Objective: People with serious mental illness in the United States have higher human immunodeficiency virus (HIV) infection rates than the general U.S. population.
View Article and Find Full Text PDFAm J Physiol Renal Physiol
September 2015
Renal hypoxia contributes to chronic kidney disease (CKD) progression, as validated in experimental and human CKD. In the early stages, increased oxygen consumption causes oxygen demand/supply mismatch, leading to hypoxia. Hence, early targeting of the determinants and regulators of oxygen consumption in CKD may alter the disease course before permanent damage ensues.
View Article and Find Full Text PDFBackground: Kidney ischemia-reperfusion is a form of acute kidney injury resulting in a cascade of cellular events prompting rapid cellular damage and suppression of kidney function. A cellular response to ischemic stress is the activation of AMP-activated protein kinase (AMPK), where AMPK induces a number of homeostatic and renoprotective mechanisms, including autophagy. However, whether autophagy is beneficial or detrimental in ischemia-reperfusion remains controversial.
View Article and Find Full Text PDFThe endoplasmic reticulum (ER) stress response is activated in the diabetic kidney and functions to reduce ER protein accumulation and improve cellular function. We previously showed that tribbles homolog 3 (TRB3), an ER stress-associated protein, is upregulated in the diabetic kidney. Here, we investigated whether absence of TRB3 alters outcomes in diabetic nephropathy.
View Article and Find Full Text PDFAMP-activated protein kinase (AMPK) is an important energy sensor that may be critical in regulating renal lipid accumulation. To evaluate the role of AMPK in mediating renal lipid accumulation, C57BL/6J mice were randomized to a standard diet, a high-fat diet, or a high-fat diet plus AICAR (an AMPK activator) for 14 weeks. Renal functional and structural studies along with electron microscopy were performed.
View Article and Find Full Text PDFOur previous work has shown that gene knockout of the sodium-glucose cotransporter SGLT2 modestly lowered blood glucose in streptozotocin-diabetic mice (BG; from 470 to 300 mg/dl) and prevented glomerular hyperfiltration but did not attenuate albuminuria or renal growth and inflammation. Here we determined effects of the SGLT2 inhibitor empagliflozin (300 mg/kg of diet for 15 wk; corresponding to 60-80 mg·kg(-1)·day(-1)) in type 1 diabetic Akita mice that, opposite to streptozotocin-diabetes, upregulate renal SGLT2 expression. Akita diabetes, empagliflozin, and Akita + empagliflozin similarly increased renal membrane SGLT2 expression (by 38-56%) and reduced the expression of SGLT1 (by 33-37%) vs.
View Article and Find Full Text PDFNephrol Dial Transplant
November 2013
Obesity is a long-term source of cellular stress that predisposes to chronic kidney disease (CKD). Autophagy is a homeostatic mechanism for cellular quality control through the disposal and recycling of cellular components. During times of cellular stress, autophagy affords mechanisms to manage stress by selectively ridding the cell of the accumulation of potentially toxic proteins, lipids and organelles.
View Article and Find Full Text PDFThe rat kidney ablation and infarction (A/I) model of subtotal or 5/6th nephrectomy is the most commonly studied model of nondiabetic chronic kidney disease (CKD). The A/I kidney at 1 wk exhibits reductions in kidney function, as determined by glomerular filtration rate, and diminished metabolic efficiency as determined by oxygen consumption per sodium transport (QO2/TNa). As renoprotective AMPK activity is affected by metabolic changes and cellular stress, we evaluated AMPK activity in this model system.
View Article and Find Full Text PDFAgmatine (decarboxylated arginine) has been known as a natural product for over 100 years, but its biosynthesis in humans was left unexplored owing to long-standing controversy. Only recently has the demonstration of agmatine biosynthesis in mammals revived research, indicating its exceptional modulatory action at multiple molecular targets, including neurotransmitter systems, nitric oxide (NO) synthesis and polyamine metabolism, thus providing bases for broad therapeutic applications. This timely review, a concerted effort by 16 independent research groups, draws attention to the substantial preclinical and initial clinical evidence, and highlights challenges and opportunities, for the use of agmatine in treating a spectrum of complex diseases with unmet therapeutic needs, including diabetes mellitus, neurotrauma and neurodegenerative diseases, opioid addiction, mood disorders, cognitive disorders and cancer.
View Article and Find Full Text PDFThe Na-glucose cotransporter SGLT2 mediates high-capacity glucose uptake in the early proximal tubule and SGLT2 inhibitors are developed as new antidiabetic drugs. We used gene-targeted Sglt2 knockout (Sglt2(-/-)) mice to elucidate the contribution of SGLT2 to blood glucose control, glomerular hyperfiltration, kidney growth, and markers of renal growth and injury at 5 wk and 4.5 mo after induction of low-dose streptozotocin (STZ) diabetes.
View Article and Find Full Text PDFAgmatine is a novel neuromodulator that plays a protective role in the CNS in several models of cellular damage. However, the mechanisms involved in these protective effects in neurodegenerative diseases are poorly understood. Fourier transform infrared (FTIR) spectroscopy analysis detects biomolecular changes in disordered cells and tissues.
View Article and Find Full Text PDFAgmatine, an endogenous arginine metabolite, has been proposed as a novel neuromodulator that plays protective roles in the CNS in several models of cellular damage. However, the mechanisms involved in these protective effects in neurodegenerative diseases are poorly understood. The present study was undertaken to investigate the effects of agmatine on cell injury induced by rotenone, commonly used in establishing in vivo and in vitro models of Parkinson's disease, in human-derived dopaminergic neuroblastoma cell line (SH-SY5Y).
