Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. DKD is a heterogeneous disease with complex pathophysiology where early endothelial dysfunction is associated with disease progression. The Tie2 receptor and Angiopoietin 1 and 2 ligands are critical for maintaining endothelial cell permeability and integrity.
View Article and Find Full Text PDFCurrent classification of chronic kidney disease (CKD) into stages using indirect systemic measures (estimated glomerular filtration rate (eGFR) and albuminuria) is agnostic to the heterogeneity of underlying molecular processes in the kidney thereby limiting precision medicine approaches. To generate a novel CKD categorization that directly reflects within kidney disease drivers we analyzed publicly available transcriptomic data from kidney biopsy tissue. A Self-Organizing Maps unsupervised artificial neural network machine-learning algorithm was used to stratify a total of 369 patients with CKD and 46 living kidney donors as healthy controls.
View Article and Find Full Text PDFAfrican Americans develop end-stage renal disease at a higher rate compared with European Americans due to 2 polymorphisms (G1 and G2 risk variants) in the apolipoprotein L1 (APOL1) gene common in people of African ancestry. Although this compelling genetic evidence provides an exciting opportunity for personalized medicine in chronic kidney disease, drug discovery efforts have been greatly hindered by the fact that APOL1 expression is lacking in rodents. Here, we describe a potentially novel physiologically relevant genomic mouse model of APOL1-associated renal disease that expresses human APOL1 from the endogenous human promoter, resulting in expression in similar tissues and at similar relative levels as humans.
View Article and Find Full Text PDFMini-organs engineered from decellularized organs repopulated with human stem cells can transform preclinical model strategies in target validation and biomarker discovery. Recellularized organs are whole humanized organs with preserved native architecture, conformity of the organ, composition of extracellular matrix and vascular matrix structures. With mini-organ models further understanding of developmental biology and assessment of potential therapeutic targets can be elucidated utilizing human induced pluripotent stem cells.
View Article and Find Full Text PDFDespite significant effort, patients with kidney disease have not seen their outcomes improved significantly over the past two decades. This has motivated clinicians and researchers to consider alternative methods to identifying risk factors, disease progression markers, and effective therapies. Genome-scale data sets from patients with renal disease can be used to establish a platform to improve understanding of the molecular basis of disease; however, such studies require expertise and resources.
View Article and Find Full Text PDFDespite improvements in pre-clinical drug testing models, predictability of clinical outcomes continues to be inadequate and costly due to poor evidence of drug metabolism. Humanized miniature organs integrating decellularized rodent organs with tissue specific cells are translational models that can provide further physiological understanding and evidence. Here, we evaluated 4-Flow cannulated rat hearts as the fundamental humanized organ model for cardiovascular drug validation.
View Article and Find Full Text PDFBeta cell dysfunction accompanies and drives the progression of type 2 diabetes mellitus (T2D), but there are few clinical biomarkers available to assess islet cell stress in humans. Secretagogin, a protein enriched in pancreatic islets, demonstrates protective effects on beta cell function in animals. However, its potential as a circulating biomarker released from human beta cells and islets has not been studied.
View Article and Find Full Text PDFUnlabelled: Pregnancy is associated with increased β-cell proliferation driven by prolactin. Long noncoding RNAs (lncRNA) are the most abundant RNA species in the mammalian genome, yet, their functional importance is mainly elusive.
Aims/hypothesis: This study tests the hypothesis that lncRNAs regulate β-cell proliferation in response to prolactin in the context of β-cell mass compensation in pregnancy.
Background: The role of myeloperoxidase in chronic kidney disease (CKD) and its association with coronary artery disease (CAD) is controversial. In this study, we compared myeloperoxidase and protein-bound 3-chlorotyrosine (ClY) levels in subjects with varying degrees of CKD and tested their associations with CAD.
Methods: From Clinical Phenotyping Resource and Biobank Core, 111 patients were selected from CKD stages 1 to 5.
Growth differentiation factor-15 (GDF-15) is a member of the TGF- cytokine superfamily that is widely expressed and may be induced in response to tissue injury. Elevations in GDF-15 may identify a novel pathway involved in loss of kidney function among patients with CKD. Among participants in the Clinical Phenotyping and Resource Biobank (C-PROBE) study and the Seattle Kidney Study (SKS), we tested whether kidney tissue expression of mRNA correlates with circulating levels of GDF-15 and whether elevations in circulating GDF-15 are associated with decline in kidney function.
View Article and Find Full Text PDFObjective: Bariatric surgery has been shown to have important long-term metabolic effects resulting in enhanced insulin sensitivity and improved glucose tolerance in patients with type 2 diabetes. The contribution of reduced caloric intake to these beneficial effects of surgery remains unclear. The aim of this study was to compare the short-term effects (1 week) of bariatric surgical procedures with a very low caloric intake (VLCI) on insulin sensitivity (IS) and insulin secretion (ISR) in nondiabetic obese subjects.
View Article and Find Full Text PDFGenerating human podocytes in vitro could offer a unique opportunity to study human diseases. Here, we describe a simple and efficient protocol for obtaining functional podocytes in vitro from human induced pluripotent stem cells. Cells were exposed to a three-step protocol, which induced their differentiation into intermediate mesoderm, then into nephron progenitors and, finally, into mature podocytes.
View Article and Find Full Text PDFChronic kidney disease (CKD) affects 8 to 16% people worldwide, with an increasing incidence and prevalence of end-stage kidney disease (ESKD). The effective management of CKD is confounded by the inability to identify patients at high risk of progression while in early stages of CKD. To address this challenge, a renal biopsy transcriptome-driven approach was applied to develop noninvasive prognostic biomarkers for CKD progression.
