Subrina Jesmin

Estrogen Deprivation and Replacement Modulate Cerebral Capillary Density with Vascular Expression of Angiogenic Molecules in Middle-Aged Female Rats

The effect of postmenopausal estrogen replacement therapy (ERT) on the risk or severity of cerebrovascular disorders is as yet unclear, and the evidence for flow preservation being a mechanism of estrogen neuroprotection remains elusive. The authors examined whether estrogen-mediated flow-preserving neuroprotective mechanisms, if any, may involve its angiogenic action. This study was conducted using middle-aged (44 weeks) female rats because of the importance of aging in cerebrovascular disease in women. Middle-aged female rats were subjected to sham operation, ovariectomy, or ovariectomy with ERT. The anatomic cerebral capillary morphology showed a significant reduction in the total capillary density in the frontal cortex after ovariectomy. This was associated with marked decreases in protein and gene expression of vascular endothelial growth factor and its angiogenic receptors in cerebral vessels, as demonstrated by immunohistochemistry and in situ hybridization. The expression levels of both estrogen receptor (ER) subtypes, ERα and ERβ, in cerebral vessels were significantly reduced after ovariectomy, but ERβ was more dramatically downregulated as assessed by the ERβ/ERα ratio. These ovariectomy-induced changes were completely prevented by ERT. Vascular endothelial growth factor appears to be a critical regulatory molecule for physiologic cerebral angiogenesis in middle-aged female rats and may play an important role in the flow-preserving neuroprotective action of estrogen through its angiogenic and antiapoptotic properties.

Role of Angiotensin II in Altered Expression of Molecules Responsible for Coronary Matrix Remodeling in Insulin-Resistant Diabetic Rats

Objective—Coronary remodeling based on collagen abnormalities in diabetes might be associated with potential interactions between the matrix metalloproteinase (MMP) system, which regulates extracellular matrix turnover, and the fibrinolytic system, which is involved in the fibrin degradation process. We characterized the profiles of the MMP and fibrinolytic systems in insulin-resistant diabetic rat hearts. Methods and Results—By immunohistochemistry and in situ hybridization, transforming growth factor-&bgr;1 (TGF-&bgr;1) expression increased in coronary vessels, the perivascular area, and cardiomyocytes in diabetic rat hearts. Increased expression of plasminogen activator inhibitor-1 (PAI-1) in coronary vessels and the perivascular area was evident in diabetic hearts. In contrast, diabetic hearts exhibited reduced activity and expression of MMP-2 and decreased expression of membrane type-1 MMP (MT1-MMP). Both intravascular and extravascular collagen type I and III immunoreactivity and fibrin deposition were seen in diabetic coronary vessels. These alterations were reversed to nondiabetic levels by the angiotensin II type 1 receptor blocker candesartan, which prevented the development of perivascular fibrosis observed after Masson’s trichrome staining. Conclusions—In addition to upregulation of PAI-1, downregulation of MMP-2 and MT1-MMP might play a crucial role in coronary matrix remodeling in insulin-resistant diabetes. These molecules appear to be regulated by angiotensin II via stimulation of TGF-&bgr;1.

Involvement of endothelin-1 in habitual exercise-induced increase in arterial compliance.

Aim:  Habitual aerobic exercise results in a significant increase in central arterial compliance. Endothelin‐1 (ET‐1) is a potent endothelium‐derived vasoconstrictor peptide and could play a role in mediating the habitual aerobic exercise‐induced increase in central arterial compliance. The aim of the present study was to examine whether ET‐1 is involved in the mechanisms underlying the increase in central arterial compliance with aerobic exercise training.

