Kidney biopsy and pathological evaluation
Indications for kidney biopsy in a diabetic patient were active urinary
sediment such as dysmorphic erythrocyte, hematuria, erythrocyte, and
leucocyte cylinders, the rapid loss of GFR, sudden onset nephrotic
syndrome, severe proteinuria, diabetic retinopathy and proteinuria in
the absence of other microvascular diseases. A kidney biopsy was
performed with a tru-cut needle percutaneously with ultrasonography
after obtaining the written consent of the patient.
Kidney biopsy samples were evaluated with light and immunofluorescence
(IF). Paraffin-embedded tissues were cut at 3 µm for light microscopy
evaluation and routine staining. All samples were stained with
hematoxylin and eosin (H&E), Jones methenamine silver, Masson trichrome
and periodic acid-schiff, crystal violet, and congo red dyes.
For direct immunofluorescence, the renal tissues were quickly frozen in
liquid nitrogen and cut into 3 µm sections. In biopsy samples,
antibodies against IgG, IgA, IgM, C3, C4, C1q, fibrinogen, kappa, and
lambda were examined. All biopsy samples contained at least ten
glomeruli. Glomerular basement membrane (GBM) thickening, mesangial
expansion, nodular glomerulosclerosis, arteriolar hyalinosis, and
arteriosclerosis were evaluated in renal biopsy specimens for the
diagnosis of DN1. Specific histopathological
diagnostic criteria were used in kidney biopsy of patients with
PGN11. Electron microscopy was used for differential
diagnosis only in suspected cases.
Chronic damage in the renal parenchyma was evaluated with interstitial
fibrosis and tubular atrophy. Renal parenchymal interstitial fibrosis
was expressed as a percent and tubular atrophy as yes/no. All biopsy
samples were evaluated by experienced nephropathologist.
Ethical Approval All procedures performed in the study were in
accordance with the ethical standards of the institutional and/or
national research committee and with the 1964 Helsinki Declaration and
its later amendments or comparable ethical standards. The ethics
committee has approved this study at our university.