American Society of Nephrology Kidney TREKS Program.

In response to decreasing numbers of individuals entering into nephrology fellowships, the American Society of Nephrology launched Kidney TREKS (Tutored Research and Education for Kidney Scholars) to stimulate interest in nephrology among medical students, graduate students, and postdoctoral fellows. The program combines a one-week intensive exposure to kidney physiology with a longitudinal mentorship program at the participants' home institutions. Ten years in, an analysis was conducted to assess its effectiveness. We surveyed participants to assess their opinions regarding nephrology before and after the course and followed them longitudinally to determine their career choices. TREKS applicants who were not selected to participate were used as a comparison group. 381 people participated in the program and 242 completed the survey. After TREKS, both medical students and graduate students showed increased interest in nephrology, with rank scores of 5.6±0.2 pre- to 7.5±0.1 post-course for medical students (mean ± standard deviation, n=189, p=0.001) and 7.3±0.3 to 8.7±0.3 (n=53, p=0.001) for graduate students. In long term follow-up, TREKS medical students chose a nephrology pipeline residency at a higher rate than medical students overall (57% vs. 31%, p=0.01) and TREKS applicants who did not participate (47% vs. 31%, p=0.04). Nephrology fellowship rates for these groups exceeded the general population but did not significantly differ between TREKS participants and applicants. PhD students and postdoctoral TREKS participants had a higher rate of participating in nephrology research compared to TREKS applicants (66% vs. 30%, p=0.01). In summary, the ASN Kidney TREKS program has demonstrated that it can improve interest in nephrology in the short term and increase the number of individuals going into nephrology careers. This long-term effect is most evident in PhD students and postdoctoral participants. Further study is needed to assess the impact of TREKS on enrollment in nephrology fellowship programs.

Rethinking the consultation paradigm: Validity evidence for a new framework, a multimethods study.

BACKGROUND: In-hospital consultation is essential for patient care. We previously proposed a framework of seven specific consultation types to classify consult requests to improve communication, workflow, and provider satisfaction. METHODS: This multimethods study's aim was to evaluate the applicability of the consult classification framework to real internal medicine (IM) consults. We sought validity evidence using Kane's validity model with focus groups and classifying consult requests from five IM specialties. Participants attended five 1 h semi-structured focus groups that were recorded, transcribed, and coded for thematic saturation. For each specialty, three specialists and three hospitalists categorized 100 (total 500) random anonymized consult requests. The primary outcome was concordance in the classification of consult requests, defined as the sum of partial concordance and perfect concordance, where respectively 4-5/6 and 6/6 participants classified a consult in the same category. We used χ2 tests to compare concordance rates across specialties and between specialists and hospitalists. RESULTS: Five major themes were identified in the qualitative analysis of the focus groups: (1) consult question, (2) interpersonal interactions, (3) value, (4) miscommunication, (5) consult framework application, barriers, and iterative development. In the quantitative analysis, the overall concordance rate was 88.8% (95% confidence interval [CI]: 85.7-91.4), and perfect concordance was 46.6% (95% CI: 42.2-51.1). Concordance differed significantly between hospitalists and specialists overall (p = .01), with a higher proportion of hospitalists having perfect concordance compared to specialists (67.2% vs. 57.8%, p = .002). CONCLUSIONS: The consult classification framework was found to be applicable to consults from five different IM specialties, and could improve communication and education.

The times they are K+-changin': bringing the potassium curriculum out of the 20th century.

PURPOSE OF REVIEW: Although most of the current medical education literature has focused on teaching strategies, little attention has been devoted to selecting appropriate course content. Despite elegant descriptions of physiologic mechanisms in recent decades, medical school curricula and students continue to rely on outdated textbooks and certification examination study aids composed to fit an antiquated exam blueprint. RECENT FINDINGS: Advances in our understanding of potassium physiology offer multiple examples of key concepts that deserve to be included in the modern-day renal physiology curriculum, including the relationship of potassium to blood pressure and the potassium 'switch', the aldosterone paradox, and novel pharmacologic agents that target dietary potassium absorption and potassium handling in the kidney. SUMMARY: Key advances in our understanding and application of renal physiology to patient care have not been readily integrated into the nephrology curriculum of medical students. Difficult questions remain regarding when new concepts are sufficiently established to be introduced to medical students in the preclinical years.

