Effects of amino acids and glucose on mesangial cell aminopeptidase a and angiotensin receptors

Effects of amino acids and glucose on mesangial cell aminopeptidase a and angiotensin receptors.BackgroundHigh protein diets and diabetes increase renal renin angiotensin system (RAS) activity, which is associated with glomerular injury. Aminopeptidase A (APA) is a cell surface metalloprotease that degrades angiotensin II (AII) in the mesangium. Mesangial cells (MC) also possess receptors for AII; the type 1 (AT1 receptor) promotes proliferation and fibrosis, while the type 2 (AT2 receptor) opposes these effects. We evaluated whether amino acids and glucose alter expression of APA, AT1 receptor and AT2 receptor in a manner that further augments RAS activity.MethodsConfluent rat MC were grown in serum-free media for 48 hours prior to exposing to experimental conditions: control (C), high amino acids (HA, mixed amino acid solution added to raise concentrations 5- to 6-fold over C), high glucose (HG 30, mM glucose). Semi-quantitative RT-PCR was used to assess mRNA for APA, AT1 receptor, AT2 receptor, and β-actin. Values are expressed relative to βbgr; actin.ResultsBoth HA and HG reduced APA mRNA (HG 1.13 ± 0.19, HA 1.12 ± 0.16 versus C 1.27 ± 0.16 P < 0.05, N = 8). HA increased AT1 receptor mRNA (HA 2.11 ± 0.43 versus C 1.14 ± 0.28 P < 0.05, N = 8). HG increased AT2 receptor mRNA (HG 1.31 ± 0.43 versus C 0.82 ± 0.33 P < 0.05, N = 6).ConclusionsA reduction of APA, in response to high levels of amino acids or glucose, could contribute to increased AII as a result of decreased degradation in MC. The effect of amino acids to increase AT1 receptor expression may further enhance adverse hemodynamic and pro-fibrotic actions of AII. Conversely, glucose increased AT2 receptor expression, which could modulate responses mediated by the AT1 receptor

Transfected CD59 protects mesangial cells from injury induced by antibody and complement

Transfected CD59 protects mesangial cells from injury induced by antibody and complement. CD59 is a complement regulatory protein on the glomerular cells that inhibits C5b-9 assembly and insertion. We employed an overexpression strategy to determine the functional significance of CD59 in mesangial cells. We made a CD59 expression vector tagged with FLAG utilizing site-directed mutagenesis and PCR, which allows transfected CD59 to be distinguished from the constitutively expressed protein. In stable clones, overexpressed CD59 was clearly detected immunocytochemically both by anti-FLAG and anti-CD59 antibody in a granular pattern. The overexpression of CD59 was also confirmed by Western blotting. To determine if overexpression of CD59 by mesangial cells protected these cells from C5b-9 attack, we performed complement-mediated cell lysis assays. CD59-transfected mesangial cells demonstrated marked resistance to complement-mediated cell lysis which was reversed in the presence of antibody to CD59. We also investigated the role of CD59 in protecting cells from the effects of membrane insertion of sublytic quantities of C5b-9. Overexpressed CD59 suppressed production of superoxide, one of the inflammatory mediators induced by sublytic C5b-9 attack. These results demonstrate directly that transfected CD59 functions as a potent protector of mesangial cells against both lytic and sublytic attack by C5b-9. CD59 may be an important regulator of complement-mediated disease in the glomerular mesangium

An Inflammatory Nexus: Serum Amyloid A and inflammation in Diabetic Kidney Disease: DOI: 10.14800/ics.959

Inflammation contributes a significant part to the advancement of diabetic kidney disease (DKD), yet relatively little is known about the root cause of these inflammatory events. Serum Amyloid A (SAA) triggers a potent inflammatory response in a variety of tissues and is up-regulated in glomerular and tubulointerstitial compartments of the diabetic kidney. Under inflammatory conditions, podocytes, along with other intrinsic cells, produce SAA locally in the kidney. Our recent work has shown that SAA induces NF-?B activation and subsequent inflammatory chemokines and cytokines in cultured podocytes. Recent evidence suggests that local production of SAA in diabetes may lead to monocyte and macrophage recruitment, neutrophil activation, and other related incidents resulting in sustained chronic inflammatory conditions in the kidney which may further exacerbate DKD

Serum amyloid a and risk of death and end-stage renal disease in diabetic kidney disease

AimsTo determine if serum levels of serum amyloid A (SAA) predict death and end-stage renal disease in a cohort of people with diabetic kidney disease.MethodsIn a longitudinal cohort study of 135 participants with type 2 diabetes and diabetic kidney disease, serum samples were assayed for SAA. Censored time-to-event analyses in Cox-proportional hazard models were utilized to assess SAA as a predictor of the primary outcome of death and end-stage renal disease.ResultsParticipants were 73% Mexican-American (99/135) and 55% men (75/135), with a mean±SD age of 57±7.5years. At baseline, participants had hemoglobin A1c of 8.6±2.3%, systolic blood pressure of 153±27mm Hg, body mass index of 31±9kg/m2, median urine-albumin-to-creatinine ratio of 1861mg/g (interquartile range 720-3912mg/g), and estimated glomerular filtration rate of 55.7±22.3ml/min/1.73m2. Over a median duration of follow-up of 3.5years, 44% (60/135) of participants experienced a primary outcome event. The hazards ratio for the primary outcome was 3.03 (95% CI 1.43-6.40, p=0.003) in the highest (&gt;1.0 μg/ml) compared to the lowest (&lt;0.55 μg/ml) SAA tertile in a model adjusted for urine-albumin-to-creatinine ratio, estimated glomerular filtration rate, age, sex, and race/ethnicity. Addition of SAA as a covariate improved the model C-statistic (Δ c=0.017).ConclusionsIn a longitudinal cohort study of participants with type 2 diabetes and DKD, higher levels of serum SAA predicted higher risk of death and ESRD. SAA is a promising targetable biomarker for DKD

Financial aspects of the implementation of wind farm in Croatia

Cilj ovoga rada je ponajprije uvidjeti važnost obnovljivih izvora energije, čijim se korištenjem i kogeneracijom ostvaruju interesi Hrvatske u području energetike, utvrđeni Strategijom energetskog razvitka RH, zakonima i drugim propisima kojima se uređuje obavljanje energetskih djelatnosti. Nadalje, izdvojiti energiju vjetra, trenutno najekonomičniju tehnologiju iskorištavanja obnovljivih izvora energije, u usporedbi sa solarnom, energijom valova i biomasom. S obzirom da Hrvatska ima ogroman vjetropotencijal koji tek odnedavno koristi, potrebno je uvidjeti važnost korištenja energije vjetra, odnosno nedostatke, kakvo je zakonodavno okruženje i analizirati opravdanost izgradnje energetskog postrojenja vjetroelektrane. Isto tako, osvrnuti se na sustav poticaja koji je jedan od ključnih faktora za investitore i izgradnju vjetroelektrana. Potrebno je analizirati utjecaj i interakciju s postojećim sustavom na osnovu saznanja iz nekih zemalja EU i svijeta, te iznijeti predviđanja razvoja vjetroenergetike u Hrvatskoj i šire