Association of galectin-3 with changes in left ventricular function in recent-onset dilated cardiomyopathy

Abstract

Background: The course of newly diagnosed dilated cardiomyopathy (DCM) varies from persistent reduction of left ventricular ejection fraction (LVEF) to recovery or even worsening. The aim of the present study was to examine the prognostic value of selected biomarkers with regard to changes in LVEF.

Methods: Main inclusion criterion was LVEF ≤45% with exclusion of coronary artery or valvular heart disease. The primary endpoint was LVEF ≤35% in the follow-up echocardiogram. Galectin-3, N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) were related to the endpoint.

Results: Data from 80 DCM patients (55 male, mean age 53 years) were analyzed. Median LVEF was 25% (IQR 25–30). The endpoint was met for 24 patients (30%). These had higher baseline levels of galectin-3 (median 20.3?ng/mL [IQR 14.3–26.9] vs. 14.7?ng/mL [IQR 10.9–17.7], p?=?0.007) and NT-proBNP (3089?pg/mL [IQR 1731–6694] vs. 1498?pg/mL [IQR 775–3890]; p?=?0.004) in univariate Cox regression analysis. ROC analysis revealed that CRP (median 0.4?mg/dL [IQR 0.2–1.2]) was also related to the endpoint (p?=?0.043).

Conclusion: Higher levels of galectin-3, NT-proBNP, and CRP were associated with LVEF ≤35% in our cohort. An approach utilizing a combination of biomarkers for patient management should be assessed in further studies.     

Oxidative stress is associated with decreased heart rate variability in patients with chronic kidney disease

Objectives: Elevated oxidative stress and reduced heart rate variability (HRV) is prevalent in patients with chronic kidney disease (CKD) and is associated with increased morbidity and mortality. Previous studies have identified a positive association between elevated oxidative stress and autonomic dysfunction, however this relationship has not yet been investigated in the CKD population.

Methods: Plasma was collected from 78 patients with stage 3–4 CKD (estimated glomerular filtration rate 25–60?ml/min/1.73?m²) for the assessment of oxidative stress, including plasma total F2-isoprostanes, glutathione peroxidase activity and total antioxidant capacity. Time and frequency HRV parameters were measured from a three lead electrocardiogram.

Results: Participants with elevated F2-isoprostanes had reduced HRV compared to patients with normal levels of F2-isoprostanes. A number of HRV parameters were found to be inversely correlated with F2-isoprostanes in all CKD patients, including SDNN (r?=??0.337; P?r?=??0.281, P?=?0.01), LF (r?=??0.315, P?r?=??0.288, P?=?0.01). Multiple linear regression found F2-isoprostanes to be an independent predictor of SDNN (r²?=?0.287, β?=??0.272, P?=?0.01).

Discussion: Oxidative stress is significantly and independently associated with HRV in patients with CKD. Identifying oxidative stress in the pathogenesis of autonomic dysfunction may help target therapeutic strategies.     

Biomarker-specific differences between transpulmonary and peripheral arterial–venous blood sampling in patients with pulmonary hypertension

Abstract

Purpose: Transpulmonary biomarkers may provide insight into pulmonary hypertension (PH) pathophysiology, but require cardiac catheterization. We investigated whether the peripheral arterial–venous ratio (PR) could substitute for the transpulmonary ratio (TPR).

Materials and methods: Blood from the pulmonary artery (PA), pulmonary arterial wedge (PAW), peripheral venous, and peripheral arterial positions was analysed for ET-1, NT-pro-BNP and cAMP levels in subjects with no PH (n?=?18) and PH due to left heart disease (PH-LHD), which included combined pre- and post-capillary PH (Cpc-PH; n?=?7) and isolated post-capillary PH (Ipc-PH; n?=?9). Bland–Altman comparisons were made between peripheral venous and PA samples and between peripheral arterial and PAW samples. TPR was defined as [PAW]/[PA].

