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Gender discrimination in the influence of hyperglycemia and hyperosmolarity on rat aortic tissue responses to insulin

Wong NL, Achike FI

Regul. Pept., 2010 Aug 9;163(1-3):113-9.
PMID: 20434492 DOI: 10.1016/j.regpep.2010.04.003

Hyperglycaemia initiates endothelial dysfunction causing diabetic macro- and micro-vasculopathy, the main causes of morbidity and mortality in diabetes mellitus. The vasculopathy exhibits gender peculiarities. We therefore explored gender differences in comparing the effects of hyperglycaemia (50 mM) per se with its hyperosmolar (50 mM) effects on vascular tissue responses to insulin. Endothelium-intact or denuded thoracic aortic rings from age-matched male and female Sprague-Dawley rats were incubated for 10 min or 6 h (acute versus chronic exposure) in normal, hyperglycaemic or hyperosmolar Krebs solution. Relaxant responses to insulin (6.9x10(-7)-6.9x10(-5) M) of the phenylephrine-contracted tissues were recorded. Endothelium denudation in both genders inhibited relaxation to insulin in all conditions, more significantly in female than in male tissues, suggesting the female response to insulin is more endothelium-dependent than the male. Acutely and chronically exposed normoglycemic endothelium-intact or -denuded tissues responded similarly to insulin. Chronic hyperglycemic or hyperosmolar exposure did not alter the endothelium-denuded tissue responses to insulin, whereas the responses of the endothelium-intact male and female hyperosmolar, and male hyperglycemic tissues were enhanced. The results show that insulin exerts an endothelium-dependent and independent relaxation with the female tissue responses more endothelium-dependent than the male. The data also suggest that hyperosmolarity per se enhances aortic tissue relaxant responses to insulin whereas hyperglycemia per se inhibits the same and more so in female than male tissues. These effects are endothelium-dependent.

Matched MeSH terms: Aorta, Thoracic/pathology
Fulltext The role of repeatedly heated soybean oil in the development of hypertension in rats: association with vascular inflammation

Ng CY, Kamisah Y, Faizah O, Jaarin K

Int J Exp Pathol, 2012 Oct;93(5):377-87.
PMID: 22974219 DOI: 10.1111/j.1365-2613.2012.00839.x

Thermally oxidized oil generates reactive oxygen species that have been implicated in several pathological processes including hypertension. This study was to ascertain the role of inflammation in the blood pressure raising effect of heated soybean oil in rats. Male Sprague-Dawley rats were divided into four groups and were fed with the following diets, respectively, for 6 months: basal diet (control); fresh soybean oil (FSO); five-time-heated soybean oil (5HSO); or 10-time-heated soybean oil (10HSO). Blood pressure was measured at baseline and monthly using tail-cuff method. Plasma prostacyclin (PGI(2) ) and thromboxane A(2) (TXA(2) ) were measured prior to treatment and at the end of the study. After six months, the rats were sacrificed, and the aortic arches were dissected for morphometric and immunohistochemical analyses. Blood pressure was increased significantly in the 5HSO and 10HSO groups. The blood pressure was maintained throughout the study in rats fed FSO. The aortae in the 5HSO and 10HSO groups showed significantly increased aortic wall thickness, area and circumferential wall tension. 5HSO and 10HSO diets significantly increased plasma TXA(2) /PGI(2) ratio. Endothelial VCAM-1 and ICAM-1 were significantly increased in 5HSO, as well as LOX-1 in 10HSO groups. In conclusion, prolonged consumption of repeatedly heated soybean oil causes blood pressure elevation, which may be attributed to inflammation.

Matched MeSH terms: Aorta, Thoracic/pathology*
Vitamin E and factors affecting atherosclerosis in rabbits fed a cholesterol-rich diet

Ismail NM, Abdul Ghafar N, Jaarin K, Khine JH, Top GM

Int J Food Sci Nutr, 2000;51 Suppl:S79-94.
PMID: 11271860

The present study aims to examine the effects of a palm-oil-derived vitamin E mixture containing tocotrienol (approximately 70%) and tocopherol (approximately 30%) on plasma lipids and on the formation of atherosclerotic plaques in rabbits given a 2% cholesterol diet. Eighteen New Zealand White rabbits (2.2-2.8 kg) were divided into three groups; group 1 (control) was fed a normal diet, group 2 (AT) was fed a 2% cholesterol diet and group 3 (PV) was fed a 2% cholesterol diet with oral palm vitamin E (60 mg/kg body weight) given daily for 10 weeks. There were no differences in the total cholesterol and triacylglycerol levels between the AT and PV groups. The PV group had a significantly higher concentrations of HDL-c and a lower TC/HDL-c ratio compared to the AT group (P < 0.003). The aortic tissue content of cholesterol and atherosclerotic lesions were comparable in both the AT and PV groups. However, the PV group had a lower content of plasma and aortic tissue malondialdehyde (P < 0.005). Our findings suggest that despite a highly atherogenic diet, palm vitamin E improved some important plasma lipid parameters, reduced lipid peroxidation but did not have an effect on the atherosclerotic plaque formation.

