Coupling metabolomics and exome sequencing reveals graded effects of rare damaging heterozygous variants on gene function and human traits.

Genetic studies of the metabolome can uncover enzymatic and transport processes shaping human metabolism. Using rare variant aggregation testing based on whole-exome sequencing data to detect genes associated with levels of 1,294 plasma and 1,396 urine metabolites, we discovered 235 gene-metabolite associations, many previously unreported. Complementary approaches (genetic, computational (in silico gene knockouts in whole-body models of human metabolism) and one experimental proof of principle) provided orthogonal evidence that studies of rare, damaging variants in the heterozygous state permit inferences concordant with those from inborn errors of metabolism.

Opportunities in Primary and Enteric Hyperoxaluria at the Cross-Roads Between the Clinic and Laboratory.

Hyperoxaluria is a condition in which there is a pathologic abundance of oxalate in the urine through either hepatic overproduction (primary hyperoxaluria [PH]) or excessive enteric absorption of dietary oxalate (enteric hyperoxaluria [EH]). Severity can vary with the most severe forms causing kidney failure and extrarenal manifestations. To address the current challenges and innovations in hyperoxaluria, the 14th International Hyperoxaluria Workshop convened in Perugia, Italy, bringing together international experts for focused presentation and discussion.

Oxalate Metabolism: From Kidney Stones to Cardiovascular Disease.

Oxalate kidney stones are common and exert a huge burden of morbidity worldwide. However, circulating or excreted concentrations of oxalate are rarely measured. We argue that oxalate and its metabolism are important above and beyond kidney stone formation.

Interleukin-16 is increased in dialysis patients but is not a cardiovascular risk factor.

Oxalate, a uremic toxin that accumulates in dialysis patients, is associated with cardiovascular disease. As oxalate crystals can activate immune cells, we tested the hypothesis that plasma oxalate would be associated with cytokine concentrations and cardiovascular outcomes in dialysis patients. In a cohort of 104 US patients with kidney failure requiring dialysis (cohort 1), we measured 21 inflammatory markers.

Challenges to Implementation of Community Health Worker-Led Chronic Obstructive Pulmonary Disease (COPD) Screening and Referral in Rural Uganda: A Qualitative Study using the Implementation Outcomes Framework.

Background: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. The burden of COPD is expected to increase in low- and middle-income countries (LMICs). COPD screening and diagnostics tools are often inaccessible in rural settings of LMICs.

Design Research to Embed mHealth into a Community-Led Blood Pressure Management System in Uganda: Protocol for a Mixed Methods Study.

Background: Uncontrolled hypertension is a leading risk factor for cardiovascular diseases. In Uganda, such diseases account for approximately 10% of all deaths, with 1 in 5 adults having hypertension (>90% of the hypertensive cases are uncontrolled). Although basic health care in the country is available free of cost at government facilities, regularly accessing medication to control hypertension is difficult because supply chain challenges impede availability.

End Point Considerations for Clinical Trials in Enteric Hyperoxaluria.

Enteric hyperoxaluria is a medical condition characterized by elevated urinary oxalate excretion due to increased gastrointestinal oxalate absorption. Causative features include fat malabsorption and/or increased intestinal permeability to oxalate. Enteric hyperoxaluria has long been known to cause nephrolithiasis and nephrocalcinosis, and, more recently, an association with CKD and kidney failure has been shown.

Principles for task shifting hypertension and diabetes screening and referral: a qualitative study exploring patient, community health worker and healthcare professional perceptions in rural Uganda.

Background: A shortage of healthcare workers in low- and middle-income countries (LMICs) combined with a rising burden of non-communicable diseases (NCDs) like hypertension and diabetes mellitus has resulted in increasing gaps in care delivery for NCDs. As community health workers (CHWs) often play an established role in LMIC healthcare systems, these programs could be leveraged to strengthen healthcare access. The objective of this study was to explore perceptions of task shifting screening and referral for hypertension and diabetes to CHWs in rural Uganda.

Strikingly conserved gene expression changes of polyamine regulating enzymes among various forms of acute and chronic kidney injury.

The polyamines spermidine and spermine and their common precursor molecule putrescine are involved in tissue injury and repair. Here, we test the hypothesis that impaired polyamine homeostasis contributes to various kidney pathologies in mice during experimental models of ischemia-reperfusion, transplantation, rhabdomyolysis, cyclosporine treatment, arterial hypertension, diabetes, unilateral ureteral obstruction, high oxalate feeding, and adenine-induced injuries. We found a remarkably similar pattern in most kidney pathologies with reduced expression of enzymes involved in polyamine synthesis together with increased expression of polyamine degrading enzymes.

Oxalate homeostasis.

