Effects of angiotensin converting enzyme inhibition on adiponectin levels and lipid profile in the ovariectomized-aged rats

Consumption of the cell-free or heat-treated fractions of a pitched kefir confers some but not all positive impacts of the corresponding whole kefir

Introduction

Kefir consumption can have many metabolic health benefits, including, in the case of specific kefirs, improvements in plasma and liver lipid profiles. Our group has previously shown that these health benefits are dependent on the microbial composition of the kefir fermentation, and that a pitched kefir (PK1) containing specific traditional microbes can recapitulate the health benefits of a traditional kefir. In this study we investigated how different preparations of kefir impact cholesterol and lipid metabolism and circulating markers of cardiovascular disease risk and determine if freeze-drying impacts health benefits relative to past studies.

Materials and methods

Eight-week-old male and female C57Bl/6 mice were fed a high fat diet (40% kcal from fat) supplemented with one of 3 freeze-dried kefir preparations (whole kefir, cell-free kefir, or heat-treated kefir) for 8 weeks prior to analysis of plasma and liver lipid profiles, circulating cardiovascular disease (CVD) biomarkers, cecal microbiome composition, and cecal short-chain fatty acid levels. These groups of mice were compared to others that were fed a control low-fat diet, control high fat diet or high fat diet supplemented with milk, respectively.

Results

All kefir preparations lowered plasma cholesterol in both male and female mice, while only whole kefir lowered liver cholesterol and triglycerides. Plasma vascular cell adhesion molecule 1 (VCAM-1) was lowered by both whole kefir and heat-treated kefir in male mice but not females, while c-reactive protein (CRP) was unchanged across all high fat diet fed groups in males and females.

Conclusion

These results indicate that some of the metabolic benefits of consumption of this kefir do not require whole kefir while also indicating that there are multiple compounds or components responsible for the different benefits observed.

Contentious role of 'Good Adiponectin' in pulmonary and cardiovascular diseases: Is adiponectin directed therapy a boon or a bane?

After two decades of its discovery, numerous facts of adiponectin (APN) biology has been uncovered, yet, APN remains an elusive adipokine. Findings from clinical studies and animal models established APN's ameliorative role in cardiovascular disease (CVD) and pulmonary disease (PD) but the same condition is prognostic for mortality in the same set of patients which cornered APN towards a dubious state. A repertoire of mechanisms associated with the positive association of APN in both lean/cachectic or obese CVD and PD patients from past publications are evaluated. Newer pharmacological agent may be explored to regulate elevated blood APN concentration in COPD or CHF patients whereas administration of recombinant APN as well as growth hormone may augment blood APN concentration in obese subjects associated with low blood and intracellular APN concentration. However, some APN directed therapy in clinical as well as in pre-clinical setup has pronounced some contentious effects. After reviewing the mechanisms of the contentious role of APN functioning in pathologic conditions of CVD and PD in both lean and obese conditions, the authors came to conclusion that APN directed therapy may be utilized with caution keeping in mind the different age group, sex and the different CVD as well as pulmonary diseases they are suffering from.

Reduction in nitric oxide bioavailability shifts serum lipid content towards atherogenic lipoprotein in rats

Nitric oxide (NO) is major endothelial relaxing factor and reduction in its bioavailabilty has been linked to hypertension. Furthermore, high lipid content is a strong risk factor predisposing to cardiovascular diseases. The principal focus of this study was to investigate the effect of blockade of nitric oxide synthase (NOS) on serum lipid content in rats. Male Wistar rats (150-170 g, n = 15) were randomly divided into two groups designated control (n = 5), and L-Name group (n = 10) and were gavage with distilled water and 60 mg/kg of L-NAME respectively daily for three weeks. After 3 weeks, the L-NAME group was sub-divided into two sub-groups (n = 5 each): L-NAME (60 mg/kg of L-NAME), and L-NAME plus ramipril (LR) (60 mg/kg of L-NAME plus 20 mg/kg of ramipril) and were treated daily for another three weeks. The blood pressure (BP) of the conscious rats was measured by tail-cuff method at the onset, at the third and at the sixth weeks of the experiment; while serum lipid contents and NO were measured at the third and sixth weeks. At the end of the experiment blood sample was drawn by ocular puncture for evaluation of lipid profile and NO, and the animals were later euthanized by overdose of anaesthesia. Data were analyzed using ANOVA at p < 0.05. There was a significant increase in BP, triglyceride, total cholesterol, low density lipoprotein-cholesterol, and atherogenic indices in L-NAME group compared to the control and LR group (p < 0.05); NO and high density lipoprotein-cholesterol was significant lower in the L-NAME group compared to control and LR (p < 0.05). In conclusion, reduction in NO bioavailability alters lipid metabolism, which was rectified by ramipril.

