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Journal: American journal of kidney diseases : the official journal of the National Kidney Foundation

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Investigation into strenuous activity and kidney function has gained interest given increasing marathon participation.

Concepts: Kidney, Nephrology, Function

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There are established guidelines for recommended dietary intake for hypertension treatment and cardiovascular disease prevention. Evidence is lacking for effective dietary patterns for kidney disease prevention.

Concepts: Death, Diet

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An endemic of chronic kidney disease (CKD) of unknown cause among rural inhabitants in Central America has been identified. Young and otherwise healthy men working in plantations are frequently affected. The name Mesoamerican nephropathy (MeN) has been suggested. Clinically, MeN presents with low-grade proteinuria and progressive kidney failure. The renal pathology of this disease has not yet been described.

Concepts: Renal failure, Chronic kidney disease, Kidney, Nephrology, Medicine, Epidemiology, Americas, Central America

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Bedbug (Cimex lectularis) infestation is becoming a worldwide epidemic due to the emergence of insecticide-resistant strains. Pyrethroids are approved by the US Environmental Protection Agency for use against bedbugs and are considered minimally toxic to humans, with known respiratory, neurologic, and gastrointestinal effects. We present the first reported case of pyrethroid-induced toxic acute tubular necrosis (ATN). A 66-year-old healthy woman receiving no prior nephrotoxic medications presented with extreme weakness, decreased urine output, and acute kidney injury. She had administered multiple applications of a bedbug spray (permethrin) and a fogger (pyrethrin), exceeding the manufacturer’s recommended amounts. She was found to have severe nonoliguric acute kidney injury associated with profound hypokalemia. Kidney biopsy revealed toxic ATN with extensive tubular degenerative changes and cytoplasmic vacuolization. With conservative management, serum creatinine level decreased from 13.0 mg/dL (estimated glomerular filtration rate, 3 mL/min/1.73 m(2)) to 1.67 mg/dL (estimated glomerular filtration rate, 37 mL/min/1.73 m(2)) within 6 weeks. Literature review uncovered no prior report of pyrethroid insecticide-induced ATN in humans, although there are reports of ATN with similar tubular vacuolization in rats exposed to this agent. Bedbug insecticides containing pyrethroids should be used with caution due to the potential development of toxic ATN after prolonged exposure.

Concepts: Renal failure, Nephrology, Renal physiology, Blood urea nitrogen, Pyrethroid, Deltamethrin, Bedbug, Cimex lectularius

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BACKGROUND: Case series suggest that long-term use of proton pump inhibitors (PPIs) is associated with hypomagnesemia, but the current literature lacks systematically collected data. Our aim was to examine whether hypomagnesemia at the time of hospital admission is associated with out-of-hospital use of PPIs. STUDY DESIGN: Nested case-control study matched for age and sex. SETTING & PARTICIPANTS: Data were collected retrospectively from a tertiary acute-care facility. Eligible cases consisted of 402 adults with hypomagnesemia (serum magnesium <1.4 mEq/L) at the time of hospital admission to medical services, age- and sex-matched with 402 control individuals with normal serum magnesium levels (1.4-2.0 mEq/L). PREDICTOR: Out-of-hospital PPI use was identified in the hospital record. An omeprazole equivalent dose was calculated when possible. Covariates included the Charlson-Deyo comorbidity index, diabetes, diuretic use, estimated glomerular filtration rate, and gastroesophageal reflux. OUTCOME: Multivariable conditional logistic regression analyses were used to examine the association of PPI use with hypomagnesemia at the time of hospital admission. RESULTS: PPI use was not associated with hypomagnesemia (adjusted OR, 0.82; 95% CI, 0.61-1.11). Neither PPI type nor omeprazole equivalent daily dose was associated with hypomagnesemia. Sensitivity analyses of PPI use restricted to patients with esophageal disorders (adjusted OR, 1.00; 95% CI, 0.69-1.45), severe hypomagnesemia (magnesium, ≤1.0 mEq/L; adjusted OR, 0.78; 95% CI, 0.13-4.61), or estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) (adjusted OR, 0.84; 95% CI, 0.53-1.34) were unrevealing. LIMITATIONS: Exposure misclassification; hospitalized patients on medical services may not be representative of a broader ambulatory-based population. CONCLUSIONS: In a hospital-based adult population, out-of-hospital PPI use is not associated with hypomagnesemia at the time of hospital admission to medical services. In light of these inconclusive results, prospective cohort studies are needed to address this rare potential medication-related adverse effect.

