Pathomorphological sequence of nephron loss in diabetic nephropathy.

Following our previous reports on mesangial sclerosis and vascular proliferation in diabetic nephropathy (DN) (Kriz W, Löwen J, Federico G, van den Born J, Gröne E, Gröne HJ. Am J Physiol Renal Physiol 312: F1101-F1111, 2017; Löwen J, Gröne E, Gröne HJ, Kriz W. Am J Physiol Renal Physiol 317: F399-F410, 2019), we now describe the advanced stages of DN terminating in glomerular obsolescence and tubulointerstitial fibrosis based on a total of 918 biopsies. The structural aberrations emerged from two defects: 1) increased synthesis of glomerular basement membrane (GBM) components by podocytes and endothelial cells leading to an accumulation of GBM material in the mesangium and 2) a defect of glomerular vessels consisting of increased leakiness and an increased propensity to proliferate. Both defects may lead to glomerular degeneration. The progressing compaction of accumulated worn-out GBM material together with the retraction of podocytes out of the tuft and the collapse and hyalinosis of capillaries results in a shrunken tuft that fuses with Bowman's capsule (BC) to glomerular sclerosis. The most frequent pathway to glomerular decay starts with local tuft expansions that result in contacts of structurally intact podocytes to the parietal epithelium initiating the formation of tuft adhesions, which include the penetration of glomerular capillaries into BC. Exudation of plasma from such capillaries into the space between the parietal epithelium and its basement membrane causes the formation of insudative fluid accumulations within BC spreading around the glomerular circumference and, via the glomerulotubular junction, onto the tubule. Degeneration of the corresponding tubule develops secondarily to the glomerular damage, either due to cessation of filtration in cases of global sclerosis or due to encroachment of the insudative spaces. The degenerating tubules induce the proliferation of myofibroblasts resulting in interstitial fibrosis.NEW & NOTEWORTHY Based on analysis of 918 human biopsies, essential derangement in diabetic nephropathy consists of accumulation of worn-out glomerular basement membrane in the mesangium that may advance to global sclerosis. The most frequent pathway to nephron dropout starts with the penetration of glomerular capillaries into Bowman's capsule (BC), delivering an exudate into BC that spreads around the entire glomerular circumference and via the glomerulotubular junction onto the tubule, resulting in glomerular sclerosis and chronic tubulointerstitial damage.

Vascular injury biomarkers and stroke risk: A population-based study.

OBJECTIVE: Because little is known about associations between biomarkers of vascular injury and stroke risk, we evaluated associations between plasma concentrations of 6 novel biomarkers of vascular injury and stroke risk in a population-based study. METHODS: A case-cohort subset of EPIC-Heidelberg (European Prospective Investigation for Cancer and Nutrition-Heidelberg) including incident stroke cases (n = 335) and a random subcohort (n = 2,418) was selected. Concentrations of intercellular adhesion molecule 3 (ICAM3), soluble E-selectin and P-selectin, soluble thrombomodulin (sTM), thrombopoietin, and glycoprotein IIb/IIIa were measured in baseline plasma samples. Weighted Cox regression analyses were used to assess associations between biomarker levels and stroke risk. RESULTS: Median follow-up in the subcohort and among cases was 9.8 (range, 0.1-12.5) years and 6.2 (range, 0.01-12.1) years, respectively. ICAM3 levels were associated with increased risk of incident stroke after multivariable adjustment (hazard ratio, highest vs lowest quartile: 1.64 [95% confidence interval, 1.15-2.32]; p linear trend < 0.001). This association was more apparent for ischemic (1.65 [1.12-2.45]; p linear trend < 0.01) than for hemorrhagic stroke (1.29 [0.60-2.78]; p linear trend = 0.3). We further observed a borderline significant trend for a positive association between sTM and overall stroke risk (1.47 [0.99-2.19]; p linear trend = 0.05). CONCLUSIONS: In this population-based study, circulating levels of ICAM3, an adhesion molecule shed by leukocytes, were associated with increased risk of incident stroke. Further mechanistic studies are needed to elucidate the pathophysiology underlying this association. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that plasma levels of ICAM3 are associated with increased stroke risk.

Biomarkers of Vascular Injury and Type 2 Diabetes: A Prospective Study, Systematic Review and Meta-Analysis.

