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

Mild mesangial proliferative IgA nephropathy with and without minimal change disease

Mild mesangial proliferative IgA nephropathy with minimal change disease (MCD-IgAN) and mild mesangial proliferative IgA nephropathy without minimal change disease (Non-MCD-IgAN) have similar characteristics on light microscopy. Nevertheless, their discrepancies in clinicopathological features and prognosis remain unknown. A total of 589 patients with biopsy-proven mild mesangial proliferative IgA nephropathy (M-IgAN) combined with light microscopy and immunofluorescence were enrolled. Firstly, the diagnoses of the patients by electron microscopy were recorded and used as the gold standard. We calculated the sensitivity and specificity using nephrotic syndrome (NS) as the diagnostic criteria to identify MCD-IgAN. Then, excluding patients with a 24-h urinary total protein less than 0.5 g/day, incomplete clinical data, or less than the six-month follow-up, we included 184 cases of non-MCD-IgAN and 98 cases of MCD-IgAN. The patients' clinicopathological and outcome data were collected and compared. Among the 589 patients, according to electron microscopy, 381 were diagnosed with non-MCD-IgAN, 167 with MCD-IgAN, and 41 with M-IgAN complicated by other glomerular diseases. Using NS as the diagnostic criteria to distinguish non-MCD-IgAN and MCD-IgAN, the sensitivity and specificity were 83.8% and 99.5%, respectively. The patients in the MCD-IgAN group tended to be younger, hypotensive, with lower urinary erythrocytes, and more likely to achieve complete remission, and fewer patients progressed to the endpoint than those in the non-MCD-IgAN group (all P < 0 .05). NS appears to be an objective indicator for differentiating MCD-IgAN from non-MCD-IgAN. Non-MCD-IgAN varies greatly from MCD-IgAN in clinicopathology and treatment response, with a poorer prognosis.

Deep learning-based multi-model approach on electron microscopy image of renal biopsy classification

BACKGROUND

Electron microscopy is important in the diagnosis of renal disease. For immune-mediated renal disease diagnosis, whether the electron-dense granule is present in the electron microscope image is of vital importance. Deep learning methods perform well at feature extraction and assessment of histologic images. However, few studies on deep learning methods for electron microscopy images of renal biopsy have been published. This study aimed to develop a deep learning-based multi-model to automatically detect whether the electron-dense granule is present in the TEM image of renal biopsy, and then help diagnose immune-mediated renal disease.

METHODS

Three deep learning models are trained to classify whether the electron-dense granule is present using 910 electron microscopy images of renal biopsies. We proposed two novel methods to improve the model accuracy. One model uses the pre-trained ResNet convolutional layers for feature extraction with transfer learning which was firstly improved with skip architecture, then uses Support Vector Machine as the classifier. We developed a multi-model to combine the traditional ResNet model with the improved one to further improve the accuracy.

RESULTS

Deep learning-based multi-model has the highest model accuracy, and the average accuracy is about 88%. The improved ReseNet + SVM model performance is much better than the traditional ResNet model. The average accuracy of the improved ResNet + SVM model is 83%, while the traditional ResNet model accuracy is only 58%.

CONCLUSIONS

This study presents the first models for electron microscopy image classification of Renal Biopsy. Identifying whether the electron-dense granule is present plays an important role in the diagnosis of immune complex nephropathy. This study made it possible for Artificial Intelligence models assist to analyze complex electron microscopy images for disease diagnosis.

Lacunae in Laboratory Medicine Services and in Pathology Education in Medical Schools in India

CONTEXT.—

Laboratories of many medical college hospitals in India do not offer important diagnostic tests, most of which are routine in the West. This detracts from the service as well as the educational function of the college.

OBJECTIVES.—

To provide the background to pathology and laboratory medicine services and education in India, and to create a questionnaire that will put the lack of tertiary care laboratory services in perspective. This article will help illustrate the lacunae in laboratory medicine services and in the education of students. For this, we present information on the health services and pathology education facilities in India. We propose a questionnaire comprising 30 questions in various disciplines in pathology and laboratory medicine. These questions will help administrators and bureaucrats evaluate the status of the laboratories with respect to the services provided.

DATA SOURCES.—

Sources include Web sites of the government of India, including that of the National Accreditation Board for Testing and Calibration Laboratories; indexed medical journal articles; and standard books and white papers on health care in India. We also used our personal experiences and interpretations of the laboratory and medical education sector in India.

CONCLUSIONS.—

Medical colleges in India need to offer specialized diagnostic services if they are to achieve the targets of universal health care as well as turning out competent doctors. The agencies responsible for health care in India should use the questionnaire as a first step toward improving laboratory services. Other low- and middle-income countries should also adopt this method.