Concepts: Regression analysis, Cohort study, Logistic regression, Experimental design, Epidemiology, Gastroesophageal reflux disease, Study design, Hypomagnesemia

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Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically occurs without detectable antineutrophil cytoplasmic antibody. It leads to aneurysm formation by affecting muscular arteries, usually those of medium size but also occasionally those of small size. Kidney involvement is common, leading to reduced glomerular filtration rate, hypertension, rupture of renal arterial aneurysms causing perinephric hematomas, and renal infarctions in those with severe vasculitis. Similar to PAN, microscopic polyangiitis (MPA) leads to aneurysm formation; however, MPA usually is associated with antineutrophil cytoplasmic antibody, and glomerulonephritis is a more common feature of MPA. Although kidney biopsy may show classic vascular changes in both PAN and MPA, this procedure is not without risk of significant bleeding due to aneurysm rupture. We present 2 cases of renal aneurysms that were diagnosed as MPA using computed tomography angiography (CTA), allowing implementation of appropriate immunosuppressive therapy. Follow-up CTA after treatment showed resolution of all previously observed abnormalities. CTA is a useful alternative to kidney biopsy in establishing both the extent of disease in renal aneurysms and allowing for tracking of disease progression and response to therapy.

Concepts: Renal failure, Kidney, Nephrology, Atherosclerosis, Blood pressure, Vasculitis, Polyarteritis nodosa, Microscopic polyangiitis

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Also known as the “second human genome,” the gut microbiome plays important roles in both the maintenance of health and the pathogenesis of disease. The symbiotic relationship between host and microbiome is disturbed due to the proliferation of dysbiotic bacteria in patients with chronic kidney disease (CKD). Fermentation of protein and amino acids by gut bacteria generates excess amounts of potentially toxic compounds such as ammonia, amines, thiols, phenols, and indoles, but the generation of short-chain fatty acids is reduced. Impaired intestinal barrier function in patients with CKD permits translocation of gut-derived uremic toxins into the systemic circulation, contributing to the progression of CKD, cardiovascular disease, insulin resistance, and protein-energy wasting. The field of microbiome research is still nascent, but is evolving rapidly. Establishing symbiosis to treat uremic syndrome is a novel concept, but if proved effective, it will have a significant impact on the management of patients with CKD.

Concepts: Immune system, Gene, Alcohol, Bacteria, Amino acid, Amine, Metabolism, Symbiosis

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Monozygotic twins have been widely studied to distinguish genetic and environmental factors in the pathogenesis of human diseases. For renal agenesis, the one-sided absence of renal tissue, the relative contributions of genetic and environmental factors to its pathogenesis are still unclear. In this study of a pair of monozygotic twins discordant for congenital renal agenesis, the genomic profile was analyzed from a set of blood samples using high-throughput exome-capture sequencing to detect single-nucleotide polymorphisms (SNPs), copy number variations (CNVs), and insertions and deletions (indels). Also, an epigenomic analysis used reduced-representation bisulfite sequencing to detect differentially methylated regions (DMRs). No discordant SNPs, CNVs, or indels were confirmed, but 514 DMRs were detected. KEGG analysis indicated the DMRs localized to 10 signaling pathways and 25 genes, including the mitogen-activated protein kinase pathway and 6 genes (FGF18, FGF12, PDGFRA, MAPK11, AMH, CTBP1) involved in organ development. Although methylation results from our adult patient and her sister may not represent the pattern that was present during kidney development, we could at least confirm a lack of obvious differences at the genome level, which suggests that nongenetic factors may be involved in the pathogenesis of renal agenesis.

Concepts: DNA, Kidney, Gene, Genetics, Bioinformatics, Molecular biology, Signal transduction, Copy number variation

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Poor adherence to immunosuppressive medications is a major cause of premature graft loss among children and young adults. Multicomponent interventions have shown promise but have not been fully evaluated.

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