The dipeptidyl peptidase-4 inhibitor-sitagliptin modulates calcium dysregulation,inflammation, and PPARs in hypertensive cardiomyocytes

Background

Hypertension induces cardiac dysfunction, calcium (Ca^2 +) dysregulation, and arrhythmogenesis. Dipeptidyl peptidase (DPP)-4 inhibitors, an antidiabetic agent with anti-inflammation and anti-hypertension potential, may regulate peroxisome proliferator-activated receptors (PPARs)-α, -γ, and -δ and Ca^2 + homeostasis.

Objective

The purpose of this study was to investigate whether DPP-4 inhibitor, sitagliptin, can modulate PPARs and Ca^2 + handling proteins in hypertensive hearts.

Methods

A Western blot analysis was used to evaluate protein expressions of myocardial PPAR isoforms, tumor necrosis factor (TNF)-α, interleukin (IL)-6, sarcoplasmic reticulum ATPase (SERCA2a), Na⁺–Ca^2 + exchanger (NCX), ryanodine receptor (RyR), voltage-dependent Ca^2 + (CaV1.2), slow-voltage potassium currents (Kvs), angiotensin II type 1 receptor (AT1R), and receptor of advanced glycated end-products (RAGE) from Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR), and SHR treated with sitagliptin (10 mg/kg for 4 weeks). Conventional microelectrodes were used to record action potentials (APs) in the ventricular myocytes from each group.

Results

Compared to the control group, SHR had lower cardiac PPAR-α and PPAR-δ protein expressions, but had greater cardiac PPAR-γ levels, and TNF-α, IL-6, RAGE, and AT1R protein expressions, which were ameliorated in the sitagliptin-treated SHR. SHR had prolonged QT interval and AP duration with less SERCA2a and RyR, and greater CaV1.2 expressions, which were also attenuated in sitagliptin-treated SHR.

Conclusions

Sitagliptin significantly changed the cardiac electrophysiological characteristics and Ca^2 + regulation, which may have been caused by its effects on cardiac PPARs, proinflammatory cytokines, and AT1R.     

Inhibition of high-mobility group box 1 improves myocardial fibrosis and dysfunction in diabetic cardiomyopathy

Background

High-mobility group box 1 (HMGB1) is an important mediator of the inflammatory response. Its expression is increased in diabetic cardiomyopathy (DCM), but its role is unclear. We investigated the potential role and mechanism of HMGB1 in diabetes-induced myocardial fibrosis and dysfunction in mice.

Methods

In vivo, type 1 diabetes was induced by streptozotocin (STZ) in mice. HMGB1 expression was knocked down by lentivirus-mediated short-hairpin RNA (shRNA). Cardiac function was assessed by echocardiography. Total collagen deposition was assessed by Masson's trichrome and Picrosirius red staining. HMGB1, collagen I and III, and transforming growth factor β1 (TGF-β1) expression was quantified by immunostaining and western bolt analysis. In vitro, isolated neonatal cardiac fibroblasts were treated with high glucose (HG) or recombinant HMGB1 (rHMGB1). Pharmacologic (neutralizing anti-HMGB1 antibody) or genetic (shRNA-HMGB1) inhibition of HMGB1 was used to investigate the role of HMGB1 in HG-induced functional changes of cardiac fibroblasts.

Results

In vivo, HMGB1 was diffusely expressed in the myocardium of diabetic mice. HMGB1 silencing ameliorated left ventricular dysfunction and remodeling and decreased collagen deposition in diabetic mice. In vitro, HG induced HMGB1 translocation and secretion in both viable cardiomyocytes and fibroblasts. Administration of rHMGB1 dose-dependently increased the expression of collagens I and III and TGF-β1 in cardiac fibroblasts. HMGB1 inhibition reduced HG-induced collagen production, matrix metalloproteinase (MMP) activities, proliferation, and activated mitogen-activated protein kinase signaling in cardiac fibroblasts.

Conclusions

HMGB1 inhibition could alleviate cardiac fibrosis and remodeling in diabetic cardiomyopathy. Inhibition of HMGB1 might have therapeutic potential in the treatment of the disease.     