Data on biomarkers of vascular injury and type 2 diabetes (T2D) risk from prospective studies are lacking. We evaluated seven biomarkers of vascular injury in relation to T2D. Additionally, a meta-analysis was performed. From the EPIC-Heidelberg cohort, 2224 participants were followed-up from baseline for 16 (median) years. E-Selectin, P-Selectin, intercellular adhesion molecule 3 (ICAM3), thrombomodulin, thrombopoietin, glycoprotein IIb/IIIa and fibrinogen levels were measured in baseline blood samples. The systematic review and meta-analysis included prospective studies identified through MEDLINE and Web of Science that investigated the association between mentioned biomarkers and T2D. The study population included 55% women, median age was 50 years, and 163 developed T2D. ICAM3 was associated with lower T2D risk (fully adjusted HRhighest vs. lowest tertile 0.62 (95% CI: 0.43, 0.91)), but no other studies on ICAM3 were identified. Overall, fifteen studies were included in the systematic review and meta-analysis (6,171 cases). E-Selectin was associated with higher T2D risk HRper SD: 1.34 (95% CI: 1.16, 1.54; I2 = 63%, n = 9 studies), while thrombomodulin was associated with lower risk HRper SD: 0.82 (95% CI: 0.71, 0.95; I2 = 0%, n = 2 studies). In the EPIC-Heidelberg, ICAM3 was associated with lower T2D risk. The meta-analysis showed a consistent positive association between E-Selectin and T2D. It was also suggestive of an inverse association between thrombomodulin and T2D, although further studies are needed to corroborate this finding.

Author Correction: Biomarkers of vascular injury in relation to myocardial infarction risk: A population-based study.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Biomarkers of vascular injury in relation to myocardial infarction risk: A population-based study.

Little is known about circulating biomarkers of vascular injury in relation to cardiovascular disease risk. Thus, we evaluated associations between six novel markers (E-Selectin, P-Selectin, thrombomodulin, thrombopoietin, intercellular adhesion molecule 3 and GPIIb/IIIa) and established cardiovascular risk factors as well as the risk of myocardial infarction (MI) in a population-based study. Biomarkers were measured in pre-diagnostic plasma samples of a case-cohort subset of EPIC-Heidelberg (incident MI cases: n = 369, random sub-cohort: n = 2,418). Generalized Linear models were used to analyse cross-sectional associations between biomarkers and cardiovascular risk factors. Multivariable Cox Regression analyses were carried out to obtain Hazard Ratios (HRs) of MI across quartiles of biomarkers levels. Cross-sectional analyses showed that sex, smoking, alcohol consumption, diabetes and exogenous hormone use were associated with biomarker levels. However, while fibrinogen was associated with MI risk (HR per standard deviation: 2.97 [95% confidence interval: 1.61, 5.46]), none of the six novel biomarkers was associated with MI risk after multivariable adjustment. In a population-based cohort, biomarkers of vascular injury were associated with established cardiovascular risk factors, but not MI risk. The tested biomarkers may reflect pathophysiological alterations in cardiovascular disease development rather than constituting independent MI risk factors.

Longitudinal airway remodeling in active and past smokers in a lung cancer screening population.

OBJECTIVES: To longitudinally investigate smoking cessation-related changes of quantitative computed tomography (QCT)-based airway metrics in a group of heavy smokers. METHODS: CT scans were acquired in a lung cancer screening population over 4 years at 12-month intervals in 284 long-term ex-smokers (ES), 405 continuously active smokers (CS), and 31 subjects who quitted smoking within 2 years after baseline CT (recent quitters, RQ). Total diameter (TD), lumen area (LA), and wall percentage (WP) of 1st-8th generation airways were computed using airway analysis software. Inter-group comparison was performed using Mann-Whitney U test or Student's t test (two groups), and ANOVA or ANOVA on ranks with Dunn's multiple comparison test (more than two groups), while Fisher's exact test or chi-squared test was used for categorical data. Multiple linear regression was used for multivariable analysis. RESULTS: At any time, TD and LA were significantly higher in ES than CS, for example, in 5th-8th generation airways at baseline with 6.24 mm vs. 5.93 mm (p < 0.001) and 15.23 mm2 vs. 13.51 mm2 (p < 0.001), respectively. RQ showed higher TD (6.15 mm vs. 5.93 mm, n.s.) and significantly higher LA (14.77 mm2 vs. 13.51 mm2, p < 0.001) than CS after 3 years, and after 4 years. In multivariate analyses, smoking status independently predicted TD, LA, and WP at baseline, at 3 years and 4 years (p < 0.01-0.001), with stronger impact than pack years. CONCLUSIONS: Bronchial dimensions depend on the smoking status. Smoking-induced airway remodeling can be partially reversible after smoking cessation even in long-term heavy smokers. Therefore, QCT-based airway metrics in clinical trials should consider the current smoking status besides pack years. KEY POINTS: • Airway lumen and diameter are decreased in active smokers compared to ex-smokers, and there is a trend towards increased airway wall thickness in active smokers. • Smoking-related airway changes improve within 2 years after smoking cessation. • Smoking status is an independent predictor of airway dimensions.

