Myocardial interstitial serotonin and its major metabolite, 5-hydroxyindole acetic acid levels determined by microdialysis technique in rat heart

Aims

The aim of this study was to elucidate myocardial interstitial serotonin (5-HT) kinetics in the heart, including 5-HT reuptake and enzymatic degradation to 5-hydroxyindole acetic acid (5-HIAA) via monoamine oxidase (MAO).

Main methods

Using microdialysis technique in anesthetized rats, we simultaneously monitored myocardial interstitial levels of 5-HT and its major metabolite, 5-HIAA, in the left ventricle and examined the effects of local administration of a MAO inhibitor, pargyline, or a 5-HT uptake inhibitor, fluoxetine.

Key findings

Pargyline increased dialysate 5-HT concentration from 1.8 ± 0.3 at baseline to 3.9 ± 0.5 nM but decreased dialysate 5-HIAA concentration from 20.7 ± 1.0 at baseline to 15.8 ± 1.4 nM at 60–80 min of administration. Fluoxetine increased dialysate 5-HT concentration from 1.9 ± 0.4 at baseline to 6.5 ± 0.9 nM at 60–80 min of administration, but did not change dialysate 5-HIAA concentration. Local administration of ADP (100 mM) increased dialysate 5-HT and 5-HIAA concentrations. Pargyline did not affect ADP-induced increase in dialysate 5-HT concentration but suppressed ADP-induced increase in dialysate 5-HIAA concentration during 60 min of ADP administration. Fluoxetine increased dialysate 5-HT concentration at 40–60 min of ADP administration, but did not affect ADP-induced increase in dialysate 5-HIAA concentration.

Significance

Simultaneous monitoring of myocardial interstitial 5-HT and 5-HIAA levels provides valuable information on 5-HT kinetics including reuptake and enzymatic degradation by MAO, which play a role in the regulation of myocardial interstitial 5-HT levels at baseline and when 5-HT levels are elevated.     

Effect of repeated allogeneic bone marrow mononuclear cell transplantation on brain injury following transient focal cerebral ischemia in rats

Aims

Transplantation of bone marrow mononuclear cells (BMMCs) exerts neuroprotection against cerebral ischemia. We examined the therapeutic timepoint of allogeneic BMMC transplantation in a rat model of focal cerebral ischemia, and determined the effects of repeated transplantation outside the therapeutic window.

Main methods

Male Sprague–Dawley rats were subjected to 90 minute focal cerebral ischemia, followed by intravenous administration of 1 × 10⁷ allogeneic BMMCs or vehicle at 0, 3 or 6 h after reperfusion or 2 × 10⁷ BMMCs 6 h after reperfusion. Other rats administered 1 × 10⁷ BMMCs at 6 h after reperfusion received additional BMMC transplantation or vehicle 9 h after reperfusion. Infarct volumes, neurological deficit scores and immunohistochemistry were evaluated 24 or 72 h after reperfusion.

Key findings

Infarct volumes at 24 h were significantly decreased in transplantation rats at 0 and 3 h, but not at 6 h, after reperfusion, compared to vehicle-treatment. Even high dose BMMC transplantation at 6 h after reperfusion was ineffective. Repeated BMMC transplantation at 6 and 9 h after reperfusion reduced infarct volumes and significantly improved neurological deficit scores at 24 and 72 h. Immunohistochemistry showed repeated BMMC transplantation reduced ionized calcium-binding adapter molecule 1, 4-hydroxy-2-nonenal and 8-hydroxydeoxyguanosine expression at 24 and 72 h after reperfusion.

Significance

Intravenous allogeneic BMMCs were neuroprotective following transient focal cerebral ischemia, and the therapeutic time window of BMMC transplantation was > 3 h and < 6 h after reperfusion in this model. Repeated transplantation at 6 and 9 h after reperfusion suppressed inflammation and oxidative stress in ischemic brains, resulting in improved neuroprotection.     