Effect of farnesyltransferase inhibition on cardiac remodeling in spontaneously hypertensive rats

Background

Farnesyltransferase (FT), an essential enzyme at the downstream of mevalonate pathway, was reported to be upregulated in hypertrophic cardiomyocytes of spontaneously hypertensive rats (SHRs) compared with myocardium of Wistar-Kyoto rats (WKYs). This upregulation was accompanied with cardiac remodeling. This study was designed to determine whether FT inhibition can alter cardiac remodeling in SHRs.

Methods

Twelve-week-old SHRs were randomized to receive infusion of either NS or FTI-276 (307 μg/kg/d i.v. each n = 10). WKY rats served as normal controls (n = 6). Echocardiography was performed before and after intervention. SHR hearts were perfused ex vivo for the evaluation of cardiac performance, collagen deposition and biochemical changes (activation of Ras, extracellular-signal regulated kinases/ERK1/2, procollagen type ?/Ш, TGF-β1, connective tissue growth factor/CTGF, and bone morphogenetic protein-7/BMP-7 expression).

Results

FTI-276 intervention decreased interventricular septum wall thickness at end- diastole (IVSd) and relative wall thickness (RWT) of SHRs (P< 0.05). Three week intervention with FTI-276 attenuated hydroxyproline content (P < 0.05), collagen deposition (P < 0.01), Ras activation, ERK1/2 phosphorylation (P < 0.01) and mRNA expression of procollagen type I, TGF-β1 and CTGF and elevated mRNA expression of BMP-7 (P < 0.05) in left ventricle of SHRs.

Conclusion

The present study indicated that FT inhibition could attenuate myocardial fibrosis and partly improve cardiac remodeling in SHRs. The beneficial effects might be mediated through suppression of the activation of Ras and ERK1/2 phosphorylation pathway. The enhanced mRNA expression of BMP-7 with inhibition of TGF-β1 and CTGF mRNA expression might be an important mechanism.     

Receptor for AGEs (RAGE) blockade may exert its renoprotective effects in patients with diabetic nephropathy via induction of the angiotensin II type 2 (AT2) receptor

Aims/hypothesis

The receptor for AGEs (RAGE) contributes to the development and progression of diabetic nephropathy. In this study, we examined whether the protective effects of RAGE blockade are exerted via modulation of the renal angiotensin II type 2 (AT2) receptor.

Methods

Control and streptozotocin diabetic mice, wild-type or deficient in the AT2 receptor (At2 knockout [KO]) or RAGE (Rage KO), were studied for 24 weeks. Adenoviral overexpression of full-length Rage in primary rat mesangial cells was also used to determine the effects on AT2 production.

Results

With diabetes, Rage-deficient mice had less albuminuria, and an attenuation of hyperfiltration and glomerulosclerosis as compared with diabetic wild-type and At2 KO mice. Renal gene and protein expression of RAGE was elevated with diabetes. Diabetic Rage KO mice had a greater increase in renal AT2 receptor protein than was seen in diabetic wild-type mice. Diabetes-induced increases in renal cytosolic and mitochondrial superoxide generation were prevented in diabetic Rage KO mice, but enhanced in all At2 KO mice. Adenoviral overexpression of RAGE or AGE treatment decreased cell surface AT2 expression, in association with increasing superoxide generation; both were reversed using antioxidants N-acetylcysteine and apocynin, and soluble RAGE in primary mesangial cells.

Conclusions/interpretation

RAGE appears to be a common and key modulator of AT2 receptor expression, a finding that would implicate a newly defined RAGE–AT2 axis in the development and progression of diabetic nephropathy.

     

Change in proteoglycan metabolism is a characteristic of human patellar tendinopathy

Objective

To determine differences in the metabolism of proteoglycans and the gene expression of proteinases and their inhibitors between patellar tendons exhibiting chronic overuse tendinopathy and normal patellar tendons in humans.

Methods

Rates of loss and synthesis of proteoglycans were determined. Radiolabeled and total proteoglycans retained in and lost from the tissue were analyzed by fluorography and Western blotting. Levels of messenger RNA for matrix metalloproteinase 1 (MMP‐1), MMP‐2, MMP‐3, MMP‐9, MMP‐13, ADAMTS‐1, ADAMTS‐4, ADAMTS‐5, tissue inhibitor of metalloproteinases 1 (TIMP‐1), TIMP‐2, TIMP‐3, and TIMP‐4 were determined in fresh tissue.

