Medical Student Experience and Outcomes, as Well as Preceptor Experience, with Rapid Conversion of a Preclinical Medical School Course to a Remote-Based Learning Format in the Setting of the COVID-19 Pandemic.

OBJECTIVES: To assess student outcomes and experiences, as well as preceptor experiences, after emergently converting a preclinical medical school renal course to a remote setting during the COVID-19 pandemic. METHODS: First-year medical student examination scores and responses to Likert-scale questions on end-of-course evaluations from the 2018-2019 (traditional) and 2019-2020 (remote) academic years were compared. Free-text responses from students and preceptors were analyzed using a qualitative summative approach to extract major themes in perceptions of remote learning. RESULTS: Mean student scores on course examinations did not significantly differ between the traditional and remote settings (p = 0.23 and 0.84 respectively). Quantitative analysis of student evaluations revealed no significant difference across all items in mean Likert-scale responses. Student and preceptor free-text responses identified course leader engagement and responsiveness as essential to the success of remote-based learning. Optimal group size and online etiquette are areas that require attention. CONCLUSIONS: Despite rapid conversion of a preclinical medical school renal course to a remote-based format in the setting of the COVID-19 pandemic, student scores and evaluations remain positive and largely unchanged.

New Views of the Glomerulus: Advanced Microscopy for Advanced Diagnosis.

New technologies are ready to revolutionize glomerular imaging and significantly improve or replace immunofluorescence and electron microscopy, which have driven research and diagnosis of glomerular diseases for over 50 years. Advanced forms of transmission and scanning electron microscopy have revealed the detailed spatial relationships of the glomerular basement membrane, podocytes, and endothelial cells. These may be overshadowed by super resolution microscopy (SRM), which combines the advantages of immunofluorescence and electron microscopy, offers high resolution identification of specific molecules, and images large, physiologically relevant volumes of the glomerulus. Rapidity, ease of use and low cost with some types of SRM make them potentially suitable for routine diagnosis. SRM visualizes structures below the classical diffraction limit of conventional light microscopy by adding a time variable to either the illumination of the specimen, or to the fluorescence signal emitted by it. Ensemble techniques vary illumination and include Structured Illumination Microscopy (SIM) and Stimulation Emission Depletion Microscopy (STED). Single molecule localization techniques vary the light emission by fluorescence labels in the specimen, and include Photoactivated Localization Microscopy (PALM) and Stochastic Optical Reconstruction Microscopy (STORM). Technologies such as expansion microscopy and genetic labeling can also create effective super resolution imaging by non-optical, specialized preparation techniques. All technologies require dark field fluorescence and some require computer image analysis and reconstruction. Replicating successful application in other areas of biology, SIM, STED, and STORM have visualized normal and nephrotic disease podocytes, and have confirmed their appearances to be similar to those seen by electron microscopy, but with added new information on cell configuration and protein localization. STORM has also localized podocyte cytoskeleton and adhesion proteins, and glomerular basement membrane proteins at a resolution never before possible. These pioneering efforts show the promise of super resolution microscopy, and lay the groundwork for future study and new diagnostic tools for glomerular diseases.

Visualization of podocyte substructure with structured illumination microscopy (SIM): a new approach to nephrotic disease.

A detailed microscopic analysis of renal podocyte substructure is essential to understand and diagnose nephrotic kidney disease. Currently only time consuming electron microscopy (EM) can resolve this substructure. We used structured illumination microscopy (SIM) to examine frozen sections of renal biopsies stained with an immunofluorescence marker for podocin, a protein localized to the perimeter of the podocyte foot processes and compared them with EM in both normal and nephrotic disease biopsies. SIM images of normal glomeruli revealed curvilinear patterns of podocin densely covering capillary walls similar to podocyte foot processes seen by EM. Podocin staining of all nephrotic disease biopsies were significantly different than normal, corresponding to and better visualizing effaced foot processes seen by EM. The findings support the first potential use of SIM in the diagnosis of nephrotic disease.

Cocaine and kidney injury: a kaleidoscope of pathology.