Monoamine oxidase-induced hydroxyl radical production and cardiomyocyte injury during myocardial ischemia–reperfusion in rats

To elucidate the involvement of monoamine oxidase (MAO) in hydroxyl radical production and cardiomyocyte injury during ischemia as well as after reperfusion, we applied microdialysis technique to the heart of anesthetized rats. Dialysate samples were collected during 30?min of induced ischemia followed by 60?min of reperfusion. We monitored dialysate 3,4-dihydrobenzoic acid (3,4-DHBA) concentration as an index of hydroxyl radical production using a trapping agent (4-hydroxybenzoic acid), and dialysate myoglobin concentration as an index of cardiomyocyte injury in the ischemic region. The effect of local administration of a MAO inhibitor, pargyline, was investigated. Dialysate 3,4-DHBA concentration increased from 1.9?±?0.5?nM at baseline to 3.5?±?0.7?nM at 20–30?min of occlusion. After reperfusion, dialysate 3,4-DHBA concentration further increased reaching a maximum (4.5?±?0.3?nM) at 20–30?min after reperfusion, and stabilized thereafter. Pargyline suppressed the averaged increase in dialysate 3,4-DHBA concentration by ～72% during occlusion and by ～67% during reperfusion. Dialysate myoglobin concentration increased from 235?±?60?ng/ml at baseline to 1309?±?298?ng/ml at 20–30?min after occlusion. After reperfusion, dialysate myoglobin concentration further increased reaching a peak (5833?±?1017?ng/ml) at 10–20?min after reperfusion, and then declined. Pargyline reduced the averaged dialysate myoglobin concentration by ～56% during occlusion and by ～41% during reperfusion. MAO plays a significant role in hydroxyl radical production and cardiomyocyte injury during ischemia as well as after reperfusion.     

Continuous oral administration of atorvastatin ameliorates brain damage after transient focal ischemia in rats

Aims

Pre-treatment with statins is known to ameliorate ischemic brain damage after experimental stroke, and is independent of cholesterol levels. We undertook pre- vs post-ischemic treatment with atorvastatin after focal cerebral ischemia in rats.

Main methods

Male Sprague–Dawley rats underwent transient 90-min middle cerebral artery occlusion (MCAO). Atorvastatin (20 mg/kg/day) or vehicle was administered orally. Rats were divided into vehicle-treated, atorvastatin pre-treatment, atorvastatin post-treatment, and atorvastatin continuous-treatment groups. In the pre-treatment, rats were given atorvastatin or vehicle for 7 days before MCAO. In the post-treatment, rats received atorvastatin or vehicle for 7 days after MCAO. Measurement of infarct volume, as well as neurological and immunohistochemical assessments, were done 24 h and 7 days after reperfusion.

Key findings

Each atorvastatin-treated group demonstrated significant reductions in infarct and edema volumes compared with the vehicle-treated group 24 h after reperfusion. Seven days after reperfusion, infarct volumes in the post-treatment group and continuous-treatment group (but not the pre-treatment group) were significantly smaller than in the vehicle-treated group. Only the continuous-treatment group had significantly improved neurological scores 7 days after reperfusion compared with the vehicle group. Post-treatment and continuous-treatment groups had significantly decreased lipid peroxidation, oxidative DNA damage, microglial activation, expression of tumor necrosis factor-alpha, and neuronal damage in the cortical ischemic boundary area after 7 days of reperfusion.

Significance

These results suggest that continuous oral administration (avoiding withdrawal) with statins after stroke may reduce the extent of post-ischemic brain damage and improve neurological outcome by inhibiting oxidative stress and inflammatory responses.     