Results: For ET-1, Bland–Altman analysis indicated negative bias (?24%) in peripheral arterial compared to PAW concentration and positive bias (23%) in peripheral venous compared to PA concentration. There was <10% absolute bias for NT-pro-BNP and cAMP. For ET-1, there was no difference in PR between Cpc-PH and Ipc-PH (0.87?±?0.4 vs. 0.94?±?0.6, p?=?0.8), whereas there was a difference in TPR (2.2?±?1.1 vs. 1.1?±?0.2, p?<?0.05).

Conclusions: In PH-LHD, peripheral samples may be inadequate surrogates for transpulmonary samples, particularly when measuring mediators with prominent pulmonary secretion or clearance, such as ET-1.     

Characterization of soluble thrombomodulin levels in patients with stage 3–5 chronic kidney disease

Abstract

Objective: This study aims to test the serum levels of soluble thrombomodulin (TM) in patients with chronic kidney disease (CKD)3–5 and to assess their connection with the different stages and severity of disease.

Methods: Sixty-seven patients with CKD are included, disease severity was evaluated accordingly to CKD staging and clinical data is collected. Nineteen healthy volunteers served as healthy controls. Serum soluble TM is analyzed by ELISA.

Results: The levels of soluble TM in all patients with CKD were significantly higher than those of healthy controls (p?<?0.001). CKD5 patients showed higher serum levels of soluble TM, in comparison to CKD4 patients (p?=?0.001), CKD3 patients (p?<?0.001), and healthy controls (p?<?0.001). The correlation analysis revealed significant correlation between serum soluble TM and disease severity (r?=?0.714, p?<?0.001). Serum soluble TM was found to be correlated with eGFR (r?=??0.766; p?<?0.001) and serum creatinine (r?=?0.778, p?<?0.001).

Conclusion: Soluble TM concentrations significantly increase in the CKD patients and are associated with the severity of the disease. Soluble TM may play critical roles in the development of CKD, as a biomarker of endothelial cells damage, anticoagulation and anti-inflammation.     

Alteration of thiol-disulphide homeostasis in acute tonsillopharyngitis

Objective: Thiol-disulphide homeostasis (TDH) has a critical role in various clinical disorders. We aimed to assess the association of TDH with acute tonsillopharyngitis (AT) in children.

Methods: This study included 94 (73 viral and 21 bacterial) tonsillopharyngitis patients and 88 control children. Their native thiol, total thiol, and disulphide levels were measured.

Results: Viral and bacterial tonsillopharyngitis patients had lower native thiol levels compared with healthy children (P?P?=?0.008, respectively). Both groups had lower total thiol levels compared with control children (P?=?0.002 for viral, P?=?0.011 for bacterial). The disulphide levels were lower in bacterial than in viral tonsillopharyngitis patients (P?=?0.04), and there was a significant difference between viral tonsillopharyngitis patients and the control group (P?P?P?=?0.017 for bacterial). The disulphide/native thiol and disulphide/total thiol ratios were significantly higher in viral (P?P?=?0.017 for both) than in healthy children. In all patients, a correlation was found between the levels of C-reactive protein (CRP) and native thiol (r?=??0.211, P?=?0.04), CRP and total thiol (r?=??0.217, P?=?0.036), white blood cell (WBC) and native thiol (r?=??0.228, P?=?0.002), WBC and total thiol (r?=??0.191, P?=?0.01), and WBC and disulphide (r?=?0.160, P?=?0.03).

Discussion: TDH is altered in AT in children. The alteration is more prominent in viral than in bacterial tonsillopharyngitis.     