Results

The rate of loss of ³⁵S‐labeled proteoglycans was greater in abnormal tendons, as was the rate of synthesis of proteoglycans. Fluorography and Western blotting revealed the presence of greater amounts of large proteoglycans (aggrecan and versican) in abnormal tendons, and these proteoglycans were rapidly lost from the matrix of abnormal tendons. There was no significant difference in the expression of ADAMTS‐1, ADAMTS‐4, ADAMTS‐5, MMP‐1, MMP‐2, MMP‐3, MMP‐13, TIMP‐2, TIMP‐3, or TIMP‐4. There was a significant increase in the expression of MMP‐9 and TIMP‐1 in abnormal tendons.

Conclusion

Our findings suggest that a change in the proteoglycan content of the extracellular matrix in abnormal tendons results from the altered metabolism of the cells, reflected in the enhanced synthesis of the large proteoglycans aggrecan and versican, and does not appear to result from changes at the level of gene expression.

     

Plasma MMP2/TIMP4 Ratio at Follow-up Assessment Predicts Disease Progression of Idiopathic Pulmonary Arterial Hypertension

Purpose

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) are of particular interest in the remodeling processes of pulmonary hypertension. The aim of this study was to investigate MMP/TIMP ratios of selected biomarkers (MMP2, MMP9, TIMP1, TIMP4) at follow-up examination (V2) and their prognostic value in patients with idiopathic pulmonary arterial hypertension (iPAH).

Methods

Blood samples were taken from iPAH patients during right heart catheterization at diagnosis (V1, from 2003 to 2012) and first follow-up examination (V2). MMP2, MMP9, TIMP1, and TIMP4 plasma levels at V2 were determined by ELISA. Coincident with sample collection hemodynamic, laboratory, and clinical parameters were acquired. Additionally, death and clinical worsening (CW) events were listed until July 2015.

Results

MMP2/TIMP1 and MMP9/TIMP1 did not correlate with hemodynamic and clinical parameters. MMP2/TIMP4 showed a good correlation with mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance, estimated glomerular filtration rate (eGFR), and tricuspid annular plain systolic excursion (TAPSE). MMP9/TIMP4 shows good correlation with mPAP and eGFR. MMP2/TIMP4 showed significant results in the receiver operating characteristics analysis predicting death (AUC = 0.922; p = 0.005) and CW event (AUC = 0.818; p = 0.026). Patients above the cut-off values had a significantly higher probability to die or experience CW, respectively, estimated by log-rank test (p = 0.010 for death; p = 0.032 for CW).

Conclusions

MMP2/TIMP4 ratio was detected as a marker of disease severity and right ventricular function as well as a predictor for survival and time to clinical worsening and therefore might help for guidance of disease progression in iPAH patients at V2.

     

Differences in biomarkers in patients with heart failure with a reduced vs a preserved left ventricular ejection fraction

Background

The differences in concentrations of biomarkers between heart failure (HF) patients with a preserved left ventricular ejection fraction (LVEF), or HF-PEF, and patients with HF with reduced LVEF (HF-REF) have yet to be defined. The objectives of this study were to compare the concentrations and correlation of biomarkers of inflammation, extracellular matrix (ECM) turnover and neurohormonal activation between these populations.

Methods

We performed a cross-sectional study of 29 subjects with symptomatic HF-REF (LVEF = 25.6 ± 5.1%) and 29 subjects with symptomatic HF-PEF (LVEF = 63.3 ± 5.3%). Concentrations of N-terminal proB-type natriuretic peptide (NT-proBNP), high sensitivity C-reactive protein (hsCRP), procollagen type III amino-terminal peptide (PIIINP), matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitor of MMP (TIMP)-1 were measured.

Results

Although NT-proBNP and PIIINP concentrations were higher in patients with HF-REF compared with patients with HF-PEF (both P < 0.05), the only significant difference between the groups remaining after adjusting for possible confounding variables was NT-proBNP (P = 0.02). In patients with HF-REF, NT-proBNP correlated with PIIINP (P < 0.05), TIMP-1 (P < 0.05), and MMP-2 (P = 0.002), while PIIINP correlated with TIMP-1 (P < 0.05) and MMP-2 (P < 0.0001). In patients with a HF-PEF, only high sensitivity C-reactive protein correlated significantly with MMP-2 (P = 0.002).