Na(+)/H(+) exchange subtype 1 inhibition reduces endothelial dysfunction in vessels from stunned myocardium

Myocardial ischemia and reperfusion cause myocyte and vascular dysfunction, frequently termed "stunning." We hypothesized that inhibiting the Na(+)/H(+) exchanger subtype 1 isoform (NHE(1)) during ischemia and reperfusion limits myocardial and coronary microvascular stunning. Anesthetized rats completed 2 x 10-min coronary artery occlusions separated by 5-min of reperfusion, followed by 15 or 60 min of reperfusion. Vehicle (saline) or the NHE(1) inhibitor cariporide (HOE-642) was administered 15 min before ischemia and was continued throughout each protocol. After reperfusion, hearts were excised, and the reactivity of resistance arteries (internal diameter, approximately 120 microm) was assessed. The first derivative of left ventricular (LV) pressure, LV developed pressure, and LV systolic wall thickening were depressed (P < 0.05) similarly in vehicle- and cariporide-treated rats during ischemia and after 15 or 60 min of reperfusion compared with sham-operated animals that were not exposed to ischemia (i.e., controls). In vessels obtained after 15 min of reperfusion, the maximal response to acetylcholine-induced relaxation (10(-8)-10(-4) M) was blunted (P < 0.05) in vessels from vehicle- (approximately 35%) and cariporide-treated rats (approximately 55%) compared with controls (approximately 85%). However, the percent relaxation to acetylcholine was greater (P < 0.05) in cariporide-treated rats compared with vehicle-treated rats. Maximal contractile responses to endothelin-1 (10(-11)-10(-7) M) were increased (P < 0.05) similarly in vehicle- and cariporide-treated rats compared with controls. Relaxation to sodium nitroprusside (10(-4) M) was not different among groups. Results were similar in vessels obtained from animals after 60 min of reperfusion. These findings suggest that NHE(1) inhibition before coronary occlusion lessens ischemia-induced microvascular dysfunction for 15-60 min after reperfusion but does not alter myocardial contractile function in the area at risk.     

Methylenetetrahydrofolate reductase 677TT genotype might be associated with an increased lung cancer risk in Asians

Background

The association between methylenetetrahydrofolate reductase (MTHFR) 677C > T polymorphism and lung cancer risk has been studied in various populations with conflicting results. The aim of this study was to assess the association strength by a meta-analysis of published studies.

Methods

We searched PubMed and Chinese Biomedical (CBM) databases for relevant literatures published by July 18, 2012. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of the association.

Results

A total of 20 studies comprising 11,653 cases and 12,032 controls were included in the final meta-analysis. Using the random effect model, we found that MTHFR 677TT variant genotype was associated with an increased lung cancer risk (OR = 1.26, 95% CI = 1.05–1.50, P = 0.011 for TT vs. CC; OR = 1.19, 95% CI = 1.03–1.37, P < 0.001 for TT vs. CC + CT; OR = 1.11, 95% CI = 1.02–1.22, P = 0.017 for T allele vs. C allele). In the further stratified analyses, the increased lung cancer risk was found in Asian subjects (OR = 1.31, 95% CI = 1.01–1.71, P = 0.045 for TT vs. CC; OR = 1.17, 95% CI = 1.00–1.38, P = 0.048 for TT vs. CC + CT). There were no evidences for obvious publication bias in the overall meta-analysis and Asian subjects.

Conclusions

MTHFR 677TT genotype might increase the susceptibility of lung cancer, especially in Asians.     

Magainin-AM2 improves glucose homeostasis and beta cell function in high-fat fed mice

Background

Magainin-AM2, a previously described amphibian host-defense peptide, stimulates insulin- and glucagon-like peptide-1-release in vitro. This study investigated anti-diabetic effects of the peptide in mice with diet-induced obesity and glucose intolerance.

Methods

Male National Institute of Health Swiss mice were maintained on a high-fat diet for 12-weeks prior to the daily treatment with magainin-AM2. Various indices of glucose tolerance were monitored together with insulin secretory responsiveness of islets at conclusion of study.

Results

Following twice daily treatment with magainin-AM2 for 15 days, no significant difference in body weight and food intake was observed compared with saline-treated high fat control animals. However, non-fasting blood glucose was significantly (P < 0.05) decreased while plasma insulin concentrations were significantly (P < 0.05) increased. Oral and intraperitoneal glucose tolerance and insulin secretion following glucose administration via both routes were significantly (P < 0.05) enhanced. The peptide significantly (P < 0.001) improved insulin sensitivity as well as the beta cell responses of islets isolated from treated mice to a range of insulin secretagogues. Oxygen consumption, CO₂ production, respiratory exchange ratio and energy expenditure were not significantly altered by sub-chronic administration of magainin-AM2 but a significant (P < 0.05) reduction in fat deposition was observed.