Effect of smoking cessation on quantitative computed tomography in smokers at risk in a lung cancer screening population.

OBJECTIVE: To longitudinally evaluate effects of smoking cessation on quantitative CT in a lung cancer screening cohort of heavy smokers over 4 years. METHODS: After 4 years, low-dose chest CT was available for 314 long-term ex-smokers (ES), 404 continuous smokers (CS) and 39 recent quitters (RQ) who quitted smoking within 2 years after baseline CT. CT acquired at baseline and after 3 and 4 years was subjected to well-evaluated densitometry software, computing mean lung density (MLD) and 15th percentile of the lung density histogram (15TH). RESULTS: At baseline, active smokers showed significantly higher MLD and 15TH (-822±35 and -936±25 HU, respectively) compared to ES (-831±31 and -947±22 HU, p<0.01-0.001). After 3 years, CS again had significantly higher MLD and 15TH (-801±29 and -896±23 HU) than ES (-808±27 and -906±20 HU, p<0.01-0.001) but also RQ (-813±20 and -909±15 HU, p<0.05-0.001). Quantitative CT parameters did not change significantly after 4 years. Importantly, smoking status independently predicted MLD at baseline and year 3 (p<0.001) in multivariate analysis. CONCLUSION: On quantitative CT, lung density is higher in active smokers than ex-smokers, and sustainably decreases after smoking cessation, reflecting smoking-induced inflammation. Interpretations of quantitative CT data within clinical trials should consider smoking status. KEY POINTS: • Lung density is higher in active smokers than ex-smokers. • Lung density sustainably decreases after smoking cessation. • Impact of smoking cessation on lung density is independent of potentially confounding factors. • Smoke-induced pulmonary inflammation and particle deposition influence lung density on CT.

Primary preventive potential for stroke by avoidance of major lifestyle risk factors: the European Prospective Investigation into Cancer and Nutrition-Heidelberg cohort.

BACKGROUND AND PURPOSE: Because primary prevention of stroke is a priority, our aim was to assess the primary preventive potential of major lifestyle risk factors for stroke in middle-aged women and men. METHODS: Among 23,927 persons, 551 (195 women and 356 men) had a first diagnosis of stroke during an average follow-up of 12.7 years. Using Cox proportional hazards models, we estimated the associations of adiposity, smoking, physical activity, alcohol consumption, and diet with risk of developing stroke. A competing risk model built from cause-specific proportional hazards models accounting for concurrent risk of death was used to calculate relative and absolute reductions in stroke occurrences that could have been achieved by maintaining a healthy lifestyle pattern. RESULTS: Obesity, smoking, alcohol consumption, diet, and physical inactivity were each identified as modifiable lifestyle risk factors for stroke. About 38% of stroke cases were estimated as preventable through adherence to a healthy lifestyle profile (never smoking, maintaining optimal body mass index and waist circumference, performing physical exercise, consuming a moderate quantity of alcohol, and following a healthy dietary pattern). Age-specific estimates of 5-year incidence rates for stroke in the actual cohort and in a hypothetical, comparable cohort of individuals following a healthy lifestyle would be reduced from 153 to 94 per 100,000 women and from 261 to 161 per 100,000 men for the age group 60 to 65 years. CONCLUSIONS: Our analysis confirms the strong primary prevention potential for stroke based on avoidance of excess body weight, smoking, heavy alcohol consumption, unhealthy diet, and physical inactivity.

Primary preventive potential of major lifestyle risk factors for acute myocardial infarction in men: an analysis of the EPIC-Heidelberg cohort.