Acid Base Disorders in Cirrhosis.

Metabolic and respiratory acid-base disorders are common in individuals with liver disease and cirrhosis. The most common disorder is respiratory alkalosis, which may be related to dyspnea or respiratory stimulation. Primary metabolic disorders are less common. Although the liver plays a role in metabolism of amino acids and generation of acid from dietary sources, it does not play a role in the regulation of pH. Instead, metabolic disorders may arise from alterations in normal metabolism or from medications, particularly diuretics and osmotic laxatives, used in the treatment of these complex patients. Understanding the mechanistic underpinnings of these disorders can aid in the management of individuals with liver disease in the hospital and in outpatient settings.

What's Old Is New Again: Harnessing the Power of Original Experiments to Learn Renal Physiology.

Although medical schools across the United States have updated their curricula to incorporate active learning techniques, there has been little discussion on the nature of the content presented to students. Here, we share detailed examples of our experience in using original experiments to lay the groundwork for foundational concepts in renal physiology and pathophysiology. We believe that this approach offers distinct advantages over standard case-based teaching by (1) starting with simple concepts, (2) analyzing memorable visuals, (3) increasing graphical literacy, (4) translating observations to "rules," (5) encouraging critical thinking, and (6) providing historical perspective to the study of medicine. Although we developed this content for medical students, we have found that many of these lessons are also appropriate as foundational concepts for residents and fellows and serve as an excellent springboard for increasingly complex discussions of clinical applications of physiology. The use of original experiments for teaching and learning in renal physiology harnesses skills in critical thinking and provides a solid foundation that will help learners with subsequent case-based learning in the preclerkship curriculum and in the clinical arena.

More than meets the I(ris): Use of manual urine microscopy to complement automated findings in acute kidney injury.

Evaluation of patients with acute kidney injury requires comprehensive assessment that includes a urinalysis, which features both semi-quantitative assessment with a urine dipstick and urine microscopy. This process is labor intensive for clinical laboratories, and availability of excellent automated instruments for urinalysis has prompted utilization and acceptance of this strategy by both by laboratories and clinicians. Recently, however, interest in provider performed microscopy has enjoyed a renaissance thanks to both improved microscopy techniques and the endorsement from social media in nephrology. Here, we present two cases of acute kidney injury in which manual microscopy added valuable information to the automated microscopy.

Incidence and risk factors of venous thromboembolism in ANCA-associated vasculitis: a metaanalysis and metaregression.

The incidence of venous thromboembolism (VTE) in ANCA-associated vasculitis patients varies in different populations. Moreover, the risk factors for VTE in these patients are poorly described due to the small number of events. Ovid MEDLINE, EMBASE, and the Cochrane Library were searched for eligible articles. The inclusion criteria included observational studies that enrolled patients age ≥ 18 years diagnosed with ANCA-associated vasculitis. The incidence of VTE is the outcome of interest. Of 1362 citations, a total of 21 studies (n = 4422) dated from 2006 to 2019 were included in the systematic review. The mean age was 54.2 ± 4.0 years. Most were male (52.0%) and Caucasian (80.9%). With a mean follow-up duration of 5.2 ± 2.8 years, the pooled incidence of VTE in ANCA-associated vasculitis patients was 12.4% (95% CI, 8.8-17.2). Of these, 63.4% (95% CI, 57.3-69.1) had deep vein thrombosis and 26.3% (95% CI, 17.6-37.4) had pulmonary embolism. Recurrent VTE occurred in 10.0% (95% CI, 5.2-18.6). From the metaregression adjusted for age, sex, and ethnicity; positive MPO-ANCA, increasing Birmingham Vasculitis Activity Score at time of vasculitis diagnosis, and presence of renal involvement were positively associated with increased VTE events. Positive PR3-ANCA profile was inversely associated with increased VTE events. Increasing follow-up duration was not associated with increased VTE events. VTE in ANCA-associated vasculitis is common. Positive MPO-ANCA, increasing vasculitis activity, and presence of renal involvement were significant risk factors for VTE while positive PR3-ANCA was inversely associated with increased VTE. Key Points • Venous thromboembolism (VTE) is common in ANCA-associated vasculitis with a pooled incidence of 12.4% • Deep vein thrombosis accounts for two-third of total VTE cases • Positive MPO-ANCA profile, higher disease activity at ANCA-associated vasculitis diagnosis, and renal involvement are risk factors for VTE • Positive PR3-ANCA profile is protective factor for VTE.