Matched MeSH terms: Aorta, Thoracic/pathology
Thoracic aortic dissection. Death may not always be due to rupture with haemorrhage. Unusual complications which can be missed at autopsy

Subramaniam K, Sheppard MN

J Forensic Leg Med, 2018 Feb;54:127-129.
PMID: 29413954 DOI: 10.1016/j.jflm.2018.01.005

OBJECTIVES: Aortic dissection (AD) can be a challenging diagnosis. At autopsy, the aorta may not be dilated and intimal tears may be missed or found without obvious rupture or haemorrhage. We report our experience of AD at a tertiary referral centre with review of 32 cases and discuss 2 unusual complications.
METHODS/RESULTS: 32 cases of which 12 females and 20 male and 18 out of 32 cases were aged below 40. All of the cases were examined macroscopically and microscopically. 30 out of 32 cases (93%) died due to rupture associated with the AD. Two unusual complications were proximal extension of AD into left coronary artery (CA) with intramural haematoma blocking the vessel and AD involving the ostium of the right CA resulting in avulsion of the right CA from the aorta. Mode of death in both these cases were myocardial ischemia. Sections of the aorta in all cases confirmed extensive cystic medial degeneration with disorganisation, fragmentation and disappearance of the elastin fibres with increased collagen and smooth muscle nuclear degeneration.
CONCLUSION: Pathologists should be thorough when examining the aorta, the aortic valve and root in AD. When a rupture site cannot be found it is important to look for unusual complications involving the CAs. Histology plays an important role to corroborate the cause of death.

Matched MeSH terms: Aorta, Thoracic/pathology*
Effect of alpha lipoic acid on oxidative stress and vascular wall of diabetic rats

Balkis Budin S, Othman F, Louis SR, Abu Bakar M, Radzi M, Osman K, et al.

Rom J Morphol Embryol, 2009;50(1):23-30.
PMID: 19221642

PREMISES AND OBJECTIVES: Antioxidant plays an important role in preventing the progression of diabetes mellitus (DM) complications. The aim of the present study was to investigate the effect of alpha lipoic acid (ALA) supplementation on plasma lipid, oxidative stress and vascular changes in diabetic rats.

Matched MeSH terms: Aorta, Thoracic/pathology
Fulltext Clinacanthus nutans Leaves Extract Reverts Endothelial Dysfunction in Type 2 Diabetes Rats by Improving Protein Expression of eNOS

Azemi AK, Mokhtar SS, Rasool AHG

Oxid Med Cell Longev, 2020;2020:7572892.
PMID: 32879653 DOI: 10.1155/2020/7572892

Diabetes mellitus is associated with endothelial dysfunction; it causes progressive vascular damage resulting from an impaired endothelium-dependent vasorelaxation. In the diabetes state, presence of hyperglycemia and insulin resistance predisposes to endothelial dysfunction. Clinacanthus nutans, widely used as a traditional medicine for diabetes is reported to have hypoglycemic, hypolipidemic, antioxidant, and anti-inflammatory properties. However, the possibility of C. nutans affecting the vascular endothelial function in diabetes remains unclear. This study was aimed at evaluating the effects of C. nutans methanolic leaves extract (CNME) on endothelial function in a type 2 diabetes (T2DM) rat model. Sixty male Sprague-Dawley rats were divided into five groups (n = 12 per group): nondiabetic control, nondiabetic treated with four weeks of CNME (500 mg/kg/daily), untreated diabetic rats, diabetic treated with metformin (300 mg/kg/daily), and diabetic treated with CNME (500 mg/kg/daily). T2DM was induced by a single intraperitoneal injection of low-dose streptozotocin (STZ) to rats fed with high-fat diet (HFD). Endothelial-dependent and endothelial-independent relaxations and contractions of the thoracic aorta were determined using the organ bath. Aortic endothelial nitric oxide synthase (eNOS) expression was determined using Western blotting. Endothelial-dependent relaxation was reduced in diabetic rats. Both diabetic groups treated with CNME or metformin significantly improved the impairment in endothelium-dependent vasorelaxation; this was associated with increased expression of aortic eNOS protein. CNME- and metformin-treated groups also reduced aortic endothelium-dependent and aortic endothelium-independent contractions in diabetics. Both of these diabetic-treated groups also reduced blood glucose levels and increased body weight compared to the untreated diabetic group. In conclusion, C. nutans improves endothelial-dependent vasodilatation and reduces endothelial-dependent contraction, thus ameliorating endothelial dysfunction in diabetic rats. This may occur due to its effect on increasing eNOS protein expression.

Matched MeSH terms: Aorta, Thoracic/pathology
Fulltext Carbon Monoxide Suppresses Neointima Formation in Transplant Arteriosclerosis by Inhibiting Vascular Progenitor Cell Differentiation

Sakihama H, Lee GR, Chin BY, Csizmadia E, Gallo D, Qi Y, et al.

Arterioscler Thromb Vasc Biol, 2021 Jun;41(6):1915-1927.
PMID: 33853347 DOI: 10.1161/ATVBAHA.120.315558

[Figure: see text].

Matched MeSH terms: Aorta, Thoracic/pathology