Publications by authors named "Sahran Yahaya"

3 Publications

  • Page 1 of 1

Calcitriol Supplementation Ameliorates Microvascular Endothelial Dysfunction in Vitamin D-Deficient Diabetic Rats by Upregulating the Vascular eNOS Protein Expression and Reducing Oxidative Stress.

Oxid Med Cell Longev 2021 2;2021:3109294. Epub 2021 Feb 2.

Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan, Malaysia.

Diabetes mellitus contributes to macro- and microvascular complications, leading to adverse cardiovascular events. This study examined the effects of vitamin D deficiency on the vascular function and tissue oxidative status in the microcirculation of diabetic rats and to determine whether these effects can be reversed with calcitriol (active vitamin D metabolite) supplementation. Streptozotocin-induced diabetic rats were fed for 10 weeks with control diet (DC) or vitamin D-deficient diet without (DD) or with oral calcitriol supplementation (0.15 g/kg) in the last four weeks (DDS) (10 rats each group). A nondiabetic rat group that received control diet was also included (NR). After 10 weeks, rats were sacrificed; mesenteric arterial rings with and without endothelium were studied using wire myograph. Western blotting of the mesenteric arterial tissue was performed to determine the protein expression of endothelial nitric oxide synthase (eNOS) enzyme. Antioxidant enzyme superoxide dismutase (SOD) activity and oxidative stress marker malondialdehyde (MDA) levels in the mesenteric arterial tissue were also measured. The DC group had significantly lower acetylcholine-induced relaxation and augmented endothelium-dependent contraction, with reduced eNOS expression, compared to NR rats. In mesenteric arteries of DD, acetylcholine-induced endothelium-dependent and sodium nitroprusside-induced endothelium-independent relaxations were lower than those in DC. Calcitriol supplementation in DDS restored endothelium-dependent relaxation. Mesenteric artery endothelium-dependent contraction of DD was greater than DC; it was not affected by calcitriol supplementation. The eNOS protein expression and SOD activity were significantly lower while MDA levels were greater in DD compared to DC; these effects were not observed in DDS that received calcitriol supplementation. In conclusion, vitamin D deficiency causes eNOS downregulation and oxidative stress, thereby impairing the vascular function and posing an additional risk for microvascular complications in diabetes. Calcitriol supplementation to diabetics with vitamin D deficiency could potentially be useful in the management of or as an adjunct to diabetes-related cardiovascular complications.
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February 2021

Vitamin D status and oxidative stress in diabetes mellitus.

Cell Mol Biol (Noisy-le-grand) 2018 May 30;64(7):60-69. Epub 2018 May 30.

Pharmacology Vascular Laboratory, School of Medical Sciences, Universiti Sains Malaysia (Health Campus), 16150 Kota Bharu, Kelantan, Malaysia.

Diabetes mellitus is an epidemic that is gaining global concern. Chronic hyperglycemia in diabetes induces the excess production of free radicals. The deleterious effects of excess free radicals are encountered by endogenous antioxidant defense system. Imbalance between free radicals production and antioxidants defense mechanisms leads to a condition known as "oxidative stress". Diabetes mellitus is associated with augmented oxidative stress that induced micro- and macrovascular complications, which presents a significant risk for cardiovascular events. Low vitamin D levels in the body have also been reported to be associated with the pathogenesis of diabetes and enhanced oxidative stress. The article is to review available literature and summarize the relationship between oxidative stress and vitamin D levels in diabetes. We also review the effects of vitamin D analogs supplementation in improving oxidative stress in diabetics.
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May 2018

The Values of Receptor Activator Nuclear Kappa-B Ligand Expression in Stage III Giant Cell Tumor of the Bone.

Indian J Orthop 2018 Jan-Feb;52(1):31-34

Department of Orthopaedics, School of Medical Science, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.

Background: Giant cell tumor (GCT) of bone is a benign locally aggressive primary bone tumor which is risky for local recurrences and pulmonary metastasis. Till date, there are still many uncertainties in predicting the aggressiveness of GCT. We aim to investigate whether receptor activator nuclear kappa-B ligand (RANKL) expression may determine the prognosis of the lesion.

Materials And Methods: We examined RANKL expression in 39 patients (21 males, 18 females) by immunohistochemistry. Four patients (10%) were presented with tumor recurrence, eight patients (20%) were complicated with lung metastasis, and two patients (5%) were presented with both recurrence and lung metastasis. Positive RANKL expression was assessed according to a scoring system evaluating the percentage of the immunostained epithelial area and the staining intensity. The cumulative score was calculated to determine the final score value. Data were analyzed using PASW version 18.0 and independent -test between nonrecurrence/recurrence groups, and nonlung metastasis/lung metastasis groups. Significance was set at < 0.05.

Results: Thirty-two patients (82%) scored 3 in RANKL-staining percentage from whole stromal cell population (>75%), 6 patients scored 2, and 1 patient scored 1. Nine patients (23%) scored 3 in RANKL-staining intensity (most intense), 19 patients (48%) scored 2, and 11 patients (29%) scored 1. Twenty six patients (67%) had strong RANKL expression (total score of 5-6), 12 patients (31%) showed moderate score (3-4) whereas only 1 patient (2%) showed weak RANKL expression. Together, the mean value of RANKL-staining percentage was 2.79, intensity 1.95 and the total score 4.77. The mean RANKL-staining percentage between recurrence and nonrecurrence groups was statistically significant ( = 0.009). There was no significant difference in the mean staining intensity and total score between nonrecurrence and recurrence groups, and staining percentage staining intensity and a total cumulative score of RANKL expression between lung metastasis and nonlung metastasis groups.

Conclusion: RANKL expression is generally high in Stage III GCT and is a reliable prognostic marker in predicting the risk of local recurrence however not in lung metastasis.
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February 2018