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Cytoadherence and severe malaria

Craig AG, Khairul MF, Patil PR

Malays J Med Sci, 2012 Apr;19(2):5-18.
PMID: 22973133

Malaria is a disease that causes enormous human morbidity and mortality. One feature of mature Plasmodium falciparum-infected erythrocytes leading to the development of severe malaria is thought to be cytoadherence and blockage of the microvasculature. Therefore, an understanding of mechanisms that mediate parasite adhesion leading to malaria pathology is needed to yield new treatments for malaria. However, to date, cytoadherence-associated pathology is still under debate. Is cytoadherence needed to develop severe malaria? This review will discuss the available information on associations of cytoadherence with the development of severe malaria.

Matched MeSH terms: Microvessels
Fulltext Escherichia coli K1 utilizes host macropinocytic pathways for invasion of brain microvascular endothelial cells

Loh LN, McCarthy EMC, Narang P, Khan NA, Ward TH

Traffic, 2017 11;18(11):733-746.
PMID: 28799243 DOI: 10.1111/tra.12508

Eukaryotic cells utilize multiple endocytic pathways for specific uptake of ligands or molecules, and these pathways are commonly hijacked by pathogens to enable host cell invasion. Escherichia coli K1, a pathogenic bacterium that causes neonatal meningitis, invades the endothelium of the blood-brain barrier, but the entry route remains unclear. Here, we demonstrate that the bacteria trigger an actin-mediated uptake route, stimulating fluid phase uptake, membrane ruffling and macropinocytosis. The route of uptake requires intact lipid rafts as shown by cholesterol depletion. Using a variety of perturbants we demonstrate that small Rho GTPases and their downstream effectors have a significant effect on bacterial invasion. Furthermore, clathrin-mediated endocytosis appears to play an indirect role in E. coli K1 uptake. The data suggest that the bacteria effect a complex interplay between the Rho GTPases to increase their chances of uptake by macropinocytosis into human brain microvascular endothelial cells.

Matched MeSH terms: Microvessels/metabolism; Microvessels/microbiology*
Fulltext Parasite biomass-related inflammation, endothelial activation, microvascular dysfunction and disease severity in vivax malaria

Barber BE, William T, Grigg MJ, Parameswaran U, Piera KA, Price RN, et al.

PLoS Pathog, 2015 Jan;11(1):e1004558.
PMID: 25569250 DOI: 10.1371/journal.ppat.1004558

Plasmodium vivax can cause severe malaria, however its pathogenesis is poorly understood. In contrast to P. falciparum, circulating vivax parasitemia is low, with minimal apparent sequestration in endothelium-lined microvasculature, and pathogenesis thought unrelated to parasite biomass. However, the relationships between vivax disease-severity and total parasite biomass, endothelial autocrine activation and microvascular dysfunction are unknown. We measured circulating parasitemia and markers of total parasite biomass (plasma parasite lactate dehydrogenase [pLDH] and PvLDH) in adults with severe (n = 9) and non-severe (n = 53) vivax malaria, and examined relationships with disease-severity, endothelial activation, and microvascular function. Healthy controls and adults with non-severe and severe falciparum malaria were enrolled for comparison. Median peripheral parasitemia, PvLDH and pLDH were 2.4-fold, 3.7-fold and 6.9-fold higher in severe compared to non-severe vivax malaria (p = 0.02, p = 0.02 and p = 0.015, respectively), suggesting that, as in falciparum malaria, peripheral P. vivax parasitemia underestimates total parasite biomass, particularly in severe disease. P. vivax schizonts were under-represented in peripheral blood. Severe vivax malaria was associated with increased angiopoietin-2 and impaired microvascular reactivity. Peripheral vivax parasitemia correlated with endothelial activation (angiopoietin-2, von-Willebrand-Factor [VWF], E-selectin), whereas markers of total vivax biomass correlated only with systemic inflammation (IL-6, IL-10). Activity of the VWF-cleaving-protease, ADAMTS13, was deficient in proportion to endothelial activation, IL-6, thrombocytopenia and vivax disease-severity, and associated with impaired microvascular reactivity in severe disease. Impaired microvascular reactivity correlated with lactate in severe vivax malaria. Findings suggest that tissue accumulation of P. vivax may occur, with the hidden biomass greatest in severe disease and capable of mediating systemic inflammatory pathology. The lack of association between total parasite biomass and endothelial activation is consistent with accumulation in parts of the circulation devoid of endothelium. Endothelial activation, associated with circulating parasites, and systemic inflammation may contribute to pathology in vivax malaria, with microvascular dysfunction likely contributing to impaired tissue perfusion.