Paediatric nephrology in under-resourced areas

BACKGROUND

Nearly 50% of the world population and 60% of children aged 0 to 14 years live in low- or lower-middle-income countries. Paediatric nephrology (PN) in these countries is not a priority for allocation of limited health resources. This article explores advancements made and persisting limitations in providing optimal PN services to children in such under-resourced areas (URA).

METHODS

Medline, PubMed and Google Scholar online databases were searched for articles pertaining to PN disease epidemiology, outcome, availability of services and infrastructure in URA. The ISN and IPNA offices were contacted for data, and two online questionnaire surveys of IPNA membership performed. Regional IPNA members were contacted for further detailed information.

RESULTS

There is a scarcity of published data from URA; where available, prevalence of PN diseases, managements and outcomes are often reported to be different from high income regions. Deficiencies in human resources, fluoroscopy, nuclear imaging, immunofluorescence, electron microscopy and genetic studies were identified. Several drugs and maintenance kidney replacement therapy are inaccessible to the majority of patients. Despite these issues, regional efforts with support from international bodies have led to significant advances in PN services and infrastructure in many URA.

CONCLUSIONS

Equitable distribution and affordability of PN services remain major challenges in URA. The drive towards acquisition of regional data, advocacy to local government and non-government agencies and partnership with international support bodies needs to be continued. The aim is to optimise and achieve global parity in PN training, investigations and treatments, initially focusing on preventable and reversible conditions.

[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.

Application of direct stochastic optical reconstruction microscopy (dSTORM) to the histological analysis of human glomerular disease

Electron microscopy (EM) following immunofluorescence (IF) imaging is a vital tool for the diagnosis of human glomerular diseases, but the implementation of EM is limited to specialised institutions and it is not available in many countries. Recent progress in fluorescence microscopy now enables conventional widefield fluorescence microscopes to be adapted at modest cost to provide resolution below 50 nm in biological specimens. We show that stochastically switched single-molecule localisation microscopy can be applied to clinical histological sections stained with standard IF techniques and that such super-resolved IF may provide an alternative means to resolve ultrastructure to aid the diagnosis of kidney disease where EM is not available. We have implemented the direct stochastic optical reconstruction microscopy technique with human kidney biopsy frozen sections stained with clinically approved immunofluorescent probes for the basal laminae and immunoglobulin G deposits. Using cases of membranous glomerulonephritis, thin basement membrane lesion, and lupus nephritis, we compare this approach to clinical EM images and demonstrate enhanced imaging compared to conventional IF microscopy. With minor modifications in established IF protocols of clinical frozen renal biopsies, we believe the cost-effective adaptation of conventional widefield microscopes can be widely implemented to provide super-resolved image information to aid diagnosis of human glomerular disease.

Improvement of allograft kidney biopsy yield by using a handheld smartphone microscope as an on-site evaluation device

Background

Smart lens is a magnifying device that turns the smartphone into a microscopic exploring instrument. It is a convenient and inexpensive tool as an on-site evaluation device for the kidney biopsy specimen. We demonstrate the benefit of using a handheld smartphone microscope compared to the standard procedure in allograft kidney specimens.

Material and methods

This was a cohort study of allograft kidney biopsies performed between June 2015 and November 2017 in Srinagarind Hospital, Khon Kaen University, Thailand. The clinical utility of the “Chula smart lens” applied to the smartphone as an on-site evaluation device was studied. Clinical data, diagnostic quality, and complications were retrospectively reviewed and compared between the smart lens group and the standard group.

Results

The study cohort consisted of 93 allograft kidney biopsies (standard:47, smart lens:46). The mean age was 40.6 (18–48) years, and 63 patients (67.7%) were male. By using the smart lens device, the number of obtained tissue cores was higher (3.5 vs 2.9, p = 0.019) and the inadequacy rate for diagnosis was significantly lower (7% vs 21.3%, p = 0.05).

Conclusion

Using a handheld smartphone microscope as an on-site evaluation device resulted in more positive glomeruli and diagnostic yield compared to the standard procedure.

Predictors of poor kidney outcome in children with C3 glomerulopathy

BACKGROUND

C3 glomerulopathy (C3G) is characterized by heterogeneous clinical presentation, outcome, and predominant C3 accumulation in glomeruli without significant IgG. There is scarce outcome data regarding childhood C3G. We describe clinical and pathological features, treatment and outcomes, and risk factors for progression to chronic kidney disease stage 5 (CKD5) in the largest pediatric series with biopsy-proven C3G.

METHODS

Sixty pediatric patients with C3G from 21 referral centers in Turkey were included in this retrospective study. Patients were categorized according to CKD stage at last visit as CKD5 or non-CKD5. Demographic data, clinicopathologic findings, treatment, and outcome data were compared and possible risk factors for CKD5 progression determined using Cox proportional hazards model.