The aim of this study was to assess the preventive potential of major lifestyle risk factors for acute myocardial infarction (AMI) in middle-aged men. Among 10,981 men in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition, aged 40.2-65.8 years when recruited, 378 developed first-ever AMI during a median follow-up period of 11.4 years. Current smoking, excess body weight, being physically inactive, but not high alcohol consumption, were identified as the major lifestyle risk factors for AMI using Cox regression analysis. A competing AMI risk model built from cause-specific Cox regression models and considering the risk of death predicted 353 AMI cases, 182 (51.6%) of which were estimated as preventable through adherence to a healthy lifestyle profile (never smoking, normal body weight, physically active, and moderate alcohol consumption). The calculated age-specific 5-year incidence rates for AMI in the actual cohort and in a hypothetical, comparable cohort with all men following the healthy lifestyle profile were 128 and 39, respectively, per 100,000 person-years for the age group 40-44, increasing to 468 and 307 per 100,000 person-years for the age group 65-69. The estimated AMI incidence rates for men with the healthy lifestyle profile are still somewhat higher than the average rates reported for documented low-incidence regions, such as parts of Japan. Our analysis confirms the strong primary preventive potential for AMI based on avoidance of smoking and excess body weight, and on regular physical activity.

Sulforaphane decreases kidney injury after transplantation in rats: role of mitochondrial damage.

BACKGROUND: Sulforaphane is a naturally occuring antioxidative and anti-inflammatory isothiocyanat. In this study, its impact on experimental kidney transplantation was evaluated. MATERIAL AND METHODS: Male Brown Norway rats (n=112) were used as experimental animals. Donor kidneys were harvested and stored for 12 hours in HTK-solution at 4°C. D,L-Sulforaphane (4.4 mg/kg BW; 0.2ml) or normal saline (0.2 ml) was given i.v. to the recipients 24 and 1 hour before, and 6 hours after transplantation. Recipients were nephrectomized bilaterally and subsequently transplantation was performed. After 6 and 48 hours, biopsies were taken and processed for light and electron microscopy. Graft function was monitored using serum values of creatinine and BUN after 6 and 24 hours. Quantitative real-time PCR was used to detect differences in SOD2-gene expression after 6 hours and apoptotic activity was detected after 6 hours using propidium iodide flow cytometry. RESULTS: Recipient preconditioning improved reperfusion damage index from 12.8±1.6 in controls to 8.8±1.8 (p<0.001). Serum levels of creatinine and BUN decreased from 4.29±0.25 mg/dl and 119±23 mg/dl in controls to 3.65±0.7 mg/dl and 81±19 mg/dl (p<0.05). The number of severely injured tubules decreased (p<0.05). Apoptotic activity was increased in SFN-treated rats. Mitochondrial microstructure was better preserved after SFN, while SOD 2 gene expression increased (p<0.05). CONCLUSIONS: SFN ameliorates ischemia/reperfusion injury after KTx, most likely through anti-oxidative effects.

Exposure of pregnant rats to cigarette-smoke condensate causes glomerular abnormalities in offspring.

BACKGROUND: Higher blood pressure and albuminuria are found in offspring of mothers who smoke during pregnancy. Whether or not kidney development is affected by maternal smoking is unknown. METHODS: Sprague-Dawley rats were randomly allocated to twice-daily cigarette smoke and nicotine condensate (1 mg/kg) or vehicle at day 10 of pregnancy until delivery. RESULTS: Exposed offspring did not differ from control offspring with respect to body weight, kidney weight, albuminuria, and creatinine clearance. Both male and female offspring had higher tail-plethysmographic blood pressures and lower mean glomerular volume, podocyte, mesangial-cell, and endothelial-cell number, compared to control offspring. CONCLUSIONS: The data document that prenatal exposure to cigarette-smoke condensate containing nicotine influences normal kidney development and could predispose to higher blood pressures later in life.

Cellular senescence limits regenerative capacity and allograft survival.

