. Calculation was based on a total 7140 measurements. All 25 cases without nodules had the mean. width their peripheral capillaries with normal limit (less than 5112 A). On the other h, BM 4 the 7 cases with nodular lesions exceeded the maximal upper limit (more than 5112 A). The residual 3 cases with nodules were with the limit controls. The study this series showed that the thickeng peripheral capillary BM diabetics occurred only glomeruli with nodular lesions. Conversely, nodular glomerulosclerosis could occur without thickeng peripheral BM2'. These data do not confirm the statements that all diabetics have thickened glomerular peripheral BM, that the thickeng the peripheral capillary BM precedes formation nodules. The glomerular BM can give the appearance thickeng with some kds deposit around the lama. This can be the case amyloid kidney which bundles peculiar amyloid fibrillae are distributed focally irregularly around the fat lama. Dense, homogeneous substance may deposit between the lama BM the endothelial or mesangial s (variant E deposit3)),. diffusely cases lupus nephritis, givg the thickened appearance BM. The so-called "membranous" change BM is characterized by irregular outer surface tremendously thickened appearance, is usually consisted irregularly spi If the over-all meann

3 "Thickn ked, towards densities ess glomerular the epithelial (Fig. 1). basement membrane side, or split The " hump ", deposit between has usually normal or mimally thned served lama h, which 3), the presence more or less spiked epithelium Cap : capillary Ed : endothelial Ep : epithelial Arrow dicates change with glomerular basement nephrotic syndrome. lumen spike-like protrusion studied)3). membrane seen membrane. BM, ob- On the from the is other hump by around it, givg the appearance R : red blood BM : basement lama various is specifically 1. Membranous erythematosus 11 the daily prote excretion which is differentiated lama diseases" with deposits glomerular small amount (less than 2. 5 g our series the so called variant Fig. three layers BM cases acute glomerulonephritis, relatively health a case lupus

4 Gengo 12 Fig. Ed : endothelial The deposit is less compact deposit buried cases large the with with participate amount type glomerulonephritis or high rate side lama nephritis, globul confirmed As that lama, (Fig. 2), two to progress, it is suggested discontuity lumen buried (Table). membranous lupus membrane. epithelial lama Cap : capillary is more or less were change, thng proteuria development Extreme basement Ep Ld the epithelial variant membranous proteuria M. D. 2. Variant glomerular U : urary space B variant drome Osawa, is cases seen nephrotic one year the mostly variant or so later, synto might changes. BM content, is observed is probably clically ten participated seen these cases hematuria cases. acute or

5 "Thicknes s glomerular basement membrane health diseases" 13

6 14 Gengo Osawa, M. D. References 1) G. Osawa, et al.: Am. J. Cl. Path., 45(1) : 7, ) P. Kimmelstiel, et al.: Am. J. Cl. Path., 45(1) : 21, ) G. Osawa, et al.: Am. J. Cl. Path., 46(3) : 295, 1966.