The Elusive Nature of ABCC8-related Maturity-Onset Diabetes of the Young (ABCC8-MODY). A Review of the Literature and Case Discussion.

PURPOSE OF REVIEW: Maturity-onset diabetes of the young (MODY) are monogenic forms of diabetes resulting from genetic defects, usually transmitted in an autosomal dominant fashion, leading to ß-cell dysfunction. Due to the lack of homogeneous clinical features and univocal diagnostic criteria, MODY is often misdiagnosed as type 1 or type 2 diabetes, hence its diagnosis relies mostly on genetic testing. Fourteen subtypes of MODY have been described to date. Here, we review ABCC8-MODY pathophysiology, genetic and clinical features, and current therapeutic options. RECENT FINDINGS: ABCC8-MODY is caused by mutations in the adenosine triphosphate (ATP)-binding cassette transporter subfamily C member 8 (ABCC8) gene, involved in the regulation of insulin secretion. The complexity of ABCC8-MODY genetic picture is mirrored by a variety of clinical manifestations, encompassing a wide spectrum of disease severity. Such inconsistency of genotype-phenotype correlation has not been fully understood. A correct diagnosis is crucial for the choice of adequate treatment and outcome improvement. By targeting the defective gene product, sulfonylureas are the preferred medications in ABCC8-MODY, although efficacy vary substantially. We illustrate three case reports in whom a diagnosis of ABCC8-MODY was suspected after the identification of novel ABCC8 variants that turned out to be of unknown significance. We discuss that careful interpretation of genetic testing is needed even on the background of a suggestive clinical context. We highlight the need for further research to unravel ABCC8-MODY disease mechanisms, as well as to clarify the pathogenicity of identified ABCC8 variants and their influence on clinical presentation and response to therapy.

Double CYP11B1/CYP11B2 Immunohistochemistry and Detection of KCNJ5 Mutations in Primary Aldosteronism.

CONTEXT: The search for somatic mutations in adrenals resected from patients with primary aldosteronism (PA) is performed by Sanger sequencing, often implemented with immunohistochemistry (IHC)-guidance focused on aldosterone-producing (CYP11B2-positive) areas. OBJECTIVE: To investigate the impact of double IHC for CYP11B1 and CYP11B2 on Sanger and next-generation sequencing (NGS). METHODS: We investigated 127 consecutive adrenal aldosterone-producing adenomas from consenting surgically cured PA patients using double IHC for CYP11B1 and CYP11B2, by Sanger sequencing and NGS. RESULTS: Double IHC for CYP11B2 and CYP11B1 revealed 3 distinct patterns: CYP11B2-positive adenoma (pattern 1), mixed CYP11B1/CYP11B2-positive adenoma (pattern 2), and adrenals with multiple small CYP11B2-positive nodules (pattern 3). Sanger sequencing allowed detection of KCNJ5 mutations in 44% of the adrenals; NGS revealed such mutations in 10% of those negative at Sanger and additional mutations in 61% of the cases. Importantly the rate of KCNJ5 mutations differed across patterns: 17.8% in pattern 1, 71.4% in pattern 2, and 10.7% in pattern 3 (χ2 = 22.492, P < .001). CONCLUSION: NGS allowed detection of mutations in many adrenals that tested negative at Sanger sequencing. Moreover, the different distribution of KCNJ5 mutations across IHC patterns indicates that IHC-guided sequencing protocols selecting CYP11B2-positive areas could furnish results that might not be representative of the entire mutational status of the excised adrenal, which is important at a time when KCNJ5 mutations are suggested to drive management of patients with aldosterone-producing adenomas.

Circulating extracellular vesicles and small non-coding RNAs cargo in idiopathic inflammatory myopathies reveal differences across myositis subsets.