Renalase attenuates hypertension,renal injury and cardiac remodelling in rats with subtotal nephrectomy

Chronic kidney disease is associated with higher risk of cardiovascular complication and this interaction can lead to accelerated dysfunction in both organs. Renalase, a kidney‐derived cytokine, not only protects against various renal diseases but also exerts cardio‐protective effects. Here, we investigated the role of renalase in the progression of cardiorenal syndrome (CRS) after subtotal nephrectomy. Sprague–Dawley rats were randomly subjected to sham operation or subtotal (5/6) nephrectomy (STNx). Two weeks after surgery, sham rats were intravenously injected with Hanks' balanced salt solution (sham), and STNx rats were randomly intravenously injected with adenovirus‐β‐gal (STNx+Ad‐β‐gal) or adenovirus‐renalase (STNx+Ad‐renalase) respectively. After 4 weeks of therapy, Ad‐renalase administration significantly restored plasma, kidney and heart renalase expression levels in STNx rats. We noticed that STNx rats receiving Ad‐renalase exhibited reduced proteinuria, glomerular hypertrophy and interstitial fibrosis after renal ablation compared with STNx rats receiving Ad‐β‐gal; these changes were associated with significant decreased expression of genes for fibrosis markers, proinflammatory cytokines and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase components. At the same time, systemic delivery of renalase attenuated hypertension, cardiomyocytes hypertrophy and cardiac interstitial fibrosis; prevented cardiac remodelling through inhibition of pro‐fibrotic genes expression and phosphorylation of extracellular signal‐regulated kinase (ERK)‐1/2. In summary, these results indicate that renalase protects against renal injury and cardiac remodelling after subtotal nephrectomy via inhibiting inflammation, oxidative stress and phosphorylation of ERK‐1/2. Renalase shows potential as a therapeutic target for the prevention and treatment of CRS in patients with chronic kidney disease.     

Proenkephalin and risk of developing chronic kidney disease: the Prevention of Renal and Vascular End-stage Disease study

Background: Proenkephalin (pro-ENK) was recently found to be associated with low estimated glomerular filtration rate (eGFR). The association of pro-ENK with urinary albumin excretion (UAE), another marker for chronic kidney disease (CKD), has not been investigated. We examined the association of pro-ENK with eGFR and UAE as markers of CKD.

Methods: We included 4375 subjects of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. CKD_eGFR was defined as development of eGFR?<60?ml/min/1.73 m² and CKD_UAE as albuminuria?>30?mg/24?h.

Results: Baseline median pro-ENK was 52.2 (IQR: 44.9–60.5) pmol/L. After a median follow-up of 8.4 (IQR: 7.9–8.9) years, 183 subjects developed CKD_eGFR and 371 developed CKD_UAE. The association of pro-ENK with CKD_eGFR was modified by sex (P_interaction?SD increase in ¹⁰log-transformed pro-ENK, 1.65; 95% CI: 1.15–2.36) and not in women (0.83; 0.58–1.20). No significant association was observed between pro-ENK and CKD_UAE risk (0.83; 0.58–1.20).

Conclusions: High pro-ENK is associated with increased risk of CKD_eGFR in men, but not in women. No association of pro-ENK with CKD_UAE was observed. These results should be interpreted with caution, since residual confounding and potential overfitting of models could have influenced the results.     

Reduced antioxidant capacity and increased subclinical inflammation markers in prepubescent obese children and their relationship with nutritional markers and metabolic parameters

Objective: There are associations between some inflammatory and oxidative markers and obesity in adults, but whether prepubescent children of different weights also have such markers has not been studied. We investigated multiple inflammatory markers and levels of erythrocyte oxidant/antioxidant enzymes in prepubescent children of different weights.

Methods: Children aged 2–11 years were divided into three groups: 80 were underweight, 90 were obese but otherwise healthy, and 80 were healthy age- and sex-matched children of normal-weight. We analyzed inflammatory markers and the total oxidant status, total antioxidant status (TAS), and total thiol level were also determined, and the oxidative stress index was calculated as an indicator of the degree of oxidative stress.

Results: The obese group exhibited higher levels of fasting glucose, insulin, total cholesterol, triglycerides, the homeostatic model assessment of insulin resistance (HOMA-IR), and the homeostatic model assessment of β-cell function (HOMA-β), C-reactive protein (CRP), neutrophils, and neutrophil/lymphocyte ratio (NLR), as well as lower TAS and total thiol levels than the other two groups (all P?<?0.001). Moreover, TAS and total thiols were negatively correlated with age in the obese group (r?=??0.212, P?=?0.001; r?=??0.231, P?<?0.001, respectively). CRP levels in plasma were positively correlated with the body mass index (BMI), insulin and glucose levels, HOMA-IR, HOMA-β, WBC and neutrophil counts, and the NLR, and were negatively correlated with TAS and total thiol levels in the overall studied population.