Systematic Review and Meta-Analysis of Native Kidney Biopsy Complications.

BACKGROUND AND OBJECTIVES: Native kidney biopsies are commonly performed in the diagnosis of acute kidney diseases and CKD. Because of the invasive nature of the procedure, bleeding-related complications are not uncommon. The National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases-sponsored Kidney Precision Medicine Project requires that all participants undergo a kidney biopsy; therefore, the objective of this analysis was to study complication rates of native kidney biopsies performed using automated devices under kidney imaging. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This is a systematic review and meta-analysis of the literature published from January 1983 to March 2018. The initial PubMed search yielded 1139 manuscripts. Using predetermined selection criteria, 87 manuscripts were included in the final analysis. A random effects meta-analysis for proportions was used to obtain combined estimates of complication rates. Freeman-Tukey double-arcsine transformations were used to stabilize variance as complications were rare. RESULTS: A total of 118,064 biopsies were included in this study. Patient age ranged from 30 to 79 years, and 45% of patients were women. On the basis of our meta-analysis, pain at the site of biopsy is estimated to occur in 4.3% of biopsied patients, hematomas are estimated to occur in 11%, macroscopic hematuria is estimated to occur in 3.5%, bleeding requiring blood transfusions is estimated to occur in 1.6%, and interventions to stop bleeding are estimated to occur in only 0.3%. Death attributed to native kidney biopsy was a rare event, occurring only in an estimated 0.06% of all biopsies but only 0.03% of outpatient biopsies. Complication rates were higher in hospitalized patients and in those with acute kidney disease. The reported complications varied on the basis of study type and geographic location. CONCLUSIONS: Although the native kidney biopsy is an invasive diagnostic procedure, the rates of bleeding complications are low. Albeit rare, death can occur postbiopsy. Complications are more frequently seen after kidney biopsies of hospitalized patients with AKI.

The Glomerular Disease Study and Trial Consortium: A Grassroots Initiative to Foster Collaboration and Innovation.

Glomerular kidney disorders account for a significant proportion of chronic kidney disease and end-stage renal disease worldwide. Nevertheless, major obstacles make breakthrough progress in diagnosis and cure an ongoing challenge. Here we report the creation of a "grassroots" initiative that aims to provide new opportunities for nephrologists, pathologists, basic and clinical scientists, patients, and industry partners to collaborate in the field of glomerular kidney disease. Members of the medical community, including trainees, nephrologists, and nephropathologists, can participate in the open-access, Web-based, multidisciplinary clinical video case conferences, which provide "peer-to-peer" exchange of clinical and pathological expertise combined with a formal didactic curriculum. Participants can also join other aspects of the broader initiative. These include the participation in a multisite research study to facilitate enrollment of patients into a longitudinal clinical data and biorepository for glomerular kidney disorders. Items included in this prospective registry include the following: an ontology-based patient medical history, which is regularly updated; interval collection and storage of blood and urine samples; DNA collection; and a contact registry for patients who wish to participate in clinical trials. Participating sites and external scientists can leverage access to the database to pursue genetic, biomarker, epidemiological, and observational clinical effectiveness studies. Patients can independently sign up for a supplementary contact registry to participate in clinical trials if eligible. The broad spectrum of activities within this initiative will foster closer collaboration among trainees, practicing nephrologists, pathologists, and researchers, and may help to overcome some of the barriers to progress in the field of glomerular kidney disease.