Long-term graft survival after kidney transplantation remains unsatisfactory and unpredictable. Interstitial fibrosis and tubular atrophy are major contributors to late graft loss; features of tubular cell senescence, such as increased p16(INK4a) expression, associate with these tubulointerstitial changes, but it is unknown whether the relationship is causal. Here, loss of the INK4a locus in mice, which allows escape from p16(INK4a)-dependent senescence, significantly reduced interstitial fibrosis and tubular atrophy and associated with improved renal function, conservation of nephron mass, and transplant survival. Compared with wild-type controls, kidneys from INK4a(-/-) mice developed significantly less interstitial fibrosis and tubular atrophy after ischemia-reperfusion injury. Consistently, mice that received kidney transplants from INK4a/ARF(-/-) donors had significantly better survival 21 days after life-supporting kidney transplantation and developed less tubulointerstitial changes. This correlated with higher proliferative rates of tubular cells and significantly fewer senescent cells. Taken together, these data suggest a pathogenic role of renal cellular senescence in the development of interstitial fibrosis and tubular atrophy and kidney graft deterioration by preventing the recovery from injury. Inhibiting premature senescence could have therapeutic benefit in kidney transplantation but has to be balanced against the risks of suspending antitumor defenses.

Effects of a preconditioning oral nutritional supplement on pig livers after warm ischemia.

Background. Several approaches have been proposed to pharmacologically ameliorate hepatic ischemia/reperfusion injury (IRI). This study was designed to evaluate the effects of a preconditioning oral nutritional supplement (pONS) containing glutamine, antioxidants, and green tea extract on hepatic warm IRI in pigs. Methods. pONS (70 g per serving, Fresenius Kabi, Germany) was dissolved in 250 mL tap water and given to pigs 24, 12, and 2 hrs before warm ischemia of the liver. A fourth dose was given 3 hrs after reperfusion. Controls were given the same amount of cellulose with the same volume of water. Two hours after the third dose of pONS, both the portal vein and the hepatic artery were clamped for 40 min. 0.5, 3, 6, and 8 hrs after reperfusion, heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), portal venous flow (PVF), hepatic arterial flow (HAF), bile flow, and transaminases were measured. Liver tissue was taken 8 hrs after reperfusion for histology and immunohistochemistry. Results. HR, MAP, CVP, HAF, and PVF were comparable between the two groups. pONS significantly increased bile flow 8 hrs after reperfusion. ALT and AST were significantly lower after pONS. Histology showed significantly more severe necrosis and neutrophil infiltration in controls. pONS significantly decreased the index of immunohistochemical expression for TNF-α, MPO, and cleaved caspase-3 (P < 0.001). Conclusion. Administration of pONS before and after tissue damage protects the liver from warm IRI via mechanisms including decreasing oxidative stress, lipid peroxidation, apoptosis, and necrosis.

Does pregnancy or pregnancy loss increase later maternal risk of diabetes?

Evidence that childbearing is associated with future development of diabetes remains conflicting and the role of pregnancy loss in this association has not been investigated. We aimed to examine whether pregnancy and/or pregnancy loss (miscarriage, abortion, or stillbirth) are associated with maternal higher risk of diabetes later in life, using a population-based prospective cohort study (mean follow-up = 10.7 years), including 13,612 women (aged 35-65 at baseline). We found pregnancy per se did not change the risk of diabetes after considering the effect of education, smoking, alcohol consumption, physical activity, BMI, waist/hip ratio, hypertension, and hyperlipidemia (fully-adjusted OR: 1.04, 95 % CI: 0.82-1.31). Having more than four live births was associated with around two times higher risk of diabetes later in life (fully-adjusted OR: 1.77, 95 % CI: 1.12-2.80). Having more than two miscarriages was associated with about two-fold higher risk of diabetes (fully-adjusted Odd ratio (OR): 1.85, 95 % CI: 1.17-2.93). After further adjustment for parity, the higher risk of diabetes in those who had history of more than two miscarriages did not change substantially (OR: 1.82; 95 % CI: 1.15-2.88), but the association between more than four live births and diabetes disappeared when the role of pregnancy loss was considered (fully-adjusted HR: 1.06; 95 % CI: 0.54-2.08). No significant association was found between abortion, stillbirth and risk of maternal diabetes. Pregnancy per se did not increase risk of diabetes. Women who experience more than two miscarriages are at around two times higher risk of diabetes later in life. The association between high parity and diabetes is mediated by history of miscarriages and known risk factors of diabetes. The underlying reason for association between miscarriage and diabetes needs further investigation.

Carnosine treatment largely prevents alterations of renal carnosine metabolism in diabetic mice.