OBJECTIVE: To investigate the epigenetic footprint of idiopathic inflammatory myopathies (IIM) through characterization of circulating extracellular vesicles (EVs) and the expression of EV-derived small non-coding RNAs (sncRNAs). METHODS: In this cross-sectional study, EVs were isolated by size-exclusion chromatography from plasma of patients with IIM and age- and sex-matched healthy donors (HD). EV-derived sncRNAs were sequenced and quantified using Next-Generation Sequencing (NGS). Following quality control and normalization, filtered count reads were used for differential microRNA (miRNA) and piwi-interacting RNA (piRNA) expression analyses. Putative gene targets enriched for pathways implicated in IIM were analyzed. Patients' clinical and laboratory characteristics at the time of sampling were recorded. RESULTS: Forty-seven IIM patients and 45 HD were enrolled. MiR-486-5p (p < 0.01), miR-122-5p, miR-192-5p, and miR-32-5p were significantly upregulated (p < 0.05 for all), while miR-142-3p (p < 0.001), miR-141-3p (p < 0.01), let-7a-5p (p < 0.05) and miR-3613-5p (p < 0.05) downregulated in EVs from IIM patients versus HD. MiR-486-5p was associated with raised muscle enzymes levels. Several target genes of up/downregulated miRNAs in IIM participate in inflammation, necroptosis, interferon and immune signaling. Six piRNAs were significantly dysregulated in IIM EVs versus HD (p < 0.05). Within IIM, miR-335-5p was selectively upregulated and miR-27a-5p downregulated in dermatomyositis (n = 21, p < 0.01). Finally, plasma EV levels were significantly increased in cancer-associated myositis (CAM, n = 12) versus non-CAM IIM (n = 35, p = 0.02) and HD (p < 0.01). EVs cargo in CAM was significantly enriched of let-7f-5p and depleted of miR-143-3p. CONCLUSION: Through an unbiased screening of EV-derived sncRNAs, we characterize miRNAs and piRNAs in the EVs cargo as potential biomarkers and modifiers of diverse IIM phenotypes.

PAR-4/Ca2+-calpain pathway activation stimulates platelet-derived microparticles in hyperglycemic type 2 diabetes.

BACKGROUND: Patients with type 2 diabetes (T2DM) have a prothrombotic state that needs to be fully clarified; microparticles (MPs) have emerged as mediators and markers of this condition. Thus, we investigate, in vivo, in T2DM either with good (HbA1c ≤ 7.0%; GGC) or poor (HbA1c > 7.0%; PGC) glycemic control, the circulating levels of MPs, and in vitro, the molecular pathways involved in the release of MPs from platelets (PMP) and tested their pro-inflammatory effects on THP-1 transformed macrophages. METHODS: In 59 T2DM, and 23 control subjects with normal glucose tolerance (NGT), circulating levels of CD62E+, CD62P+, CD142+, CD45+ MPs were determined by flow cytometry, while plasma levels of ICAM-1, VCAM-1, IL-6 by ELISA. In vitro, PMP release and activation of isolated platelets from GGC and PGC were investigated, along with their effect on IL-6 secretion in THP-1 transformed macrophages. RESULTS: We found that MPs CD62P+ (PMP) and CD142+ (tissue factor-bearing MP) were significantly higher in PGC T2DM than GGC T2DM and NGT. Among MPs, PMP were also correlated with HbA1c and IL-6. In vitro, we showed that acute thrombin exposure stimulated a significantly higher PMP release in PGC T2DM than GGC T2DM through a more robust activation of PAR-4 receptor than PAR-1 receptor. Treatment with PAR-4 agonist induced an increased release of PMP in PGC with a Ca2+-calpain dependent mechanism since this effect was blunted by calpain inhibitor. Finally, the uptake of PMP derived from PAR-4 treated PGC platelets into THP-1 transformed macrophages promoted a marked increase of IL-6 release compared to PMP derived from GGC through the activation of the NF-kB pathway. CONCLUSIONS: These results identify PAR-4 as a mediator of platelet activation, microparticle release, and inflammation, in poorly controlled T2DM.

Low P66shc with High SerpinB3 Levels Favors Necroptosis and Better Survival in Hepatocellular Carcinoma.

Cell proliferation and escape from apoptosis are important pathological features of hepatocellular carcinoma (HCC), one of the tumors with the highest mortality rate worldwide. The aim of the study was to evaluate the expression of the pro-apoptotic p66shc and the anti-apoptotic SerpinB3 in HCCs in relation to clinical outcome, cell fate and tumor growth. p66shc and SerpinB3 were evaluated in 67 HCC specimens and the results were correlated with overall survival. Proliferation and cell death markers were analyzed in hepatoma cells overexpressing SerpinB3, under different stress conditions. p66shc-/- mice and xenograft models were also used to assess the effects of p66shc and SerpinB3 on tumor growth. In patients with HCC, the best survival was observed in the subgroup with p66shc levels below median values and SerpinB3 levels above median values. Mice p66shc-/- showed high levels of SerpinB3, while in HepG2 cells overexpressing SerpinB3, p66shc expression was trivial. HepG2 overexpressing SerpinB3 cells were more prone to die after oxidizing treatments, such as diamide or high concentration H2O2. These cells injected in nude mice developed tumors five times smaller than those from control HepG2 cells. Tumors originating from HepG2 overexpressing SerpinB3 cells showed decreased activated Caspase-8, with concomitant increase of RIP3K and decreased levels of cleaved RIP3K, typical features of necroptosis. In conclusion, in patients affected by HCC, the pattern characterized by p66shc downregulation and elevated SerpinB3 levels was associated with markedly better survival. This pattern favored necroptosis in experimental high-stress conditions.