RESULTS

Mean age at diagnosis was 10.6 ± 3.0 years and follow-up time 48.3 ± 36.3 months. Almost half the patients had gross hematuria and hypertension at diagnosis. Nephritic-nephrotic syndrome was the commonest presenting feature (41.6%) and 1/5 of patients presented with nephrotic syndrome. Membranoproliferative glomerulonephritis was the leading injury pattern, while 40 patients had only C3 staining. Patients with DDD had significantly lower baseline serum albumin compared with C3GN. Eighteen patients received eculizumab. Clinical remission was achieved in 68.3%. At last follow-up, 10 patients (16.6%) developed CKD5: they had lower baseline eGFR and albumin and higher frequency of nephrotic syndrome and dialysis requirement than non-CKD5 patients. Lower serum albumin and eGFR at diagnosis were independent predictors for CKD5 development.

CONCLUSIONS

Children with C3G who have impaired kidney function and hypoalbuminemia at diagnosis should be carefully monitored for risk of progression to CKD5. Graphical abstract.

Electron microscopy study of 496 cases of lupus nephritis: A single-center experience

INTRODUCTION

Renal involvement is seen in about 40-82% of systemic lupus erythematosus (SLE) Asian patients. The exact diagnosis and classification of lupus nephritis are important for treatment and prognosis. This study aimed to investigate the value of electron microscopy (EM) in the diagnosis and classification of lupus nephritis compared with light microscopy.

METHOD

In this cross-sectional referral-center 16-year study of lupus nephritis, the final diagnosis was based on the EM study. Primary light microscopy findings were compared with EM diagnosis. Moreover, Immunofluorescence patterns distribution was assessed.

RESULTS

From 496 patients diagnosed with lupus nephritis based on EM, 225(45.4%) of patients were categorized in class IV, followed by 98(19.7%), 93(18.8%), 46(9.3%), and 14(2.8%) who were categorized into classes of II, III, V, and VI respectively. Only 1(0.2%) patient belonged to class I, and 19(3.8%) cases were diagnosed with mixed two classes. Using EM was essential for diagnosing 25.6% of cases taking the correct classification by light microscopy into account; however, disregarding correct classification, this could change to a 7.4% contribution rate of EM. The most common cause of misdiagnosis, disregarding incorrect classification, was inadequate or wrong tissue. Positive associations were detected between tubular atrophy and interstitial fibrosis of both electron and light microscopy with different classes (P < 0.001).

CONCLUSION

While light microscopy is highly accurate for diagnosing lupus nephritis regardless of correct classification, EM contributes substantially to the correct classification of lupus nephritis types.

Dense deposit disease: a greatly increased biopsy incidence in India versus the USA

Background

We present the largest clinicopathologic case series to date of dense deposit disease (DDD) in an Indian population and compare the renal biopsy incidence rate to that seen in a large renal laboratory in USA.

Methods

Cases of DDD were identified and evaluated from native kidney biopsies reported at Renopath, India and at Arkana Laboratories, in the USA. Renopath receives biopsies from four states, located in the South and Eastern part of India. Arkana Laboratories’ biopsies came from 37 states across the USA.

Results

During the study period, there were a total of 25 patients diagnosed with DDD among the 7335 native kidney biopsies at Renopath. Thus, the biopsy incidence rate (cases of DDD/total renal biopsies/year) is 0.0034. By comparison, there were 10 cases of DDD diagnosed among 26 319 native kidney biopsies at Arkana Laboratories during the same time period, with a renal biopsy incidence rate of 0.00038.

Conclusions

DDD in this Indian subpopulation has similar clinical and pathologic characteristics when compared to previously reported studies. However, the biopsy incidence rate is about 890% or 8.9 times more common in this subset of the Indian population when compared with a broad cross-section of the US population. In addition to potential genetic factors, environmental conditions and chronic infections likely contribute to the markedly higher biopsy incidence rate. Given the much greater number of patients with DDD in this population, further retrospective and prospective studies would allow more rapid progress in understanding the pathogenesis of DDD and thus potential treatment of patients with DDD.

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.

The Impact of Renal Tissue Procurement at Bedside on Specimen Adequacy and Best Practices

Objectives

Renal biopsy is the gold standard for the diagnosis of both native and allograft renal diseases. We studied the impact of tissue procurement at bedside (TPB) omission on the adequacy of renal biopsies.

Methods

We compared 120 renal biopsies collected during 2015 using TPB with 111 renal biopsies collected during 2016 when TPB was discontinued. Adequacy criteria were applied as follows: by light microscopy, 10 glomeruli and two arteries for allograft biopsies and seven glomeruli for native biopsies. At least one glomerulus was considered adequate for immunofluorescence and electron microscopy in both groups.

Results

The rate of inadequacies in allograft biopsies increased significantly, from 12.50% to 21.61% (P < .05), when TPB was discontinued.

Conclusions

Elimination of TPB service had a negative impact on allograft specimen adequacy. Repeat biopsies add cost and delay patient care. Institutions should take this into consideration when considering omission of TPB.