J Clin Pathol: first published as 10.1136/jcp.24.9.846 on 1 December 1971. Downloaded from J. clin. Path., 1971, 24, 846-850 Light and electron microscopical studies offocal glomerular sclerosis A. H. NAGI, F. ALEXANDER, AND R. LANNIGAN From the Department ofPathology, Queen's University of Belfast sYNopsIs Renal biopsy material from seven cases ofthe nephrotic syndrome due to focal glomerular sclerosis has been studied by light, electron, and immunofluorescent microscopy. The nature of glomerular basement membrane changes and the scar tissue was also studied. It was found that the glomerular basement membrane and mesangial matrix formed the major components of scar tissue. On the basis of a short history in some of our cases, a poor response to steroid therapy in the early stages, and the distinct morphological changes, it is suggested that focal glomerular sclerosis has an independent origin and is not a stage of minimal change lesion. Focal glomerular sclerosis is characterized by the Materials and Methods presence of glomerular sclerosis which may be focal copyright. or segmental in distribution. Rich (1957) for the The renal tissues from all the patients were obtained first time described 20 cases (all children) of what by open renal biopsies. Before operation each he called 'intercapillary or membranous glomerulo- patient was investigated for renal function (including sclerosis'. He thought that with the passage of time an intravenous pyelogram). Each biopsy was divided in some lesions of minimal change the basement into three portions for light, electron, and immuno- membrane of the glomerular tufts tends to become fluorescent microscopy. The specimens were treated increasingly thickened with the formation of cap- as follows. sular adhesions in some of them. These changes http://jcp.bmj.com/ were characteristically seen in the juxtamedullary LIGHT MICROSCOPY region. Williams (1965) reported a similar series in The tissue was fixed in 10% formol-saline and children and confirmed the findings of Rich. embedded in paraffin. Each block was cut into Following these two reports various other investi- sections 3-4 ,u thick which were stained with haema- gators (McGovern, 1967; White, 1970; White, toxylin and eosin, periodic acid-Schiff reaction, Glasgow, and Mills, 1970; Churg, Habib, and methenamine-silver, and Lendrum's acid picro- White, 1970) have also recognized this change in Mallory stains. on September 29, 2021 by guest. Protected some cases of the nephrotic syndrome, and thought it to be a different type of lesion from thatofminimal ELECTRON MICROSCOPY change. White et al (1970) and Churg et al (1970) Small blocks (three to five in number) of renal found that most of the cases of focal glomerular tissue were fixed in 5% glutaraldehyde, washed in sclerosis are resistant to steroid therapy. The ultra- sucrose cacodylate buffer, and postfixed in Caul- structural changes in various stages of focal glom- field's osmium tetroxide, dehydrated, and embedded erular sclerosis have not been previously described. in Epon. The glomeruli were selected from 1 ,u thick This paper describes the results of histological, sections stained with toluidine-blue. Ultra-thin electronmicroscopical, and immunofluorescent stu- sections of three to five glomeruli from each case dies in seven cases of focal glomerular sclerosis. were cut and stained with uranyl-acetate and lead The effect of steroid therapy on these cases is also citrate. The sections were examined on uncoated discussed. grids on an EM-GB6 electron microscope. 'Correspondence should be addressed to Dr A. H. Nagi, Department of Pathology, Lahore General Hospital, Lahore, W. Pakistan. IMMUNOFLUORESCENT MICROSCOPY Received for publication 9 June 1971. A third portion from each renal biopsy was wrapped 846 J Clin Pathol: first published as 10.1136/jcp.24.9.846 on 1 December 1971. Downloaded from Light andelectron microscopical studies offocalglomerular sclerosis 847 in parafilm and kept at - 20°C. Sections, 4 ,u thick, of illness at the time of biopsy varied between two were cut using a cryostat and fixed in 4% buffered months and 14 months. formol-saline, pH 7-2, for two to three minuteF. The 24-hour urinary protein excretion was higher These sections were stained using monospecific in children than in adults. It varied between 4-1 and antihuman sera to IgG, IgA, IgM, complement, 15-7 g per 24 hours. Total serum proteins were less fibrinogen, and glomerular basement membrane. than 3.9 g/100 ml of serum in five out of seven The specificity of each antiserum was tested by patients. Serum cholesterol levels were above 285 immunoelectrophoresis and Ouchterloney's gel mg% in six of the seven cases. The glomerular precipitation technique. filtration rate was assessed by creatinine clearances which were found to be less than 60 ml/minute in Clinical Features and Laboratory Findings the majority of cases. Blood urea levels varied between 52 and 82 mg%. All the seven patients presented as cases of the nephrotic syndrome. Their ages varied between 9 Results and 