Macrolides for KCNJ5-mutated aldosterone-producing adenoma (MAPA): design of a study for personalized diagnosis of primary aldosteronism.

PURPOSE: Aldosterone-producing adenoma (APA) is the main curable cause of endocrine hypertension cause of primary aldosteronism (PA) and it is in up to 66% of all cases investigated with adrenal vein sampling (AVS). Mutations in the KCNJ5 potassium channel involve up to 70% of APA and cause the most florid PA phenotypes. The recent finding that macrolide antibiotics specifically inhibit in vitro the altered function of mutated KCNJ5 channels has opened new horizons for the diagnosis and treatment of APA with KCNJ5 mutations in that it can allow identification and target treatment of PA patients harbouring a mutated APA. Thus, we aimed at investigating if clarithromycin and roxithromycin, two macrolides that potently blunt mutated Kir3.4 channel function in vitro, affect plasma aldosterone concentration in adrenal vein blood during AVS and in peripheral blood, respectively, in PA patients with a mutated APA. METHODS AND DESIGN: We designed two proof of concept studies. In study A: consecutive patients with an unambiguous biochemical evidence of PA will be exposed to a single dose of 250 mg clarithromycin during AVS, to assess its effect on the relative aldosterone secretion index in adrenal vein blood from the gland with and without APA. In study B: consecutive hypertensive patients submitted to the work-up for hypertension will receive a single oral dose of 150 mg roxithromycin. The experimental endpoints will be the change induced by roxithromycin of plasma aldosterone concentration and other steroids, direct active renin concentration, serum K+, systolic and diastolic blood pressure. DISCUSSION: We expect to prove that: (i) clarithromycin allows identification of mutated APA before adrenalectomy and sequencing of tumour DNA; (ii) the acute changes of plasma aldosterone concentration, direct active renin concentration, and blood pressure in peripheral venous blood after roxithromycin can be a proxy for the presence of an APA with somatic mutations.

miR-30c-5p regulates macrophage-mediated inflammation and pro-atherosclerosis pathways.

AIMS: Atherosclerosis is an inflammatory disease wherein cholesterol-loaded macrophages play a major role. MicroRNAs and microparticles propagate inflammatory pathways and are involved in cardiovascular disease. We aimed to screen and validate circulating microRNAs correlated with atherosclerosis development in humans, and to dissect the molecular mechanisms associated with atherogenesis using in vitro and in vivo approaches. METHODS AND RESULTS: A panel of 179 secreted microRNAs was screened in plasma samples of patients with and without atherosclerosis, and validated cross-sectionally and prospectively in patients followed for up to 11 years. miR-30c-5p was inversely correlated with total and LDL cholesterol, carotid intimal media thickness (CIMT), presence and future development of plaques. Using a human macrophage line and in vitro gene silencing strategies, we found that miR-30c-5p was downregulated by oxidized LDL (oxLDL) via the scavenger receptor CD36 and inhibition miR processing by Dicer. In turn, miR-30c-5p downregulation was responsible for the effects of oxLDL on macrophage IL-1ß release, caspase-3 expression, and apoptosis. miR-30c-5p loaded into microparticles was uptaken by macrophages and regulated target genes, like caspase-3, at transcriptional level. To establish the relevance of this pathway on endothelial damage as the earliest step of atherogenesis, we show that systemic miR-30c-5p knockdown induced caspase-3 and impaired endothelial healing after carotid injury in C57Bl/6 J mice. CONCLUSIONS: With an unbiased screening of secreted microRNAs, we identify reduction of miR-30c-5p in microparticles as a promoter of early atherosclerosis, by conveying pro-inflammatory pro-apoptotic signals and impairing endothelial healing. Therefore, stimulation of miR-30c-5p is a candidate direct anti-atherosclerotic therapy.

Human IgGs induce synthesis and secretion of IgGs and neonatal Fc receptor in human umbilical vein endothelial cells.