Matched MeSH terms: Microvessels/parasitology; Microvessels/physiopathology*
Vitamin D deficiency attenuates endothelial function by reducing antioxidant activity and vascular eNOS expression in the rat microcirculation

Wee CL, Mokhtar SS, Banga Singh KK, Rasool AHG

Microvasc Res, 2021 Nov;138:104227.
PMID: 34324883 DOI: 10.1016/j.mvr.2021.104227

This study examined the effects of vitamin D deficiency on vascular function and tissue oxidative status in the microcirculation; and whether or not these effects can be ameliorated with calcitriol, the active vitamin D metabolite. Three groups (n = 10 each) of male Sprague Dawley rats were fed for 10 weeks with control diet (CR), vitamin D-deficient diet without (DR), or with oral calcitriol supplementation (0.15 μg/kg) for the last four weeks (DSR). After 10 weeks, rats were sacrificed; mesenteric arterial rings were studied using wire myograph. Oxidative stress biomarkers malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were measured in the mesenteric arterial tissue. Vascular protein expression of endothelial nitric oxide synthase (eNOS) was determined by Western blotting. Acetylcholine-induced endothelium-dependent relaxation of DR was lower than CR. eNOS expression and SOD activity were lower in mesenteric arterial tissue of DR compared to CR. Calcitriol supplementation to DSR did not ameliorate the above parameters; in fact, augmented endothelium-dependent contraction was observed. Serum calcium was higher in DSR compared to CR and DR. In conclusion, vitamin D deficiency impaired microvascular vasodilation, associated with eNOS downregulation and reduced antioxidant activity. Calcitriol supplementation to vitamin D-deficient rats at the dosage used augmented endothelium-dependent contraction, possibly due to hypercalcaemia.

Matched MeSH terms: Microvessels/drug effects; Microvessels/enzymology*; Microvessels/physiopathology
Reproducibility of laser Doppler fluximetry and the process of iontophoresis in assessing microvascular endothelial function using low current strength

Al-Tahami BA, Yvonne-Tee GB, Halim AS, Ismail AA, Rasool AH

Methods Find Exp Clin Pharmacol, 2010 Apr;32(3):181-5.
PMID: 20448860 DOI: 10.1358/mf.2010.32.3.1423887

Iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) combined with laser Doppler fluximetry (LDF) is a tool used to determine microvascular endothelial function. Our aim was to study the reproducibility of different parameters of this technique using iontophoresis with low current strength on the forearm skin of healthy subjects. Baseline skin perfusion was done before application of five current pulses with 1 min of current-free interval. Current strength of 0.007 mA, current density of 0.01 mA/cm(2) and charge density of 6 mC/cm(2) were used, along with 1% ACh and 1% SNP. The absolute maximum change in perfusion (max), percent change in perfusion (% change), peak change in perfusion (peak) and area under the curve during iontophoresis (AUC) at the anodal and cathodal leads were recorded. Measurements were performed in three sessions for 2 days. The coefficient of variation (CV) was calculated for each parameter. Among the parameters studied, maximum change in perfusion and peak flux were the most reproducible parameters.

Matched MeSH terms: Microvessels/metabolism
Impaired microvascular endothelial function in relatively young obese humans is associated with altered metabolic and inflammatory markers

Al-Tahami BA, Bee YT, Ismail AA, Rasool AH

Clin. Hemorheol. Microcirc., 2011;47(2):87-97.
PMID: 21339629 DOI: 10.3233/CH-2010-1370

