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There is increasing evidence that proteins in tubular fluid are "nephrotoxic." In vivo it is difficult to study protein loading of tubular epithelial cells in isolation, i.e., without concomitant glomerular damage or changes of renal hemodynamics, etc. Recently, a unique amphibian model has been described which takes advantage of the special anatomy of the amphibian kidney in which a subset of nephrons drains the peritoneal cavity (open nephrons) so that intraperitoneal injection of protein selectively causes protein storage in and peritubular fibrosis around open but not around closed tubules. There is an ongoing debate as to what degree albumin per se is nephrotoxic and whether modification of albumin alters its nephrotoxicity. We tested the hypothesis that carbamylation and glycation render albumin more nephrotoxic compared with native albumin and alternative albumin modifications, e.g., lipid oxidation and lipid depletion. Preparations of native and modified albumin were injected into the axolotl peritoneum. The kidneys were retrieved after 10 days and studied by light microscopy as well as by immunohistochemistry [transforming growth factor (TGF)-β, PDGF, NF-κB, collagen I and IV, RAGE], nonradioactive in situ hybridization, and Western blotting. Two investigators unaware of the animal groups evaluated and scored renal histology. Compared with unmodified albumin, glycated and carbamylated albumin caused more pronounced protein storage. After no more than 10 days, selective peritubular fibrosis was seen around nephrons draining the peritoneal cavity (open nephrons), but not around closed nephrons. Additionally, more intense expression of RAGE, NF-κB, as well as PDGF, TGF-β, EGF, ET-1, and others was noted by histochemistry and confirmed by RT-PCR for fibronectin and TGF-β as well as nonradioactive in situ hybridization for TGF-β and fibronectin. The data indicate that carbamylation and glycation increase the capacity of albumin to cause tubular cell damage and peritubular fibrosis. [ABSTRACT FROM AUTHOR]

Most kidney transplant patients who undergo biopsies are classified as having no rejection based on consensus thresholds. However, we hypothesized that because these patients have normal adaptive immune systems, T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR) may exist as subthreshold activity in some transplants currently classified as no rejection. To examine this question, we studied genome-wide microarray results from 5086 kidney transplant biopsies (from 4170 patients). An updated molecular archetypal analysis designated 56% of biopsies as no rejection. Subthreshold molecular TCMR and/or ABMR activity molecular activity was detectable as elevated classifier scores in many biopsies classified as no rejection, with ABMR activity in many TCMR biopsies and TCMR activity in many ABMR biopsies. In biopsies classified as no rejection histologically and molecularly, molecular TCMR classifier scores correlated with increases in histologic TCMR features and molecular injury, lower estimated glomerular filtration rate, and higher risk of graft loss, and molecular ABMR activity correlated with increased glomerulitis and donor-specific antibody. No rejection biopsies with high subthreshold TCMR or ABMR activity had a higher probability of having TCMR or ABMR, respectively, diagnosed in a future biopsy. We conclude that many kidney transplant recipients have unrecognized subthreshold TCMR or ABMR activity, with significant implications for future problems., Competing Interests: Declaration of competing interest The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. P.F. Halloran holds shares in Transcriptome Sciences Inc., a University of Alberta research company dedicated to developing molecular diagnostics, supported in part by a licensing agreement between Transcriptome Sciences Inc. and Thermo Fisher Scientific, and by a research grant from Natera, Inc. P.F. Halloran is a consultant to Natera, Inc. and Argenx BV. The other authors have declared no conflict of interest exists., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients., Methods: In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months., Results: There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (χ 2  = 20.8; P  < .001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (r partial  = 0.340, P  < .001). KDRI values were valuable in the determination of both early and long-term graft function., Conclusion: The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome., Competing Interests: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the ERA.)

Adequate tacrolimus blood exposure is crucial in the early post-renal transplant period and a gut epithelial barrier integrity may play a role. We prospectively investigated several markers of intestinal permeability in recent kidney transplant recipients (KTRs) treated with different tacrolimus extended-release formulations. Within each of the 49 KTR pairs that received grafts from the same donor, an early randomized conversion was performed from twice-daily (Prograf) to once-daily tacrolimus formulation: Advagraf or Envarsus. Plasma zonulin, calprotectin, circulating lipopolysaccharide (LPS), LPS-binding protein (LBP), intestinal fatty acid binding protein (FABP-2), and CD-14 levels were measured. There was no difference in the recipient age, dialysis vintage, BMI, and residual diuresis between Advagraf and Envarsus groups. FABP-2 and LPS levels were significantly associated with tacrolimus trough level, 3-h level, and area under the curve (AUC) in the Envarsus but not in the Advagraf group. AUC was independently increased by LPS and decreased by age, FABP-2 concentration, and the use of Envarsus formulation as compared with Advagraf. Functional changes of gastrointestinal tract in patients treated with Envarsus may influence intestinal tacrolimus absorption to a greater extent than in Advagraf-treated KTRs and may lead to inadequate variability of tacrolimus exposure early after kidney transplantation.