Conclusions

Patients with HF-REF or HF-PEF presenting similar symptoms and functional limitations exhibit similar concentrations of biomarkers of ECM and inflammation. However, patients with HF-REF exhibit significantly higher NT-proBNP concentrations than patients with HF-PEF. The differences in the correlations observed between the biomarkers between these 2 populations suggest some heterogeneity and differences in the mechanisms related to the release or clearance of biomarkers in HF-REF vs HF-PEF.     

Fibrosis in endstage human heart failure: Severe changes in collagen metabolism and MMP/TIMP profiles

Objectives

We studied fibrosis, collagen metabolism, MMPs/TIMPs and cytokine expression in various forms of human heart failure (HF) by quantitative immunofluorescent microscopy, Western blot, zymography, RT-PCR and in situ hybridization. In explanted human hearts with HF due to either dilated (DCM, n = 6) or ischemic (ICM-BZ-borderzone, ICM-RZ-remote zone, n = 7) or inflammatory (myocarditis, MYO, n = 6) cardiomyopathy and 8 controls MMP2, 8, 9, 19, and TIMP1, 2, 3, 4 as well as procollagens I and III (PINP, PIIINP), mature collagen III (IIINTP) and the cross-linked collagen I degradation product (ICTP) were measured.

Results

In comparison with controls, MMPs and TIMPs were significantly upregulated ranging (from highest to lowest) from ICM-BZ, DCM, ICM-RZ, MYO for all MMPs with the exception of MMP9 (highest in DCM), and for TIMPs from ICM-BZ, ICM-RZ, DCM and MYO. MMP2 and 9 were activated in all groups. The TIMP/MMP ratio was 1.3 for control, 1.9 in ICM-BZ (TIMP > MMP) and lowered to 1.0 in the other groups. Collagen I/collagen III ratio correlated significantly with the decrease in LVEDP. PINP was higher than ICTP in all groups. PIIINP elevation was present in DCM and ICM-RZ and IIINTP was up to 4-fold augmented in all groups. Fibrosin mRNA was upregulated in ICM-BZ, activin A in MYO but FGF1 and FGF2 remained unchanged. ANP mRNA was increased in all groups.

Conclusions

Although different degrees of severity of collagen metabolism, MMP/TIMP imbalance and cytokine expression in diverse forms of HF are present, the end product is collagen deposition. These findings suggest multiple mechanisms acting alone or in concert in fibrosis development in HF.     

Mesenchymal stem cells transplantation ameliorates glomerular injury in streptozotocin-induced diabetic nephropathy in rats via inhibiting oxidative stress

Aims

Mesenchymal stem cells (MSCs) have been demonstrated to be protective in diabetic nephropathy (DN) by reducing albuminuria and attenuating glomerular injury. However, the mechanisms remain unclear. The aim of this study was to explore the effects of MSCs on oxidative stress in DN.

Materials/methods

Streptozotocin-induced diabetic rats received no treatment or treatment with MSCs (2 × 10⁶, via tail vein) for two continuous weeks. Two other control groups received the antioxidant-probucol or insulin. Eight weeks after treatment, physical, biochemical, renal functional and morphological parameters were measured. Glomerular mesangial cells were cultured for the in vitro experiment.

Results

Green fluorescent protein-labeled MSCs were only detected around the glomeruli and near vessels in the kidney. MSCs treatment dramatically reduced blood glucose, urinary albumin excretion, creatinine clearance and renal mass index. The glomerulosclerosis as revealed by periodic acid Schiff staining and expression of collagen I and fibronectin was significantly reduced by MSC treatment. Oxidative stress was also markedly inhibited in the MSCs group. Furthermore, the expression of TGF-β and membrane localization of GLUT1 were also down-regulated by MSCs. MSCs secreted a significant amount of hepatocyte growth factor (HGF). In vitro, MSC conditioned medium inhibited up-regulation of TGF-β expression stimulated by high glucose and HGF neutralizing antibody blocked the inhibitory effect of MSC conditioned medium.