View Article and Find Full Text PDFAm J Physiol Renal Physiol
December 2010
The 5/6(th) nephrectomy or ablation/infarction (A/I) preparation has been used as a classic model of chronic kidney disease (CKD). We observed increased kidney oxygen consumption (Q(O2)) and altered renal hemodynamics in the A/I kidney that were normalized after combined angiotensin II (ANG II) blockade. Studies suggest hypoxia inducible factor as a protective influence in A/I.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
August 2010
Diabetic nephropathy is the commonest cause of end-stage renal disease. Inordinate kidney growth and glomerular hyperfiltration at the very early stages of diabetes are putative antecedents to this disease. The kidney is the only organ that grows larger with the onset of diabetes mellitus, yet there remains confusion about the mechanism and significance of this growth.
View Article and Find Full Text PDFThe arginine metabolite agmatine is able to protect brain mitochondria against the drop in energy capacity by the Ca(2+)-dependent induction of permeability transition (MPT) in rat brain mitochondria. At normal levels, the amine maintains the respiratory control index and ADP/O ratio and prevents mitochondrial colloid-osmotic swelling and any electrical potential (DeltaPsi) drop. MPT is due to oxidative stress induced by the interaction of Ca(2+) with the mitochondrial membrane, leading to the production of hydrogen peroxide and, subsequently, other reactive oxygen species (ROS) such as hydroxyl radicals.
View Article and Find Full Text PDFAgmatine, an endogenous metabolite of arginine, selectively suppresses growth in cells with high proliferative kinetics, such as transformed cells, through depletion of intracellular polyamine levels. In the present study, we depleted intracellular polyamine content with agmatine to determine if attrition by cell death contributes to the growth-suppressive effects. We did not observe an increase in necrosis, DNA fragmentation, or chromatin condensation in Ha-Ras-transformed NIH-3T3 cells administered agmatine.
View Article and Find Full Text PDFBackground: In early type 1 diabetes mellitus, changes in proximal reabsorption influence glomerular filtration rate (GFR) through tubuloglomerular feedback (TGF). Due to TGF, a primary increase in proximal reabsorption causes early diabetic hyperfiltration, while a heightened sensitivity of the proximal tubule to dietary salt leads to the so-called salt paradox, where a change in dietary salt causes a reciprocal change in GFR ('tubulocentric principle'). Here, experiments were performed in adenosine A(1) receptor knockout mice (A(1)R-/-), which lack an immediate TGF response, to determine whether A(1)Rs are essential for early diabetic hyperfiltration and the salt paradox.
View Article and Find Full Text PDFAngiotensin II blockade delays progression of chronic kidney disease by modifying intrarenal hemodynamics, but the effects on metabolic adaptations are unknown. Using the remnant kidney model of chronic kidney disease in rats, we measured the effects of combined angiotensin II blockade with captopril and losartan on renal oxygen consumption (QO(2)) and factors influencing QO(2). Remnant kidneys had proteinuria and reductions in the glomerular filtration rate (GFR), renal blood flow (RBF) and nitric oxide synthase-1 protein expression while QO(2), factored by sodium reabsorption (QO(2)/TNa), was markedly increased.
View Article and Find Full Text PDFAgmatine, decarboxylated arginine, is produced in the kidney and can increase nephron and kidney filtration rate via renal vasodilatation and increases in plasma flow. This increase in filtration rate after agmatine is prevented by administration of nitric oxide synthase (NOS) inhibitors. In endothelial cells, agmatine-stimulated nitrite production is accompanied by induction of cytosolic calcium.
View Article and Find Full Text PDFActivation of adenosine A(1) receptors (A(1)R) can inhibit arginine vasopressin (AVP)-induced cAMP formation in isolated cortical and medullary collecting ducts. To assess the in vivo consequences of the absence of A(1)R, we performed experiments in mice lacking A(1)R (A(1)R(-/-)). We assessed the effects of the vasopressin V(2) receptor (V(2)R) agonist 1-desamino-8-d-arginine vasopressin (dDAVP) on cAMP formation in isolated inner medullary collecting ducts (IMCD) and on water excretion in conscious water-loaded mice.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
August 2007
Polyamines are small cationic molecules required for cellular proliferation. Agmatine is a biogenic amine unique in its capacity to arrest proliferation in cell lines by depleting intracellular polyamine levels. We previously demonstrated that agmatine enters mammalian cells via the polyamine transport system.
View Article and Find Full Text PDFAmino Acids
August 2007
Michael Brownlee has proposed a 'Unifying Mechanism' of hyperglycemia-induced damage in diabetes mellitus. At the crux of this hypothesis is the generation of reactive oxygen species (ROS), and their impact on glycolytic pathways. Diabetes is the leading cause of chronic kidney failure.
View Article and Find Full Text PDFPeople with severe mental illness evidence significantly higher rates of HIV infection than the general population in the United States. Frequently, the only access to health care for this population is through their outpatient mental health care providers. In order to determine how these providers were dealing with the increased risk of HIV infection among this group, a survey of all licensed and certified outpatient mental health care centers in New York State was conducted.
View Article and Find Full Text PDFPolyamines play an essential role in the growth and differentiation of mammalian cells. The depletion of intracellular polyamines results in the suppression of growth. Proliferation of glomerular mesangial cells (MC) is the most common pathologic change in many forms of glomerulonephritis.
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