To extend previous molecular analyses of rejection in liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov #NCT03193151), the present study aimed to define the gene expression selective for parenchymal injury, fibrosis, and steatohepatitis. We analyzed genome-wide microarray measurements from 337 liver transplant biopsies from 13 centers. We examined expression of genes previously annotated as increased in injury and fibrosis using principal component analysis (PCA). PC1 reflected parenchymal injury and related inflammation in the early posttransplant period, slowly regressing over many months. PC2 separated early injury from late fibrosis. Positive PC3 identified a distinct mildly inflamed state correlating with histologic steatohepatitis. Injury PCs correlated with liver function and histologic abnormalities. A classifier trained on histologic steatohepatitis predicted histologic steatohepatitis with cross-validated AUC = 0.83, and was associated with pathways reflecting metabolic abnormalities distinct from fibrosis. PC2 predicted histologic fibrosis (AUC = 0.80), as did a molecular fibrosis classifier (AUC = 0.74). The fibrosis classifier correlated with matrix remodeling pathways with minimal overlap with those selective for steatohepatitis, although some biopsies had both. Genome-wide assessment of liver transplant biopsies can not only detect molecular changes induced by rejection but also those correlating with parenchymal injury, steatohepatitis, and fibrosis, offering potential insights into disease mechanisms for primary diseases., (© 2021 The American Society of Transplantation and the American Society of Transplant Surgeons.)

There are several premises that the body composition of kidney transplant recipients may play a role in tacrolimus metabolism early after transplantation. The present study aimed at analyzing the relationship between the body composition parameters assessed by bioimpedance analysis (BIA) and initial tacrolimus metabolism. Immediately prior to transplantation, BIA using InBody 770 device was performed in 122 subjects. Tacrolimus concentration-to-dose (C/D) ratio was calculated based on the first blood trough level measurement. There was no difference in phase angle, visceral fat area, lean body mass index (LBMI) and the proportion of lean mass as a percentage of total body mass between the subgroups of slow and fast metabolizers. However, subjects with LBMI ≥ median value of 18.7 kg/m 2 , despite similar initial tacrolimus dose per kg of body weight, were characterized by a significantly lower tacrolimus C/D ratio (median 1.39 vs. 1.67, respectively; p < 0.05) in comparison with the subgroup of lower LBMI. Multivariate regression analysis confirmed that age (r partial = 0.322; p < 0.001) and LBMI (r partial = -0.254; p < 0.01) independently influenced the tacrolimus C/D ratio. A LBMI assessed by BIA may influence the tacrolimus metabolism in the early post-transplant period and can be a useful in the optimization of initial tacrolimus dosing.

The role of endogenous mammalian cardiotonic steroids (CTS) in the physiology and pathophysiology of the cardiovascular system and the kidneys has interested researchers for more than 20 years. Cardiotonic steroids extracted from toads or plants, such as digitalis, have been used to treat heart disease since ancient times. CTS, also called endogenous digitalis-like factors, take part in the regulation of blood pressure and sodium homeostasis through their effects on the transport enzyme called sodium-potassium adenosine triphosphatase (Na/K-ATPase) in renal and cardiovascular tissue. In recent years, there has been increasing evidence showing deleterious effects of CTS on the structure and function of the heart, vasculature and kidneys. Understanding the role of CTS may be useful in the development of potential new therapeutic strategies.