The Interdialytic Creatinine Rise is a novel marker of volume overload and mortality risk in hemodialysis patients.

BACKGROUND: Volume overload poses a major risk in hemodialysis patients but simple detection methods are lacking. We propose a novel marker, the Interdialytic Creatinine Rise (IDCR), readily calculated as the change in serum creatinine over time (in mg/dL/h), to assess volume overload and predict mortality risk in hemodialysis patients. METHODS: First, we calculated IDCR changes with volume in a prospective cohort of 35 hospitalized hemodialysis patients awaiting hemodialysis and 33 hospitalized patients undergoing hemodialysis every other day. Second, in a prospective cohort of 25 outpatients, IDCR cutoff values associated with hypervolemia were determined between two treatments and compared with simultaneous volume assessments by their nephrologist. Third, IDCR as a mortality predictor was studied using survival analysis in a longitudinal retrospective cohort study of 39 maintenance hemodialysis patients followed from 2012 until death or 2017. RESULTS: IDCR decreased by - 0.014 mg/dL/h each day (95%CI - 0.017,- 0.010; p < 0.001) without dialysis due to fluid volume gain and increased by 0.013 mg/dL/h (95%CI 0.008,0.017; p < 0.001) from before to after each successive hemodialysis due to fluid removal. Choosing an IDCR cutoff value of ≤0.1 had sensitivity of 82% and specificity of 79% in diagnosing volume overload with the area under the ROC curve of 0.78 (95%CI 0.59,0.97). The hazard ratio of death for each 0.01 decrease in IDCR was 1.64 (95%CI 1.31,2.07; p < 0.001). If IDCR decreased to less than 0.05 mg/dL/h, the median survival was 32 days and the odds ratio of death within 2 months was 38 (95%CI 8, 131; p < 0.001). CONCLUSIONS: In this pilot study, IDCR is shown to be a novel metric that decreases with fluid retention and increases after fluid removal. IDCR can assist clinicians in detection or exclusion of volume overload in hemodialysis patients and provide prognostic value in identifying those at high risk for death.

A branched-chain amino acid metabolite drives vascular fatty acid transport and causes insulin resistance.

Epidemiological and experimental data implicate branched-chain amino acids (BCAAs) in the development of insulin resistance, but the mechanisms that underlie this link remain unclear. Insulin resistance in skeletal muscle stems from the excess accumulation of lipid species, a process that requires blood-borne lipids to initially traverse the blood vessel wall. How this trans-endothelial transport occurs and how it is regulated are not well understood. Here we leveraged PPARGC1a (also known as PGC-1α; encoded by Ppargc1a), a transcriptional coactivator that regulates broad programs of fatty acid consumption, to identify 3-hydroxyisobutyrate (3-HIB), a catabolic intermediate of the BCAA valine, as a new paracrine regulator of trans-endothelial fatty acid transport. We found that 3-HIB is secreted from muscle cells, activates endothelial fatty acid transport, stimulates muscle fatty acid uptake in vivo and promotes lipid accumulation in muscle, leading to insulin resistance in mice. Conversely, inhibiting the synthesis of 3-HIB in muscle cells blocks the ability of PGC-1α to promote endothelial fatty acid uptake. 3-HIB levels are elevated in muscle from db/db mice with diabetes and from human subjects with diabetes, as compared to those without diabetes. These data unveil a mechanism in which the metabolite 3-HIB, by regulating the trans-endothelial flux of fatty acids, links the regulation of fatty acid flux to BCAA catabolism, providing a mechanistic explanation for how increased BCAA catabolic flux can cause diabetes.