Recently, we identified an allelic variant of human carnosinase 1 (CN1) that results in increased enzyme activity and is associated with susceptibility for diabetic nephropathy in humans. Investigations in diabetic (db/db) mice showed that carnosine ameliorates glucose metabolism effectively. We now investigated the renal carnosinase metabolism in db/db mice. Kidney CN1 activity increased with age and was significantly higher in diabetic mice compared to controls. Increased CN1 activity did not affect renal carnosine levels, but anserine concentrations were tenfold lower in db/db mice compared to controls (0.24±0.2 vs. 2.28±0.3 nmol/mg protein in controls; p<0.001). Homocarnosine concentrations in kidney tissue were low in both control and db/db mice (below 0.1 nmol/mg protein, p=n.s.). Carnosine treatment for 4 weeks substantially decreased renal CN1 activity in diabetic mice (0.32±0.3 in non-treated db/db vs. 0.05±0.05 µmol/mg/h in treated db/db mice; p<0.01) close to normal activities. Renal anserine concentrations increased significantly (0.24±0.2 in non-treated db/db vs. 5.7±1.2 µmol/mg/h in treated db/db mice; p<0.01), while carnosine concentrations remained unaltered (53±6.4 in non-treated vs. 61±15 nmol/mg protein in treated db/db mice; p=n.s.). Further, carnosine treatment halved proteinuria and reduced vascular permeability to one-fifth in db/db mice. In renal tissue of diabetic mice carnosinase activity is significantly increased and anserine concentrations are significantly reduced compared to controls. Carnosine treatment largely prevents the alterations of renal carnosine metabolism.

Transforming growth factor ß1 oppositely regulates the hypertrophic and contractile response to ß-adrenergic stimulation in the heart.

BACKGROUND: Neuroendocrine activation and local mediators such as transforming growth factor-ß1 (TGF-ß1) contribute to the pathobiology of cardiac hypertrophy and failure, but the underlying mechanisms are incompletely understood. We aimed to characterize the functional network involving TGF-ß1, the renin-angiotensin system, and the ß-adrenergic system in the heart. METHODS: Transgenic mice overexpressing TGF-ß1 (TGF-ß1-Tg) were treated with a ß-blocker, an AT1-receptor antagonist, or a TGF-ß-antagonist (sTGFßR-Fc), were morphologically characterized. Contractile function was assessed by dobutamine stress echocardiography in vivo and isolated myocytes in vitro. Functional alterations were related to regulators of cardiac energy metabolism. RESULTS: Compared to wild-type controls, TGF-ß1-Tg mice displayed an increased heart-to-body-weight ratio involving both fibrosis and myocyte hypertrophy. TGF-ß1 overexpression increased the hypertrophic responsiveness to ß-adrenergic stimulation. In contrast, the inotropic response to ß-adrenergic stimulation was diminished in TGF-ß1-Tg mice, albeit unchanged basal contractility. Treatment with sTGF-ßR-Fc completely prevented the cardiac phenotype in transgenic mice. Chronic ß-blocker treatment also prevented hypertrophy and ANF induction by isoprenaline, and restored the inotropic response to ß-adrenergic stimulation without affecting TGF-ß1 levels, whereas AT1-receptor blockade had no effect. The impaired contractile reserve in TGF-ß1-Tg mice was accompanied by an upregulation of mitochondrial uncoupling proteins (UCPs) which was reversed by ß-adrenoceptor blockade. UCP-inhibition restored the contractile response to ß-adrenoceptor stimulation in vitro and in vivo. Finally, cardiac TGF-ß1 and UCP expression were elevated in heart failure in humans, and UCP--but not TGF-ß1--was downregulated by ß-blocker treatment. CONCLUSIONS: Our data support the concept that TGF-ß1 acts downstream of angiotensin II in cardiomyocytes, and furthermore, highlight the critical role of the ß-adrenergic system in TGF-ß1-induced cardiac phenotype. Our data indicate for the first time, that TGF-ß1 directly influences mitochondrial energy metabolism by regulating UCP3 expression. ß-blockers may act beneficially by normalizing regulatory mechanisms of cellular hypertrophy and energy metabolism.

Stimulation of the calcium-sensing receptor stabilizes the podocyte cytoskeleton, improves cell survival, and reduces toxin-induced glomerulosclerosis.