Increased marinobufagenin (MBG) synthesis has been suggested in response to high dietary salt intake. The aim of this study was to determine the effects of short-term changes in sodium intake on plasma MBG levels in patients with primary salt-sensitive and salt-insensitive hypertension. In total, 51 patients with primary hypertension were evaluated during acute sodium restriction and sodium loading. Plasma or serum concentrations of MBG, natriuretic pro-peptides, aldosterone, sodium, potassium, as well as hematocrit (Hct) value, plasma renin activity (PRA) and urinary sodium and potassium excretion were measured. Ambulatory blood pressure monitoring (ABPM) and echocardiography were performed at baseline. In salt-sensitive patients with primary hypertension plasma MBG correlated positively with diastolic blood pressure (ABPM) and serum NT-proANP concentration at baseline and with serum NT-proANP concentration after dietary sodium restriction. In this subgroup plasma MBG concentration decreased during sodium restriction, and a parallel increase of PRA was observed. Acute salt loading further decreased plasma MBG concentration in salt-sensitive subjects in contrast to salt insensitive patients. No correlation was found between plasma MBG concentration and left ventricular mass index. In conclusion, in salt-sensitive hypertensive patients plasma MBG concentration correlates with 24-h diastolic blood pressure and dietary sodium restriction reduces plasma MBG levels. Decreased MBG secretion in response to acute salt loading may play an important role in the pathogenesis of salt sensitivity.

Molecular diagnosis of rejection is emerging in kidney, heart, and lung transplant biopsies and could offer insights for liver transplant biopsies. We measured gene expression by microarrays in 235 liver transplant biopsies from 10 centers. Unsupervised archetypal analysis based on expression of previously annotated rejection-related transcripts identified 4 groups: normal "R1 normal " (N = 129), T cell-mediated rejection (TCMR) "R2 TCMR " (N = 37), early injury "R3 injury " (N = 61), and fibrosis "R4 late " (N = 8). Groups differed in median time posttransplant, for example, R3 injury 99 days vs R4 late 3117 days. R2 TCMR biopsies expressed typical TCMR-related transcripts, for example, intense IFNG-induced effects. R3 injury displayed increased expression of parenchymal injury transcripts (eg, hypoxia-inducible factor EGLN1). R4 late biopsies showed immunoglobulin transcripts and injury-related transcripts. R2 TCMR correlated with histologic rejection although with many discrepancies, and R4 late with fibrosis. R2 TCMR , R3 injury , and R4 late correlated with liver function abnormalities. Supervised classifiers trained on histologic rejection showed less agreement with histology than unsupervised R2 TCMR scores. No confirmed cases of clinical antibody-mediated rejection (ABMR) were present in the population, and strategies that previously revealed ABMR in kidney and heart transplants failed to reveal a liver ABMR phenotype. In conclusion, molecular analysis of liver transplant biopsies detects rejection, has the potential to resolve ambiguities, and could assist with immunosuppressive management., (© 2020 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Proteasome inhibitor bortezomib has been used in the treatment of refractory cases of acute and chronic antibody-mediated rejection (AMR) in kidney transplant recipients. However, its efficacy and safety as a primary treatment for early AMR has been scarcely investigated. We herein present our preliminary experience with bortezomib- and plasmapheresis-based primary treatment for early AMR. Thirteen patients transplanted between October 2015 and September 2019 were treated (starting at median 19th post-transplant day) with bortezomib/plasmapheresis protocol for early biopsy-proven AMR. Twelve out of thirteen patients received 4 doses and one patient recieved 3 doses of bortezomib (1.3 mg/m 2 per dose). In 11/13 patients, 4-7 concomitant plasmapheresis sessions were performed, with or without intravenous immunoglobulin (IVIG). Of note, rituximab was not used in all study patients. The kidney graft and patient survival were 100%. The mean 3-month estimated glomerular filtration rate (eGFR) was 55.3 (95%CI: 44.9-65.8) mL/min/1.73m 2 , 8/13 patients completed 12-month follow-up with mean eGFR 60.4 (45.4-75.4) mL/min/1.73m 2 , and 6/13 patients completed a 24-month follow-up period with mean eGFR 73.9 (56.7-91.1) mL/min/1.73m 2 . Neutropenia < 1 G/L was observed in one patient, third or fourth grade thrombocytopenia in two patients, and eleven patients needed a blood transfusion (median: 2 units/patient). The mid-term results of a primary bortezomib-based treatment for kidney AMR showed its non-inferiority as compared to preceding regimens and acceptable safety. However, our data should be validated in a multicenter randomized trial.