Conclusion

These results indicate that magainin-AM2 improves glucose tolerance, insulin sensitivity and islet beta cells secretory responsiveness in mice with obesity-diabetes.

General significance

The activity of magainin-AM2 suggests the possibility of exploiting this peptide for treatment of type 2 diabetes.     

Association of glutathione S-transferase M1/T1 polymorphisms with susceptibility to vitiligo

Background

Some studies suggested that Glutathione S-transferases M1/T1(GSTM1/T1) null polymorphisms may be associated with the risk of vitiligo.

Aims

The purpose of this study is to further evaluate the association between GSTM1/T1 null polymorphisms and the susceptibility to vitiligo.

Methods

We carried out a retrieval of studies in the databases. Odds ratios (OR) and 95% confidence intervals (95% CIs) were used to assess the strength of this association. We analyzed the data using Stata 11.0.

Results

Six case–control studies including 1358 cases and 1673 controls were included in this meta-analysis. Our overall results showed the GSTM1 or GSTT1 null polymorphism was associated with vitiligo (GSTM1:OR = 1.59, 95% CI: 1.21–2.08, P = 0.001; GSTT1: OR = 1.30, 95% CI: 1.12–1.51, P = 0.001). In the subgroup analysis, the GSTM1 null polymorphism might be a genetic risk factor to vitiligo in East Asian (OR = 1.71, 95% CI: 1.12–2.63, P = 0.014) but not in the Mediterranean, however individuals with the GSTT1 null polymorphism in the Mediterranean (OR = 1.76, 95% CI: 1.15–2.71, P = 0.010) but not in East Asian have a greater predisposition to vitiligo. In addition there was also a significant trend toward an association with the combination of the GSTM1 null and GSTT1 null in either East Asians or Mediterraneans.

Conclusion

The GSTM1/T1 null polymorphisms may be associated with vitiligo. More studies are needed to confirm this conclusion.     

Cyclooxygenase-2 169C > G and 8473T > C gene polymorphisms and prostaglandin E2 level in breast cancer: A case–control study

Aims

Cyclooxygenase 2 (COX-2) with the resulting prostaglandin E2 (PGE2) is linked to increased risk of human breast cancer (BC). The aim of this study was to determine COX-2 169C > G and 8473T > C gene polymorphisms and PGE2 level at various stages of BC clarifying the role of COX-2 gene polymorphism and PGE2 in relation to BC.

Methods

The study population comprised 160 women at different stages of BC and 150 gender- and age-matched healthy control subjects. Plasma PGE2 was measured by ELISA, the COX-2 gene polymorphisms were determined using PCR-RFLP.

Results

The variant alleles COX-2 169G and 8473C were significantly associated with BC susceptibility [OR = 3.1, 95% CI (2.2–4.4), P < 0.001 for 169C>G and OR = 1.74, 95%CI (1.3–2.4), P = 0.005 for 8473C]. However, both COX-2 gene polymorphisms were not associated with breast cancer stage. Plasma PGE2 levels were significantly increased in patients compared to the controls. In early and late stages of BC, there was a significant increase in the plasma PGE2 levels towards the presence of homozygous GG compared with homozygous CC (P < 0.001) for 169 C>G, also towards the presence of CC than TT (P < 0.001) for 8473T>C SNP.

Conclusion

The 169C>G and 8473T>C polymorphisms of the COX-2 gene were associated with the BC in Egyptian women. Furthermore, individuals with COX-2 169GG and 8473CC genotypes showed significant increase in plasma PGE2 levels. PGE2 levels may serve as a predictor of poor prognosis in patients with BC.     

Characterization of ecto-ATPase activity in the surface of LLC-PK1 cells and its modulation by ischemic conditions

Background

The concentration of extracellular nucleotides is regulated by enzymes that have their catalytic site facing the extracellular space, the so-called ecto-enzymes.

