Uridine triphosphate (UTP) is released during cardiac ischemia

BACKGROUND: Extracellular uridine triphosphate (UTP) stimulates vasodilatation, automaticity in ventricular myocytes and release of tissue-plasminogen activator (t-PA), indicating that UTP may be important in cardiac regulation. We took advantage of a recently developed quantitative assay for UTP to test the hypothesis that UTP is released in the circulation during cardiac ischemia. METHODS: In ten pigs, a balloon catheter in the left anterior descending artery was introduced to induce ischemia. Samples were collected from the coronary sinus. Blood flow in the coronary sinus was assessed by a Doppler velocity transducer. RESULTS: Plasma UTP levels increased early during ischemia and early after reperfusion (by 257+/-100 and 247+/-72%, p<0.05). Cardiac blood flow, ventricular arrhythmias and t-PA release were markedly increased at the same time points. In contrast, after 30 min, a second period of ischemia did not result in any significant increase of UTP or blood flow. Furthermore, ventricular arrhythmias were less frequent. UTP levels correlated with ventricular arrhythmia and blood flow. Similar results were found for ATP. CONCLUSION: For the first time we have shown that UTP is released during cardiac ischemia. UTP released during ischemia may stimulate blood flow, arrhythmia and t-PA release.     

Full-length HERV-H elements with env SU open reading frames in the human genome

Human endogenous retroviruses (HERVs) are estimated to represent at least 1% of the human genome. An HERV-H env SU sequence (HERV-H19) was used to screen the high-throughput (htgs) and nonredundant (nr) databases for other HERV-H SU open reading frames (ORFs) and thus possible functional proteins. Using PCR with primers derived from HERV-H19 SU, we also obtained several new sequences with ORFs from a human DNA sample. In a phylogenetic analysis, ORF-containing sequences clustered with HERV-H sequences from chromosomes 1 and 2. SU ORF- and non-SU ORF-containing elements had about the same difference between 5' and 3' long terminal repeats (LTRs) (about 4%), indicating a similar time of integration. SU ORF sequences had a moderately high number of synonymous-versus-nonsynonymous mutations, which indicates a selection for maintenance of the HERV-H SU ORFs.     

Impaired Glucose Tolerance at Five-year Follow-up of Young Men with Borderline Hypertension

Wall U, Bergbrant A, Jern S. Impaired glucose tolerance at five-year, follow-up of young men with borderline. hypertension. Blood Pressure 1996; 5: 139-147.

Background: Recent studies suggest that patients with essential hypertension have impaired glucose tolerance and are hyperinsulinemic compared with normotensive subjects. The aims of the study were (I) to follow blood pressures of 56 young men with borderline hypertension for 5 years, (2) to investigate glucose tolerance in these subjects, and (3) to determine the relation of insulin/glucose metabolism to structural vascular changes and hemodynamic patterns in borderline hypertension. Methods: Thirty-nine young (age 22-34 years) male subjects with borderline hypertension (SBP 140-160 and/or DBP 85-95 mmHg initially) and 17 normotensive control subjects (SBP 110-130 and DBP 60-80mmHg) participated in the study. Blood pressure was measured, a standard oral glucose tolerance test (OGTT) was performed, and glucose, insulin and C-peptide were determined before and 30, 60, 90 and 120 minutes after a standard 75-g glucose load. Post-ischemic forearm vasodilatory responses were examined by plethysmography. Results: At follow-up, the borderline hypertensives had maintained significantly higher blood pressures than control subjects. Borderline hypertensives also had significantly impaired glucose tolerance compared to control subjects. The insulin response had a somewhat more sluggish descent, but did not differ significantly from the response of normotensives. The C-peptide response pattern resembled that of insulin, but C-peptide was significantly elevated after 120 min. On the whole group level, there were only weak relations of insulin to blood pressure. By contrast, fasting insulin and post-load insulin levels were strongly correlated with body mass index, the waist-hip circumference ratio, triglyceride, and both total and LDL cholesterol. Across the whole group, there were significant correlations between forearm minimal vascular resistance and fasting insulin (r = + 0.37 p = 0.007) and insulin area-under-the-curve (r = + 0.28 p = 0.044). However, R_min was even more strongly correlated with body mass index, suggesting that this relationship was related to degree of obesity. Conclusion: Borderline hypertension in young men is a persistent condition which is associated with impaired glucose tolerance without hyperinsulinemia. This finding suggests that impaired glucose tolerance might be a more primary phenomenon in early hypertension devoid of lipid metabolic aberrations.     

Increased number of B-cells in the red pulp of the spleen in ITP

Platelets are targeted by autoantibodies and destroyed in the reticuloendothelial system in the spleen, liver and bone marrow in patients with immune thrombocytopenia (ITP). Other mechanisms such as destruction by cytotoxic T-cells and defective production of platelets in the bone marrow also exist. Splenectomy normalizes the platelet count in 70% of ITP patients, however, precious little is known about the spleen in this disease. Our aim was therefore to investigate the splenic morphology and especially the number and localization of splenic leukocytes in patients with ITP and controls and to evaluate factors predicting outcome of splenectomy. Spleen sections from 29 ITP patients and 11 individuals splenectomized due to trauma were analyzed by immunohistochemistry. All except one of the ITP patients had a normalized platelet count 12 months after splenectomy and the platelet count was inversely correlated with age. ITP patients had an increased number of B-cells in the red pulp. The number of white pulp B-cells and number of T-cells in both compartments was unchanged. In conclusion, B-cells are increased in the red pulp of the spleen and together with cytotoxic T-cells, helper T-cells and macrophages line the sinusoids enabling the immunological attack on platelets in ITP.     