Background: Marinobufagenin (MBG) is an endogenous cardiotonic steroid (CTS) that inhibits the Na+/K+-ATPase. Human MBG is significantly increased in end-stage renal disease and immunization against MBG attenuates cardiovascular fibrosis in a rat model of uremic cardiomyopathy. Mineralocorticoid antagonists (MRA) block MBG binding sites and decrease proteinuria in chronic kidney disease (CKD) patients. We therefore aimed to investigate the association of MBG and albuminuria, as a marker of renal damage, as well as MBG and decline of glomerular filtration rate (GFR)., Methods: The Graz endocrine causes of hypertension (GECOH) study is a single center study of adults routinely referred for screening of endocrine hypertension. Plasma MBG was measured by an enzyme-linked immunoassay, and in a post-hoc analysis, follow-up creatinine levels were obtained. Patients with proteinuria >3.5g/day at baseline were excluded from further evaluation., Results: We measured MBG concentrations in 40 hypertensive subjects and excluded one patient due to pre-existing proteinuria. Plasma MBG was significantly correlated with albuminuria (Spearman ρ = .357; p = .028) and proteinuria (ρ = .336; p = .039). In linear regression analysis, the association remained significant after adjustment for age, sex, and BMI (β = .306; p = .036), and for mean systolic blood pressure (β = .352; p = .034). In follow-up analyses (N = 30), MBG was significantly associated with decline in GFR after adjustment for time-to-follow-up (β = -.374; p = .042)., Conclusion: The findings suggest that MBG plasma concentrations were associated with albuminuria as well as decline in kidney function. Whether MBG predicts hard renal endpoints warrants further investigations., Competing Interests: The authors have declared that no competing interests exist.

High dietary salt intake has been listed among the top ten risk factors for disability-adjusted life years. We discuss the role of endogenous cardiotonic steroids in mediating the dietary salt-induced hypertension and organ damage.

Experimental data have shown increased plasma levels of marinobufagenin in kidney failure. In this case-controlled retrospective analysis, we evaluated plasma marinobufagenin immunoreactivity in hemodialysis patients compared with subjects with normal kidney function. Sixty-eight adult hemodialysis patients with chronic kidney disease (34 females and 34 males) as well as 68 age-, gender-, and blood pressure-matched subjects without chronic kidney disease were enrolled. Patients on stable hemodialysis regimen for at least 3 mo before the study were included. Exclusion criteria were: age <18 yr, severe liver or heart insufficiency, and overhydration. Subjects without chronic kidney disease must have had an estimated glomerular filtration rate ≥60 ml·min -1 ·1.72 m -2 according to the Modification of Diet in Renal Disease formula. Plasma marinobufagenin immunoreactivity was significantly ( P < 0.001) higher in hemodialysis patients (1.66 ± 1.13 nmol/l) compared with subjects with normal kidney function (0.46 ± 0.23). In hemodialysis patients, plasma marinobufagenin immunoreactivity was higher in men compared with women. A significant positive correlation has been found between plasma marinobufagenin immunoreactivity and serum NT-proBNP, NT-proANP, or aldosterone concentrations in all analyzed subjects. In hemodialyzed patients with plasma marinobufagenin immunoreactivity above median value 5-yr, all-cause mortality was higher compared with those with plasma marinobufagenin concentration below median. We have shown that plasma marinobufagenin immunoreactivity is increased in patients with end-stage kidney failure treated with hemodialysis parallel to the increase in serum NT-proBNP, NT-proANP, and aldosterone concentrations. Higher marinobufagenin immunoreactivity has been associated with worse survival in hemodialyzed patients.

INTRODUCTION Adipose tissue has been recently recognized as an endocrine organ secreting a number of adipokines contributing to the development of atherosclerosis, hypertension, chronic kidney disease, endothelial dysfunction, insulin resistance, and vascular remodeling. OBJECTIVES The aim of this study was to determine whether treatment with a β-blocker, calcium antagonist, thiazide-like diuretic, or angiotensin II receptor type 1 influences plasma concentrations of apelin, resistin, and visfatin in obese hypertensive patients. PATIENTS AND METHODS The study included 84 obese patients with essential hypertension. One control group included obese subjects without hypertension, and the other, lean subjects without hypertension. Patients with hypertension were randomized into 4 groups treated for 6 weeks with bisoprolol, amlodipine, indapamide, or candesartan, respectively. RESULTS Mean daily plasma apelin concentrations in patients treated with amlodipine was significantly higher than the baseline values, whereas the difference in plasma apelin concentrations in other treatment groups was not significant. Mean daily plasma resistin concentrations were significantly lower after 6-week treatment with amlodipine, bisoprolol, or indapamide compared with the baseline values. In patients treated with candesartan, no significant differences in resistin concentrations were shown. After 6-week treatment with bisoprolol, mean daily plasma concentrations of visfatin were significantly lower compared with the baseline values. Treatment with amlodipine, candesartan, or indapamide did not significantly affect plasma visfatin levels. CONCLUSIONS Antihypertensive treatment exerts significant and varied effects on adipokine secretion in obese hypertensive patients. Changes in apelin secretion, caused by the use of different antihypertensive drugs, may protect the cardiovascular system and kidneys. The involvement of adipokins in the mechanism of diverse protective effects of antihypertensive drugs, independently of the effect on blood pressure, requires further research.