Methods

We used LLC-PK1 cells, a well-characterized porcine renal proximal tubule cell line, to biochemically characterize ecto-ATPase activity in the luminal surface. The [γ-³²P]Pi released after reaction was measured in aliquots of the supernatant by liquid scintillation.

Results

This activity was linear with time up to 20 min of reaction and stimulated by divalent metals. The ecto-ATPase activity measured in the presence of 5 mM MgCl₂ was (1) optimum at pH 8, (2) insensitive to different inhibitors of intracellular ATPases, (3) inhibited by 1 mM suramin, an inhibitor of ecto-ATPases, (4) sensitive to high concentrations of sodium azide (NaN₃) and (5) also able to hydrolyze ADP in the extracellular medium. The ATP:ADP hydrolysis ratio calculated was 4:1. The ecto-ADPase activity was also inhibited by suramin and NaN₃. The dose–response of ATP revealed a hyperbolic profile with maximal velocity of 25.2 ± 1.2 nmol Pi x mg^− 1 x min^− 1 and K_0.5 of 0.07 ± 0.01 mM. When cells were submitted to ischemia, the E-NTPDase activity was reduced with time, achieving 71% inhibition at 60 min of ischemia.

Conclusion

Our results suggest that the ecto-ATPase activity of LLC-PK1 cells has the characteristics of a type 3 E-NTPDase which is inhibited by ischemia.

General Significance

This could represent an important pathophysiologic mechanism that explains the increase in ATP concentration in the extracellular milieu in the proximal tubule during ischemia.     

In vitro ruminal methanogenesis of a hay-rich substrate in response to different combination supplements of nitrocompounds; pyromellitic diimide and 2-bromoethanesulphonate

Sixteen combinations of 5 treatments at 4 levels were designed in a L₁₆(4⁵) orthogonal experimental design to evaluate associative effects of five methanogenesis inhibitors at four dose levels: nitroethane (NE, 0 mM, 5 mM, 10 mM and 15 mM), 2-nitroethanol (NEOH, 0 mM, 5 mM, 10 mM and 15 mM), 2-nitro-1-propanol (NPOH, 0 mM, 5 mM, 10 mM and 15 mM), pyromellitic diimide (PMDI, 0 mM, 0.02 mM, 0.05 mM and 0.07 mM) and 2-bromoethanesulphonate (BES, 0 mM, 0.01 mM, 0.03 mM and 0.05 mM) on in vitro ruminal methane production of the mixed substrate (Chinese wildrye hay:maize meal = 4:1) using a cumulative gas production technique. After 48 h incubation, in vitro dry matter disappearance (IVDMD), total gas production (GP₄₈, ml/g DM) and total volatile fatty acids (VFA) production in various combinations of these inhibitors were decreased by 10.6-56.0, 26.5-44.5 and 20.3-47.6%, respectively (P<0.05). The molar proportion of acetate in the inhibitor combination groups was decreased by 6.6-12.5% while those of propionate and butyrate were increased by 7.0-19.2 and 21.9-56.5% (P<0.01), respectively. Methane proportion (MP) in total gas production was reduced by 79.4-98.5% (P<0.01), and the highest inhibition occurred in the combination of 10 mM NE, 10 mM NPOH, 0.07 mM PMDI and 0.01 mM BES in cultures. The partial correlation coefficients between NE, NEOH, NPOH, PMDI or BES and CH₄ proportion were −0.465 (P<0.01), −0.417 (P<0.01), −0.355 (P<0.05), −0.408 (P<0.01) and −0.345 (P<0.05), respectively, indicating that NE was the most potent inhibitor, followed by NEOH and PMDI, and finally NPOH and BES. In general, VFA production in the inhibitor combinations was substantially shifted to produce much more butyrate and propionate and less acetate. The combination of 15 mM NE, 10 mM NEOH, 5 mM NPOH, 0.07 mM PMDI and 0.01 mM BES in cultures, leading to >95% methane inhibition, may be the optimal application of these inhibitors with less depression of total VFA production. Further feeding trials to validate these combinations is still required on rumen function, methane production, growth performance and milk production.     