Discussion: The coexistence of increased obesity-related subclinical inflammation and decreased antioxidant capacity can be observed even in prepubescence, and may eventually increase the risk of long-term vascular damage.     

Mycophenolate mofetil and curcumin provide comparable therapeutic benefit in experimental chronic kidney disease: role of Nrf2-Keap1 and renal dopamine pathways

Increased oxidative stress and inflammation have an important role in the pathophysiology of chronic kidney disease (CKD). On the other hand, more affordable therapeutic alternatives for treating this disease are urgently needed. Therefore, we compared the therapeutic efficacy of curcumin and mycophenolate mofetil (MMF) in 5/6 nephrectomy (5/6 Nx) model of CKD. Also, we evaluated whether both compounds provide benefit through the preservation of similar antioxidant mechanisms. Four groups of male Wistar were studied over a period of 4 wk. Control sham group (n=?12), 5/6 Nx (n?=?12), 5/6 Nx?+?MMF (30?mg/k BW/day, n?=?11) and 5/6 Nx?+?Curcumin (120?mg/k BW/day, n?=?12). Renal function and markers of oxidative stress and inflammation were evaluated. Also Nrf2-Keap1 and renal dopamine, antioxidant pathways were assessed. 5/6 Nx induced an altered renal autoregulation response, proteinuria, and hypertension; these effects were in association with increased oxidative stress, endothelial dysfunction and renal inflammation. The mechanisms associated with these alterations included a reduced nuclear translocation of Nrf2 and hyperphosphorylation of dopamine D1 receptor with a concurrent overactivation of renal NADPH oxidase. Treatments with MMF and curcumin provided equivalent therapeutic efficacy as both prevented functional renal alterations as well as preserved antioxidant capacity and avoided renal inflammatory infiltration. Moreover, both treatments preserved Nrf2-Keap1 and renal dopamine antioxidant pathways. In summary, therapeutic strategies aimed to preserve renal antioxidant pathways can help to retard the progression of CKD.     

Pedometer-determined physical activity levels of healthy children and children with Down’s syndrome

Purpose: Children with Down’s syndrome (DS) are considered sedentary and less engaged in recommended physical activity (PA) levels. This study compared the PA levels between children with DS and healthy children in Saudi Arabia.

Methods: The study included 85 children divided into two groups. The DS group comprised 37 children with DS aged 8–12?years recruited from the Down Syndrome Charitable Association and Al-Nahda Schools for DS. The healthy group comprised 41 healthy children aged 8–12?years recruited from regular schools in the same region. PA levels were measured over 7?days using a pedometer.

Results: The healthy group was more active than the DS group (p?p?p?Conclusions: The DS group had a high body mass index and physical inactivity compared with the second group. Obesity and physical inactivity among Saudi Arabian children with and without DS are major health concerns. Therefore, concerted efforts are needed to combat childhood obesity, promote PA, improve patient quality of life, and reduce the sedentary lifestyle among Saudi children and adolescents.     

The role of the saliva antioxidant barrier to reactive oxygen species with regard to caries development

Objectives: The aim of this study was to evaluate the role of the antioxidant barrier in the saliva of children with caries, and its impact on the colonization of cariogenic bacteria.

Methods: This is a cross-sectional study of 81 children aged 1–5 years. Antioxidant levels and salivary bacterial profiles were measured. Patients were divided into two groups as follows: initial stage decay, termed non-cavitated (1–2 in International Caries Detection and Assessment System (ICDAS)), and extensive decay, termed cavitated lesions (5–6 in ICDAS). The control group includes children without caries.

Results: The linear regression model demonstrated that the GSH, GSSG, GSH/GSSG, and total antioxidant capacity levels are influenced (P?P?Discussion: Our results indicate that the high levels of antioxidants in saliva increase significantly in children in line with the salivary cariogenic bacterial profiles and caries progression.     