Conclusions

MSC treatment reduced urinary albumin excretion and ameliorated glomerulosclerosis. The mechanisms underlying these effects involved reduced blood glucose levels and cellular glucose uptake mediated by GLUT1, thus inhibiting oxidative stress.     

The PI3K/p-Akt signaling pathway participates in calcitriol ameliorating podocyte injury in DN rats

Objectives

The present study aimed to investigate the relationship between PI3K/p-Akt signaling pathway and podocyte impairment in DN rats as well as the protective effect of calcitriol.

Methods

SD rats were randomly divided into four groups: normal control (NC), normal treated with calcitriol (NC + VD), diabetic nephropathy (DN) and DN treated with calcitriol (DN + VD); all VD rats were treated with 0.1 μg/kg/d calcitriol by gavage. DN model rats were established by intraperitoneal injections of streptozotocin (STZ). Rats were sacrificed after 18 weeks of treatments.

Results

In the present study, increased albuminuria was observed as early as 3 weeks of diabetes and continued to increase more than six-fold throughout the length of the study (18 weeks). Expectedly, animals receiving the treatment with calcitriol was protected from this increase, lower about one third. Meanwhile, the expression of podocyte specific markers, including nephrin and podocin, together with PI3K/p-Akt was significantly decreased in DN rats, whereas calcitriol reversed these above changes accompanied by elevated the expression levels of VDR. Additionally, a positive correlation was observed between the expression levels of nephrin and VDR (r = 0.776, P < 0.05). Likewise, the expression of nephrin was positively correlated with both PI3K-p85 and p-Akt (r = 0.736, P < 0.05; r = 0.855, P < 0.05, respectively).

Conclusion

PI3K/p-Akt signaling pathway participates in calcitriol ameliorating podocyte injury in DN rats. The manipulation of calcitriol might act as a promising therapeutic intervention for diabetic nephropathy.     

Berberine attenuates lipopolysaccharide-induced extracelluar matrix accumulation and inflammation in rat mesangial cells: Involvement of NF-κB signaling pathway

Background

Our previous studies demonstrated that berberine could improve the renal function in rats and mice with diabetic nephropathy (DN) and inhibit extracellular matrix (ECM) component, fibronectin (FN) expression in rat mesangial cells (MCs) cultured under high glucose. However, the molecular mechanisms have not been fully elucidated.

Objective

To explore the potential mechanisms of berberine in the treatment of DN, we investigated the effects of berberine on lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-κB) activation and its downstream inflammatory mediators, such as intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-β1), inducible nitric oxide synthase (iNOS) and fibronectin (FN) protein expression in rat MCs.

Method

Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The activation of NF-κB was detected by Western blot and confocal microscopy. The protein levels of ICAM-1, TGF-β1, iNOS and FN in rat MCs were detected by Western blot.

Results

Our results revealed that berberine significantly suppressed LPS-induced cell proliferation and inhibited LPS-induced NF-κB nuclear translocation in MCs, as well as protein expression of ICAM-1, TGF-β1, iNOS and FN.

Conclusion

Berberine significantly repressed LPS-induced cell proliferation and FN expression in rat MCs through inhibiting the activation of NF-κB signaling pathway and protein expression of its downstream inflammatory mediators. The ameliorative effects of berberine on DN might be associated with this inhibition effect on NF-κB signaling pathway which was independent of its hypoglycemic effect.     

Association of RAGE (p.Gly82Ser) and MnSOD (p.Val16Ala) polymorphisms with diabetic retinopathy in T2DM patients from north India

Aims

The present study aimed to examine the association of RAGE (p.Gly82Ser) and MnSOD (p.Val16Ala) polymorphisms with diabetic retinopathy (DR) in north Indian T2DM patients.

Methods

In this case-control association study, 758 T2DM patients were recruited. 446 with retinal neovascularization, microneurysms and hemorrhages were considered as cases (DR) and 312 patients with T2DM and no clinical signs of retinopathy (DNR), were recruited as controls. Genotypes for RAGE (p.Gly82Ser) and MnSOD (p.Val16Ala) polymorphisms were generated by direct sequencing of amplified products.

