Glucagon-like peptide-1 and vitamin D: anti-inflammatory response in diabetic kidney disease in db/db mice and in cultured endothelial cells.

BACKGROUND: Glucagon-like peptide-1 (GLP-1) is a gut incretin hormone that stimulates insulin secretion and may affect the inflammatory pathways involved in diabetes mellitus. Calcitriol, an active form of vitamin D, plays an important role in renal, endothelial and cardiovascular protection. We evaluated the anti-inflammatory and histologic effects of a GLP-1 analogue (liraglutide) and of calcitriol in a db/db mouse diabetes model and in endothelial cells exposed to a diabetes-like environment. METHODS: Diabetic db/db mice were treated with liraglutide and calcitriol for 14 weeks, after which the kidneys were perfused and removed for mRNA and protein analysis and histology. Endothelial cells were stimulated with advanced glycation end products (AGEs), glucose, liraglutide and calcitriol. Total RNA and protein were extracted and analysed for the expression of selected inflammatory markers. RESULTS: Typical histological changes, glomerular enlargement and mesangial expansion were seen in db/db mice compared with control mice. Glomerular hypertrophy was ameliorated with liraglutide, compared with db/db controls. Liraglutide up-regulated endothelial nitric oxide synthase protein expression compared with the db/db control group and down-regulated p65 protein expression. Calcitriol did not further improve the beneficial effect observed on protein expression. In endothelial cells, liraglutide treatment exhibited a dose-dependent ability to prevent an inflammatory response in the selected markers: thioredoxin-interacting protein, p65, IL6 and IL8. In most gene and protein expressions, addition of calcitriol did not enhance the effect of liraglutide. CONCLUSIONS: The GLP-1 analogue liraglutide prevented the inflammatory response observed in endothelial cells exposed to a diabetes-like environment and in db/db mice at the level of protein expression and significantly ameliorated the glomerular hypertrophy seen in the diabetic control group. Copyright © 2016 John Wiley & Sons, Ltd.

Vitamin D manipulates miR-181c, miR-20b and miR-15a in human umbilical vein endothelial cells exposed to a diabetic-like environment.

BACKGROUND: High blood and tissue concentrations of glucose and advanced glycation end-products are believed to play an important role in the development of vascular complications in patients with diabetes mellitus (DM) and chronic kidney disease. MicroRNAs (miRNA) are non-coding RNAs that regulate gene expression in a sequence specific manner. MiRNA are involved in various biological processes and become novel biomarkers, modulators and therapeutic targets for diseases such as cancer, atherosclerosis, and DM. Calcitriol (the active form of vitamin D) may inhibit endothelial proliferation, blunt angiogenesis, and be a cardioprotective agent. Calcitriol deficiency is a risk factor for DM and hypertension. The aim of this project was to study the miRNA microarray expression changes in human umbilical vein endothelial cells (HUVEC) treated in a diabetic-like environment with the addition of calcitriol. METHODS: HUVEC were treated for 24 h with 200 µg/ml human serum albumin (HSA) and 100 mg/dl glucose (control group) or 200 µg/ml AGE-HSA, and 250 mg/dl glucose (diabetic-like environment), and physiological concentrations (10-10 mol/l) of calcitriol. miRNA microarray analysis and real time PCR to validate the miRNA expression profile and mRNA target gene expression were carried out. RESULTS: Compared to control, 31 mature human miRNA were differentially expressed in the presence of a diabetic-like environment. Addition of physiological concentrations of calcitriol revealed 39 differentially expressed mature human miRNA. MiR-181c, miR-15a, miR-20b, miR-411, miR-659, miR-126 and miR-510 were selected for further analysis because they are known to be modified in DM and in other biological disorders. The predicted targets of these miRNA (such as KLF6, KLF9, KLF10, TXNIP and IL8) correspond to molecular and biological processes such as immune and defense responses, signal transduction and regulation of RNA. CONCLUSION: This study identified novel miRNA in the field of diabetic vasculopathy and might provide new information about the effect of vitamin D on gene regulation induced by a diabetic-like environment. New gene targets that are part of the molecular mechanism and the therapeutic treatment in diabetic vasculopathy are highlighted.

The potential roles of FGF23 and Klotho in the prognosis of renal and cardiovascular diseases.