Quantitation of plasma thiamine,related metabolites and plasma protein oxidative damage markers in children with autism spectrum disorder and healthy controls

Abstract

Aims/hypothesis: To assess thiamine and related metabolite status by analysis of plasma and urine in autistic children and healthy controls, correlations to clinical characteristics and link to plasma protein markers of oxidative damage.

Methods: 27 children with autism (21 males and 6 females) and 21 (15 males and 6 females) age-matched healthy control children were recruited. The concentration of thiamine and related phosphorylated metabolites in plasma and urine and plasma protein content of dityrosine, N-formylkynurenine and 3-nitrotyrosine was determined.

Results: Plasma thiamine and thiamine monophosphate concentrations were similar in both study groups (median [lower–upper quartile]): autistic children – 6.60?nM (4.48–8.91) and 7.00?nM (5.51–8.55), and healthy controls – 6.82?nM (4.47–7.02) and 6.82?nM (5.84–8.91), respectively. Thiamine pyrophosphate (TPP) was decreased 24% in autistic children compared to healthy controls: 6.82?nM (5.81–8.52) versus 9.00?nM (8.41–10.71), p?<?.01. Urinary excretion of thiamine and fractional renal clearance of thiamine did not change between the groups. No correlation was observed between clinical markers and the plasma and urine thiamine concentration. Plasma protein dityrosine content was increased 88% in ASD. Other oxidative markers were unchanged.

Conclusions/interpretation: Autistic children had normal plasma and urinary thiamine levels whereas plasma TPP concentration was decreased. The latter may be linked to abnormal tissue handling and/or absorption from gut microbiota of TPP which warrants further investigation. Increased plasma protein dityrosine may reflect increased dual oxidase activity in response to change in mucosal immunity and host–microbe homeostasis.     

Atorvastatin and losartan may upregulate renalase activity in hypertension but not coronary artery diseases: The role of gene polymorphism

The aim is to explore the treatment effect of coronary artery disease (CAD) and hypertension on plasma levels of renalase activity and also the possible association of renalase rs10887800 gene polymorphism with CAD and hypertension. A total of 286 patients who received coronary angiography were included in the study. Subjects were divided into four groups including (1) hypertensive with no CAD (H-Tens, n = 60); (2) CAD with hypertension (CAD + H-Tens, n = 71); (3) CAD with no hypertension (CAD, n = 61); and (4) nonhypertensive with no CAD as a control group (Con, n = 69). The plasma renalase activity was measured using the Amplex Red Monoamine Oxidase Assay Kit. Renalase rs10887800 single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Atorvastatin (P = 0.005), losartan (P < 0.001), and captopril (P = 0.001) were administered significantly more in case groups compared with the Con group. Significant higher and lower levels of renalase activity were observed in H-Tens and CAD patients compared with control subjects (P < 0.001 for both comparisons). Furthermore, no significant differences were obtained in the risk or protective effects of renalase rs10887800 SNP against hypertension and/or CAD in both recessive and dominant genetic models (P > 0.05). According to the findings of the present study, atorvastatin and losartan therapy assumes considerable significance in alleviating hypertension, but not CAD, by increasing the renalase activity. Furthermore, it was found that renalase rs10887800 is less likely a predisposing factor for susceptibility to hypertension and/or CAD in an Iranian southeast population.     

Thyroid Functions and Trace Elements in Pediatric Patients with Exogenous Obesity

Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sex-matched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p?=?0.006). Zn levels in the patient group were significantly low compared to the control group (p?=?0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly higher than those of the control group (p?=?0.001, p?=?0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations.     