INTRODUCTION: This study aims to assess microvascular endothelial function in obese compared to age matched lean controls. Serum lipid profile, fasting glucose, high sensitivity C-reactive protein (hs-CRP) and adiponectin levels were also determined.
METHODS: This cross-sectional study involved 36 healthy lean and 36 obese subjects. Microvascular endothelial function was assessed using Laser Doppler fluximetry and iontophoresis with acetylcholine and sodium nitroprusside.
RESULTS: Mean age of subjects was 26.54 ± 0.60 years. Obese subjects had higher systolic (118.8 ± 1.5 vs 105.7 ± 2.0 mmHg, p < 0.001) and diastolic blood pressure (71.61 ± 1.35 vs 64.53 ± 1.40 mmHg, p = 0.001), higher triglyceride (1.35 ± 0.13 vs 0.79 ± 0.05 mmol/l, p < 0.001), lower high density lipoprotein cholesterol (HDL-C) (1.43 ± 0.04 vs 1.62 ± 0.05 mmol/l, p = 0.003), higher hs-CRP (11.58 ± 1.88 vs 1.88 ± 0.35 mg/l, p < 0.001), and lower adiponectin levels (8.80 ± 0.43 vs 25.93 ± 0.40 μg/ml, p < 0.001) compared to lean subjects. Endothelial dependent vasodilatation was lower in obese compared to lean subjects (40.53 ± 6.59 vs 71.03 ± 7.13 AU, p = 0.001).
CONCLUSION: Microvascular endothelial function is reduced in obese compared to age matched controls. This is associated with higher BP, triglyceride and lower HDL-C and adiponectin levels in obese group.
Study site: not mentioned

Matched MeSH terms: Microvessels/metabolism*
Assessment of macrovascular endothelial function using pulse wave analysis and its association with microvascular reactivity in healthy subjects

Ibrahim NNIN, Rasool AHG

Skin Res Technol, 2017 Aug;23(3):321-325.
PMID: 27868242 DOI: 10.1111/srt.12338

BACKGROUND: Pulse wave analysis (PWA) and laser Doppler fluximetry (LDF) are non-invasive methods of assessing macrovascular endothelial function and microvascular reactivity respectively. The aim of this study was to assess the correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF.
METHOD: 297 healthy and non-smoking subjects (159 females, mean age (±SD) 23.56 ± 4.54 years) underwent microvascular reactivity assessment using LDF followed by macrovascular endothelial function assessments using PWA.
RESULTS: Pearson's correlation showed no correlation between macrovascular endothelial function and microvascular reactivity (r = -0.10, P = 0.12).
CONCLUSION: There was no significant correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF in healthy subjects.

Matched MeSH terms: Microvessels/drug effects; Microvessels/physiopathology
Impaired microvascular endothelial function in vitamin D-deficient diabetic nephropathy patients

Munisamy S, Kamaliah MD, Suhaidarwani AH, Zahiruddin WM, Rasool AH

J Cardiovasc Med (Hagerstown), 2013 Jun;14(6):466-71.
PMID: 22964652 DOI: 10.2459/JCM.0b013e3283590d3d

AIMS: This study aims to compare microvascular endothelial function between vitamin D-deficient and nondeficient groups of patients with diabetic nephropathy. Serum levels of the inflammatory marker high-sensitivity C-reactive protein (hsCRP) were also measured.
METHODS: This prospective cross-sectional study involved 70 patients with diabetic nephropathy; 40 were categorized into the group with nondeficient serum 25-hydroxyvitamin D levels [25(OH)D >50 nmol/l], whereas 30 patients were categorized to the group with deficient serum 25(OH)D (<50 nmol/l). Microvascular endothelial function was determined using laser Doppler fluximetry and the process of iontophoresis. Acetylcholine and sodium nitroprusside were used to determine endothelium-dependent and independent vasodilatation.
RESULTS: Mean age of patients was 56.7 ± 3.8 years; 50 were men, whereas 20 were women. Mean serum 25(OH)D in the vitamin D-nondeficient group was 69.4 ± 2.9 nmol/l; the level in the vitamin D-deficient group was 42.1 ± 1.3 nmol/l, P < 0.001. Endothelium-dependent vasodilatation was lower in the vitamin D-deficient group compared with the vitamin D-nondeficient group (23.6 ± 2.7 versus 37.3 ± 3.8 arbitrary units, P = 0.004). No significant differences were observed between the two groups in their hsCRP levels, mean age, estimated glomerular filtration rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) and glycosylated haemoglobin.
CONCLUSION: Microvascular endothelial function was significantly reduced in diabetic nephropathy patients with deficient vitamin D levels compared with those with nondeficient levels.

Matched MeSH terms: Microvessels/drug effects; Microvessels/metabolism; Microvessels/physiopathology*
Deregulation of hsa-miR-20b expression in TNF-α-induced premature senescence of human pulmonary microvascular endothelial cells

Wong PF, Jamal J, Tong KL, Khor ES, Yeap CE, Jong HL, et al.