Fibroblast growth factor (FGF) 23 and Klotho are two factors associated with several metabolic disorders. Similar to humans, accelerated aging processes characterized by chronic vascular disease, bone demineralization, skin atrophy and emphysema have been recognized in FGF23-null mice and Klotho-deficient mice. The role of these factors in the control of mineral metabolism homeostasis have been shown recently, particularly at the level of parathyroid cells and also in modulating active vitamin D production, two phenomena which are relevant in the presence of chronic kidney disease. In addition, the hormonal affect of circulating FGF23 and Klotho proteins on vascular reactivity, either directly on endothelial cell functions or indirectly by modulating the brain endothelin-1-dependent sympathetic nervous system activity, has contributed to understanding their role in the pathophysiology of hypertension and atherosclerotic vasculopathies. Consequently, very recent clinical investigations seem to confirm the involvement of Klotho in modulating the severity and prognosis of human cardiovascular (CV) disorders and longevity. The present review reports data related to the possible interactive effects of Klotho and FGF23 on the prognosis of renal and CV diseases.

Blood pressure values in 8-12 year old children with a history of intrauterine growth retardation.

BACKGROUND: Epidemiological studies have found that intrauterine growth retardation (IUGR) is closely related to hypertension and is associated with a reduced number of nephrons that may be a predisposing factor for the development of hypertension. OBJECTIVES: To determine whether blood pressure levels of children with a history of IUGR are higher than those of children without IUGR. METHODS: Diastolic, systolic and mean arterial blood pressure levels were measured in 64 children aged 8-12 years old with a history of IUGR (mean birth weight 1780 +/- 422 g) and compared with 64 age and gender-matched controls who had a normal birth weight (mean 3134 +/- 594 g). RESULTS: Contrary to previous reports, systolic blood pressure values were significantly lower in the IUGR group compared to the controls (91.6 +/- 11.3 vs. 96.6 +/- 13.9, P = 0.027). There was no difference in diastolic blood pressure values. In the IUGR group, systolic blood pressure correlated significantly with current weight (P < 0.01) and body mass index (P < 0.05), and diastolic blood pressure with weight gain between age 2 and 4 years (P < 0.05). None of the blood pressure values correlated with birth weight. CONCLUSIONS: Children born with IUGR have lower systolic blood pressure levels than matched controls at age 8-12 years. These data indicate that postnatal weight gain in this group has a greater impact on systolic blood pressure than birth weight.

[Laparoscopic management of peritoneal dialysis catheters].

INTRODUCTION: Peritoneal dialysis (PD) is one of the established methods for the management of patients with end-stage renal failure. Laparoscopy has been used to assist in the insertion of new catheters as well as for the salvage of malfunctioning peritoneal dialysis catheters (PDC). OBJECTIVES: The purpose of this retrospective study was to review our experience in the utilization of laparoscopy for the management of PDC. METHODS: We reviewed the charts of all consecutive patients who had undergone either a ap-assisted insertion of a PDC utilizing a modified peritoneoscopic Y-TEC [Medigroup, Inc, Oswego, Ill) technique (YT) under direct laparoscopic vision or laparoscopic-assisted procedures for the salvage of a malfunctioning PD catheter. RESULTS: Twenty nine patients had undergone 43 procedures that included the insertion of a new PD catheter using the modified YT technique, YT with simultaneous adhesiolysis and omentectomy; YT with repair of an epigastric hernia, omentectomy, adhesiolysis and repositioning of PDC; and ravage and repositioning of the obstructed PD catheter in all patients who needed repositioning of the catheter, the PDC was fixed with an intraperitoneal suture to the lower anterior abdominal wall. Postoperatively, malfunction of the catheter was found in one patient due to reclotting of PDC caused by oozing as a result of extensive adhesiolysis. One patient needed emergent laparotomy due to small bowel perforation that was missed during a difficult laparoscopic adhesiolysis. CONCLUSIONS: Laparoscopic surgery may be helpfuL for the diagnosis and the management of a malfunctioning PDC. A modified YT technique is safe and may be one of the alternative methods for the placement of a PDC.

Endothelial pro-atherosclerotic response to extracellular diabetic-like environment: possible role of thioredoxin-interacting protein.

BACKGROUND. High blood and tissue concentrations of glucose and advanced glycation end-products (AGEs) are thought to play an important role in the development of vascular diabetic complications. Therefore, the impact of extracellular AGEs and different glucose concentrations was evaluated by studying the gene expressions and the underlying cellular pathways involved in the development of inflammatory pro-atherosclerotic processes observed in cultured endothelial cells. METHODS. Fresh human umbilical vein cord endothelial cells (HUVEC) were treated in the presence of elevated extracellular glucose concentrations (5.5-28 mmol/l) with and without AGE-human serum albumin (HSA). Affymetrix GeneChip(R) Human Gene 1.0 ST arrays were used for gene expression analysis (total 20 chips). Genes of interest were further validated using real-time PCR and western blot techniques. RESULTS. Microarray analysis revealed significant changes in some gene expressions in the presence of the different stimuli, suggesting that different pathways are involved. Six genes were selected for validation as follows: thioredoxin-interacting protein (TXNIP), thioredoxin (TXN), nuclear factor of kappa B (NF-kappaB), interleukin 6 (IL6), interleukin 8 (IL8) and receptor of advanced glycation end-products (RAGE). Interestingly, it was found that the association of AGEs together with the highest pathophysiological concentration of glucose (28 mmol/l) diminished the expression of these specific genes, excluding TXN. CONCLUSIONS. In the present model that mimics a diabetic environment, the relatively short-term experimental conditions used showed an unexpected blunting action of AGEs in the presence of the highest glucose concentration (28 mmol/l). The interactive cellular pathways involved in these processes should be further investigated.