Time-dependent expression of renal vaso-regulatory molecules in LPS-induced endotoxemia in rat

To elucidate roles of microvascular factors in the pathogenesis of renal complications during endotoxemia, that is characterized by renal vasoconstriction and systemic hypotension/generalized non-renal vasodilation, we profile the expression pattern and time-course of three key vaso-regulators, namely endothelin (ET)-1, nitric oxide (NO), and angiotensin II (Ang II). We hypothesize that disruption of the overall balance between vasodilatation and vasoconstriction in the kidney, during the early phase of sepsis, contribute to its (kidney) predisposition to acute renal failure. Adult male Wistar rats were rendered endotoxemic at different time points (1, 3, 6 and 10 h) by a single i.p. injection of lipopolysaccharide (LPS) (15 mg/kg) dissolved in saline. Control group was injected vehicle only (saline). Both systolic and diastolic blood pressures significantly decreased at different time points after LPS administration. Surprisingly, renal histopathological evaluation showed no remarkable changes in LPS-induced endotoxemia. However, overall, levels of the vaso-regulators and, where applicable, their respective receptors were upregulated: (1) plasma ET-1 increased 25-fold and peaked, as renal ET-1 mRNA, at 3 h; renal ET-1 protein and its receptors, ET type A (ET(A)) receptor (vasoconstrictive) and ET type B (ET(B)) receptor (vasodilatatory) increased in a time-dependent fashion, (2) Ang II increased by 53% compared to control, peaking at 6 h. However, while levels of Ang II type 1 (AT1) receptor increased over time after LPS injection, those of Ang II type 2 (AT2) receptor were downregulated, (3) data of NO system (NO-NOS), the key vasodilator, were the most intriguing. Whereas levels of renal NO increased time-dependently following LPS administration, with a 2240-fold increase in renal iNOS expression, levels of eNOS, were almost unchanged. In conclusion, the present study overall reveals intriguing and complex dynamics between levels of vasoconstrictors and vasodilators during the early phase of LPS-induced endotoxemia. These shifts in molecular expressions are likely triggered by compensatory mechanisms aimed at counteracting the undesirable and dominant effects of one group of vaso-regulatory moiety over the other.

Characterization of Vascular Endothelial Growth Factor (VEGF) in the Uterine Cervix over Pregnancy: Effects of Denervation and Implications for Cervical Ripening

Bilateral neurectomy of the pelvic nerve (BLPN) that carries uterine cervix-related sensory nerves induces dystocia, and administration of its vasoactive neuropeptides induces changes in the cervical microvasculature, resembling those that occur in the ripening cervix. This study was designed to test the hypothesis that (a) the cervix of pregnant rats expresses vascular endothelial growth factor (VEGF) and components of the angiogenic signaling pathway [VEGF receptors (Flt-1, KDR), activity of protein kinase B, Akt (phosphorylated Akt), and endothelial nitric oxide synthase (eNOS)] and von Willebrand Factor (vWF) and that these molecules undergo changes with pregnancy, and (b) bilateral pelvic neurectomy (BLPN) alters levels of VEGF concentration in the cervix. Using RT-PCR and sequencing, two VEGF isoforms, 120 and 164, were identified in the rat cervix. VEGF, VEGF receptor-1 (Flt-1), eNOS, and vWF immunoreactivities (ir) were localized in the microvasculature of cervical stroma. Their protein levels increased during pregnancy but decreased to control levels by 2 days postpartum. VEGF receptor-2 (KDR)-ir was confined to the epithelium of the endocervix. BLPN downregulated levels of VEGF by a third. Therefore, the components of the angiogenic signaling pathway are expressed in the cervix and change over pregnancy. Furthermore, angiogenic and sensory neuronal factors may be important in regulating the dynamic microvasculature in the ripening cervix and may subsequently play a role in cervical ripening and the birth process.

Normal prothrombinase activity, increased systemic thrombin activity, and lower antithrombin levels in patients with disseminated intravascular coagulation at an early phase of trauma: comparison with acute coagulopathy of trauma-shock.