Human IgGs are increasingly used in the therapy of many different immune and inflammatory diseases, however their mechanism of action still remains unclear in most diseases. To gain insight into the mechanism by which IgGs might also exert their effects on endothelial cells, we tested human IgGs on human umbilical vein endothelial cells (HUVECs). IgGs induced a time-dependent increase in the synthesis and secretion of IgGs, together with a marked angiogenic-like transformation of HUVECs that was maximal after a 20-h incubation. IgGs stimulated IG gene transcription without affecting the process of gene rearrangement, already present in control HUVECs. The mechanism involved the activation of transcription factors with the increased expression of HSP90, HSP70 and inactive MMP-9 responsible for the phenotypic differentiation associated with the most intense IgG synthesis and secretion. However, even a short incubation with IgGs followed by recovery of cells was sufficient to trigger and sustain in time the synthesis and secretion of new IgGs, independently of the angiogenic-like transformation visible only when cells were continuously exposed to IgGs. Under the stimulus of IgGs, specific secretory pathways were also activated in HUVECs together with the expression of FcRn, which was always associated with IgGs of new synthesis, forming complexes that were also secreted. Our results disclose a so far unknown and unexpected mechanism of IgGs on HUVECs that behave as Ig-producing immune cells. Results might have relevance for the effects that IgGs also exert in vivo in physiological conditions.

Prospective validation of an automated chemiluminescence-based assay of renin and aldosterone for the work-up of arterial hypertension.

BACKGROUND: The availability of simple and accurate assays of plasma active renin (DRC) and aldosterone concentration (PAC) can improve the detection of secondary forms of arterial hypertension. Thus, we investigated the performance of an automated chemiluminescent assay for DRC and PAC in referred hypertensive patients. METHODS: We prospectively recruited 260 consecutive hypertensive patients referred to an ESH Center for Hypertension. After exclusion of six protocol violations, 254 patients were analyzed: 67.3% had primary hypertension, 17.3% an aldosterone producing adenoma (APA), 11.4% idiopathic hyperaldosteronism (IHA), 2.4% renovascular hypertension (RVH), 0.8% familial hyperaldosteronism type 1 (FH-1), 0.4% apparent mineralocorticoid excess (AME), 0.4% a renin-producing tumor, and 3.9% were adrenalectomized APA patients. Bland-Altman plots and Deming regression were used to analyze results. The diagnostic accuracy (area under the curve, AUC of the ROC) of the DRC-based aldosterone-renin ratio (ARRCL) was compared with that of the PRA-based ARR (ARRRIA) using as reference the conclusive diagnosis of APA. RESULTS: At Bland-Altman plot, the DRC and PAC assay showed no bias as compared to the PRA and PAC assay. A tight relation was found between the DRC and the PRA values (concordance correlation coefficient=0.92, p<0.0001) and the PAC values measured with radioimmunoassay and chemiluminescence (concordance correlation coefficient=0.93, p<0.001). For APA identification the AUC of the ARRCL was higher than that of the ARRRIA [0.974 (95% CI 0.940-0.991) vs. 0.894 (95% CI 0.841-0.933), p=0.02]. CONCLUSIONS: This rapid automated chemiluminescent DRC/PAC assay performed better than validated PRA/PAC radioimmunoassays for the identification of APA in referred hypertensive patients.

Expression and functional role of the prorenin receptor in the human adrenocortical zona glomerulosa and in primary aldosteronism.

OBJECTIVES: Prorenin can be detected in plasma of hypertensive patients. If detected in patients with primary aldosteronism could implicate prorenin in the development of primary aldosteronism. To address this issue, we measured the plasma prorenin levels in primary aldosteronism patients, the expression of the prorenin receptor (PRR) in the normal human adrenocortical zona glomerulosa and aldosterone-producing adenoma (APA), and we investigated the functional effects of PRR activation in human adrenocortical cells. METHOD: Plasma renin activity, aldosterone, and active and total trypsin-activated renin were measured in primary aldosteronism patients, essential hypertensive patients, and healthy individuals, and then prorenin levels were calculated. Localization and functional role of PRR were investigated in human and rat tissues, and aldosterone-producing cells. RESULTS: Primary aldosteronism patients had detectable plasma levels of prorenin. Using digital-droplet real-time PCR, we found a high PRR-to-porphobilinogen deaminase ratio in both the normal adrenal cortex and APAs. Marked expression of the PRR gene and protein was also found in HAC15 cells. Immunoblotting, confocal, and immunogold electron microscopy demonstrated PRR at the cell membrane and intracellularly. Renin and prorenin significantly triggered both CYP11B2 expression (aldosterone synthase) and ERK1/2 phosphorylation, but only CYP11B2 transcription was prevented by aliskiren. CONCLUSION: The presence of detectable plasma prorenin in primary aldosteronism patients, and the high expression of PRR in the normal human adrenal cortex, APA tissue, CD56+ aldosterone-producing cells, along with activation of CYP11B2 synthesis and ERK1/2 phosphorylation, suggest that the circulating and locally produced prorenin may contribute to the development or maintenance of human primary aldosteronism.

