Long-term effects of oral vitamin C supplementation on the endothelial dysfunction in the iris microvessels of diabetic rats

Jariyapongskul, Amporn; Rungjaroen, Tippawan; Kasetsuwan, Ngamjit; Patumraj, Suthiluk; Seki, Junji; Niimi, Hideyukii

doi:10.1016/j.mvr.2007.03.002

Cited by 28 publications

(19 citation statements)

References 34 publications

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“…The anatomical structure of iridial vascular structure in sheep was precisely described using a casting method (Olver & McCartney, 1989) and several studies evaluated iris microvascular flow in rats using laser Doppler flowmetry or other methods. However, these studies did not assess capillary density and focused mainly on iris vessel diameter changes in different disease models and treatments (Meinen et al ., 1975; Jariyapongskul, et al ., 2006; Jariyapongskul et al ., 2007; Stauss et al ., 2011). SDF imaging may, therefore, represent a novel, specific technique to examine changes in iris vascular bed, e.g.…”

Section: Discussionmentioning

confidence: 99%

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Noninvasive assessment of the iridial microcirculation in rats using sidestream dark field imaging

Černý

Kelly

Alotibi

et al. 2012

Journal of Microscopy

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Summary Sidestream dark field imaging represents a novel, noninvasive method to study the microcirculation in humans and animals. To‐date, it has been used extensively in various peripheral tissues (e.g. sublingual area, intestinal mucosa), however no data for the ocular vasculature, including the iridial microcirculation, are currently available. Therefore, the aim of this study was to examine the reliability and reproducibility of sidestream dark field imaging within the iridial microcirculation in experimental animals. Male Lewis rats were anaesthetized and the iris microvasculature was observed using an sidestream dark field probe gently placed against a cover slip covering the right eye. All video sequences recorded were analysed off‐line by using AVA 3.0 software (MicroVision Medical, Amsterdam, The Netherlands). Results are expressed as mean (±SE) or median (interquartile range). Clear images were recorded from each animal and the total number of analysable video sequences was 50. All raw data for selected vessel density parameters passed normality test. The total all and small vessel density (in mm mm‐2) were 22,6 (±0,58) and 19,6 (±0,68), respectively. The perfused all and small vessel density were 20,9 (±0,61) and 19,1 (±0,65), respectively. The mean values of all iris vessel density parameters are shown in Figure 4. The DeBacker Score (n/mm) was 15,2 (±0,45), the proportion of perfused vessel was 94,5% (89,8–99,1%), and the MFI was 3 points (3–3). Taken together, these results indicate that SDF imaging provides a reliable and noninvasive method to examine the iridial microvascular bed in vivo and, thus, may provide unique opportunities for the study of the iridial vascular network in various experimental and clinical settings and disease models. 4 Vessel Density. TAVD = Total all vessel density; PAVD = Perfused all vessel density; TSVD = Total small vessel density; PSVD = Perfused small vessel density. Data are shown as a mean (±SE), small vessels are referred to diameter ≤ 25 um.

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Section: Discussionmentioning

confidence: 99%

“…Moreover, vascular changes, e.g. in diabetic vascular damage, can be seen in the iris earlier than in the retina, which further underlines the importance of iris vascular bed research (Jariyapongskul et al ., 2007).…”

Section: Introductionmentioning

confidence: 90%

Noninvasive assessment of the iridial microcirculation in rats using sidestream dark field imaging

Černý

Kelly

Alotibi

et al. 2012

Journal of Microscopy

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“…Leukocyte adhesion in postcapillary venules of iris was determined by rhodamine-6G (R6G) which can label mitochondria especially in leukocyte (Sigma, USA) at 0.15 mg/kg BW following the method described by Jariyapongskul et al [37]. The emission wavelength of R6G lies between 530 and 540 nm.…”

Section: Methodsmentioning

confidence: 99%

“…The lipid material is simply heated with TBA under acidic condition, and the formation of a pink color is measured at or close to 532 nm. The pink color is formed by reaction of one molecule of MDA with two molecules of TBA [37]. …”