Association of the CAG repeat polymorphisms in androgen receptor gene with polycystic ovary syndrome: A systemic review and meta-analysis

Background

Many studies have reported the associations of polymorphic CAG repeats in androgen receptor (AR) gene with PCOS risk, but with inconsistent results. So, the aim of present meta-analysis was to clarify such inconsistence, so as to provide more conclusive results.

Methods

PubMed was searched for the eligible reports published until February 2012 without language limitation. The studies reporting the relationship between CAG repeat length and PCOS were selected for the meta-analysis according to the inclusion criteria. Two reviewers independently extracted the data and evaluated the study quality.

Principal findings

As for the relationship between CAG repeat length and PCOS risk, the pooled results showed that the biallelic mean was not significantly different between PCOS and controls (SMD − 0.03, 95% CI − 0.16–0.10, P = 0.603), and that the ORs of PCOS were not demonstrated for the individuals with the biallelic mean less than median (OR 0.96, 95% CI 0.68–1.35, P = 0.794), with the short CAG allele (OR 0.94, 95% CI 0.80–1.10, P = 0.424), or with the X-weighted biallelic mean (OR 0.81, 95% CI 0.46–1.41, P = 0.447). Further, as for the relationship between CAG repeat length and T levels in PCOS patients, the biallelic mean was not significantly different between PCOS patients with high T and those with low T (SMD 0.79, 95% CI − 0.12–1.70, P = 0.088), while the summary correlation r indicated that the CAG biallelic mean appeared to be positively associated with T levels in PCOS (r 0.20, 95% CI 0.11–0.30, p = 0.000).

Conclusions

This meta-analysis demonstrates no evident association between the CAG length variations in AR gene and PCOS risk, while the CAG length appears to be positively associated with T levels in PCOS patients.     

Meta-analysis of genetic association of chromosome 9p21 with early-onset coronary artery disease

Purpose

A number of studies reported on associations of single nucleotide polymorphisms (SNPs) present in chromosome 9p21 with early-onset coronary artery disease (CAD). The present study was then undertaken to perform a meta-analysis of all the results published to date.

Methods

All studies of the 9p21 association with early-onset CAD that were published between 2007 and 2012 were retrieved from the PubMed database. RevMan 5.0 software was used to perform meta-analysis of the data that fulfilled the criteria for our meta-analysis. The effect size of four SNPs in the 9p21 region on early-onset CAD risk was assessed based on the odds ratios (ORs) with calculation of 95% confidence interval (CI).

Results

A total of 7123 subjects from 7 case–control studies were genotyped. Meta-analysis demonstrated disease association for rs2383207 (OR = 0.79, 95% CI 0.71–0.88, P < 0.0001), rs2383206 (OR = 1.17, 95% CI 1.10–1.25, P < 0.00001), rs10757278 (OR = 1.28, 95% CI 1.15–1.42, P < 0.00001), and rs10757274 (OR = 1.17, 95% CI 1.08–1.33, P = 0.02).

Conclusion

Genetic variation in the chromosome 9p21 region may contribute to the etiology of early-onset CAD although their effect size is rather small.     

The MTMR9 rs2293855 polymorphism is associated with glucose tolerance,insulin secretion,insulin sensitivity and increased risk of prediabetes

Background

Polymorphism of rs2293855 in gene MTMR9 has been associated with obesity and metabolic syndrome. We aim to study the association of rs2293855 with type 2 diabetes mellitus (T2DM) intermediate phenotypes in a Han Chinese population.

Methods

The polymorphism was genotyped in 838 Han Chinese individuals using Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS); all participants underwent a 75 g oral glucose tolerance test (OGTT); associations between the polymorphism and glucose tolerance, indices of insulin secretion and indices of insulin sensitivity were analyzed.