Microvasc Res, 2017 11;114:26-33.
PMID: 28595801 DOI: 10.1016/j.mvr.2017.06.002

miRNAs are important regulators of cellular senescence yet the extent of their involvement remains to be investigated. We sought to identify miRNAs that are involved in cytokine-induced premature senescence (CIPS) in endothelial cells. CIPS was established in young human pulmonary microvascular endothelial cells (HMVEC-Ls) following treatment with a sublethal dose (20ng/ml) of tumor necrosis factor alpha (TNF-α) for 15days. In parallel, HMVEC-Ls were grown and routinely passaged until the onset of replicative senescence (RS). Differential expression analysis following miRNA microarray profiling revealed an overlapped of eight deregulated miRNAs in both the miRNA profiles of RS and TNF-α-induced premature senescence cells. Amongst the deregulated miRNAs were members of the miR 17-92 cluster which are known regulators of angiogenesis. The role of hsa-miR-20b in TNF-α-induced premature senescence, a paralog member of the miR 17-92 cluster, was further investigated. Biotin-labeled hsa-miR-20b captured the enriched transcripts of retinoblastoma-like 1 (RBL1), indicating that RBL1 is a target of hsa-miR-20b. Knockdown of hsa-miR-20b attenuated premature senescence in the TNF-α-treated HMVEC-Ls as evidenced by increased cell proliferation, increased RBL1 mRNA expression level but decreased protein expression of p16INK4a, a cellular senescence marker. These findings provide an early insight into the role of hsa-miR-20b in endothelial senescence.

Matched MeSH terms: Microvessels/drug effects*; Microvessels/metabolism; Microvessels/pathology
Microvascular endothelial function and severity of primary open angle glaucoma

Bukhari SM, Kiu KY, Thambiraja R, Sulong S, Rasool AH, Liza-Sharmini AT

Eye (Lond), 2016 Dec;30(12):1579-1587.
PMID: 27540832 DOI: 10.1038/eye.2016.185

PurposeThe role of microvascular endothelial dysfunction on severity of primary open angle glaucoma (POAG) was investigated in this study.Patients and methodsA prospective cohort study was conducted. One hundred and fourteen ethnically Malay patients (114 eyes) with POAG treated at the eye clinic of Hospital University Sains Malaysia between April 2012 and December 2014 were recruited. Patients aged between 40 and 80 years with two consecutive reliable and reproducible Humphrey visual field 24-2 analyses were selected. Patients who were diagnosed with any other type of glaucoma, previous glaucoma-filtering surgery, or other surgeries except uncomplicated cataract and pterygium surgery were excluded. Humphrey visual field analysis 24-2 was used to stratify the severity of glaucoma using Advanced Glaucoma Intervention Study (AGIS) score at the time of recruitment. Microvascular endothelial function was assessed using Laser Doppler fluximetry and iontophoresis. Iontophoresis process with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and -independent vasodilatation, respectively.ResultsBased on the AGIS score, 55 patients showed mild glaucoma, with 29 moderate and 30 severe. There was statistically significant difference in microvascular endothelial function (ACh% and AChmax) between mild and moderate POAG cases (P=0.023) and between mild and severe POAG cases (P<0.001). There was negative correlation between microvascular endothelial function and severity of POAG (r=-0.457, P<0.001).ConclusionMicrovascular endothelial dysfunction may have a role in influencing the severity of POAG in Malay patients.

Study site: Eye clinic Hospital Universiti Sains Malaysia (HUSM)

Matched MeSH terms: Microvessels/physiopathology*
Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studies

Yusof SR, Mohd Uzid M, Teh EH, Hanapi NA, Mohideen M, Mohamad Arshad AS, et al.