Low extracellular Ca2+: a mediator of endothelial inflammation.

BACKGROUND: Recent studies have suggested that vitamin D and an imbalance in calcium homeostasis may have an impact on the cardiovascular system. The aim of this study was to assess the impact of different concentrations of extracellular Ca(2+) on human umbilical vein cord endothelial cells (HUVEC) by measuring its effect on parameters involved in the pathogenesis of vascular inflammatory responses. METHODS: HUVEC were grown in the 3.5, 4.5 or 5.8 mg/dL concentration of extracellular Ca(2+) for 2-3 weeks. Expression of adhesion molecules was analysed by flow cytometry. Endothelial nitric oxide synthase (eNOS), receptor of advanced glycation end-product (RAGE) and interleukin-6 (IL-6) mRNA expressions were determined by real-time PCR. eNOS, inhibitor kappa Balpha (IkappaBalpha) and phosphorylated IkappaBalpha protein levels by Western blot, eNOS activity by conversion of [(14)C]-arginine to [(14)C]-citrulline, IL-6 and osteoprotegerin (OPG) secretion by ELISA and DNA-binding activity of nuclear factor kappa B (NFkappaB)-p65 were assayed colorimetrically in nuclear extracts. RESULTS: In the presence of low Ca(2+) (3.5 mg/dL), protein expressions and activity of eNOS were diminished, while the protein expressions of intercellular adhesion molecule-1 (ICAM-1), as well as the mRNA expressions of RAGE and IL-6, were elevated. The protein secretions of IL-6 and OPG were also stimulated in low Ca(2+) concentration. At this concentration, the DNA-binding activity of NFkappaB was enhanced, probably due to the decreased level of IkappaBalpha. CONCLUSIONS: These results suggest that lower extracellular ionized Ca(2+) may play a relevant role in modifying endothelial cells functions.

[Stents in dialysis vascular access--do they promise improved high quality prolonged access use].

UNLABELLED: The life expectancy of dialysis patients depends, to a large extent, on blood access which provides uninterrupted and efficient treatment. Dialysis access created by a direct anastomosis between artery and vein usually allows normal dialysis for many years. Blood access by a bridge graft between artery and vein functions for a much shorter time and occludes chiefly because of endothelial hyperplasia at the graft vein anastomosis. This type of fistula is created when the veins of the patient are small. During the last few years the dialysis population is increasingly composed of adult and elderly patients suffering from diabetes mellitus, hypertension, dyslipidemias and atheromatous vascular disease so that a relatively large proportion of dialysis accesses are created using a bridge graft. Since we currently do not have the knowledge of how to arrest or delay the processes which lead to access occlusion, attempts are made to implement prophylactic strategies, find stenoses and dilate them before the access fails. Up to date, controlled trials have not succeeded in proving that this method prolongs access use. These trials did not describe the use of stents following dilatation. MATERIALS AND METHODS: Between July 2002 and May 2005, 238 angiographies were performed on blood accesses including 179 angioplasties of stenoses. In sixteen patients a stent was deployed during the angioplasty. RESULTS: In ten patients dialysis was performed using the same access up to the end of the study period, an average of 43 months from the creation of the access. Three patients died with a functioning access and in three the access occluded during the period of followup. DISCUSSION: This study shows that the use of stents following angioplasty of dialysis access stenoses can improve the duration of use of accesses created through grafts.

Blood-pressure categories in adolescence predict development of hypertension in accordance with the European guidelines.