Results

The frequency of genotypes and alleles differed significantly between normal glucose tolerance and prediabetes (P = 0.043 and P = 0.009, respectively). The GG homozygous presented higher fasting plasma glucose (P = 0.009), higher 2-hour plasma glucose (P = 0.024) and higher glucose area under the curve (AUC, P = 0.01). Moreover, the G allele of rs2293855 was associated with glucose intolerance (fasting glucose, P = 0.012; glucose AUC, P = 0.006; 2-h glucose, P = 0.024); it is also associated with decreased indices of insulin sensitivity (fasting insulin, P = 0.043; insulin sensitivity index composite, P = 0.009; homeostasis model assessment of insulin resistance, HOMA-IR, P = 0.008) and decreased indices of insulin secretion (HOMA of beta cell function, HOMA-B, P = 0.028; insulinogenic index, P = 0.003). In addition, the minor allele G was also associated with increased risk of prediabetes (OR = 1.463, 95%CI: 1.066–2.009, P = 0.018).

Conclusions

Polymorphism of rs2293855 in MTMR9 is associated with measures of glucose tolerance, indices of insulin secretion and indices of insulin sensitivity. We also suggest that allele G is likely to increase the risk of prediabetes by influencing both insulin secretion and insulin sensitivity.     

Relationship between CCR2-V64I polymorphism and cancer risk: A meta-analysis

Background and objectives

The role of CCR2-V64I polymorphism in various cancers has been reported in many studies. However, results from published studies on the association between CCR2-V64I polymorphism and cancer risk are conflicting. Therefore, we performed a meta-analysis to estimate the overall cancer risk associated with the polymorphism.

Methods

Electronic searches of PubMed and EMBASE were conducted for all publications on the association between this variant and cancer. Odds ratios (OR) with 95% confidence intervals (95% CI) were used to access the strength of this association.

Results

Sixteen studies with 2661 cancer patients and 5801 healthy controls were included. Overall, significant association was found between the CCR2-V64I polymorphism and cancer risk (OR = 1.84, 95% CI = 1.35–2.51, AA vs GA/GG, P = 0.37). In the subgroup analysis stratified by cancer types, there was a significant association between this polymorphism and bladder cancer (OR = 2.06, 95% CI = 1.02–4.15, AA vs GA/GG, P = 0.11), cervical cancer (OR = 3.34, 95% CI = 1.48–7.50, AA vs GG, P = 0.56), and oral cancer (OR = 2.04, 95% CI = 1.46–2.84, GA vs GG, P = 0.70). In the subgroup analysis stratified by ethnicities, an increased cancer risk was also found in Europeans (OR = 2.31, 95% CI = 1.45–3.68, AA vs GA/GG, P = 0.16) and Asians (OR = 1.88, 95% CI = 1.12–3.16, AA vs GA/GG, P = 0.92).

Conclusion

This meta-analysis suggested that CCR2-V64I polymorphism may contribute to an increased risk of cancer.     

Melatonin renders neuroprotection by protein kinase C mediated aquaporin-4 inhibition in animal model of focal cerebral ischemia

Aim

Aquaporin-4(AQP4) expression in the brain with relation to edema formation following focal cerebral ischemia was investigated. Studies have shown that brain edema is one of the significant factors in worsening stroke outcomes. While many mechanisms may aggravate brain injury, one such potential system may involve AQP4 up regulation in stroke patients that could result in increased edema formation. Post administration of melatonin following ischemic stroke reduces AQP4 mediated brain edema and confers neuroprotection.

Materials and methods

An in-silico approach was undertaken to confirm effective melatonin-AQP4 binding. Rats were treated with 5 mg/kg, i.p. melatonin or placebo at 30 min prior, 60 min post and 120 min post 60 min of middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. Rats were evaluated for battery of neurological and motor function tests just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, biochemical analysis, apoptosis study and western blot experiments.

Key findings

Melatonin at 60 min post ischemia rendered neuroprotection as evident by reduction in cerebral infarct volume, improvement in motor and neurological deficit and reduction in brain edema. Furthermore, ischemia induced surge in levels of nitrite and malondialdehyde (MDA) were also found to be significantly reduced in ischemic brain regions in treated animals. Melatonin potentiated intrinsic antioxidant status, inhibited acid mediated rise in intracellular calcium levels, decreased apoptotic cell death and also markedly inhibited protein kinase C (PKC) influenced AQP4 expression in the cerebral cortex and dorsal striatum.