Cocaine is abused worldwide as a recreational drug. It is a potent activator of the sympathetic nervous system leading to intense vasoconstriction, endothelial dysfunction, oxidative stress, platelet activation and decrease in prostaglandins E2 and prostacyclin. Cocaine can lead to widespread systemic adverse effects such as stroke, myocardial infarction, arterial dissection, vascular thrombosis and rhabdomyolysis. In human and rat kidneys, cocaine has been associated with glomerular, tubular, vascular and interstitial injury. It is not uncommon to diagnose cocaine-related acute kidney injury (AKI), malignant hypertension and chronic kidney disease. Cocaine abuse can lead to AKI by rhabdomyolysis, vasculitis, infarction, thrombotic microangiopathy and malignant hypertension. It is reported that 50-60% of people who use both cocaine and heroin are at increased risk of HIV, hepatitis and additional risk factors that can cause kidney diseases. While acute interstitial nephritis (AIN) is a known cause of AKI, an association of AIN with cocaine is unusual and seldom reported. We describe a patient with diabetes mellitus, hypertension and chronic hepatitis C, who presented with AKI. Urine toxicology was positive for cocaine and a kidney biopsy was consistent with AIN. Illicit drugs such as cocaine or contaminants may have caused AIN in this case and should be considered in the differential diagnosis of causes of AKI in a patient with substance abuse. We review the many ways that cocaine adversely impacts on kidney function.

Cytosine methylation changes in enhancer regions of core pro-fibrotic genes characterize kidney fibrosis development.

BACKGROUND: One in eleven people is affected by chronic kidney disease, a condition characterized by kidney fibrosis and progressive loss of kidney function. Epidemiological studies indicate that adverse intrauterine and postnatal environments have a long-lasting role in chronic kidney disease development. Epigenetic information represents a plausible carrier for mediating this programming effect. Here we demonstrate that genome-wide cytosine methylation patterns of healthy and chronic kidney disease tubule samples obtained from patients show significant differences. RESULTS: We identify differentially methylated regions and validate these in a large replication dataset. The differentially methylated regions are rarely observed on promoters, but mostly overlap with putative enhancer regions, and they are enriched in consensus binding sequences for important renal transcription factors. This indicates their importance in gene expression regulation. A core set of genes that are known to be related to kidney fibrosis, including genes encoding collagens, show cytosine methylation changes correlating with downstream transcript levels. CONCLUSIONS: Our report raises the possibility that epigenetic dysregulation plays a role in chronic kidney disease development via influencing core pro-fibrotic pathways and can aid the development of novel biomarkers and future therapeutics.

Transcriptome analysis of human diabetic kidney disease.

OBJECTIVE: Diabetic kidney disease (DKD) is the single leading cause of kidney failure in the U.S., for which a cure has not yet been found. The aim of our study was to provide an unbiased catalog of gene-expression changes in human diabetic kidney biopsy samples. RESEARCH DESIGN AND METHODS: Affymetrix expression arrays were used to identify differentially regulated transcripts in 44 microdissected human kidney samples. DKD samples were significant for their racial diversity and decreased glomerular filtration rate (~25-35 mL/min). Stringent statistical analysis, using the Benjamini-Hochberg corrected two-tailed t test, was used to identify differentially expressed transcripts in control and diseased glomeruli and tubuli. Two different web-based algorithms were used to define differentially regulated pathways. RESULTS: We identified 1,700 differentially expressed probesets in DKD glomeruli and 1,831 in diabetic tubuli, and 330 probesets were commonly differentially expressed in both compartments. Pathway analysis highlighted the regulation of Ras homolog gene family member A, Cdc42, integrin, integrin-linked kinase, and vascular endothelial growth factor signaling in DKD glomeruli. The tubulointerstitial compartment showed strong enrichment for inflammation-related pathways. The canonical complement signaling pathway was determined to be statistically differentially regulated in both DKD glomeruli and tubuli and was associated with increased glomerulosclerosis even in a different set of DKD samples. CONCLUSIONS: Our studies have cataloged gene-expression regulation and identified multiple novel genes and pathways that may play a role in the pathogenesis of DKD or could serve as biomarkers.

Expression of Notch pathway proteins correlates with albuminuria, glomerulosclerosis, and renal function.

Recent studies indicate that the Notch signaling pathway plays an important role in the development of diabetic kidney disease and focal segmental glomerulosclerosis (FSGS). Here we analyzed the degree of expression and localization of Notch ligands (Jagged1 and Delta1) and activated (cleaved) receptors (Notch1 and Notch2) in healthy human kidneys and in renal biopsies from a wide variety of kidney diseases. These included patients with minimal change disease, membranous nephropathy, lupus nephritis ISN/RPS classes III/IV/V, hypertensive nephrosclerosis, crescentic glomerulonephritis, tubulointerstitial fibrosis, IgA nephropathy, diabetic kidney disease, and FSGS. We found that cleaved Notch1, Notch2, and Jagged1 are expressed on podocytes in proteinuric nephropathies and their level of expression correlated with the amount of proteinuria across all disease groups. The degree of glomerulosclerosis correlated with podocyte expression of cleaved Notch1, while the severity of tubulointerstitial fibrosis and the estimated glomerular filtration rate correlated with expression of cleaved Notch1 in the tubulointerstitium. Hence, our results raise the possibility that Notch pathway activation is a common mechanism in the pathophysiology of a wide range of acquired renal diseases.