Addict Biol, 2019 09;24(5):935-945.
PMID: 30088322 DOI: 10.1111/adb.12661

Mitragyna speciosa is reported to be beneficial for the management of chronic pain and opioid withdrawal in the evolving opioid epidemic. Data on the blood-brain barrier (BBB) transport of mitragynine and 7-hydroxymitragynine, the active compounds of the plant, are still lacking and inconclusive. Here, we present for the first time the rate and the extent of mitragynine and 7-hydroxymitragynine transport across the BBB, with an investigation of their post-BBB intra-brain distribution. We utilized an in vitro BBB model to study the rate of BBB permeation of the compounds and their interaction with efflux transporter P-glycoprotein (P-gp). Mitragynine showed higher apical-to-basolateral (A-B, i.e. blood-to-brain side) permeability than 7-hydroxymitragynine. 7-Hydroxymitragynine showed a tendency to efflux, with efflux ratio (B-A/A-B) of 1.39. Both were found to inhibit the P-gp and are also subject to efflux by the P-gp. Assessment of the extent of BBB transport in vivo in rats from unbound brain to plasma concentration ratios (Kp,uu,brain ) revealed extensive efflux of both compounds, with less than 10 percent of unbound mitragynine and 7-hydroxymitragynine in plasma crossing the BBB. By contrast, the extent of intra-brain distribution was significantly different, with mitragynine having 18-fold higher brain tissue uptake in brain slice assay compared with 7-hydroxymitragynine. Mitragynine showed a moderate capacity to accumulate inside brain parenchymal cells, while 7-hydroxymitragynine showed restricted cellular barrier transport. The presented findings from this systematic investigation of brain pharmacokinetics of mitragynine and 7-hydroxymitragynine are essential for design and interpretation of in vivo experiments aiming to establish exposure-response relationship.

Matched MeSH terms: Microvessels/physiology
Expression of Bax and Bcl-2 in tumour cells and blood vessels of breast cancer and their association with angiogenesis and hormonal receptors

Jaafar H, Abdullah S, Murtey MD, Idris FM

Asian Pac J Cancer Prev, 2012;13(8):3857-62.
PMID: 23098483

A total of 96 cases of invasive breast ductal carcinoma were examined for immunohistochemical expression of Bax and Bcl-2 in the epithelial tumor cells and endothelial cells of the blood vessels. We also investigated the association between both proteins in the epithelium in relation to tumor characteristics such as tumor size, grade, lymph node involvement, microvessel density (MVD), hormonal receptors expression and c-erbB-2 overexpression. Bax expression showed a significant association between tumor and endothelial cells (p<0.001) while Bcl-2 expression in tumor cells was inversely associated with that in the endothelial cells (p<0.001). Expression of Bcl-2 in tumor cells was strongly associated with expression of estrogen and progesterone receptors (p=0.003 and p=0.004, respectively). In addition, intratumoral MVD was significantly higher than peritumoral MVD (p<0.001) but not associated with Bax or Bcl-2 expression and other tumor characteristics. We concluded that the number of endothelial cells undergoing apoptosis was in direct linkage with the number of apoptotic tumor cells. Anti-apoptotic activity of the surviving tumor cells appears to propagate cancer progression and this was influenced by the hormonal status of the cells. Tumor angiogenesis was especially promoted in the intratumoral region and angiogenesis was independent of anti-apoptotic activity.

Matched MeSH terms: Microvessels/metabolism; Microvessels/pathology
Characteristics of invasive breast ductal carcinoma, NOS, diagnosed in a tertiary institution in the East Coast of Malaysia with a focus on tumor angiogenesis

Ch'ng ES, Tuan Sharif SE, Jaafar H

Asian Pac J Cancer Prev, 2012;13(9):4445-52.
PMID: 23167359

BACKGROUND: Prognosis of breast cancer depends on classic pathological factors and also tumor angiogenesis. This study aimed to evaluate the clinicopathological factors of breast cancer in a tertiary centre with a focus on the relationship between tumor angiogenesis and clinicopathological factors.
METHODS: Clinicopathological data were retrieved from the archived formal pathology reports for surgical specimens diagnosed as invasive ductal carcinoma, NOS. Microvessels were immunohistochemically stained with anti-CD34 antibody and quantified as microvessel density.
RESULTS: At least 50% of 94 cases of invasive breast ductal carcinoma in the study were advanced stage. The majority had poor prognosis factors such as tumor size larger than 50mm (48.9%), positive lymph node metastasis (60.6%), and tumor grade III (52.1%). Higher percentages of estrogen and progesterone receptor negative cases were recorded (46.8% and 46.8% respectively). Her-2 overexpression cases and triple negative breast cancers constituted 24.5% and 22.3% respectively. Significantly higher microvessel density was observed in the younger patient age group (p=0.012). There were no significant associations between microvessel density and other clinicopathological factors (p>0.05).
CONCLUSIONS: Majority of the breast cancer patients of this institution had advanced stage disease with poorer prognostic factors as compared to other local and western studies. Breast cancer in younger patients might be more proangiogenic.