23 years (four patients were under 15 years of age). Three patients gave a history of frequent sore HISTOLOGY throat before the onset of the symptoms, but no The severity of histological changes varied with the laboratory evidence was found to suggest a strep- duration of illness. The early lesion (one case) tococcal infection. Oedema was the presenting consisted of focal thickening of the capillary wall symptom in all the seven patients. Four patients in the free loops of a few glomeruli. In two cases (children) had moderate to severe oedema of both glomeruli showed adhesions to the Bowman's face and legs. In the remaining three patients capsule. The lumens of the capillaries involved were (adults) it was of lesser severity and was confined partially or completely obliterated (Fig. 1). In three to either the periorbital region or ankles. Two cases the sclerosis involved one or two lobules of up (children) of the seven patients showed evidence of to 400% of the glomeruli (Fig. 2). In one case all the microscopical haematuria. No evidence of hyper- above mentioned changes were seen and a few tension was found in any ofthe patients. The duration glomeruli were completely sclerosed (Fig. 3). copyright. am. -.rj' -__........ http://jcp.bmj.com/ *;. on September 29, 2021 by guest. Protected £ r ; > s>~~~~~~~~~~.ztX ;~~~~~;.;>2 - K-;;'i .4L< ..V a. ,,X,A'w';,9. S "'* Fig. 1 Glomerulus. Focal sclerosis and capsular adhesion Fig 2 Glomerulus. Capsular adhesions andfocal involving two to three loops. Haematoxylin and eosin. glomerular sclerosis involving three lobules. Haema- x 410. toxylin and eosin. x 410. J Clin Pathol: first published as 10.1136/jcp.24.9.846 on 1 December 1971. Downloaded from 848 A. H. Nagi, F. Alexander, and R. Lannigan _... WEIN AV. S * 44 Cr.~~AW A Fig. 3. Fig. 4 copyright. Fig. 3 Glomerulus. Sclerosis has involved the whole glomerular tuft W Y ~~~with comiplete obliteration of ) ~~~capillary lumens. Haematoxylin and eosin. 460. http://jcp.bmj.com/ Fig. 4 A glomerular capillary loop containing a red blood cell (R) and an endothelial cell (En). The basemient membrane (Bin) in a portion of it is thickened towards the endothelial aspect. 5,600. 4 Fig. 5 A glomerular capillary loop on September 29, 2021 by guest. Protected showing grossly thickened basementt miembrane (Bin). The capillary lumiten containing an endothelial cell (En) is completely obliterated by basemienti membrane-like material (arrow). 6,100. Fig. 5. J Clin Pathol: first published as 10.1136/jcp.24.9.846 on 1 December 1971. Downloaded from Light andelectron microscopicalstudies offocalglomerular sclerosis 849 4~~~~~~~~~~~~~~~~~~~~4- jt#A ' ~ < + ;JS NW XI. t.S ,% i,> --s < t f- j * . / # s* 4 wS.t 4|fi ediSr S } s tAU f X ..s /^.. * * W t* ' Rts S copyright. *V__ w*_sSe,j es vs < _ Fig. 6 Portion of a completely sclerosed glomerulus, showing large masses of basement membrane-like material4: '(B). o @Two '<epithelial . : cell (Ep) nuclei are seen compressed by the suirrounding tissue. x 6,900. Methenamine-silver stained sections revealed that The affected tubules showed diffuse thickening the_ tsclerosed ,f ,tissue a ^ vmainly consisted of basement of the basement membrane. Their epithelial cells membrane-like material. The tubular atrophy and contained numerous protein reabsorption droplets. http://jcp.bmj.com/ the interstitial fibrosis were seen only in relatively advanced cases. FLUORESCENT MICROSCOPY All the unaffected glomeruli showed the features Immunofluorescent microscopy was carried out on of a minimal change lesion. all the seven cases. None of them showed the pre- sence of gamma globulins or fibrin in the glomeruli. ELECTRON MICROSCOPY Electron microscopy was done in all the seven cases. RESPONSE TO TREATMENT Glomerular basement membrane in the mildly All seven patients were treated with corticosteroids. on September 29, 2021 by guest. Protected affected case showed slight to moderate irregular One patient with an early lesion showed an initial thickening in most of the loops (Fig. 4). However, response to treatment, but soon became resistant in some of the loops the basement membrane was to steroids. The remaining six patients showed a slightly darker in appearance, but did not show any very poor or no response to the treatment. definite deposits. In more advanced cases the base- ment membrane was much thickened and the Discussion capillary lumens were completely obliterated by basement membrane-like material (Fig. 5). The Focal glomerular sclerosis has recently been shown completely sclerosed glomeruli were composed of a good deal of attention due to its distinct morpho- basement membrane-like material and some collagen logical appearances and its poor response to steroid fibres (Fig. 6). All the capillaries were completely therapy. Rich (1957), who originally described this obliterated in the affected glomeruli. None of them lesion, thought that in some lesions of minimal showed electron-dense deposits in relation to the change, the glomeruli in the juxtamedullary region glomerular basement membrane.