BACKGROUND We tested the hypotheses that an increase in systemic thrombin activity occurs in both disseminated intravascular coagulation (DIC) with the fibrinolytic phenotype and in acute coagulopathy of trauma shock (ACoTS), and that the patients diagnosed as having ACoTS overlap or are identical with those diagnosed as having DIC. METHODS We made a prospective study of 57 trauma patients, including 30 patients with DIC and 27 patients without DIC. Patients with ACoTS, defined as a prothrombin time ratio >1.2, were also investigated. We included 12 healthy volunteers as controls. The levels of soluble fibrin, antithrombin, prothrombinase activity, soluble thrombomodulin, and markers of fibrin(ogen)olysis were measured on days 1 and 3 after the trauma. The systemic inflammatory response syndrome and the Sequential Organ Failure Assessment were scored to evaluate the extent of inflammation and organ dysfunction. RESULTS Patients with DIC showed more systemic inflammation and greater Sequential Organ Failure Assessment scores and were transfused with more blood products than the patients without DIC. On day 1, normal prothrombinase activity, increased soluble fibrin, lesser levels of antithrombin, and increased soluble thrombomodulin were observed in patients with DIC in comparison with controls and non-DIC patients. These changes were more prominent in patients with DIC who met the overt criteria for DIC established by the International Society on Thrombosis and Haemostasis. Multiple regression analysis showed that antithrombin is an independent predictor of high soluble fibrin in DIC patients. Greater levels of fibrin and fibrinogen degradation products, D-dimer, and the fibrin and fibrinogen degradation products/D-dimer ratio indicated increased fibrin(ogen)olysis in DIC patients. Almost all ACoTS patients overlapped with the DIC patients. The changes in the measured variables in ACoTS patients coincided with those in DIC patients. CONCLUSION Normal prothrombinase activity and insufficient control of coagulation give rise to systemic increase in thrombin generation and its activity in patients with DIC with the fibrinolytic phenotype at an early phase of trauma. The same is true in patients with ACoTS, and shutoff of thrombin generation was not observed.

Association of age at menarche with metabolic syndrome and its components in rural Bangladeshi women.

BackgroundEarly age at menarche is associated with increased risk of metabolic syndrome in both China and the West. However, little is known about the impact of age at menarche and metabolic syndrome in South Asian women, including those from low-income country, where age at menarche is also falling. The aim of the present study was to investigate whether age at menarche is inversely associated with metabolic syndrome in Bangladeshi women, who are mostly poor and have limited access to and or poor health care facilities.MethodsThis community-based cross-sectional study was performed using 1423 women aged between 15–75 years from rural Bangladesh in 2009 and 2010. Metabolic syndrome was defined according to standard NCEP-ATP III criteria. Logistic regression was used to estimate the association between age at menarche and metabolic syndrome, with adjustment of potential confounding variables, including age, education, marital status, tobacco users, use of contraceptives and number of pregnancies.ResultsEarly onset of menarche (<12 years) as compared to late onset (>13 years) was found to be associated with a higher prevalence of metabolic syndrome (odds ratio=1.55; 95 % confidence interval =1.05-2.30). Age at onset of menarche was also inversely associated with prevalence of high triglycerides (P for trend <0.01) and low high-density lipoprotein cholesterol (P for trend = 0.01), but positively associated with prevalence of high fasting blood glucose (P for trend =0.02). However, no significant association was found between age at menarche, high blood pressure and elevated waist circumference.ConclusionEarly onset of menarche might promote or trigger development of metabolic syndrome. Thus, knowledge of the history of age at onset of menarche may be critical in identifying women at risk of developing metabolic syndrome and those likely to benefit the most from early interventions.

Coagulofibrinolytic changes in patients with disseminated intravascular coagulation associated with post-cardiac arrest syndrome― Fibrinolytic shutdown and insufficient activation of fibrinolysis lead to organ dysfunction

INTRODUCTION Post-cardiac arrest syndrome (PCAS) is often associated with disseminated intravascular coagulation (DIC), thus leading to the development of multiple organ dysfunction syndrome (MODS). The aim of this study was to examine the pathophysiological relationships between coagulation, fibrinolysis and fibrinolytic shutdown by evaluating the levels of coagulofibrinolytic markers, including soluble fibrin, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator-plasminogen activator inhibitor-1 complex (tPAIC), plasmin-alpha2 plasmin inhibitor complex (PPIC), neutrophil elastase and fibrin degradation product by neutrophil elastase (EXDP). MATERIALS AND METHODS Fifty-two resuscitated patients were divided into two groups: 22 DIC and 30 non-DIC patients. RESULTS The levels of soluble fibrin, PPIC, tPAIC, EXDP and neutrophil elastase in the DIC patients with PCAS were significantly higher than those observed in the non-DIC patients. The values of the tPAIC and JAAM DIC scores were found to be independent predictors of increased SOFA scores in the DIC patients. The MODS patients demonstrated significantly higher levels of soluble fibrin and tPAIC; however, the levels of TAFI and EXDP were identical between the patients with and without MODS. In addition, positive correlations were observed between the levels of tPAIC and EXDP in the patients with non-MODS; however, no correlations were observed between these markers in the MODS patients. CONCLUSIONS Thrombin activation and fibrinolytic shutdown play important roles in the development of organ dysfunction in PCAS patients. Neutrophil elastase-mediated fibrinolysis cannot overcome the fibrinolytic shutdown that occurs in DIC patients with PCAS, thus resulting in the development of MODS.