GPER-1 and estrogen receptor-ß ligands modulate aldosterone synthesis.

Fertile women have lower blood pressure and cardiovascular risk than age-matched men, which suggests that estrogens exert cardiovascular protective effects. However, whether 17 ß-estradiol (E2) blunts aldosterone secretion, and thereby affects the gender dimorphism of blood pressure, is unknown. We therefore sought for the estrogen receptor (ER) subtypes in human adrenocortical tissues ex vivo by performing gene and protein expression studies. We also investigated the effect of E2 on aldosterone synthesis and the involved receptors through in vitro functional experiments in the adrenocortical cells HAC15. We found that in the human adrenal cortex and aldosterone-producing adenoma cells, the most expressed ERs were the ERß and the G protein-coupled receptor-1 (GPER-1), respectively. After selective ERß blockade, E2 (10 nmol/L) markedly increased both the expression of aldosterone synthase and the production of aldosterone (+5- to 7-fold vs baseline, P < .001). Under the same condition, the GPER-1 receptor agonist 1-[4-(6-bromo-benzo (1, 3)dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c] quinolin-8-yl]-ethanone (G-1) (10 nmol/L) mimicked this effect, which was abrogated by cotreatment with either the GPER-1 receptor antagonist (3aS*,4R*,9bR*)-4-(6-Bro-mo-1,3-benzodioxol-5-yl)-3a,4,5,9b-3H-cyclopenta[c]quinoline (G-15), or a selective protein kinase A inhibitor 8-Bromo-2-monobutyryladenosine-3,5-cyclic mono-phosphorothioate, Rp-isomer. Silencing of the ERß significantly raised aldosterone synthase expression and aldosterone production. Conversely, silencing of the GPER-1 lowered aldosterone synthase gene and protein expression. Moreover, it blunted the stimulatory effect of E2 on aldosterone synthase that was seen during ERß blockade. These results support the conclusion that in humans, E2 inhibits aldosterone synthesis by acting via ERß. Pharmacologic disinhibition of ERß unmasks a potent secretagogue effect of E2 that involves GPER-1 and protein kinase A signaling.

Sirtuin 1 stabilization by HuR represses TNF-α- and glucose-induced E-selectin release and endothelial cell adhesiveness in vitro: relevance to human metabolic syndrome.

Chronic inflammation and hyperglycaemia, typical features of metabolic diseases, trigger endothelial damage and release of E-selectin, a marker of endothelial activation. In the present study, we investigated molecular pathways involved in the regulation of endothelial cell activation induced by tumour necrosis factor-α (TNF-α) and high glucose. In cultured human umbilical vein endothelial cells (HUVECs), we studied the role of HuR, an ELAV (embryonic lethal, abnormal vision, Drosophila) family RNA-binding protein, and Sirtuin 1 (SIRT1) on E-selectin release and cell adhesion at different glucose concentrations. HuR expression and binding to SIRT1 were also analysed ex vivo in peripheral blood mononuclear cells (PBMCs) of subjects with and without the metabolic syndrome (MS), by immunoprecipitation (IP) of the ribonucleoprotein (RNP) complex. We found that SIRT1 overexpression prevented TNF-α- and high-glucose-dependent nuclear factor-κB (NF-κB)-p65 acetylation, E-selectin promoter activity, E-selectin release and adhesion of THP-1 cells to HUVECs. The same was mimicked by HuR overexpression, which binds and stabilizes SIRT1 mRNA. Importantly, in PBMCs of individuals with MS compared with those without, SIRT1 expression was lower, and the ability of HuR to bind SIRT1 mRNA was significantly reduced, while plasma E-selectin was increased. We conclude that post-transcriptional stabilization of SIRT1 by HuR represses inflammation- and hyperglycaemia-induced E-selectin release and endothelial cell activation. Therefore, increasing SIRT1 expression represents a strategy to counter the accelerated vascular disease in metabolic disorders.

Diabetes causes bone marrow autonomic neuropathy and impairs stem cell mobilization via dysregulated p66Shc and Sirt1.