Results

Genotype distribution of p.Gly82Ser (RAGE) and p.Val16Ala (MnSOD) polymorphisms were significantly different between DR and DNR (p < 0.05) whereas distribution of allele frequency did not differ significantly (p > 0.05). A significantly higher frequency of homozygous Ser82 genotype in DR patients was detected compared with DNR (2.4% vs 0.64%) for p.Gly82Ser (RAGE) polymorphism whereas there was a higher frequency of homozygous Ala16 genotype for p.Val16Ala (MnSOD) polymorphism in DR patients compared with DNR (22.6% vs 19.3%). Binary logistic analyses showed an association of homozygous recessive genotype Ser82 with DR (OR: 2.63%, 95% CI: 0.16–15.88, p < 0.033) for p.Gly82Ser (RAGE) polymorphism. However, we did not find a significant association of p.Val16Ala polymorphism in MnSOD with retinopathy.

Conclusions

The findings indicate a statistically significant association of p.Gly82Ser polymorphism in RAGE with DR in T2DM patients.     

Inhibition of adjuvant‐induced arthritis by systemic tissue inhibitor of metalloproteinases 4 gene delivery

Objective

An imbalance in the matrix metalloproteinase:tissue inhibitor of metalloproteinases (MMP:TIMP) ratio in favor of MMP appears to be an important determinant of tissue damage in arthritis. We undertook this study to explore whether reversal of this imbalance in favor of TIMP would alter this process and to examine the mechanism of this alteration.

Methods

We administered human TIMP‐4 by electroporation‐mediated intramuscular injection of naked DNA using the rat adjuvant‐induced arthritis (AIA) model.

Results

Intramuscular naked TIMP‐4 gene administration resulted in high circulating TIMP‐4 levels and completely abolished arthritis development in the rat AIA model. This inhibition was associated with significantly decreased MMP activity in the joint tissue as well as with significantly decreased serum and tissue tumor necrosis factor α levels and serum interleukin‐1α levels compared with animals with arthritis. The mutation of cysteine at position 1 of TIMP‐4 failed to block the development of AIA.

Conclusion

Our data indicate that TIMP‐4 is a potent antiinflammatory agent, and that its antiarthritis function may be mediated by MMPs. Arthritis‐inhibiting effects of TIMP‐4 may suggest a unique application of this gene therapy method for arthritis.

     

Effects of intraarticular glucocorticoids on macrophage infiltration and mediators of joint damage in osteoarthritis synovial membranes: Findings in a double‐blind,placebo‐controlled study

Objective

To investigate the effects of intraarticular glucocorticoid treatment on macrophage infiltration, the expression of the chemokines monocyte chemoattractant protein 1 (MCP‐1) and macrophage inflammatory protein 1α (MIP‐1α), and the expression of matrix metalloproteinases 1 and 3 (MMPs 1 and 3) and their inhibitors, the tissue inhibitors of metalloproteinases 1 and 2 (TIMPs 1 and 2), in osteoarthritis (OA) synovial membranes.

Methods

Forty patients underwent arthroscopic biopsy before and 1 month after intraarticular injection of glucocorticoids. Twenty‐one patients received 120 mg of methylprednisolone acetate (Depo‐Medrol; Upjohn, Kalamazoo, MI), and 20 patients received placebo (1 patient received placebo in 1 knee and methylprednisolone acetate in the other). Immunoperoxidase staining for the expression of CD68, MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 was performed, and the immunostaining was quantified by color video image analysis.

Results

CD68, MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 immunostaining was observed in all synovial membranes. Intraarticular glucocorticoid treatment was associated with a small (30%) but statistically significant (P = 0.048) reduction in CD68+ macrophage staining in the synovial lining layer, but there was no change in the CD68 expression in the synovial sublining layer. No significant differences were observed for MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 immunostaining in the synovial lining or sublining layers.

Conclusion

Intraarticular glucocorticoids may reduce CD68+ macrophage infiltration into the synovial lining layer, but not the expression of MCP‐1, MIP‐1α, MMP‐1, MMP‐3, TIMP‐1, and TIMP‐2 in the synovial membrane, in patients with OA.

     

Eplerenone in systemic right ventricle: Double blind randomized clinical trial. The evedes study

Background

There is no proven pharmacological strategy for the treatment of the failing systemic right ventricle (SRV) but myocardial fibrosis may play a role in its pathophysiology.