Significance

Melatonin confers neuroprotection by protein kinase C mediated AQP4 inhibition in ischemic stroke.     

Dobutamine mediates cytoprotection by induction of heat shock protein 70 in vitro

Aims

Dobutamine is cytoprotective when applied before a subsequent stress. However, the underlying molecular mechanism is unknown. Dobutamine also inhibits nuclear factor (NF)-κB in human T lymphocytes. Other inhibitors of NF-κB induce a so-called heat shock response. We hypothesized that dobutamine mediates protection from apoptotic cell death by the induction of a heat shock response.

Main methods

Jurkat T lymphoma cells were preincubated with dobutamine (0.1, 0.5 mM) before the induction of apoptosis (staurosporine, 2 μM). DNA-binding of heat shock factor (HSF)-1 was analyzed by electrophoretic mobility shift assay, mRNA-expression of heat shock protein (hsp)70 and hsp90 by Northern Blot, activity of caspase-3 by fluorogenic caspase activity assay and cleavage of pro-caspase-3 by Western Blot. Apoptosis was assessed by flow cytometry after annexin V-fluorescein isothiocyanate staining. Hsp70 and hsp90 were inhibited using N-formyl-3,4-methylenedioxy-benzylidene-gamma-butyrolaetam and 17-allylamino-17-demethoxygeldana-mycin, respectively. All data are given as median and 25/75% percentile.

Key findings

Pre-incubation with dobutamine inhibited staurosporine-induced annexin V-fluorescence (28 [20–32] % vs. 12 [9–15] % for dobutamine 0.1 mM and 7 [5–12] % for dobutamine 0.5 mM, p < 0.001), cleavage of pro-caspase-3 as well as caspase-3-like activity (0.46 [0.40–0.48] vs. 0.32 [0.27–0.39] for Dobutamine 0.1 mM and 0.20 [0.19–0.23] for Dobutamine 0.5 mM, p < 0.01). Dobutamine induced DNA-binding of HSF-1 and mRNA-expression of hsp70 and hsp90. While inhibition of Hsp90 had no effect, inhibition of Hsp70 increased the number of annexin V-positive cells (33 [32–36] % vs. 18 [16–24] %) and caspase-3-like activity (0.21 [0.19–0.23] vs. 0.16 [0.13–0.17], p < 0.05).

Significance

Dobutamine protects from apoptotic cell death via the induction of Hsp70.     

The role of nitric oxide,reactive oxygen species,and protein kinase C in oxytocin-induced cardioprotection in ischemic rat heart

Ischemia–reperfusion injury is a common complication of heart disease that is the leading cause of death worldwide. Here, we plan to elucidate oxytocin cardioprotection effects against ischemia–reperfusion via nitric oxide (NO), reactive oxygen species (ROS), and protein kinase C (PKC) in anesthetized rat preconditioned myocardium. Forty-eight Sprague-Dawley rats were equally divided into eight groups. All animals were subjected to 25 min ischemia and 120 min reperfusion. Oxytocin (OT), L-NAME (LNA, a nitric oxide synthase inhibitor), chelerythrine (CHE, a PKC enzyme inhibitor), and N-acetylcysteine (NAC, a ROS scavenger) were used prior to ischemia. Results showed that mean arterial pressure significantly reduced during the first 10 min of ischemia and reperfusion in IR, LNA, CHE, and NAC groups (p < 0.05). OT prevented mean arterial pressure decline during early phase of ischemia and reperfusion. Cardioprotective effects of OT in infarct size, plasma levels of creatine kinase-MB and lactate dehydrogenase, severity and incidence of ventricular arrhythmias were abolished by L-NAME, chelerythrine, and N-acetylcysteine (p < 0.05). The present study showed that OT pretreatment reduces myocardial infarct size and ventricular arrhythmias, and improves mean arterial pressure via NO production, PKC activation, and ROS balance. These findings provide new insight into therapeutic strategies for ischemic heart disease.