Oxalate homeostasis is maintained through a delicate balance between endogenous sources, exogenous supply and excretion from the body. Novel studies have shed light on the essential roles of metabolic pathways, the microbiome, epithelial oxalate transporters, and adequate oxalate excretion to maintain oxalate homeostasis. In patients with primary or secondary hyperoxaluria, nephrolithiasis, acute or chronic oxalate nephropathy, or chronic kidney disease irrespective of aetiology, one or more of these elements are disrupted.

Randomized Placebo-Controlled Trial of Reloxaliase in Enteric Hyperoxaluria.

BACKGROUND: Enteric hyperoxaluria is caused by increased intestinal oxalate absorption and can lead to kidney stones, chronic kidney disease, and kidney failure. Reloxaliase is an orally administered recombinant enzyme that degrades oxalate along the gastrointestinal tract, thereby preventing its absorption. METHODS: We randomly assigned participants with enteric hyperoxaluria to reloxaliase or placebo, three to five times per day with food for 4 weeks.

Hemodialysis and biotransformation of erythrocyte epoxy fatty acids in peripheral tissue.

Cardiovascular disease is the leading cause of mortality in patients with renal failure. Red blood cells (RBCs) are potential reservoirs for epoxy fatty acids (oxylipins) that regulate cardiovascular function. Hemoglobin exhibits pseudo-lipoxygenase activity in vitro.

Effectiveness of a community health worker-delivered care intervention for hypertension control in Uganda: study protocol for a stepped wedge, cluster randomized control trial.

Background: Over 80% of the morbidity and mortality related to non-communicable diseases (NCDs) occurs in low-income and middle-income countries (LMICs). Community health workers (CHWs) may improve disease control and medication adherence among patients with NCDs in LMICs, particularly in sub-Saharan African settings. In Uganda, and the majority of LMICs, management of uncontrolled hypertension remains limited in constrained health systems.

Bioaccumulation of Blood Long-Chain Fatty Acids during Hemodialysis.

Long-chain fatty acids (LCFAs) serve as energy sources, components of cell membranes, and precursors for signaling molecules. Uremia alters LCFA metabolism so that the risk of cardiovascular events in chronic kidney disease (CKD) is increased. End-stage renal disease (ESRD) patients undergoing dialysis are particularly affected and their hemodialysis (HD) treatment could influence blood LCFA bioaccumulation and transformation.

Hemodialysis and Plasma Oxylipin Biotransformation in Peripheral Tissue.

Factors causing the increased cardiovascular morbidity and mortality in hemodialysis (HD) patients are largely unknown. Oxylipins are a superclass of lipid mediators with potent bioactivities produced from oxygenation of polyunsaturated fatty acids. We previously assessed the impact of HD on oxylipins in arterial blood plasma and found that HD increases several oxylipins.

Dissection of Barrier Dysfunction in Organoid-Derived Human Intestinal Epithelia Induced by Giardia duodenalis.

Background & Aims: The protozoa Giardia duodenalis is a major cause of gastrointestinal illness worldwide, but underlying pathophysiological mechanisms remain obscure, partly due to the absence of adequate cellular models. We aimed at overcoming these limitations and recapitulating the authentic series of pathogenic events in the primary human duodenal tissue by using the human organoid system.

Methods: We established a compartmentalized cellular transwell system with electrophysiological and barrier properties akin to duodenal mucosa and dissected the events leading to G.

The rural Uganda non-communicable disease (RUNCD) study: prevalence and risk factors of self-reported NCDs from a cross sectional survey.

Background: Non-communicable diseases (NCDs) are an increasing global concern, with morbidity and mortality largely occurring in low- and middle-income settings. We established the prospective Rural Uganda Non-Communicable Disease (RUNCD) cohort to longitudinally characterize the NCD prevalence, progression, and complications in rural Africa.

Methods: We conducted a population-based census for NCD research.

Determinants and Outcomes Associated With Urinary Calcium Excretion in Chronic Kidney Disease.

Context: Abnormalities in calcium metabolism are common in chronic kidney disease (CKD). Diminished urinary calcium excretion may promote vascular calcification and increased urinary calcium excretion may lead to nephrolithiasis and nephrocalcinosis, conditions associated with CKD.

Objective: To study predictors of urinary calcium excretion and its association with adverse clinical outcomes in CKD.

High Oxalate Concentrations Correlate with Increased Risk for Sudden Cardiac Death in Dialysis Patients.

Background: The clinical significance of accumulating toxic terminal metabolites such as oxalate in patients with kidney failure is not well understood.

Methods: To evaluate serum oxalate concentrations and risk of all-cause mortality and cardiovascular events in a cohort of patients with kidney failure requiring chronic dialysis, we performed a analysis of the randomized German Diabetes Dialysis (4D) Study; this study included 1255 European patients on hemodialysis with diabetes followed-up for a median of 4 years. The results obtained Cox proportional hazards models were confirmed by competing risk regression and restricted cubic spline modeling in the 4D Study cohort and validated in a separate cohort of 104 US patients on dialysis after a median follow-up of 2.