Diabetes compromises the bone marrow (BM) microenvironment and reduces the number of circulating CD34(+) cells. Diabetic autonomic neuropathy (DAN) may impact the BM, because the sympathetic nervous system is prominently involved in BM stem cell trafficking. We hypothesize that neuropathy of the BM affects stem cell mobilization and vascular recovery after ischemia in patients with diabetes. We report that, in patients, cardiovascular DAN was associated with fewer circulating CD34(+) cells. Experimental diabetes (streptozotocin-induced and ob/ob mice) or chemical sympathectomy in mice resulted in BM autonomic neuropathy, impaired Lin(-)cKit(+)Sca1(+) (LKS) cell and endothelial progenitor cell (EPC; CD34(+)Flk1(+)) mobilization, and vascular recovery after ischemia. DAN increased the expression of the 66-kDa protein from the src homology and collagen homology domain (p66Shc) and reduced the expression of sirtuin 1 (Sirt1) in mice and humans. p66Shc knockout (KO) in diabetic mice prevented DAN in the BM, and rescued defective LKS cell and EPC mobilization. Hematopoietic Sirt1 KO mimicked the diabetic mobilization defect, whereas hematopoietic Sirt1 overexpression in diabetes rescued defective mobilization and vascular repair. Through p66Shc and Sirt1, diabetes and sympathectomy elevated the expression of various adhesion molecules, including CD62L. CD62L KO partially rescued the defective stem/progenitor cell mobilization. In conclusion, autonomic neuropathy in the BM impairs stem cell mobilization in diabetes with dysregulation of the life-span regulators p66Shc and Sirt1.

SERPINB3 is associated with longer survival in transgenic mice.

The physiological roles of the protease inhibitor SERPINB3 (SB3) are still largely unknown. The study was addressed to assess the biological effects of this serpin in vivo using a SB3 transgenic mouse model. Two colonies of mice (123 transgenic for SB3 and 148 C57BL/6J controls) have been studied. Transgenic (TG) mice showed longer survival than controls and the difference was more remarkable in males than in females (18.5% vs 12.7% life span increase). In TG mice decreased IL-6 in serum and lower p66shc in the liver were observed. In addition, TG males showed higher expression of mTOR in the liver. Liver histology showed age-dependent increase of steatosis and decrease of glycogen storage in both groups and none of the animals developed neoplastic lesions. In conclusion, the gain in life span observed in SB3-transgenic mice could be determined by multiple mechanisms, including the decrease of circulating IL-6 and the modulation of ageing genes in the liver.

Positive cardiac inotropic effect of albumin infusion in rodents with cirrhosis and ascites: molecular mechanisms.

UNLABELLED: The aim of this study was to evaluate the effect and molecular mechanism of albumin infusion on cardiac contractility in experimental cirrhosis with ascites. Cardiac contractility was recorded ex vivo in rats with cirrhosis and ascites and in control rats after the injection in the caudal vein of albumin, saline, or hydroxyethyl starch (HES). Gene and protein expression of ß-receptors and pathways involved in their intracellular signaling such as Gα(i2) protein (Gα(i2)), adenylate cyclase 3 (Adcy3), protein expression of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS), were evaluated in cardiac tissue in both groups. Phosphorylation and membrane-translocation of the cytosolic components of nicotinamide adenine dinucleotide phosphate (NAD(P)H)-oxidase and translocation of nuclear factor kappa B (NF-κB) were also evaluated. After saline intravenous injection, cardiac contractility was significantly reduced in rats with cirrhosis as compared to control rats (P < 0.01). This was associated with: (1) increased expression of protein Gα(i2) (P < 0.05), TNF-α (P < 0.05), iNOS (P < 0.05); (2) increased NAD(P)H-oxidase activity (P < 0.05); (3) increased nuclear translocation of NF-κB (P < 0.05); and (4) lower expression of Adcy 3 (P < 0.05) in cardiac tissue of rats with cirrhosis. After albumin injection cardiac contractility (P < 0.01), protein expression of TNF-α, iNOS, Gα(i2), and Adcy3, NAD(P)H-oxidase activity and nuclear translocation of NF-κB in cardiac tissue of rats with cirrhosis were reversed to control levels (P < 0.05). HES injection did not modify cardiac contractility and nuclear translocation of NF-κB in cardiac tissue of rats with cirrhosis. CONCLUSION: Albumin exerts a positive cardiac inotropic effect in rats with cirrhosis and ascites counteracting the negative effects of oxidative stress- and TNF-α-induced activation of NF-κB-iNOS pathway and oxidative stress-induced alteration of ß-receptor signaling.

Prevalence, clinical, and molecular correlates of KCNJ5 mutations in primary aldosteronism.