Weight Loss Reduces Plasma Endothelin-1 Concentration in Obese Men

Obesity is associated with endothelial dysfunction that may contribute to the development of diabetes, hypertension, and atherosclerosis. Endothelin-1 (ET-1), which is produced mostly by vascular endothelial cells, has potent vasoconstrictor and proliferative activity in vascular smooth muscle cells and, therefore, has been implicated in regulation of vascular tonus and the progression of atherosclerosis, suggesting that ET-1 may be important in endothelial dysfunction. We studied whether diet-induced weight loss (i.e., lifestyle modification) affects plasma ET-1 concentration in obese individuals. We measured plasma ET-1 concentration in seven obese men (age: 48 ± 4 years old, body mass index: 27.7 ± 0.5 kg/m2) before and after a 3-month, diet-induced weight reduction program (i.e., lifestyle modification program). Caloric restriction reduced body weight from 78 ± 3 to 68 ± 2 kg (P < 0.001) and resulted in 12.1 ± 1.2% reduction in body mass index (24.3 ± 0.3 kg/m2, P < 0.0001). After the weight reduction program, systolic and diastolic blood pressure significantly decreased (128 ± 7 vs. 115 ± 4 mm Hg, P < 0.05 and 88 ± 4 vs. 77 ± 2 mm Hg, P < 0.01, respectively). The plasma level of ET-1 significantly decreased after the program (5.1 ± 0.4 vs. 4.0 ± 0.3 pg/ml, P < 0.05). The percentage systolic blood pressure reduction and percentage plasma ET-1 concentration reduction was in a linear relationship (r = 0.86, P < 0.05). Furthermore, the relationship between percentage weight reduction and percentage plasma ET-1 concentration reduction was linear (r = 0.87, P < 0.05). We conclude that weight loss by low-calorie diet (i.e., lifestyle modification) reduces plasma ET-1 concentration in obese individuals. This reduction may contribute to the improvement of obesity-induced endothelial dysfunction.

In Vivo Estrogen Manipulations on Coronary Capillary Network and Angiogenic Molecule Expression in Middle-Aged Female Rats

Objective—Estrogen replacement therapy (ERT) ameliorates symptoms in postmenopausal women with syndrome X. We hypothesized that estrogen deprivation and replacement may modulate coronary expressions of angiogenic molecules, thereby modifying the coronary capillary network in perimenopausal women. Methods and Results—Middle-aged (40-week-old) female rats were subjected to sham surgery, ovariectomy, or ovariectomy with ERT. Using immunohistochemical and in situ hybridization techniques, we showed that protein and gene expressions of estrogen receptor &bgr;, but not &agr;, in coronary vessels were regulated by in vivo estrogen manipulations. Morphometric analysis showed a reduction in total coronary capillary density with decreased arteriolar capillaries after ovariectomy. ERT resulted in normalization of total capillary number with increased venular capillaries. Coronary expressions of vascular endothelial growth factor (VEGF) and its angiogenic receptor (fetal liver kinase-1) were diminished after ovariectomy, and ERT restored it to intact levels. Higher expressions of VEGF and fetal liver kinase-1 in middle-aged compared with young female rats were associated with an accumulation of hypoxia-inducible factor-1 protein, which was highly expressed in middle-aged female rats. Conclusions—The coronary capillary network in middle-aged women may be regulated by physiological angiogenesis via VEGF, and reduction in coronary VEGF expression by estrogen deficiency could play a role as a molecular pathogenesis in the development of coronary heart disease in postmenopausal women.