Matched MeSH terms: Microvessels/metabolism; Microvessels/pathology*
Fulltext Intravascular haemolysis in severe Plasmodium knowlesi malaria: association with endothelial activation, microvascular dysfunction, and acute kidney injury

Barber BE, Grigg MJ, Piera KA, William T, Cooper DJ, Plewes K, et al.

Emerg Microbes Infect, 2018 Jun 06;7(1):106.
PMID: 29872039 DOI: 10.1038/s41426-018-0105-2

Plasmodium knowlesi occurs throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Severe disease in humans is characterised by high parasite biomass, reduced red blood cell deformability, endothelial activation and microvascular dysfunction. However, the roles of intravascular haemolysis and nitric oxide (NO)-dependent endothelial dysfunction, important features of severe falciparum malaria, have not been evaluated, nor their role in acute kidney injury (AKI). In hospitalised Malaysian adults with severe (n = 48) and non-severe (n = 154) knowlesi malaria, and in healthy controls (n = 50), we measured cell-free haemoglobin (CFHb) and assessed associations with the endothelial Weibel-Palade body (WPB) constituents, angiopoietin-2 and osteoprotegerin, endothelial and microvascular function, and other markers of disease severity. CFHb was increased in knowlesi malaria in proportion to disease severity, and to a greater extent than previously reported in severe falciparum malaria patients from the same study cohort. In knowlesi malaria, CFHb was associated with parasitaemia, and independently associated with angiopoietin-2 and osteoprotegerin. As with angiopoietin-2, osteoprotegerin was increased in proportion to disease severity, and independently associated with severity markers including creatinine, lactate, interleukin-6, endothelial cell adhesion molecules ICAM-1 and E-selectin, and impaired microvascular reactivity. Osteoprotegerin was also independently associated with NO-dependent endothelial dysfunction. AKI was found in 88% of those with severe knowlesi malaria. Angiopoietin-2 and osteoprotegerin were both independent risk factors for acute kidney injury. Our findings suggest that haemolysis-mediated endothelial activation and release of WPB constituents is likely a key contributor to end-organ dysfunction, including AKI, in severe knowlesi malaria.

Matched MeSH terms: Microvessels/metabolism; Microvessels/physiopathology*
Fulltext Calcitriol Supplementation Ameliorates Microvascular Endothelial Dysfunction in Vitamin D-Deficient Diabetic Rats by Upregulating the Vascular eNOS Protein Expression and Reducing Oxidative Stress

Wee CL, Mokhtar SS, Singh KKB, Yahaya S, Leung SWS, Rasool AHG

Oxid Med Cell Longev, 2021;2021:3109294.
PMID: 33623633 DOI: 10.1155/2021/3109294

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 μg/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.

Matched MeSH terms: Microvessels/drug effects; Microvessels/physiopathology*
Obesity indices and metabolic markers are related to hs-CRP and adiponectin levels in overweight and obese females

Sanip Z, Ariffin FD, Al-Tahami BA, Sulaiman WA, Rasool AH

Obes Res Clin Pract, 2013 Jul-Aug;7(4):e315-20.
PMID: 24306161 DOI: 10.1016/j.orcp.2012.05.002

Obese subjects had increased serum high sensitivity C-reactive protein (hs-CRP), decreased adiponectin levels, and impaired microvascular endothelial function compared to lean subjects. We investigated the relationships of serum hs-CRP, adiponectin and microvascular endothelial function with obesity indices and metabolic markers in overweight and obese female subjects. Anthropometric profile, body fat composition, biochemical analysis, serum hs-CRP and adiponectin levels, and microvascular endothelial function were measured in 91 female subjects. Microvascular endothelial function was determined using laser Doppler fluximetry and the process of iontophoresis. Mean age and body mass index (BMI) of subjects were 34.88 (7.87) years and 32.93 (4.82) kg/m(2). hs-CRP levels were positively correlated with weight, BMI, waist circumference, hip circumference, body fat and visceral fat. Adiponectin levels were positively correlated with insulin sensitivity index (HOMA-%S), and inversely correlated with waist hip ratio, triglyceride, fasting insulin and insulin resistance index (HOMA-IR). No relationship was seen between microvascular endothelial function and obesity indices, and metabolic markers. In overweight and obese female subjects, hs-CRP levels were correlated with obesity indices while adiponectin levels were inversely correlated with obesity indices and metabolic markers. No significant relationship was seen between microvascular endothelial function with obesity indices and metabolic markers including hs-CRP and adiponectin in female overweight and obese subjects.