The potential signaling pathway between peroxisome proliferator-activated receptor gamma and retinoic acid receptor alpha in renal interstitial fibrosis disease

Abstract

Peroxisome proliferator-activated receptorγ (PPARγ) can regulate the process of cell apoptosis and is related to the progression of renal disorders. Retinoic acid receptor alpha (RARα) is one of the nuclear receptors involved in a variety of kidney diseases. Renal interstitial fibrosis (RIF) is a common denominator of chronic kidney disease (CKD). This study investigated whether a potential signaling pathway existed between PPARγ and RARα in RIF rats with unilateral ureteral obstruction (UUO). The rats were randomly divided into four groups: a model group subjected to UUO (GU), and three other groups treated with rosiglitazone sodium (GRS), GW9662 and dimethyl sulfoxide (DMSO), n?=?40, respectively. Renal tissues were collected two and four weeks after post-surgery. The relevant indicators were detected. In comparison with the GU group, the expressions of PPARγ and RARα (protein and mRNA) were increased in the GRS group, and decreased in the GW9662 group (all p?<?0.01). The RIF index, mRNA and protein expression of transforming growth factor-β1 (TGF-β1), and the protein expressions of collagen-IV (Col-IV) and fibronectin (FN) in the GRS group were more markedly reduced than those in the GU group; their levels in the GW9662 group were elevated (all p?<?0.01). PPARγ or RARα was negatively correlated to the RIF index, TGF-β1, Col-IV and FN. PPARγ was positively correlated with RARα (all p?<?0.01). In conclusion, PPARγ agonist can elevate the expression of PPARγ or RARα in RIF rats. There might be a potential signaling pathway between PPARγ and RARα in RIF disease.     

Renalase contributes to the renal protection of delayed ischaemic preconditioning via the regulation of hypoxia‐inducible factor‐1α

Ischaemic preconditioning (IPC) attenuates acute kidney injury (AKI) from renal ischaemia reperfusion. Renalase, an amine oxidase secreted by the proximal tubule, not only degrades circulating catecholamines but also protects against renal ischaemia reperfusion injury. Here, it has been suggested that the renoprotective effect of renal IPC is partly mediated by renalase. In a model of brief intermittent renal IPC, the increased cortex renalase expression was found to last for 48 hrs. IPC significantly reduced renal tubular inflammation, necrosis and oxidative stress following renal ischaemia reperfusion injury. Such effects were attenuated by blocking renalase with an anti‐renalase monoclonal antibody. We further demonstrated that renalase expression was up‐regulated by hypoxia in vitro via an hypoxia‐inducible factor (HIF)‐1α mechanism. The IPC‐induced up‐regulation of renalase in vivo was also reduced by pre‐treatment with an HIF‐1α inhibitor, 3‐(5′‐Hydroxymethyl‐2′‐furyl)‐1‐benzyl indazole. In summary, the renoprotective effect of IPC is partly dependent on the renalase expression, which may be triggered by hypoxia via an HIF‐1α mechanism. Endogenous renalase shows potential as a therapeutic agent for the prevention and treatment of AKI.     

Expression and kinetic analysis of carboxylesterase LmCesA1 from Locusta migratoria

Objective

To investigate the biochemical characterization of the carboxylesterase LmCesA1 from Locusta migratoria.

Results

We expressed recombinant LmCesA1 in Sf9 cells by using the Bac-to-bac baculovirus expression system. Enzyme kinetic assays showed that the K_m values of LmCesA1 for α-naphthyl acetate (α-NA) and β-naphthyl acetate (β-NA) were 0.08?±?0.01 mM and 0.22?±?0.03 mM, respectively, suggesting that LmCesA1 has a higher affinity for α-NA. LmCesA1 retained its enzymatic activity during incubations at pH 7–10 and at 10–30 °C. In an inhibition experiment, two organophosphate pesticides (malaoxon and malathion) and one pyrethroid pesticide (deltamethrin) showed different inhibition profiles against purified LmCesA1. Recombinant LmCesA1 activity was significantly inhibited by malaoxon in vitro. UPLC analysis showed that no metabolites were detected.

Conclusions

These results suggest that overexpression of LmCesA1 enhances malathion sequestration to confer malathion tolerance in L. migratoria.

