Contribution of Electron Microscopy to the Final Diagnosis of Renal Biopsies in Egyptian Patients

Role of Ultrastructural Study in the Diagnosis of Medical Renal Diseases: A Tertiary Medical Center Experience and Review of the Literature

The 20th century unfolded many mysteries regarding renal pathology with the advent of ancillary techniques such as immunofluorescence (IF) and electron microscopy (EM) studies. EM plays a major role in confirming the routine and IF findings or may uncover new and unsuspected features. The aim of the study is to elucidate the role of ultrastructural findings in patients with medical kidney diseases on whom kidney biopsy was performed at the American University of Beirut Medical Center, between November 2018 and June 2019. A total of 188 renal biopsies were examined during the study period. EM confirmed the light microscopy diagnosis in 54% of the cases while completely changed the diagnosis in 23% of the cases. In 23% of the sample, EM provided additional features and a secondary diagnosis. Our study emphasizes the important diagnostic role of EM and its significance, particularly in minimal change disease, basement membrane abnormalities, and glomerulopathies.

Molecular Studies on the Nephroprotective Potential of Celastrus paniculatus against Lead-Acetate-Induced Nephrotoxicity in Experimental Rats: Role of the PI3K/AKT Signaling Pathway

Chemicals can induce nephrotoxicity, with damage to different segments of the nephron and deterioration of renal function. Nephrotoxicity due to exposure to a toxin such as carbon tetrachloride, sodium oxalate, or heavy metals is the most common cause of kidney injury. The current study aimed to evaluate the protective effects of Celastrus paniculatus seed extract against lead-acetate-induced nephrotoxicity by evaluating the histopathology, immunohistochemistry, ultrastructure, and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Twenty-four rats were divided into four groups (n = 6 per group): group 1 contained normal animals and served as the control; group 2 received lead acetate (30 mg/kg body weight (b.w.)/day, oral); group 3 received lead acetate and the standard drug N-acetylcysteine (NAC, 200 mg/kg b.w./day, oral); and group 4 received lead acetate and the ethanolic extract of C. paniculatus seed (EECP; 800 mg/kg b.w./day, oral). Treatment was given for 28 consecutive days. The data were analyzed using one-way analysis of variance with SIGMA PLOT 13 using SYSTAT software followed by Newman–Keul’s test for comparison between the groups. EECP ameliorated the adverse changes caused by lead acetate. PI3K and AKT messenger RNA (mRNA) levels were diminished in lead-acetate-treated rats. Treatment with EECP inhibited the occurrence of shrunken cells, the atrophy of glomeruli, and degenerative changes in renal tubules caused by lead acetate. Interestingly, the PI3K and AKT mRNA levels were significantly increased in EECP-treated animals. Our results clearly evidence for the first time that C. paniculatus seed extract inhibits lead-acetate-induced detrimental changes in kidneys by regulating PI3K/AKT signaling pathways.

[The relevance of electron microscopy in kidney biopsies to 21st century pathology]

INTRODUCTION

Electron microscopy (EM) has been used in the study of renal biopsies for more than 5 decades; however, it is expensive and the possibility of restricting it to selected cases has been considered. This study aims to reevaluate the necessity for EM in the diagnosis of renal biopsies today.

MATERIAL AND METHODS

All renal biopsies taken between 2016 and 2019 with adequate light microscopy (LM), immunofluorescence (IF) and EM studies were included. The initial diagnosis (without EM) and the final diagnosis (with EM) was recorded. EM was considered necessary in cases in which the initial and final diagnoses did not concur, when diagnosis could not be made with LM and IF only or if the EM study revealed further clinically relevant findings.

RESULTS

A total of 621 biopsies were included, 498 (80.2%) of native kidneys and 123 (19.8%) of transplanted kidneys. In 115 cases (18.5%) EM had been deemed necessary for diagnosis; it was required more frequently in hereditary diseases (96.8%) and isolated hematuria (88.9%) but less often in nephrotic syndrome (6.7%) and renal transplant biopsy (5.7%) (p < 0.001).

CONCLUSIONS

EM was required in less than a fifth of renal biopsies, being more necessary in isolated hematuria and hereditary diseases and less so in nephrotic syndrome and in renal graft biopsies. These findings may prove useful as a guide to case selection protocols in which EM could be considered as a non-mandatory technique.

Value of electron microscopy in the pathological diagnosis of native kidney biopsies in children

BACKGROUND

Pediatric native kidney diseases are common worldwide. The pathological diagnosis of kidney lesions is crucial for clinical treatment and prognosis. The aim of the current study was therefore to evaluate the value of electron microscopy (EM) to the final diagnosis of native kidney biopsies in children.

METHODS

A retrospective evaluation of 855 pediatric kidney biopsies obtained from the Department of Pediatrics in Peking University First Hospital between November 2010 and December 2017 was performed to assess the contribution of EM to the final diagnosis.