Matched MeSH terms: Microvessels/physiopathology
The effects of anti-obesity intervention with orlistat and sibutramine on microvascular endothelial function

Al-Tahami BA, Ismail AA, Bee YT, Awang SA, Salha Wan Abdul Rani WR, Sanip Z, et al.

Clin. Hemorheol. Microcirc., 2015;59(4):323-34.
PMID: 24002121 DOI: 10.3233/CH-131765

INTRODUCTION: Obesity is associated with impaired microvascular endothelial function. We aimed to determine the effects of orlistat and sibutramine treatment on microvascular endothelial function, anthropometric and lipid profile, blood pressure (BP), and heart rate (HR).
METHODS: 76 subjects were recruited and randomized to receive orlistat 120 mg three times daily or sibutramine 10 mg daily for 9 months. Baseline weight, BMI, BP, HR and lipid profile were taken. Microvascular endothelial function was assessed using laser Doppler fluximetry and iontophoresis process. Maximum change (max), percent change (% change) and peak flux (peak) in perfusion to acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis were used to quantify endothelium dependent and independent vasodilatations.
RESULTS: 24 subjects in both groups completed the trial. After treatment, weight and BMI were decreased for both groups. AChmax, ACh % change and ACh peak were increased in orlistat-treated group but no difference was observed for sibutramine-treated group. BP and total cholesterol (TC) were reduced for orlistat-treated group. HR was reduced for orlistat-treated group but was increased in sibutramine-treated group.
CONCLUSION: 9 months treatment with orlistat significantly improved microvascular endothelial function. This was associated with reductions in weight, BMI, BP, HR, TC and low density lipoprotein cholesterol. No effect was seen in microvascular endothelial function with sibutramine.
KEYWORDS: Microvascular endothelial function; obesity; orlistat; sibutramine

Matched MeSH terms: Microvessels/drug effects
Anaerobic respiration: In vitro efficacy of Nitazoxanide against mitochondriate Acanthamoeba castellanii of the T4 genotype

Aqeel Y, Siddiqui R, Farooq M, Khan NA

Exp Parasitol, 2015 Oct;157:170-6.
PMID: 26297676 DOI: 10.1016/j.exppara.2015.08.007

Acanthamoeba is an opportunistic protist pathogen that is responsible for serious human and animal infection. Being one of the most frequently isolated protists from the environment, it is likely that it readily encounters microaerophilic environments. For respiration under anaerobic or low oxygen conditions in several amitochondriate protists, decarboxylation of pyruvate is catalyzed by pyruvate ferredoxin oxidoreductase instead of pyruvate dehydrogenase. In support, Nitazoxanide, an inhibitor of pyruvate ferredoxin oxidoreductase, is effective and non-mutagenic clinically against a range of amitochondriate protists, Giardia intestinalis, Entamoeba histolytica and Trichomonas vaginalis. The overall aim of the present study was to determine in vitro efficacy of Nitazoxanide against Acanthamoeba castellanii. At micromolar concentrations, the findings revealed that Nitazoxanide neither affected A. castellanii growth or viability nor amoeba-mediated host cell monolayer damage in vitro or extracellular proteolytic activities. Similarly, microaerophilic conditions alone had no significant effects. In contrast, microaerophilic conditions together with Nitazoxanide showed amoebicidal effects and inhibited A. castellanii-mediated host cell monolayer damage as well as extracellular proteases. Using encystation assays, it was observed that Nitazoxanide inhibited trophozoite transformation into cysts both under aerophilic and microaerophilic conditions. Furthermore, pre-treatment of cysts with Nitazoxanide inhibited A. castellanii excystation. These findings are important in the identification of potential targets that could be useful against parasite-specific respiration as well as to understand the basic biology of the life cycle of Acanthamoeba.