Analysis of skeletal muscle gene expression patterns and the impact of functional capacity in patients with systolic heart failure.

BACKGROUND: Declining physical function is common among systolic heart failure (HF) patients and heralds poor clinical outcomes. We hypothesized that coordinated shifts in expression of ubiquitin-mediated atrophy-promoting genes are associated with muscle atrophy and contribute to decreased physical function. METHODS: Systolic HF patients (left ventricular ejection fraction [LVEF] ≤40%) underwent skeletal muscle biopsies (nondominant vastus lateralis) and comprehensive physical assessments. Skeletal muscle gene expression was assessed with the use of real-time polymerase chain reaction. Aerobic function was assessed with the use of cardiopulmonary exercise and 6-minute walk tests. Strength capacity was assessed with the use of pneumatic leg press (maximum strength and power). Serologic inflammatory markers also were assessed. RESULTS: 54 male patients (66.6 ± 10.0 years) were studied: 24 systolic HF patients (mean LVEF 28.9 ± 7.8%) and 30 age-matched control subjects. Aerobic and strength parameters were diminished in HF versus control. FoxO1 and FoxO3 were increased in HF versus control (7.9 ± 6.2 vs 5.0 ± 3.5, 6.5 ± 4.3 vs 4.3 ± 2.8 relative units, respectively; P ≤ .05 in both). However, atrogin-1 and MuRF-1 were similar in both groups. PGC-1α was also increased in HF (7.9 ± 5.4 vs. 5.3 ± 3.6 relative units; P < .05). Muscle levels of insulin-like growth factor (IGF) 1 as well as serum levels of tumor necrosis factor α, C-reactive protein, interleukin (IL) 1ß, and IL-6 were similar in HF and control. CONCLUSION: Expression of the atrophy-promoting genes FoxO1 and FoxO3 were increased in skeletal muscle in systolic HF compared with control, but other atrophy gene expression patterns (atrogin-1 and MuRF-1), as well as growth promoting patterns (IGF-1), were similar. PGC-1α, a gene critical in enhancing mitochondrial function and moderating FoxO activity, may play an important counterregulatory role to offset ubiquitin pathway-mediated functional decrements.

Suppression of atrogin-1 and MuRF1 prevents dexamethasone-induced atrophy of cultured myotubes.

OBJECTIVE: The mechanistic role of the ubiquitin ligases atrogin-1 and MuRF1 in glucocorticoid-induced muscle wasting is not fully understood. Here, we tested the hypothesis that glucocorticoid-induced muscle atrophy is at least in part linked to atrogin-1 and MuRF1 expression and that the ubiquitin ligases are regulated by compensatory mechanisms. METHODS: The expression of atrogin-1 and MuRF1 was suppressed individually or in combination in cultured L6 myotubes by using siRNA technique. Myotubes were treated with dexamethasone followed by determination of mRNA and protein levels for atrogin-1 and MuRF1, protein synthesis and degradation rates, and myotube morphology. RESULTS: Suppression of atrogin-1 resulted in increased expression of MuRF1 and vice versa, suggesting that the ubiquitin ligases are regulated by compensatory mechanisms. Simultaneous suppression of atrogin-1 and MuRF1 resulted in myotube hypertrophy, mainly reflecting stimulated protein synthesis, and prevented dexamethasone-induced myotube atrophy, mainly reflecting inhibited protein degradation. CONCLUSIONS: The results provide evidence for a link between upregulated atrogin-1 and MuRF1 expression and glucocorticoid-induced muscle atrophy. The study also suggests that atrogin-1 and MuRF1 levels are regulated by compensatory mechanisms and that inhibition of both ubiquitin ligases may be needed to prevent glucocorticoid-induced muscle proteolysis and atrophy.