Endogenous cardiotonic steroids (CTS), also called digitalis-like factors, are a group of steroid hormones linking high salt intake and elevated blood pressure and in part responsible for target organ damage in arterial hypertension. CTS act primarily through their ability to inhibit the ubiquitous transport enzyme sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). A portion of Na⁺/K⁺-ATPase does not seem to actively "pump" sodium and potassium but is closely associated with other key signaling proteins. Plasma concentration and urine excretion of CTS are increased in experimental models with volume expansion and on a high salt diet. Elevated plasma concentration of marinobufagenin has been shown in volume-expanded states such as essential hypertension, primary aldosteronism, chronic renal failure, congestive heart failure and pregnancy. In experimental models marinobufagenin induces heart and kidney fibrosis to the same extent as observed in uremia. Neutralization of marinobufagenin with antibodies prevents such heart remodeling. Expanding our understanding of this new class of hormones may lead to development of novel and effective therapeutic strategies in hypertensive patients with renal and cardiovascular complications.

Background: The cardiotonic steroid marinobufagenin (MBG) is increasingly suggested to be responsible for some of the cardiovascular injury that has been previously attributed to aldosterone. We examined the clinical correlates of circulating MBG concentrations in hypertensive patients and tested the hypothesis that MBG serves as a reliable diagnostic tool for detecting primary aldosteronism (PA)., Methods: Plasma MBG concentrations (mean: 0.51±0.25 nmol/l) were measured in the morning fasting samples in 20 patients with PA and 20 essential hypertensive (EH) controls matched for age, sex, body mass index, renal function, urinary sodium and intake of antihypertensive medication (mean age: 51.6 years; 52.2% women)., Results: Overall, plasma MBG was directly correlated with plasma aldosterone, aldosterone to active renin ratio (AARR), diastolic blood pressure, mean carotid intima-media thickness, serum sodium, urinary protein to creatinine ratio and inversely with serum potassium levels. Plasma MBG levels were significantly higher in patients with PA compared to EH (mean: 0.68±0.12 versus 0.35±0.24 nmol/l; p<0.001). ROC analysis yielded a greater AUC for plasma MBG compared to the AARR, PAC and serum potassium levels for detecting PA. Youden's Index analyses yielded the optimal plasma MBG cut-off score for diagnosing PA at >0.49 nmol/l with specificity and sensitivity values of 0.85 and 0.95, respectively, which were higher than those at the optimum AARR cut-off at >3.32 ng/dl/µU/ml., Conclusions: In a well-characterized cohort, values of plasma MBG were significantly related to clinical correlates of cardiovascular and renal disease. Plasma MBG emerged as a valuable alternative to the AARR for screening of PA.

Calcimimetics are indicated for secondary hyperparathyroidism in chronic kidney disease, and some data have suggested their protective role for progression of renal damage. We aimed to evaluate whether a calcimimetic can slow the progression of kidney damage in uninephrectomized apolipoprotein E (ApoE)-deficient (ApoE-/-) mice. To this end, we compared its effect with that of calcitriol. Male ApoE-/- mice (12 wk old) were randomized to undergo sham operation (sham) or unilateral nephrectomy (UNX) and subsequently received the calcimimetic R-568 (4 μg·kg⁻¹·day⁻¹), calcitriol (0.03 μg·kg⁻¹·day⁻¹), or vehicle intraperitoneally. Glomerular number and volume, damage indexes (glomerular, vascular, and interstitial), and glomerular (podocytes, mesangial, and endothelial) cell number and volume were assessed in perfused kidneys after a 12-wk treatment period. Lower numbers of podocytes per glomerulus were observed in the UNX + vehicle group compared with the sham group, and this was prevented in the UNX + R-568 group but not in the UNX + calcitriol group. In parallel, albuminuria was higher in the untreated UNX group compared with the sham group, and the increase was prevented in the UNX + R-568 group. Interstitial fibrosis was more prevalent in the vehicle-treated UNX group compared with the sham group, and this was prevented in the UNX group treated with R-568 and less effectively with calcitriol treatment. In all UNX groups, the weight of the residual kidney was significantly higher compared with all sham groups. No differences were observed in serum ionized calcium and systolic blood pressure between the groups. The calcimimetic R-568 prevented interstial fibrosis and podocyte loss after uninephrectomy in ApoE-/- mice. Minor renal dysfunction, lack of secondary hyperparathyroidism, and hypertension in this model support the hypothesis of direct effects of this compound on glomerular cells.