Matched MeSH terms: Microvessels/cytology
Dual l-Carnosine/Aloe vera Nanophytosomes with Synergistically Enhanced Protective Effects against Methylglyoxal-Induced Angiogenesis Impairment

Darvishi B, Dinarvand R, Mohammadpour H, Kamarul T, Sharifi AM

Mol Pharm, 2021 09 06;18(9):3302-3325.
PMID: 34297586 DOI: 10.1021/acs.molpharmaceut.1c00248

Microvascular complications are among the major outcomes of patients with type II diabetes mellitus, which are the consequences of impaired physiological functioning of small blood vessels and angiogenic responses in these patients. Overproduction and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl byproduct of glycolysis pathway, has been acclaimed as the main inducer of impaired angiogenic responses and microvascular dysfunction in diabetic patients with uncontrolled hyperglycemia. Hence, an effective approach to overcome diabetes-associated microvascular complications is to neutralize the deleterious activity of enhanced the concentration of MGO in the body. Owing to the glycation inhibitory activity of Aloe vera whole extract, and capability of l-carnosine, an endogenous dipeptide, in attenuating MGO's destructive activity, we examined whether application of a combination of l-carnosine and A. vera could be an effective way of synergistically weakening this reactive dicarbonyl's impaired angiogenic effects. Additionally, overcoming the poor cellular uptake and internalization of l-carnosine and A. vera, a nanophytosomal formulation of the physical mixture of two compounds was also established. Although l-carnosine and A. vera at whole studied combination ratios could synergistically enhance viability of human umbilical vein endothelial cells (HUVECs) treated with MGO, the 25:1 w/w ratio was the most effective one among the others (27 ± 0.5% compared to 12 ± 0.3 to 18 ± 0.4%; F (4, 15) = 183.9, P < 0.0001). Developing dual nanophytosomes of l-carnosine/A. vera (25:1) combination ratio, we demonstrated superiority of the nanophytosomal formulation in protecting HUVECs against MGO-induced toxicity following a 24-72 h incubation period (17.3, 15.8, and 12.4% respectively). Moreover, 500 μg/mL concentration of dual l-carnosine/A. vera nanophytosomes exhibited a superior free radical scavenging potency (63 ± 4 RFU vs 83 ± 5 RFU; F (5, 12) = 54.81, P < 0.0001) and nitric oxide synthesizing capacity (26.11 ± 0.19 vs 5.1 ± 0.33; F (5, 12) = 2537, P < 0.0001) compared to their physical combination counterpart. Similarly, 500 μg/mL dual l-carnosine/A. vera nanophytosome-treated HUVECs demonstrated a superior tube formation capacity (15 ± 3 vs 2 ± 0.3; F (5, 12) = 30.87, P < 0.001), wound scratch healing capability (4.92 ± 0.3 vs 3.07 ± 0.3 mm/h; F (5, 12) = 39.21, P < 0.0001), and transwell migration (586 ± 32 vs 394 ± 18; F (5, 12) = 231.8, P < 0.001) and invasion (172 ± 9 vs 115 ± 5; F (5, 12) = 581.1, P < 0.0001) activities compared to the physical combination treated ones. Further confirming the proangiogenic activity of the dual l-carnosine/A. vera nanophytosomes, a significant shift toward expression of proangiogenic genes including HIF-1α, VEGFA, bFGF, KDR, and Ang II was reported in treated HUVECs. Overall, dual l-carnosine/A. vera nanophytosomes could be a potential candidate for attenuating type II DM-associated microvascular complications with an impaired angiogenesis background.

Matched MeSH terms: Microvessels/drug effects
Fulltext Capilliposide B blocks VEGF-induced angiogenesis in vitro in primary human retinal microvascular endothelial cells

Han H, Yang Y, Wu Z, Liu B, Dong L, Deng H, et al.

Biomed Pharmacother, 2021 Jan;133:110999.
PMID: 33227710 DOI: 10.1016/j.biopha.2020.110999

Abnormal angiogenesis is associated with intraocular diseases such as proliferative diabetic retinopathy and neovascular age-related macular degeneration, and current therapies for these eye diseases are not satisfactory. The purpose of this study was to determine whether capilliposide B (CPS-B), a novel oleanane triterpenoid saponin derived from Lysimachia capillipes Hemsl, can inhibit vascular endothelial growth factor (VEGF)-induced angiogenesis signaling events and cellular responses in primary human retinal microvascular endothelial cells (HRECs). Our study revealed that the capilliposide B IC50 for HRECs was 8.5 μM at 72 h and that 1 μM capilliposide B specifically inhibited VEGF-induced activation of VEGFR2 and its downstream signaling enzymes Akt and Erk. In addition, we discovered that this chemical effectively blocked VEGF-stimulated proliferation, migration and tube formation of the HRECs, suggesting that capilliposide B is a promising prophylactic for angiogenesis-associated diseases such as proliferative diabetic retinopathy.

Matched MeSH terms: Microvessels/cytology

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