Section: Methodsmentioning

confidence: 99%

Molecular Mechanisms of Curcumin on Diabetes-Induced Endothelial Dysfunctions: Txnip, ICAM-1, and NOX2 Expressions

Wongeakin

Bhattarakosol

Patumraj

2014

BioMed Research International

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We aim to investigate the effects of curcumin on preventing diabetes-induced vascular inflammation in association with its actions on Txnip, ICAM-1, and NOX2 enzyme expressions. Male Wistar rats were divided into four groups: control (CON), diabetic (DM; streptozotocin (STZ), i.v. 55 mg/kg BW), control-treated with curcumin (CONCUR; 300 mg/kg BW), and diabetes treated with curcumin (DMCUR; 300 mg/kg BW). 12th week after STZ injection, iris blood perfusion, leukocyte adhesion, Txnip, p47phox, and malondialdehyde (MDA) levels were determined by using laser Doppler, intravital fluorescent confocal microscopy, Western Blot analysis, and TBAR assay, respectively. The iris blood perfusion of DM and DMCUR was decreased significantly compared to CON and CONCUR (P < 0.001). Plasma glucose and HbA1c of DM and DMCUR were increased significantly compared to CON and CONCUR (P < 0.001). Leukocyte adhesion, ICAM-1, p47phox expression, and MDA levels in DM were increased significantly compared to CON, CONCUR, and DMCUR (P < 0.05). Txnip expression in DM and DMCUR was significantly higher than CON and CONCUR (P < 0.05). From Pearson's analysis, the correlation between the plasma MDA level and the endothelial functions was significant. It suggested that curcumin could ameliorate diabetic vascular inflammation by decreasing ROS overproduction, reducing leukocyte-endothelium interaction, and inhibiting ICAM-1 and NOX2 expression.

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“…Several antioxidants such as ascorbic acid (vitamin C), α-tocopherol (vitamin E), glutathione, BH4, and N-acetylcysteine have been shown to improve endothelial function. 39, [123][124][125][126] Vitamin C, a potent water-soluble scavenger of free radicals, reduces monocyte adhesion to endothelial cells, inhibits LDL oxidation, decreases inactivation of NO and stimulates eNOS activity. 125,127) Vitamin C has been shown to improve the function of endothelium in patients with cardiovascular diseases.…”

Section: Antioxidants On Endothelial Dysfunctionmentioning

confidence: 99%

Pharmacological Interventions to Prevent Vascular Endothelial Dysfunction: Future Directions

Balakumar¹,

Koladiya

Ramasamy

et al. 2008

JOURNAL OF HEALTH SCIENCE

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Endothelium forms an innermost lining of blood vessel and it regulates the vascular tone and permeability. A healthy vascular endothelium is antiatherogenic in nature because of its properties such as inhibition of platelet aggregation, adhesion cascades, smooth muscle cell proliferation and leukocyte adhesion. Vascular endothelial dysfunction (VED) is associated with reduced synthesis and release of nitric oxide, proinflammatory and prothrombotic properties followed by diminished vasodilation. VED has been implicated in the pathogenesis of artherosclerosis, hypertension, myocardial infarction, heart failure, renal failure and stroke. Various pharmacological interventions such as angiotensin converting enzyme (ACE) inhibitors, statins, insulin sensitizers, L-arginine as well as agents that target endothelial nitric oxide synthase (eNOS) "coupling" such as folates or tetrahydrobiopterin (BH4) have been noted to improve the function of vascular endothelium. In this review, we discussed various recently developed pharmacological interventions to improve the function of endothelium. Moreover, the novel targets sites involved in the pathogenesis of vascular endothelial dysfunction have been delineated.

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Long-term effects of oral vitamin C supplementation on the endothelial dysfunction in the iris microvessels of diabetic rats

Cited by 28 publications

References 34 publications

Noninvasive assessment of the iridial microcirculation in rats using sidestream dark field imaging

Noninvasive assessment of the iridial microcirculation in rats using sidestream dark field imaging

Molecular Mechanisms of Curcumin on Diabetes-Induced Endothelial Dysfunctions: Txnip, ICAM-1, and NOX2 Expressions

Pharmacological Interventions to Prevent Vascular Endothelial Dysfunction: Future Directions

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