Background: Cardiovascular disease is the primary cause of mortality in patients with chronic kidney disease (CKD). Heart remodeling in CKD comprises mainly interstitial fibrosis and capillary loss. Beyond correcting renal anemia, erythropoietin (Epo) has potentially beneficial pleiotropic effects on heart remodeling., Methods: 12-week-old male Sprague-Dawley rats were randomized to 5/6 nephrectomy (NX) or sham operation (sham-op); subsequently, they received murine Epo (2.5 μg/kg/week), enalapril (12 mg/kg/day), Epo + enalapril, Epo + dihydralazine (25 mg/kg/day), or vehicle. Heart function and morphology was assessed after 16 weeks of treatment., Results: Compared with sham-op (81.2%), left ventricle fractional shortening was reduced in vehicle-treated NX (66.3%) and this was ameliorated by Epo (72.6%) and even prevented by enalapril (80.6%). Capillary length density was lower and the area of fibrosis more marked in vehicle-treated NX compared to sham-op. Capillary rarefaction and heart fibrosis were prevented in NX treated with Epo + enalapril and reduced in NX treated with enalapril and Epo + dihydralazine. Despite higher blood pressure, treatment with Epo reduced heart fibrosis but failed to prevent capillary loss. In parallel, expression of the p47phox NADPH oxidase was higher in untreated NX and was effectively reduced in NX treated with Epo + enalapril. Under basal conditions there was no difference between the groups regarding myocardial hypoxia as reflected by pimonidazole staining., Conclusion: Epo in combination with enalapril caused additive reduction of cardiac fibrosis and microvessel disease in 5/6 nephrectomized rats presumably by decreasing myocardial oxidative stress.

Renovascular hypertension (hypertension induced by renal artery stenosis) is a form of secondary hypertension caused by overactivation of the renin-angiotensin system by the ischemic kidney. Prevalence of renal artery stenosis (RAS) is estimated to be between 2% (unselected hypertensives) and 40% (older patients with other atherosclerotic comorbidities). Most cases of RAS are caused by atherosclerosis; other causes, including fibromuscular dysplasia, vasculitis, thromboembolism and aneurysms, are less frequent. The most frequent clinical presentation of RAS is hypertension. Acute kidney injury, rapid loss of kidney function and episodes of flash pulmonary edema are other symptoms of RAS, especially in bilateral disease. In current practice, RAS therapy includes antiplatelet (aspirin) and lipid-lowering (statin) therapy as well as angiotensin II receptor blockers or angiotensin-converting enzyme inhibitors as a first choice of antihypertensive agents. Angiotensin blockade, however, is contraindicated in bilateral RAS and in RAS of the solitary kidney. This review summarizes the current status and perspectives on the epidemiology and management of renovascular hypertension.

In humans, low glomerular numbers are related to hypertension, cardiovascular, and renal disease in adult life. The present study was designed 1) to explore whether above- or below-normal dietary salt intake during pregnancy influences nephron number and blood pressure in the offspring and 2) to identify potential mechanisms in kidney development modified by maternal sodium intake. Sprague-Dawley rats were fed low (0.07%)-, intermediate (0.51%)-, or high (3.0%)-sodium diets during pregnancy and lactation. The offspring were weaned at 4 wk and subsequently kept on a 0.51% sodium diet. The kidney structure was assessed at postnatal weeks 1 and 12 and the expression of proteins of interest at term and at week 1. Blood pressure was measured in male offspring by telemetry from postnatal month 2 to postnatal month 9. The numbers of glomeruli at weeks 1 and 12 were significantly lower and, in males, telemetrically measured mean arterial blood pressure after month 5 was higher in offspring of dams on a high- or low- compared with intermediate-sodium diet. A high-salt diet was paralleled by higher concentrations of marinobufagenin in the amniotic fluid and an increase in the expression of both sprouty-1 and glial cell-derived neutrophic factor in the offspring's kidney. The expression of FGF-10 was lower in offspring of dams on a low-sodium diet, and the expression of Pax-2 and FGF-2 was lower in offspring of dams on a high-sodium diet. Both excessively high and excessively low sodium intakes during pregnancy modify protein expression in offspring kidneys and reduce the final number of glomeruli, predisposing the risk of hypertension later in life.