Effect of Notoginsenoside R1 on autologous adipose graft in rats

Autologous fat particle transplantation has been widely used by surgeons. The present study evaluated the effect of Notoginsenoside R1 (NR1) treatment on rat autologous fat graft, along with the quality and retention rates. Male Sprague‑Dawley rats (n=60) received fat particle auto‑transplantation from the left abdominal cavity into lateral dorsum. A total of 14 days after surgery, NR1 in different doses (50, 100 and 200 mg/kg/day) was injected into rats, following which blood and fat graft samples were harvested at days 7, 14 and 28. Assessments were carried out by hematoxylin and eosin staining, western blotting, ELISA and immunohistochemistry (IHC). The survival rate of fat grafts was increased in three experimental groups, as detected by weight measurement. Histological scoring demonstrated that there were significant differences in tissue integrity between the 100 mg/kg/day group and the other 3 groups. hepatocyte growth factor, vascular endothelial growth factor, fibroblast growth factor, angiotensin and S100 levels in the 100 mg/kg/day NR1 group was increased compared with the other 2 treatment groups; however, all 3 treatment groups demonstrated increased expression of these proteins compared with the control group. Additionally, cluster of differentiation (CD)68 exhibited negative expression and CD31 showed weakly positive expression in all three experiments, as assessed by IHC. In conclusion, 100 mg/kg/day NR1 may potentially promote the retention rate and enhance the quality of autologous fat grafts via increasing vascularity in the recipient site. These results implicate NR1 as a therapeutic strategy for the improvement of outcome following fat graft surgery.

Chronic treatment with angiotensin-converting enzyme inhibitor increases cardiac fibrosis in young rats submitted to early ovarian failure

BACKGROUND

We investigated whether the treatment with enalapril maleate, combined with aerobic physical training, promotes positive effects on the autonomic balance, the morphology and the cardiac function in female rats submitted to early ovarian failure.

METHODS

Thirty-five female Wistar rats, ovariectomized at 10weeks of age, were assigned into Ovariectomized rats (OVX) and Ovariectomized rats treated with enalapril maleate (OVX-EM, 10mg^-1·kg^-1·d^-1) Each group was subdivided into sedentary and trained (aerobic swimming training for 10weeks). All animals were submitted to a) double pharmacological autonomic blockade, b) study of morphology and cardiac function by echocardiography, and c) analysis of cardiac fibrosis.

RESULTS

The OVX-EM sedentary group showed a significant increase in cardiac fibrosis, relative heart weight, interventricular septum thickness and increased sympathetic participation and reduced participation of the vagal tone in the determination of the basal heart rate when compared to the OVX sedentary group. Physical training reduced cardiac fibrosis in both groups, however, with less intensity in the OVX-EM group. It also increased the absolute and relative heart weight and the end-systolic volume. Finally, the OVX-EM trained group showed higher values for left ventricular end-systolic volume and lower values for ejection fraction and shortening fraction than the sedentary OVX-EM group.

CONCLUSION

Enalapril maleate exacerbated cardiac fibrosis and increased sympathetic participation in the basal heart rate determination, without significantly affecting the cardiac function. Aerobic physical training did not change the cardiac autonomic control, but reduced cardiac fibrosis and had little effect on the cardiac function.

Renin-angiotensin system blockers regulate the metabolism of isolated fat cells in vitro

Due to the presence of the renin-angiotensin system (RAS) in tissues and its specific influence on white adipose tissue, fat cells are possible targets of pharmacological RAS blockers commonly used as anti-hypertensive drugs. In the present study, we investigated the effects of different RAS blockers on fat cell metabolism, more specifically on lipolysis, lipogenesis and oxidation of energy substrates. Isolated primary adipocytes were incubated with different RAS blockers (aliskiren, captopril and losartan) in vitro for 24 h and lipolysis, lipogenesis and glucose oxidation capacities were determined in dose-response assays to a β-adrenergic agonist and to insulin. Although no change was found in lipolytic capacity, the RAS blockers modulated lipogenesis and glucose oxidation in a different way. While captopril decreased insulin-stimulated lipogenesis (−19% of maximal response and −60% of insulin responsiveness) due to reduced glucose derived glycerol synthesis (−19% of maximal response and 64% of insulin responsiveness), aliskiren increased insulin-stimulated glucose oxidation (+49% of maximal response and +292% of insulin responsiveness) in fat cells. Our experiments demonstrate that RAS blockers can differentially induce metabolic alterations in adipocyte metabolism, characterized by a reduction in lipogenic responsiveness or an increase in glucose oxidation. The impact of RAS blockers on adipocyte metabolism may have beneficial implications on metabolic disorders during their therapeutic use in hypertensive patients.

Review of Angiotensin-converting Enzyme Inhibitory Assay: Rapid Method in Drug Discovery of Herbal Plants

The renin-angiotensin-aldosterone system is a signaling pathway which responsible in the blood pressure regulation. Angiotensin-converting enzyme (ACE) is one of the key elements responsible for the hypertensive mechanism. It converts angiotensin-I to angiotensin-II. The discovery history of the ACE inhibitory activity assay method has been through a long stage for decades and development continues until today. The ACE inhibitory activity has become an effective screening method in the search for new antihypertensive agents from herbal plants. Some of in vitro assay methods were used to examine the activity of ACE inhibitors based on the substrate usage, such as; Cushman and Cheung Method using a substrate hippuryl-histidyl-leucine (HHL), Holmquist method using a substrate furanacryloyl-tripeptide, Elbl and Wagner method using a substrate benzoil-[l-14C] glicyl-L-histidine-L-leucine, Carmel and Yaron method using a substrate o-aminobenzoylglycyl-p-nitrophenylalanilproline, and Lam method using 3-hydroxybutyrylglycyl-glycyl-glycine as substrate. Several different methods to measure the results of enzymatic reactions or separating substrate with products, including spectrophotometric, fluorometric, high-performance liquid chromatography, electrophoresis, and radiochemistry. Application of the test method for screening the ACE inhibitors activity and investigation of active compounds from natural products can be done easily with this method, it is very helpful in research because the results obtained are simple, accurate, and rapid.