Platelets synthesize large amounts of active plasminogen activator inhibitor 1

Previous studies have suggested that plasminogen activator inhibitor 1 (PAI-1) released from platelets convey resistance of platelet-rich blood clots to thrombolysis. However, the majority of PAI-1 in platelets is inactive and therefore its role in clot stabilization is unclear. Because platelets retain mRNA and capacity for synthesis of some proteins, we investigated if platelets can de novo synthesize PAI-1 with an active configuration. PAI-1 mRNA was quantified with real-time polymerase chain reaction and considerable amounts of PAI-1 mRNA were detected in all platelet samples. Over 24 hours, the amount of PAI-1 protein as determined by an enzyme-linked immunosorbent assay increased by 25% (P = .001). Metabolic radiolabeling with (35)S-methionine followed by immunoprecipitation confirmed an ongoing PAI-1 synthesis, which could be further stimulated by thrombin and inhibited by puromycin. The activity of the newly formed PAI-1 was investigated by incubating platelets in the presence of tissue-type plasminogen activator (tPA). This functional assay showed that the majority of the new protein was in an active configuration and could complex-bind tPA. Thus, there is a continuous production of large amounts of active PAI-1 in platelets, which could be a mechanism by which platelets contribute to stabilization of blood clots.     

Associations between oxytocin receptor gene (OXTR) polymorphisms and self-reported aggressive behavior and anger: Interactions with alcohol consumption

Oxytocin has been implicated in the regulation of social as well as aggressive behaviors, and in a recent study we found that the effect of alcohol on aggressive behavior was moderated by the individual's genotype on an oxytocin receptor gene (OXTR) polymorphism (Johansson et al., 2012). In this study we wanted to deepen and expand the analysis by exploring associations between three (rs1488467, rs4564970, rs1042778) OXTR polymorphisms and aggressive behavior, trait anger as well as anger control in a population-based sample of Finnish men and women (N=3577) aged between 18 and 49 years (M=26.45 years, SD=5.02). A specific aim was to investigate if the polymorphisms would show interactive effects with alcohol consumption on aggressive behavior and trait anger, as well as to explore whether these polymorphisms affect differences in anger control between self-reported sober and intoxicated states. The results showed no main effects of the polymorphisms, however, three interactions between the polymorphisms and alcohol consumption were found. The effect of alcohol consumption on aggressive behavior was moderated by the genotype of the individual on the rs4564970 polymorphism, in line with previous results (Johansson et al., 2012). For trait anger, both the rs1488467 and the rs4564970 polymorphisms interacted with alcohol consumption. It appears that the region of the OXTR gene including both the rs4564970 and the rs1488467 polymorphisms may be involved in the regulation of the relationship between alcohol and aggressive behavior as well as between alcohol and the propensity to react to situations with elevated levels of anger.     

Gene expression in human brown adipose tissue

Brown adipose tissue (BAT) has profound effects on body weight and metabolism in rodents. Recent reports show that human adults have significant amounts of BAT. Our aim was to study the gene expression profile of human BAT. Biopsies of adipose tissue with brown-red color and subcutaneous white adipose tissue (WAT) were obtained from 24 patients undergoing surgery in the thyroid region. Intrascapular BAT and epididymal WAT biopsies were obtained from 10 mice. Expression was analyzed by DNA microarray, real-time PCR and immunohistochemistry. Using the expression of the brown adipocyte-specific gene uncoupling protein 1 (UCP1) as a marker, approximately half of the human brown-red adipose tissue biopsies taken in the thyroid region contained BAT, and the presence of cells with brown adipocyte morphology was also verified by histology. Microarray analysis of 9 paired human BAT and WAT samples showed that 17 genes had at least a 4-fold higher expression in BAT compared to WAT and five of them (CKMT1, KCNK3, COBL, HMGCS2, TGM2) were verified using real-time PCR (P<0.05 for all). In addition, immunohistochemistry showed that the UCP1, KCNK3 and CKMT1 proteins are expressed in brown adipocytes. Except for UCP1 and KCNK3, the genes overexpressed in human BAT were not overexpressed in mouse BAT compared to mouse WAT. Our analysis identified genes that are differentially expressed in human BAT compared to WAT. The results also show that there are species-specific differences in BAT gene expression and this emphasizes the need for further molecular characterization of human BAT to clarify the mechanisms involved in regulated heat production in humans.     

Plasminogen activator inhibitor 1 expression in platelets is not influenced by the 4G/5G promoter polymorphism

In the present study we investigated the influence of the 4G/5G promoter polymorphism of the PAI-1 gene on the levels of PAI-1 mRNA and protein in platelets. After a screening of healthy male subjects, thirty-eight subjects homozygote for either the 4G or 5G allele were investigated. mRNA levels were quantified by real-time PCR and PAI-1 antigen in platelets and plasma was analysed by ELISA. The platelet PAI-1 mRNA levels correlated significantly with the PAI-1 antigen content, but there was no association between the polymorphism and mRNA levels, or protein levels in platelets. Also, plasma levels of PAI-1 antigen were not associated with homozygosity of the 4G/5G polymorphism, but as expected BMI and triglycerides emerged as significant predictors of plasma PAI-1 levels. The importance of the 4G/5G polymorphism on PAI-1 levels is controversial and the present study shows that although levels of platelet mRNA are related to its content of PAI-1 protein, there is no association between the 4G/5G promoter polymorphism and platelet PAI-1 mRNA or protein expression.