Despite an only minor reduction in the glomerular filtration rate, uninephrectomy (UNX) markedly accelerates the rate of growth of atherosclerotic plaques in ApoE-/- mice. It has been suggested that vitamin D receptor (VDR) activation exerts an antiproliferative effect on vascular smooth muscle cells, but the side effects may limit its use. To assess a potentially different spectrum of actions, we compared the effects of paricalcitol and calcitriol on remodeling and calcification of the aortic wall in sham-operated and UNX ApoE-/- mice on a diet with normal cholesterol content. Sham-operated and UNX mice were randomly allotted to treatment with solvent, calcitriol (0.03 μg/kg) or paricalcitol (0.1 μg/kg) 5 times/wk intraperitoneally for 10 wk. Semithin (0.6 μm) sections of the aorta were analyzed by 1) morphometry, 2) immunohistochemistry, and 3) Western blotting of key proteins involved in vascular calcification and growth. Compared with sham-operated animals (5.6 ± 0.24), the wall-to-lumen ratio (x100) of the aorta was significantly higher in solvent- and calcitriol-treated UNX animals (6.64 ± 0.27 and 7.17 ± 0.81, respectively, P < 0.05), but not in paricalcitol-treated UNX (6.1 5 ± 0.32). Similar differences were seen with respect to maximal plaque height. Expression of transforming growth factor (TGF)-β1 in aortic intima/plaque was also significantly higher in UNX solvent and UNX calcitriol compared with sham-operated and UNX paricalcitol animals. Treatment with both paricalcitol and calcitriol caused significant elevation of VDR expression in the aorta. While at the dose employed paricalcitol significantly reduced TGF-β expression in plaques, calcitriol in contrast caused significant vascular calcification and elevated expression of related proteins (BMP2, RANKL, and Runx2).

Purpose of Review: There is an increasing evidence for a specific form of focal segmental glomerulosclerosis (FSGS) related to obesity. Its prevalence has progressively increased in past decades. This form of FSGS represents the tip of an iceberg: a much broader spectrum of renal malfunction is linked to visceral obesity, which is closely connected to, but not completely identical with, the concept of 'metabolic syndrome'., Recent Findings: The obesity-associated FSGS (obFSGS) is characterized by massive proteinuria and glomerular lesions which are similar to but less pronounced than in idiopathic FSGS, but the long-term prognosis is still dubious. The patholophysiology underlying obesity-associated renal pathology includes insulin resistance and salt sensitivity of blood pressure (BP); more recently adiponectin deficiency, hyperaldosteronism and many other pathogenetic factors have been identified. The abnormalities of renal structure in obese and morbidly obese individuals include increased kidney weight, glomerulomegaly, disorder of podocytes, mesangial expansion and more recently also abnormalities of the renal interstitium. This is accompanied by functional abnormalities, that is renal hyperperfusion, increased filtration fraction and albuminuria. Both obesity and metabolic syndrome have been identified as powerful predictors of chronic kidney disease (CKD) and end-stage renal disease (ESRD). This correlation is not fully explained by associated hypertension and prediabetes/diabetes., Summary: The link between progressive kidney disease and visceral obesity is of enormous public health importance. Apart from causing obFSGS, obesity aggravates most primary kidney diseases. Beyond standard therapy and weight loss, bariatric surgery has recently emerged as a successful intervention for obFSGS.

Unlabelled: The renin-angiotensin-aldosterone system (RAAS) plays an important role in the pathogenesis of hypertension as well as cardiovascular diseases and chronic kidney diseases. Among the most frequently studied RAAS gene polymorphisms are the angiotensin-converting enzyme insertion/deletion (I/D), angiotensinogen M235T and angiotensin II receptor type 1 A1166C polymorphisms. A significant correlation was found between the I/D polymorphism and cardiovascular morbidity and mortality rates. However, there was no significant correlation between I/D, M235T, A1166C polymorphism and arterial hypertension. The role of I/D polymorphism in the development and progression of chronic kidney disease is also non-conclusive. However, DD genotype has been identified as relevant for loss of renal function both in patients with IgA nephropathy and in patients of Asian origin with diabetic nephropathy. The relationship between RAAS gene polymorphism and transplanted kidney function has not been confirmed in large prospective and retrospective studies., Conclusion: there is no clear opinion concerning the influence of RAAS genotypes on the prevalence of post-transplant hypertension or erythrocytosis. Although a role of RAAS gene polymorphism in kidney function deterioration could not be ruled out, it is more likely that a variety of genetic and environmental factors influence the progression of chronic kidney diseases.