BACKGROUND: It is estimated that by 2025, >1.5 billion adults worldwide will be hypertensive. Early identification of the population at risk would lead to improved utilization of preventive measures. We aimed to evaluate whether baseline body mass index (BMI) and blood-pressure (BP) values during adolescence (categorized according to the guidelines of the European Society of Hypertension-European Society of Cardiology) are of use in predicting the development of hypertension in young adulthood. METHODS: The study population consisted of 18,513 male regular army personnel who were initially recruited at 16.5 and 19 years of age between 1976 and 1996. The main outcome was the percentage of subjects who developed hypertension (> or =140 systolic and > or =90 diastolic) at ages 26 to 45 years. RESULTS: At baseline, BP categories were: optimal, 5961 (32.2%); normal, 7998 (43.2%); and high normal, 4554 (24.6%). Moreover, 1377 (7.4%) were overweight (BMI 25-30 kg/m(2)), and 199 (1.1%) were obese (BMI >30 kg/m(2)). At follow-up, 2277 (12.3%) subjects developed hypertension. The percentages progressing to hypertension were 9.46%, 11.99%, and 16.56% for optimal, normal, and high-normal categories, respectively (P < .01). Odds ratios (OR) for the development of hypertension in the normal and high-normal categories versus optimal were 1.30 (95% confidence interval [CI], 1.22-1.39) and 1.79 (95% CI, 1.67-1.93), respectively, adjusted for age and BMI. The ORs for hypertension in overweight and obese versus normal BMI were 1.75 (95% CI, 1.66-1.86) and 3.75 (95% CI, 3.45-4.07), adjusted for age and BP. Of 9762 remaining at ideal BMI at follow-up, the percentages progressing to hypertension were 5.3%, 6.4%, and 9.5% for optimal, normal, and high normal (at baseline) (P < .01). CONCLUSIONS: The risk of developing hypertension in young adulthood may be predicted by BP categories and BMI at adolescence.

Halofuginone reduces the occurrence of renal fibrosis in 5/6 nephrectomized rats.

BACKGROUND: Halofuginone is a novel antifibrotic agent that can reverse the fibrotic process by specific inhibition of collagen type I synthesis. OBJECTIVES: To evaluate the effect of Halo on the development of glomerulosclerosis and interstitial fibrosis in the 5/6 nephrectomy rat model METHODS: Male Wistar rats were assigned to undergo 5/6 NX or sham operation, and then divided into three groups: 5/6 NX rats (NX-Halo and NX-Control) and sham. Systolic blood pressure, proteinuria and body weight were determined every 2 weeks. At sacrifice (10 weeks) creatinine clearance was evaluated and remnant kidneys removed for histologic examination, sirius red staining and in situ hybridization RESULTS: Systolic blood pressure increased progressively in both 5/6 NX groups. Halo slowed the increase in proteinuria in 5/6 NX rats. As expected, creatinine clearance was lower in 5/6 NX groups when compared to sham rats. Creatinine clearance was significantly higher in the NX-Halo group at the end of the study period. Histologic examination by light microscopy showed significantly less severe interstitial fibrosis and glomerulosclerosis in Halo-treated rats. The increase in collagen alpha1 (I) gene expression and collagen staining after nephrectomy was almost completely abolished by Halo. CONCLUSIONS: Halofuginone reduced proteinuria as well as the severity of interstitial fibrosis and glomerulosclerosis in 5/6 NX rats. The renal beneficial effect of Halo was also demonstrated by the blunted decrease in creatinine clearance observed in the treated animals.

Prehypertension and obesity in adolescents: a population study.

BACKGROUND: Current blood pressure (BP) classification is based on the recent recommendations of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-7) and the 2003 European Society of Hypertension-European Society of Cardiology Guidelines for the Management of Arterial Hypertension. The JNC-7 introduced a new concept, prehypertension, and recommended health-promoting lifestyle modifications for these individuals. Obesity is also recognized as a major risk factor for the development of hypertension. We aimed to determine the prevalence of hypertension and obesity in a large cohort of adolescents and to assess whether prehypertension and body mass index (BMI) increase with increasing age. METHODS: A cross-sectional population-based study was performed using data collected during 1996 to 2002 in an army recruitment examination of 560,588 Israeli individuals 16.5 to 19 years of age. The subjects were divided according to gender and stratified by increasing 6-month intervals into five groups. Prehypertension was defined as BP 120 to 139 / 80 to 89 mm Hg. Overweight was defined as BMI 25 to < or = 30 and obesity as BMI >30 kg/m2. RESULTS: Mean systolic BP (SBP) and diastolic BP (DBP) were significantly higher in male subjects for all groups. By applying the JNC-7 criteria, 56.8% of male subjects and 35.8% of female subjects would be considered prehypertensive. There was a statistically significant increase in the mean SBP and DBP with age and BMI. Among male subjects 10.9% were overweight and 3.3% were obese; among female subjects, 11.1% were overweight and 3.2% were obese. The BMI did not increase with increasing age. The prevalence of prehypertension was significantly higher in obese subjects. CONCLUSIONS: Prehypertension is very common among Israeli adolescents. A substantial number of adolescents exhibit a BMI greater than normal. As both of these factors are known to be asssociated with increased cardiovascular risk, early institution of healthful lifestyle changes in a large proportion of this age group is recommended.