Primary aldosteronism is the most common form of secondary hypertension. Mutations in the KCNJ5 gene have been described recently in aldosterone-producing adenomas (APAs). The aim of this study was to investigate the prevalence of KCNJ5 mutations in unselected patients with primary aldosteronism and their clinical, biological and molecular correlates. KCNJ5 sequencing was performed on somatic (APA, n=380) and peripheral (APA, n=344; bilateral adrenal hyperplasia, n=174) DNA of patients with primary aldosteronism, collected through the European Network for the Study of Adrenal Tumors. Transcriptome analysis was performed in 102 tumors. Somatic KCNJ5 mutations (p.Gly151Arg or p.Leu168Arg) were found in 34% (129 of 380) of APA. They were significantly more prevalent in females (49%) than males (19%; P<10(-3)) and in younger patients (42.1±1.0 versus 47.6±0.7 years; P<10(-3)) and were associated with higher preoperative aldosterone levels (455±26 versus 376±17 ng/L; P=0.012) but not with therapeutic outcome after surgery. Germline KCNJ5 mutations were found neither in patients with APA nor those with bilateral adrenal hyperplasia. Somatic KCNJ5 mutations were specific for APA, because they were not identified in 25 peritumoral adrenal tissues or 16 cortisol-producing adenomas. Hierarchical clustering of transcriptome profiles showed that APAs with p.Gly151Arg or p.Leu168Arg mutations were indistinguishable from tumors without KCNJ5 mutations. In conclusion, although a large proportion of sporadic APAs harbors somatic KCNJ5 mutations, germline mutations are not similarly causative for bilateral adrenal hyperplasia. KCNJ5 mutation carriers are more likely to be females; younger age and higher aldosterone levels at diagnosis suggest that KCNJ5 mutations may be associated with a more florid phenotype of primary aldosteronism.

Widespread increase in myeloid calcifying cells contributes to ectopic vascular calcification in type 2 diabetes.

RATIONALE: Acquisition of a procalcific phenotype by resident or circulating cells is important for calcification of atherosclerotic plaques, which is common in diabetes. OBJECTIVE: We aim to identify and characterize circulating calcifying cells, and to delineate a pathophysiological role for these cells in type 2 diabetes. METHODS AND RESULTS: We demonstrate for the first time that a distinct subpopulation of circulating cells expressing osteocalcin and bone alkaline phosphatase (OC(+)BAP(+)) has procalcific activity in vitro and in vivo. The study of naïve patients with chronic myeloid leukemia indicated that OC(+)BAP(+) cells have a myeloid origin. Myeloid calcifying OC(+)BAP(+) cells (MCCs) could be differentiated from peripheral blood mononuclear cells, and generation of MCCs was closely associated with expression of the osteogenic transcription factor Runx2. In gender-mismatched bone marrow-transplanted humans, circulating MCCs had a much longer half-life compared with OC(-)BAP(-) cells, suggesting they belong to a stable cell repertoire. The percentage of MCCs was higher in peripheral blood and bone marrow of type 2 diabetic patients compared with controls but was lowered toward normal levels by optimization of glycemic control. Furthermore, diabetic carotid endoarterectomy specimens showed higher degree of calcification and amounts of cells expressing OC and BAP in the α-smooth muscle actin-negative areas surrounding calcified nodules, where CD68(+) macrophages colocalize. High glucose increased calcification by MCCs in vitro, and hypoxia may regulate MCC generation in vitro and in vivo. CONCLUSIONS: These data identify a novel type of blood-derived procalcific cells potentially involved in atherosclerotic calcification of diabetic patients.

Downregulation of the longevity-associated protein sirtuin 1 in insulin resistance and metabolic syndrome: potential biochemical mechanisms.