RESULTS

The role of EM in the final diagnosis was determined to be crucial in 300 cases (35.1%), important in 280 cases (32.7%), and auxiliary in 275 cases (32.2%). EM is considered most valuable in a large percentage of glomerular diseases, mainly including minimal change disease, early-stage membranous nephropathy, postinfectious glomerulonephritis, Alport syndrome, thin basement membrane nephropathy, and thrombotic microangiopathy. EM also provided helpful diagnostic information in cases of focal segmental glomerulosclerosis, lupus nephritis, IgA nephropathy, and IgA vasculitis (Henoch-Schonlein purpura nephritis). Additionally, EM was crucial in 90.0% of cases of subtle pathological changes observed with light microscopy (LM) and immunofluorescence (IF) and in 69.3% of the IF-negative specimens. Patients with nephrotic syndrome or hematuria also benefit from ultrastructural examination.

CONCLUSIONS

The present study demonstrated the crucial or important role of EM in the diagnosis of a majority of native kidney biopsies in children. The application of EM should be integrated together with LM and IF as a routine method of assessing pediatric kidney specimens. Graphical abstract.

Contribution of Electron Microscopy to the Clinicopathologic Diagnosis in Childhood Glomerular Renal Diseases

Background: Electron microscopy (EM) provides another diagnostic assessment of glomerular lesions in addition to light and fluorescent microscopy. Objectives: We evaluated the contribution of diagnostic EM in childhood glomerular diseases. Patients and methods: Forty-eight renal biopsies which were assessed by EM between 2000 and 2014 were evaluated. Results: There were 21 (44%) females and 27 (56%) males, ages ranged between 6 and 204 months. EM findings were compatible with light and immunofluorescence microscopy in 65%, made additional contributions to diagnosis in 31% (especially in focal segmental glomerulosclerosis, Alport disease, membranoproliferative glomerulonephritis, dense deposit disease, thin basement membrane disease, and nephronophthisis), and was non-contributory in 4%. Conclusion: Electron microscopic evaluation supports other histopathological diagnoses in most cases, contributes additional diagnostic information in pediatric glomerular disease, especially in FSGS, thin glomerular basement membrane nephropathy, Alport disease, MPGN, and dense deposit disease, and its utilization should clinically justify the increase in cost and testing time.

Lack of electron microscopy hinders correct renal biopsy diagnosis: A study from India

Electron microscopy (EM) is performed routinely on all native kidney biopsies in the western world. However, in India, it is not regularly performed due to non-availability and financial constraints. The aim of this prospective study was to evaluate the usefulness of routinely performing EM on native kidney biopsies. In order to eliminate selection bias, all consecutive native kidney biopsies were included in this study, provided they had adequate tissue for light, immunofluorescence (IF), and EM. The biopsies were reported on the basis of light and IF microscopy. EM was performed on each case by another pathologist who also independently reviewed the light microscopic slides and IF images. The findings were then reviewed to assess how the ultrastructural features contributed to the primary diagnosis and assigned to one of the following categories: 1. Crucial for diagnosis, 2. Important contribution, or 3. Not required. Of the 115 cases evaluated, EM was crucial in 12% of the cases. In 20% of the cases, it provided important confirmatory information and in the remaining 68% cases, EM was not considered required. This study supports the use of EM as a routine diagnostic tool in the evaluation of native kidney biopsies. There is an urgent need for availability and accessibility of EM in our country.

Electron microscopy in determining the etiology of kidney allograft dysfunction

BACKGROUND

Biopsy of the transplanted kidney serves a definitive role in elucidating the possible causes of allograft dysfunction. At our transplant clinic we have observed that electron microscopy (EM) does not usually refine the findings initially disclosed by light microscopy with direct immunofluorescence (LM).

METHODS

We studied whether EM results differ from or add to LM results. We compared the reports of 65 allograft biopsies performed on 60 patients over 82 consecutive weeks. We classified biopsy interpretations by 15 possible diagnoses and categorically by glomerular versus nonglomerular disease. We determined agreement between LM and EM reports by Cohen's kappa statistic, and applied the McNemar test to determine whether EM interpretation yielded significantly more glomerular diagnoses on the same biopsy samples.

RESULTS

There was strong agreement (kappa, 0.94: 95% confidence interval [CI], 0.88-1.00), between the EM- and LM-based interpretations. EM did not detect more glomerular disease than LM (discordance rate, 4.6%: 95% CI, -1.92% to 4.62%: P = .25). EM did not add to the diagnosis of rejection. EM described 3 additional cases of transplant glomerulopathy, but did not lead in a change in management of kidney allograft dysfunction.

CONCLUSION

Electron microscopy, used routinely, does not add to light microscopy in the evaluation of kidney transplant dysfunction.