Calcimimetics increase the sensitivity of the parathyroid calcium-sensing receptor to extracellular calcium for efficient control of hyperparathyroidism. Recent studies suggest that there are beneficial effects of calcimimetics beyond the control of bone and mineral homeostasis. Here, we tested whether the calcium-sensing receptor is also expressed and functionally relevant in podocytes. Analysis of microarray data using Gene Set Enrichment Analysis found that the calcimimetic R-568 influenced various pathways related to oxidative stress, cytoskeletal regulation, cell proliferation, and survival in cultured podocytes. R-568 induced a dose- and time-dependent phosphorylation of the ERK1/2-P90RSK-CREB signaling cascade, and induced pro-survival phosphorylation of BAD and Bcl-xl, thus reducing puromycin aminonucleoside (PAN)-induced podocyte apoptosis by half. Moreover, R-568 preserved the actin cytoskeleton in podocytes exposed to PAN and improved recovery from exposure to cytochalasin D, a reversible inhibitor of actin polymerization. In rats, co-administration of R-568 prevented the proteinuria caused by a single dose of PAN and attenuated the glomerulosclerosis and loss of GFR caused by repetitive puromycin treatment. Hence, calcimimetics limit podocyte damage by antiapoptotic and cytoskeleton-stabilizing effects and may constitute a new approach in the prevention and treatment of glomerular disease.

Benfotiamine protects against peritoneal and kidney damage in peritoneal dialysis.

Residual renal function and the integrity of the peritoneal membrane contribute to morbidity and mortality among patients treated with peritoneal dialysis. Glucose and its degradation products likely contribute to the deterioration of the remnant kidney and damage to the peritoneum. Benfotiamine decreases glucose-induced tissue damage, suggesting the potential for benefit in peritoneal dialysis. Here, in a model of peritoneal dialysis in uremic rats, treatment with benfotiamine decreased peritoneal fibrosis, markers of inflammation, and neovascularization, resulting in improved characteristics of peritoneal transport. Furthermore, rats treated with benfotiamine exhibited lower expression of advanced glycation endproducts and their receptor in the peritoneum and the kidney, reduced glomerular and tubulointerstitial damage, and less albuminuria. Increased activity of transketolase in tissue and blood contributed to the protective effects of benfotiamine. In primary human peritoneal mesothelial cells, the addition of benfotiamine led to enhanced transketolase activity and decreased expression of advanced glycation endproducts and their receptor. Taken together, these data suggest that benfotiamine protects the peritoneal membrane and remnant kidney in a rat model of peritoneal dialysis and uremia.

High-dose enalapril treatment reverses myocardial fibrosis in experimental uremic cardiomyopathy.

AIMS: Patients with renal failure develop cardiovascular alterations which contribute to the higher rate of cardiac death. Blockade of the renin angiotensin system ameliorates the development of such changes. It is unclear, however, to what extent ACE-inhibitors can also reverse existing cardiovascular alterations. Therefore, we investigated the effect of high dose enalapril treatment on these alterations. METHODS: Male Sprague Dawley rats underwent subtotal nephrectomy (SNX, n = 34) or sham operation (sham, n = 39). Eight weeks after surgery, rats were sacrificed or allocated to treatment with either high-dose enalapril, combination of furosemide/dihydralazine or solvent for 4 weeks. Heart and aorta were evaluated using morphometry, stereological techniques and TaqMan PCR. RESULTS: After 8 and 12 weeks systolic blood pressure, albumin excretion, and left ventricular weight were significantly higher in untreated SNX compared to sham. Twelve weeks after SNX a significantly higher volume density of cardiac interstitial tissue (2.57±0.43% in SNX vs 1.50±0.43% in sham, p<0.05) and a significantly lower capillary length density (4532±355 mm/mm(3) in SNX vs 5023±624 mm/mm(3) in sham, p<0.05) were found. Treatment of SNX with enalapril from week 8-12 significantly improved myocardial fibrosis (1.63±0.25%, p<0.05), but not capillary reduction (3908±486 mm/mm(3)) or increased intercapillary distance. In contrast, alternative antihypertensive treatment showed no such effect. Significantly increased media thickness together with decreased vascular smooth muscles cell number and a disarray of elastic fibres were found in the aorta of SNX animals compared to sham. Both antihypertensive treatments failed to cause complete regression of these alterations. CONCLUSIONS: The study indicates that high dose ACE-I treatment causes partial, but not complete, reversal of cardiovascular changes in SNX.