Methods

We designed a double-blind, placebo-controlled clinical trial to assess the effects of eplerenone 50 mg during 12 months on cardiac magnetic resonance parameters (SRV mass and ejection fraction) and neurohormonal and collagen turnover biomarker (CTB) levels.

Results

Twenty six patients with atrial switch repair for transposition of the great arteries were randomized to eplerenone (n = 14) or placebo (n = 12) and 14 healthy volunteers served as controls for comparison of baseline neurohormones and CTB levels. The study population showed a good baseline profile in terms of SRV mass (57.4 ± 17 g/m²) and ejection fraction (54.9 ± 7.5%). However, levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), C terminal propeptide of type I procollagen (CICP) and C-terminal Telopeptide of type I Collagen (ICTP) were significantly elevated when compared to healthy controls. After one year of treatment, a trend toward reduction of CICP, N-terminal pro-Matrix Metalloproteinase 1 (NT-proMMP1), Tissue Inhibitor of Metalloproteinases 1 (TIMP1) and galectin 3 levels and a lower increase in ICTP in patients under eplerenone was observed. The reduction of SRV mass and the improvement of SRV function with eplerenone were not conclusive.

Conclusions

Patients with SRV treated with eplerenone showed an improvement of an altered baseline CTB profile suggesting that reduction of myocardial fibrosis might be a therapeutic target in these patients.     

Correlation between MMP and TIMP levels and elastic moduli of ascending thoracic aortic aneurysms

Objective

The objective of this preliminary investigation is to determine if there is a relation between the biological levels of matrix metalloproteinases and tissue inhibitor of matrix metalloproteinase (TIMP) and the elastic moduli of the ascending aortic wall in patients with ascending thoracic aortic aneurysms (ATAA). Methods: Circumferential specimens from twelve patients with ATAA were obtained from the greater curvature and their tensile properties (maximum elastic modulus) were tested uniaxially. The levels of MMP1, 2, 3, 8, and 9 as well as TIMP1 and 2 were determined in these aortic wall specimens using MMP/TIMP antibodies array.

Einfluss von Vitamin D auf Knochen und Muskel

Vitamin D metabolism

Vitamin D is converted in the liver to 25-hydroxyvitamin D, which represents the storage form and is the most abundant circulating metabolite. The further activation (1-α-hydroxylation) leads to the hormone 1?α,25-dihydroxyvitamin D (calcitriol), which takes place in the kidneys under hormonal control and contributes to circulating calcitriol but some target organs (such as bone) can produce calcitriol in an autocrine/paracrine fashion. Muscle and bone are the classical target organs for calcitriol. The hormone calcitriol has direct effects on muscle tissue, which are mediated by the nuclear vitamin D receptor (VDR) and also by non-genomic pathways (membrane receptors). Calcitriol modulates differentiation of muscle cells and stimulates protein synthesis.

Vitamin D deficiency

Vitamin D deficiency leads to muscle weakness, which is prominent in patients with rickets and osteomalacia; however, even subclinical vitamin D deficiency is associated with diminished muscle function. In populations with vitamin D deficiency (e.?g. elderly people), controlled intervention studies with vitamin D demonstrated improved muscle function and reduction in falls. In bone, calcitriol exerts anabolic and catabolic effects. Calcitriol stimulates intestinal absorption of calcium and phosphate providing mineral supply for bone mineralization. Calcitriol also has direct effects on proliferation and differentiation of bone cells. Calcitriol stimulates alkaline phosphatase and regulates bone matrix proteins (such as osteocalcin and osteopontin); therefore, calcitriol regulates mineralization in a direct manner. In high concentrations calcitriol also stimulates bone resorption. People with severe vitamin D deficiency have a higher risk for fractures. Vitamin D supplementation can reduce the risk of fractures.

Vitamin D supplementation

The best evidence exists for the daily administration of 800–2000 IU of vitamin D. Active vitamin D metabolites (also called vitamin D receptor agonists), such as calcitriol, alfacalcidol (1-α-hydroxyvitamin D) and paricalcitol are used for the pharmacological treatment of metabolic bone diseases and in these conditions reduce falls, improve muscle function and reduce the risk of fractures.