Primary hyperparathyroidism may occur as a part of an inherited syndrome in a combination with pancreatic endocrine tumours and/or pituitary adenoma, which is classified as Multiple Endocrine Neoplasia type 1 (MEN-1). This syndrome is caused by a germline mutation in MEN-1 gene encoding a tumour-suppressor protein, menin. Primary hyperparathyroidism is the most frequent clinical presentation of MEN-1, which usually appears in the second decade of life as an asymptomatic hypercalcemia and progresses through the next decades. The most frequent clinical presentation of MEN-1-associated primary hyperparathyroidism is bone demineralisation and recurrent kidney stones rarely followed by chronic kidney disease. The aim of this paper is to present the pathomechanism, screening procedures, diagnosis, and management of primary hyperparathyroidism in the MEN-1 syndrome. It also summarises the recent advances in the pharmacological therapy with a new group of drugs-calcimimetics.

Dyslipidemia is a known cardiovascular risk factor in subjects without kidney disease. In patients with kidney disease, however, the relation of dyslipidemia to cardiovascular risk is confounded and the underlying pathomechanisms are complex. Statins have proven to be highly effective in patients with initial stages of chronic kidney disease (CKD). Definite evidence from prospective controlled trials in hemodialyzed (diabetic) patients and transplanted patients is not available. Although no significant impact on the primary composite endpoint was observed, significant effects on secondary endpoints were noted. In our opinion, in view of excessive cardiovascular risk statins should be administered in patients with advanced CKD as well.

In patients with chronic renal failure, the heart undergoes remodeling, characterized by hypertrophy, fibrosis, and capillary/myocyte mismatch. In this study, we observed the effects of the calcimimetic agent R-568 on microvascular disease and interstitial fibrosis of the heart. Three-month-old male Sprague-Dawley rats were randomized to subtotal nephrectomy (SNX) or sham operation and subsequently received vehicle or R-568 under two experimental protocols, one for 1 month and the other for 3 months. Echocardiography, capillary length density, volume density of interstitial tissue, and immunohistochemistry and western blots (calcium-sensing receptor, collagen I and III, transforming growth factor (TGF)-beta, mitogen-activated protein kinases, and nitrotyrosine) were assessed. After SNX, weight and wall thickness of the left and the right ventricle were elevated. The ratio of heart to body weight and interventricular septum thickness were not changed by R-568 treatment. The left ventricle fractional shortening (by echocardiography) was lower in SNX; this was ameliorated by R-568. Reduced capillary length density and increased interstitial fibrosis in SNX were improved by R-568, which also reduced the expression of TGF-beta, and collagen I and III. The calcimimetic increased the activation of ERK-1/2, normalized p38 and JNK signaling, and prevented oxidative stress. We conclude that lowering parathyroid hormone with a calcimimetic significantly improves cardiac histology and function but not the left ventricular mass in SNX.

Background: Remodelling of the heart, characterized by hypertrophy, fibrosis and capillary/myocyte mismatch, is observed in patients with chronic renal failure. Low vitamin D levels have been associated with increased cardiovascular risk. In the present experimental study, we studied the effects of non-hypercalcaemic doses of calcitriol on microvascular disease and interstitial fibrosis of the heart., Methods: Three-month-old male Sprague-Dawley rats were randomized to subtotal nephrectomy (SNX) or sham operation and received calcitriol (6 ng/kg) or vehicle starting immediately thereafter. Blood pressure was measured by tail pletysmography. Albuminuria was measured by rat-specific ELISA. Capillary length density, volume density of interstitial tissue, immunohistochemistry and western blots (vitamin D receptor, collagen I, III, TGF-beta(1), MAP kinases and nitrotyrosine) were assessed after 12 weeks of treatment., Results: After SNX blood pressure, albuminuria and heart weight were elevated, capillary length density reduced and interstitial fibrosis increased. Treatment with calcitriol reduced albuminuria and prevented reduction of capillary density and expansion of interstitium without affecting significant blood pressure and heart weight after perfusion fixation. Calcitriol left high VEGF unchanged, but upregulated VEGF receptor 2 (presumably reversing VEGF resistance). Calcitriol reduced expression of profibrotic TGF-beta(1) and the accumulation of collagens I and III., Conclusions: Non-hypercalcaemic doses of calcitriol ameliorated, directly or indirectly, cardiac remodelling in sub- totally nephrectomized rats.