Advanced glycation end products stimulate tumor necrosis factor-alpha and interleukin-1 beta secretion by peritoneal macrophages in patients on continuous ambulatory peritoneal dialysis.

BACKGROUND: Advanced glycation end products, formed by the non-enzymatic glycation of proteins with reducing sugars, are thought to play a pathogenetic role in the vascular complications of diabetes, uremia and atherosclerosis. 132-microglobulin is a major constituent of amyloid fibrils in dialysis-related amyloidosis. AGE1-modified beta2m has been found in amyloid deposits of long-term hemodialysis patients. AGE-modified 132m has also been shown to enhance chemotaxis and increase tumor necrosis factor-alpha and interleukin-1 beta secretion by circulating and tissue monocytes/macrophages. OBJECTIVES: To investigate the effect of AGE-modified 132m and AGE-human serum albumin on TNF-alpha and IL-1beta secretion by human peritoneal macrophages derived from patients on continuous ambulatory peritoneal dialysis. METHODS: Human PMO were isolated from peritoneal dialysis effluent of stable CAPD patients and were incubated for 24 hours with AGE-modified beta2m, beta2m, AGE-HSA, HSA or lipopolysaccharide. TNF-alpha or IL-1beta secretion was measured by enzyme-linked immunosorbent assay in cell-free culture supernatants. RESULTS: Both AGE-modified beta2m and AGE-HSA significantly increased TNF-alpha and IL-1beta secretion by human PMO in a dose-dependent manner (50-200 microg/ml). In contrast, beta2m or HSA had no such stimulatory effect on TNF-alpha secretion but had a small significant increase in IL-1beta secretion. CONCLUSIONS: AGE-modified beta2m promotes in vitro TNF-alpha and IL-13 secretion by human PMO of CAPD patients. Activation of these macrophages by AGE-modified beta2m may be a contributory factor to the morphologic changes and altered permeability of the peritoneal membrane in long-term CAPD.

Kruppel-like factors in an endothelial and vascular smooth muscle cell coculture model: impact of a diabetic environment and vitamin D.

Endothelial cells (EC) and vascular smooth muscle cells (VSMC) are involved in the development of local and diffuse vasculopathies by participating in inflammatory processes that can lead to uncontrolled vascular complications. Our aim was to study the possible interactions of EC and VSMC in an in vitro coculture model exposed to diabetic-like conditions and the effect of vitamin D on cellular pathways that might lead to an inflammatory response. EC and VSMC were isolated from different umbilical cords and stimulated in an in vitro coculture model in a diabetic-like environment and calcitriol for 24 h. Total RNA and protein were extracted from cells and analyzed for the expression of selected inflammatory-related markers. The EC-VSMC coculture in a diabetic-like environment induced the expression of inflammatory markers such as Kruppel-like factors, thioredoxin-interacting protein (TXNIP), IL-6, and IL-8. Addition of vitamin D to the EC-VSMC coculture induced selective changes in the inflammatory response. This model could lead to a better understanding of the interactions between EC and VSMC in the inflammatory processes involved in diabetes and emphasizes the role of vitamin D in the inflammatory response. The use of different donors strengthens the significance of our findings showing that genetic variations do not affect the impact of vitamin D on the expression of inflammatory-related proteins in our model.

Should aspirin therapy be withheld before insertion and/or removal of a permanent peritoneal dialysis catheter?

The necessity of withdrawal of aspirin [acetylsalicylic acid (ASA)] for fear of perioperative or postoperative bleeding in patients about to undergo surgery is as yet controversial. In this study we prospectively evaluated the effect of ASA on postoperative bleeding in end-stage renal failure patients who underwent insertion, removal, and/or replacement of a peritoneal dialysis (PD) catheter at our institution from November 1999 to March 2001. During the study period 52 of the above procedures were consecutively performed in 46 patients. Patients whose catheters were removed as a result of refractory peritonitis were excluded from the study. In all cases the PD catheter used was the coiled two-cuff Tenckhoff (NIPRO, Manchester, GA) catheter and the surgery was performed in the operating room under local anesthesia. No drains were left in the operating wound. Postoperative bleeding (wound hematoma or persistent oozing from the incision or exit site) was classified as either minor (requiring no professional intervention and/or blood replacement) or major [necessitating blood transfusion (> or = 1 unit red blood cells). Of the 52 procedures 29 (in 24 patients) were performed while the patient was receiving aspirin at the time of operation (aspirin group). The remaining 23 were without aspirin and constituted the control group. ASA dose was 100 mg/day in all but three who were on buffered ASA (325 mg/day). The groups were well matched with regard to age; sex; mean residual renal function; and preoperative international normalized ratio, activated partial thromboplastin time, and platelet count. In no case was there significant intraoperative bleeding. There were five (17.2%) and three (13.0%) minor bleeds in the aspirin group and control group, respectively. One major bleed occurred in the control group ending in an exploratory laparotomy. Of the nine bleeding complications six were observed after catheter removal. From these data we conclude that PD catheter insertion/removal can be safely performed under conventional low-dose aspirin therapy.