OBJECTIVE: Sirtuins (SIRTs) are NAD(+)-dependent deacetylases that regulate metabolism and life span. We used peripheral blood mononuclear cells (PBMCs) to determine ex vivo whether insulin resistance/metabolic syndrome influences SIRTs. We also assessed the potential mechanisms linking metabolic alterations to SIRTs in human monocytes (THP-1) in vitro. RESEARCH DESIGN AND METHODS: SIRT1-SIRT7 gene and protein expression was determined in PBMCs of 54 subjects (41 with normal glucose tolerance and 13 with metabolic syndrome). Insulin sensitivity was assessed by the minimal model analysis. Subclinical atherosclerosis was assessed by carotid intima-media thickness (IMT). In THP-1 cells exposed to high glucose or fatty acids in vitro, we explored SIRT1 expression, p53 acetylation, Jun NH(2)-terminal kinase (JNK) activation, NAD(+) levels, and nicotinamide phosphoribosyltransferase (NAMPT) expression. The effects of SIRT1 induction by resveratrol and of SIRT1 gene silencing were also assessed. RESULTS: In vivo, insulin resistance and metabolic syndrome were associated with low PBMC SIRT1 gene and protein expression. SIRT1 gene expression was negatively correlated with carotid IMT. In THP-1 cells, high glucose and palmitate reduced SIRT1 and NAMPT expression and reduced the levels of intracellular NAD(+) through oxidative stress. No effect was observed in cells exposed to linoleate or insulin. High glucose and palmitate increased p53 acetylation and JNK phosphorylation; these effects were abolished in siRNA SIRT1-treated cells. Glucose- and palmitate-mediated effects on NAMPT and SIRT1 were prevented by resveratrol in vitro. CONCLUSIONS: Insulin resistance and subclinical atherosclerosis are associated with SIRT1 downregulation in monocytes. Glucotoxicity and lypotoxicity play a relevant role in quenching SIRT1 expression.

Green tea attenuates angiotensin II-induced cardiac hypertrophy in rats by modulating reactive oxygen species production and the Src/epidermal growth factor receptor/Akt signaling pathway.

We previously documented a clear-cut antihypertensive effect of green teat extract (GTE), which was associated with correction of endothelial dysfunction and prevention of left ventricular hypertrophy in an angiotensin II (Ang II)-dependent model of hypertension, but the molecular mechanisms remain to be defined. As several effects of Ang II involve production of reactive oxygen species (ROS) and activation of 2nd messengers, such as mitogen-activated protein kinase (MAPK) and Akt, we investigated the effect of GTE on these signal transduction pathways in Ang II-treated rats. Rats were treated for 2 wk with Ang II infusion (700 mug.kg(-1).d(-1); n = 6, via osmotic minipumps), Ang II plus GTE (6 g/L) dissolved in the drinking water; n = 6), or vehicle (n = 6) to serve as controls. Blood pressure was monitored by telemetry throughout the study. The activation and expression of NAD(P)H oxidase subunits, protein kinase C isoforms, Src, epidermal growth factor receptor (EGFR), Akt, and MAPK were determined in the heart in vitro through immunoprecipitation and western blot analysis with specific antibodies. NAD(P)H oxidase enzymatic activity was measured by cytochrome c reduction assay. GTE blunted Ang II-induced blood pressure increase and cardiac hypertrophy. In Ang II-treated rats, GTE decreased the expression of the NAD(P)H oxidase subunit gp91(phox) and the translocation of Rac-1, as well as NAD(P)H oxidase enzymatic activity. Furthermore, it specifically reduced Ang II-induced Src, EGFR, and Akt phosphorylation. These results show that GTE blunts Ang II-induced cardiac hypertrophy specifically by regulating ROS production and the Src/EGFR/Akt signaling pathway activated by Ang II.

Rosiglitazone reduces glucose-induced oxidative stress mediated by NAD(P)H oxidase via AMPK-dependent mechanism.

OBJECTIVE: Hyperglycemia is the main determinant of long-term diabetic complications, mainly through induction of oxidative stress. NAD(P)H oxidase is a major source of glucose-induced oxidative stress. In this study, we tested the hypothesis that rosiglitazone (RSG) is able to quench oxidative stress initiated by high glucose through prevention of NAD(P)H oxidase activation. METHODS AND RESULTS: Intracellular ROS were measured using the fluoroprobe TEMPO-9-AC in HUVECs exposed to control (5 mmol/L) and moderately high (10 mmol/L) glucose concentrations. NAD(P)H oxidase and AMPK activities were determined by Western blot. We found that 10 mmol/L glucose increased significantly ROS production in comparison with 5 mmol/L glucose, and that this effect was completely abolished by RSG. Interestingly, inhibition of AMPK, but not PPARgamma, prevented this effect of RSG. AMPK phosphorylation by RSG was necessary for its ability to hamper NAD(P)H oxidase activation, which was indispensable for glucose-induced oxidative stress. Downstream of AMPK activation, RSG exerts antioxidative effects by inhibiting PKC. CONCLUSIONS: This study demonstrates that RSG activates AMPK which, in turn, prevents hyperactivity of NAD(P)H oxidase induced by high glucose, possibly through PKC inhibition. Therefore, RSG protects endothelial cells against glucose-induced oxidative stress with an AMPK-dependent and a PPARgamma-independent mechanism.