     

FAD-binding site and NADP reactivity in human renalase: a new enzyme involved in blood pressure regulation

Renalase is a recently discovered flavoprotein that regulates blood pressure, regulates sodium and phosphate excretion, and displays cardioprotectant action through a mechanism that is barely understood to date. It has been proposed to act as a catecholamine-degrading enzyme, via either O₂-dependent or NADH-dependent mechanisms. Here we report the renalase crystal structure at 2.5 Å resolution together with new data on its interaction with nicotinamide dinucleotides. Renalase adopts the p-hydroxybenzoate hydroxylase fold topology, comprising a Rossmann-fold-based flavin adenine dinucleotide (FAD)-binding domain and a putative substrate-binding domain, the latter of which contains a five-stranded anti-parallel β-sheet. A large cavity (228 Å³), facing the flavin ring, presumably represents the active site. Compared to monoamine oxidase or polyamine oxidase, the renalase active site is fully solvent exposed and lacks an ‘aromatic cage’ for binding the substrate amino group. Renalase has an extremely low diaphorase activity, displaying lower k_cat but higher k_cat/K_m for NADH compared to NADPH. Moreover, its FAD prosthetic group becomes slowly reduced when it is incubated with NADPH under anaerobiosis, and binds NAD⁺ or NADP⁺ with K_d values of ca 2 mM. The absence of a recognizable NADP-binding site in the protein structure and its poor affinity for, and poor reactivity towards, NADH and NADPH suggest that these are not physiological ligands of renalase. Although our study does not answer the question on the catalytic activity of renalase, it provides a firm framework for testing hypotheses on the molecular mechanism of its action.     

Ischaemia-modified albumin in pulmonary hypertension

Background: Pulmonary hypertension (PH) may be associated with subendocardial ischaemia. We investigated whether ischaemia-modified albumin (IMA), an established marker of ischaemia, is elevated in stable patients with PH.

Methods: We studied 32 patients with PH and an equal number of age-matched normal volunteers. We assessed serum IMA levels with the albumin cobalt-binding test.

Results: Patients’ mean ± SD (range) pulmonary arterial pressure was 56?±?12 (33–73) mmHg and their exercise capacity was 394?±?145 (121–688) m in the 6-min walk test. IMA was 92?±?14 (69–115) U ml^?1 in the patient group and 93?±?9.4 (76–122) U ml^?1 in the control group with no significant difference between the two (p?=?0.85), although almost one-third of the patients had detectable troponin-I.

Conclusions: We conclude that IMA, a marker of ischaemia, does not differ in patients with advanced clinically stable PH compared with normal subjects.     

Assessment of post-stroke elbow flexor spasticity in different forearm positions

Abstract

Purpose/Aim: There have been conflicting results regarding which muscle contribute most to the elbow spastic flexion deformity. This study aimed to investigate whether flexor spasticity of the elbow changed according to the position of the forearm, and to determine the muscle or muscles that contributed most to the elbow spastic flexion deformity by clinical examination.

Methods: This study is a single group, observational and cross-sectional study. Sixty patients were assessed for elbow flexor spasticity in different forearm positions (pronation, neutral and supination) with Modified Tardieu Scale. The primary outcome measure was a domain of the Modified Tardieu Scale, the dynamic component of spasticity (spasticity angle).

Results: In general, there was a significant difference between forearm positions regarding spasticity angle (p?<?.001). In pairwise comparisons, median spasticity angles in pronation (70 degrees) and neutral position (60 degrees) were significantly higher than those in supination (57.5 degrees) (adjusted p?<?.001 and adjusted p?=?.003, respectively). However, median spasticity angle in pronation did not differ significantly from those in neutral position in favour of pronation (adjusted p?=?.274).

Conclusions: The severity of spasticity changes according to the elbow position which suggests that the magnitude of contribution of each elbow flexor muscle to spastic elbow deformity is different. Reduction of spasticity from pronation to supination leads us to consider brachialis as the most spastic muscle. Since biceps was suggested to be the least spastic muscle in this study, and also to avoid spastic pronation deformity of the forearm, it should be rethought before performing chemodenervation into biceps muscle.