Insulin-induced hypertension, L-arginine, and endothelial nitric oxide synthase in pregnant rats.

Pregnancy-induced hypertension in rats with chronic exogenous hyperinsulinemia is associated with reduced urinary excretion of nitric oxide metabolites. We tested the hypothesis that there are perturbations of endothelial nitric oxide synthase in their kidneys. We studied three groups of rats: control pregnant rats (n = 6); pregnant rats with hyperinsulinemia by subcutaneous sustained-release insulin pellet (n = 5); and hyperinsulinemic pregnant rats treated with l-arginine 2 gL in drinking water (n = 5). By the end of pregnancy blood pressure was 78 +/- 12 mm Hg in controls, 119 +/- 15 mm Hg in hyperinsulinemic rats, and 77 +/- 8 mm Hg in l-arginine-treated hyperinsulinemic rats, p < 0.007. Serum creatinine was 0.4 mg/dl in controls, 0.6 mg/dl in hyperinsulinemic rats, and 0.5 mg/dl in l-arginine-treated rats, p < 0.05. Corresponding urinary excretion of nitric oxide metabolites was 2.1 +/- 0.5, 1.2 +/- 0.2, and 1.5 +/- 0.2 micromols/mg creatinine, p < 0.01. Expression of endothelial nitric oxide synthase protein in kidneys by Western blot was not different between controls and hyperinsulinemic rats, 5.6 +/- 2.4 and 5.8 +/- 3.4 OD x mm2, but was nearly doubled in l-arginine-treated rats, 10.8 +/- 2.3, p < 0.03. Thus, the salutary effect of l-arginine on hyperinsulinemic pregnancy-induced hypertension (PIH) may be mediated, in part, by endothelial nitric oxide synthase in their kidneys.

Effect of tetrahydrobiopterin on blood pressure in rats after subtotal nephrectomy.

BACKGROUND: Previous studies have shown that endothelial dysfunction after 5/6 nephrectomy (5/6 Nx) in rats is associated with decreased nitric oxide (NO) bioavailability and increased vascular superoxide production. Blood pressure is significantly increased by day 10 after surgery. Tetrahydrobiopterin (BH4) is a key cofactor of NO synthase. Suboptimal levels of BH4 result in uncoupling of NO synthase, low NO synthesis and augmented production of superoxide anions. The aim of this study was to evaluate whether BH4 supplementation may improve NO production and prevent the increase of blood pressure after 5/6 Nx. METHODS: Three groups were evaluated: 5/6 Nx (untreated rats), BH4 (5/6 Nx rats treated with BH4, 10 mg/day i.p. for 10 days) and L-ARG (5/6 Nx rats treated with L-arginine, 260 mg/kg BW, p.o for 10 days). Systolic blood pressure (SBP), urinary nitrate excretion (UNO(3)) and creatinine clearance (CCR) were measured before surgery and on days 3 and 10 after surgery. Endothelial NO synthase (eNOS) protein content of mesenteric resistance vessels was measured at the end of the study. RESULTS: SBP increased from 107 +/- 2 to 127 +/- 4 mm Hg in untreated 5/6 Nx rats (p < 0.01). By contrast, rats treated with BH4 or L-ARG remained normotensive. Ten days after 5/6 Nx, creatinine clearance decreased similarly in all groups. Both BH4 and L-ARG supplementation markedly increased UNO(3) excretion. The mesenteric vascular expression of eNOs protein was significantly higher in BH4 but not in L-ARG, compared with Nx rats. CONCLUSIONS: BH4 supplementation prevents the earlier increase in blood pressure observed in rats after 5/6 Nx, possibly by upregulating eNOS in resistance vessels.

Normokalemic hyperaldosteronism in patients with resistant hypertension.