View Article and Find Full Text PDFLiving in the earth's oxygenated environment forced organisms to develop strategies to cope with the damaging effects of molecular oxygen known as reactive oxygen species (ROS). Here, we show that Per2, a molecular component of the mammalian circadian clock, is involved in regulating a cell's response to oxidative stress. Mouse embryonic fibroblasts (MEFs) containing a mutation in the Per2 gene are more resistant to cytotoxic effects mediated by ROS than wild-type cells, which is paralleled by an altered regulation of bcl-2 expression in Per2 mutant MEFs.
View Article and Find Full Text PDFDiabetic cardiomyopathy is a complication of type 2 diabetes, with known contributions of lifestyle and genetics. We develop environmentally and genetically driven in vitro models of the condition using human-induced-pluripotent-stem-cell-derived cardiomyocytes. First, we mimic diabetic clinical chemistry to induce a phenotypic surrogate of diabetic cardiomyopathy, observing structural and functional disarray.
View Article and Find Full Text PDFBackground: Animal data suggest that natriuretic peptides play an important role in energy metabolism, but prospective studies evaluating a relationship between these peptides and type 2 diabetes mellitus (T2DM) in humans are few and results are conflicting.
Methods: We used a prospective case-cohort approach (n = 491 T2DM cases, n = 561 reference subcohort) within the Women's Health Study to evaluate baseline N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations and the risk of incident T2DM. We also tested for associations between 4 common variants in the natriuretic peptide A and B genes (NPPA and NPPB) and NT-proBNP concentrations (n = 458) and incident T2DM (n = 1372 cases among 22 607 women).
Objective: Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that is increased in obesity and established type 2 diabetes. We assessed whether GDF-15 can predict future insulin resistance and impaired glucose control in obese nondiabetic individuals.
Design And Methods: Plasma GDF-15 concentrations were measured with an automated electrochemiluminescent immunoassay at baseline and after 4 years in 496 obese nondiabetic individuals (52% men, median age 48 years, median body mass index (BMI) 37.
Background: Very low levels of cardiac troponin T are associated with an increased risk of cardiovascular death in patients with stable chronic coronary disease. Whether high-sensitivity cardiac troponin T levels are associated with adverse cardiovascular outcomes in individuals without cardiovascular disease (CVD) has not been well studied.
Methods And Results: Using 2 complementary study designs, we evaluated the relationship between baseline cardiac troponin and incident CVD events among diabetic and nondiabetic participants in the Women's Health Study (median follow-up, 12.
Background: The present study has investigated the protein tyrosine phosphatase H1 (PTPH1) expression pattern in mouse brain and its impact on CNS functions.
Methods: We have previously described a PTPH1-KO mouse, generated by replacing the PTP catalytic and the PDZ domain with a LacZ neomycin cassette. PTPH1 expression pattern was evaluated by LacZ staining in the brain and PTPH1-KO and WT mice (n = 10 per gender per genotype) were also behaviorally tested for CNS functions.
Several protein-tyrosine phosphatases (PTPs) have been implicated in the control of growth hormone receptor (GHR) signaling, but none have been shown to affect growth in vivo. We have applied a battery of molecular and cellular approaches to test a family-wide panel of PTPs for interference with GHR signaling. Among the subset of PTPs that showed activity in multiple readouts, we selected PTP-H1/PTPN3 for further in vivo studies and found that mice lacking the PTP-H1 catalytic domain show significantly enhanced growth over their wild type littermates.
View Article and Find Full Text PDFPredicting time of food availability is key for survival in most animals. Under restricted feeding conditions, this prediction is manifested in anticipatory bouts of locomotor activity and body temperature. This process seems to be driven by a food-entrainable oscillator independent of the main, light-entrainable clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus .
View Article and Find Full Text PDFThe suprachiasmatic nuclei (SCN) contain a major circadian pacemaker, which is regulated by photic and nonphotic stimuli. Although enkephalins are present in the SCN, their role in phase regulation of the pacemaker is largely unknown. The opioid agonist fentanyl, a homologue of morphine, is an addictive drug that induces phase shifts of circadian rhythms in hamsters.
View Article and Find Full Text PDFWhen exposed to the cold, the body temperature of the ruin lizard (Podarcis sicula), an ectothermic vertebrate, comes into equilibrium with that low environmental temperature. During this time, the behavioral output of the circadian clock, locomotor activity, disappears. We tested the activity of the circadian clockwork at low temperature (6 degrees C) by following the expression of one of its essential components, the Period2 (Per2) gene.
View Article and Find Full Text PDFPeriod (Per) genes are involved in regulation of the circadian clock and are thought to modulate several brain functions. We demonstrate that Per2(Brdm1) mutant mice, which have a deletion in the PAS domain of the Per2 protein, show alterations in the glutamatergic system. Lowered expression of the glutamate transporter Eaat1 is observed in these animals, leading to reduced uptake of glutamate by astrocytes.
View Article and Find Full Text PDFWe have shown previously that in ruin lizards (Podarcis sicula) the ablation of all known photoreceptive structures (lateral eyes, pineal and parietal eye) in the same individual animal does not prevent entrainment of their circadian locomotor rhythms to light. The present study was aimed at identifying the circadian brain photoreceptors mediating entrainment. For this purpose, we looked for opsin expression in the brain by means of immunocytochemistry.
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