Actual practices in nephropathology: a survey and comparison with best practices.

Nephropathology is a specialized field requiring routine tissue evaluation by immunofluorescence (IF), electron microscopy (EM), and light microscopy, and has published standards of best practice. Actual practices are less well documented. We therefore evaluated actual practices in nephropathology and their divergence from best practices. One hundred and twenty Renal Pathology Society members were given questionnaires regarding tissue handling, processing, and staining. Appropriate statistics for each question were calculated from results compiled into Microsoft Excel. Responses from 75 members showed that most received 16 or 18 gauge core biopsies, examined 9 slides for native kidneys, 8 slides for transplant kidneys, and for both used hematoxylin and eosin, periodic acid-Schiff, trichrome, and silver stains. For native kidney biopsies, most collected for IF and EM if tissue was adequate, while clinical input could influence the rest. Almost all performed IF on adequate samples, with a minimum of 8 antibodies, including both light chains, those from Europe sometimes without proof of adequacy. Half performed EM unconditionally, the remainder based on specimen adequacy or clinical input. For transplant kidney biopsies, most collected tissue for IF and EM only with specific clinical indications, performed C4d IF on frozen tissue if available, but few used the native kidney IF panel. Very few performed EM unconditionally, but most would if given specific indications. We conclude that actual nephropathology practices within the Renal Pathology Society are geographically uniform and similar to published best practices, with divergence in performing IF and EM on the basis of specimen adequacy and clinical input, particularly in transplant biopsies.

Acute renal failure in a pediatric kidney allograft recipient treated with intravenous immunoglobulin for parvovirus B19 induced pure red cell aplasia.

Infection with parvovirus B19 (PV-B19) after solid organ transplantation may cause pure red cell aplasia (PRCA). Intravenous immunoglobulin (IVIg) may be of benefit in clearing the infection. Acute renal failure is a known adverse effect of IVIg administration. A 14-yr-old male received a cadaveric renal transplant. Three weeks after surgery he developed symptomatic anemia (hemoglobin 4.5 g/dL, reticulocyte count 0.2%). Anti-PV-B19 IgM and IgG titers, which had been negative pretransplant, were positive. He received two IVIg infusions as treatment for the PV-B19 infection. Four days after the IVIg infusions he developed non-oliguric acute renal failure (ARF) with a rise in serum creatinine from 1 to 1.8 mg/dL. Allograft biopsy showed changes consistent with an osmotic load. Anemia and the renal failure resolved after transfusions and IVIg. PV-B19 infection in immunosuppressed transplant recipients is associated with significant morbidity and may respond to IVIg therapy. High sucrose IVIg preparations may be associated with renal failure in renal allograft recipients. Adding PV-B19 testing of the donor and recipient to the standard pretransplant evaluation may be beneficial in diagnosing and managing a potential infection. If IVIg is to be used it may be safer to use a sucrose-free IVIg preparation.

Chronic hyperosmolarity mediates constitutive expression of molecular chaperones and resistance to injury.

Renal medullary cells are exposed to elevated and variable osmolarities and low oxygen tension. Despite the harsh environment, these cells are resistant to the effects of many harmful events. To test the hypothesis that this resistance is a consequence of these cells developing a stress tolerance phenotype to survive in this milieu, we created osmotically tolerant cells [hypertonic (HT) cells] by gradually adapting murine inner medullary collecting duct 3 cells to hyperosmotic medium containing NaCl and urea. HT cells have a reduced DNA synthesis rate, with the majority of cells arrested in the G(0)/G(1) phase of the cell cycle, and show constitutive expression of heat shock protein 70 that is proportional to the degree of hyperosmolarity. Unlike acute hyperosmolarity, chronic hyperosmolarity failed to activate MAPKs. Moreover, HT cells acquired protein translational tolerance to further stress treatment, suggesting that HT cells have an osmotolerant phenotype that is analogous to thermotolerance but is a permanent condition. In addition to osmotic shock, HT cells were more resistant to heat, H(2)O(2), cyclosporin, and apoptotic inducers, compared with isotonic murine inner medullary duct 3 cells, but less resistant to amphotericin B and cadmium. HT cells demonstrate that in renal medullary cells, hyperosmotic stress activates biological processes that confer cross-tolerance to other stressful conditions.