BACKGROUND: Primary aldosteronism is a common cause of non-renal secondary hypertension. A correct diagnosis results in curing the hypertension or targeting appropriate pharmacotherapy. In patients with low renin resistant hypertension (after treatment with three or more different anti-hypertensive drugs the blood pressure remains above 140/90 mmHg), screening for aldosteronism is mandatory. OBJECTIVES: To demonstrate that normal blood levels of potassium in resistant hypertensive patients do not exclude the possible presence of hyperaldosteronism, and to suggest the use of the plasma aldosterone concentration (ng/dl)/plasma renin activity (ng/ml/hour) ratio in screening for hyperaldosteronism. METHODS: Blood tests, suppression and stimulation tests (2 L normal saline i.v./4 hours and 20 mg furosemide i.v. for 60 minutes in a standing position) were systematically performed in 20 low renin normokalemic resistant hypertensive patients. None had renal disorders, known endocrine abnormalities or heart failure. They did not receive anti-hypertensive drugs affecting PAC or PRA. Basal PRA and PAC were measured twice: PAC after saline infusion and PAC/PRA after stimulation. RESULTS: PAC/PRA above 50 was used to denote hyperaldosteronism. Serum K was 4 +/- 0.07 mM/L, PAC 22.8 +/- 1.8 ng/dl, PRA 0.13 +/- 0.02 ng/ml/hour, PAC/PRA 190 +/- 22 (above 100 in 17). After suppression PAC decreased from 25 +/- 1.8 to 11 +/- 1 ng/dl (normal < 5 ng/dl). Stimulation did not affect PRA and PAC/PRA. Abdominal computed tomography scan revealed normal adrenal glands in 15 patients. Spironolactone (116 +/- 60 mg/day) normalized blood pressure in all patients; it was used as a single therapy in 8, and in association with only one anti-hypertensive drug in the remaining 12 patients. In one patient the treatment was discontinued due to the presence of hyperkalemia. CONCLUSIONS: Low renin resistant hypertension associated with normokalemia may be due to hyperaldosteronism. Normal aldosterone levels in the basal condition do not exclude the possibility of hyperaldosteronism. Using a PAC/PRA ratio above 50 as a screening test can aid the physician in deciding when to perform dynamic tests, thus increasing the sensitivity of the diagnosis of hyperaldosteronism. CT scan is frequently normal. Targeted pharmacotherapy leads to a normalization of blood values.

The clinical spectrum of acute renal infarction.

BACKGROUND: Acute renal infarction is an oft-missed diagnosis. As a result, its true incidence, although presumed to be low, is actually unknown. Surprisingly, the medical literature on the subject, other than anecdotal case reports, is scarce. OBJECTIVES: To increase physician awareness of the diagnosis and to identify predictive clinical and laboratory features of the entity. METHOD: Between 1 November 1997 and 31 October 2000, 11 cases of acute renal infarction in 10 patients were diagnosed in our center by contrast-enhanced computerized tomography. The medical charts of these patients were reviewed regarding risk factors, clinical presentation, possible predictive laboratory examinations, and outcome. RESULTS: During the 36 month observation period, the incidence of acute renal infarction was 0.007%. The mean age of the patients (5 men and 5 women) was 67.4 +/- 21.1 (range 30-87 years). In four cases the right and in five the left kidney was involved; in the other two cases bilateral involvement was seen. In 7/10 patients, an increased risk for thromboembolic events was found. Six had chronic atrial fibrillation and one had a combined activated protein C resistance and protein S deficiency. Three patients had suffered a previous thromboembolic event. Two cases were receiving anticoagulant therapy with an INR of 1.6 and 1.8, respectively. On admission, flank pain was recorded in 10/11, fever in 5 and nausea/vomiting in 4 cases. Hematuria was detected in urine reagent strips in all cases. Serum lactate dehydrogenase and white blood cell count were elevated in all cases (1,570 +/- 703 IU/L and 12,988 +/- 3,841/microliter, respectively). In no case was the diagnosis of acute renal infarction initially entertained. The working diagnoses were renal colic in 2, pyelonephritis in 3, renal carcinoma, digitalis intoxication, and suspected endocarditis in one patient each, and an acute abdomen in 3. Time from admission to definitive CT diagnosis ranged from 24 hours to 6 days. Three patients were treated with intravenous heparin and another with a combination of i.v. heparin and renal intra-arterial urokinase infusion with, in the latter case, no recovery of function of the affected kidney. With the exception of this one patient (with a contralateral contracted kidney) who required maintenance dialysis, in all other cases serum creatinine levels remained unchanged or reverted to the baseline mean of 1.1 mg/dl (0.9-1.2). CONCLUSIONS: Acute renal infarction is not as rare as previously assumed. The entity is often misdiagnosed. Unilateral flank pain in a patient with an increased risk for thromboembolism should raise the suspicion of renal infarction. In such a setting, hematuria, leucocytosis and an elevated LDH level are strongly supportive of the diagnosis.

Reduction in resting metabolic rate and ratio of plasma leptin to urinary nitric oxide: influence on obesity-related hypertension.

BACKGROUND: Multiple factors are involved in the pathogenesis of hypertension in the obese individual OBJECTIVE: To evaluate the role of a decrease in sympathetically mediated thermogenesis and the effect of the correlation between the plasma leptin and daily urinary nitric oxide levels on obesity-related hypertension. METHODS: We evaluated three groups: 25 obese hypertensive patients (age 45.7 +/- 1.37 years, body mass index 34.2 +/- 1.35 kg/m2, systolic/diastolic blood pressure 155 +/- 2.9/105 +/- 1.3, mean arterial pressure 122 +/- 1.50 mmHg); 21 obese normotensive patients (age 39.6 +/- 1.72, BMI 31.3 +/- 0.76, SBP/DBP 124 +/- 2.1/85.4 +/- 1.8, MAP 98.2 +/- 1.80); and 17 lean normotensive subjects (age 38.1 +/- 2.16, BMI 22.1 +/- 0.28, SBP/DBP 117 +/- 1.7/76.8 +/- 1.5, MAP 90.1 +/- 1.50). We determined basal resting metabolic rates, plasma insulin (radio-immunoassay), norepinephrine (high performance liquid chromatography) in all subjects. Thereafter, 14 obese hypertensives underwent a weight reduction diet. At weeks 6 (n = 14) and 14 (n = 10) of the diet the above determinations were repeated. Plasma leptin (enzyme-linked immunosorbent assay) and UNOx (spectrophotometry) were assayed in 17 obese hypertensives and 17 obese normotensives, and in 19 obese hypertensives versus 11 obese normotensives, respectively. RESULTS: Obese hypertensive patients had significantly higher basal RMR and plasma NE levels insulin levels were lower in the lean group, with no difference between the hypertensive and normotensive obese groups. At weeks 6 and 14, BMI was significantly lower, as were insulin and NE levels. RMR decreased to values of normotensive subjects. MAP normalized but remained significantly higher than in obese normotensives. Leptin blood levels and the leptin/UNOx ratio were significantly higher in the obese hypertensive compared to the obese normotensive patients. Both these parameters were strongly correlated to BMI, MAP, RMR, and plasma NE and insulin. Obese hypertensive patients excreted less urinary NO metabolites. A strong correlation was found between MAP and the leptin/UNOx ratio. CONCLUSIONS: A reduction in sympathetically mediated thermogenesis, as reflected by RMR, results in normalization of obesity-related hypertension. In contrast, insulin does not seem to play a major role in the pathogenesis of hypertension associated with obesity. Increased leptin levels in conjunction with decreased NO production in the presence of enhanced sympathetic activity may contribute to blood pressure elevation in the obese.

[Long-term follow-up on the treatment of diffuse proliferative glomerulonephritis in patients with systemic lupus erythematosus].

BACKGROUND: Diffuse Proliferative Glomerulonephritis (DPGN) is the most ominous form of lupus nephritis. Treatment according to the "NIH Protocol" is considered by many physicians to be the treatment of choice for this form of disease, but this is not accepted exclusively. OUR AIM: To evaluate the outcome of SLE patients with biopsy proven DPGN diagnosed and treated in our department, between the years 1976-1996, and to compare the results achieved by using the "NIH Protocol" as opposed to other forms of treatment. PATIENTS AND METHODS: The archive of the Department of Pathology was screened for patients with SLE and DPGN. The specimens were re-examined to confirm the diagnosis and calculate the activity and chronicity scores. The pertinent data was extracted from the patients medical records. RESULTS: Twenty-six patients fulfilled the inclusion criteria, 22 females and 4 males. We followed-up on these patients for an average period of 89 +/- 74 months (range 9-255). More than 80% of the patients achieved remission, about a third experienced at least one relapse. Only one patient died during the follow-up period and 4 others developed end stage renal failure necessitating chronic renal replacement therapy. Sixteen patients were treated according to the NIH protocol, the other 10 were treated with high dose Prednisone, either alone or in combination with oral immunosuppressive drugs. At time of diagnosis there was no statistically significant difference between the two groups regarding the age and gender distribution, blood levels of creatinine and C3 and the level of proteinuria. We were unable to demonstrate any statistically significant difference between the two groups in any of the evaluated parameters, regarding neither patient and kidney survival nor the type and rate of complications. CONCLUSION: Following treatment, patient and kidney survival is good. The NIH protocol is the treatment of choice, but the use of high dose steroids for six months with or without oral immunosuppressive drugs may yield comparable results in selected cases.