Structural data and immunomodulatory properties of a water-soluble heteroglycan extracted from the mycelium of an Italian isolate of Ganoderma lucidum.

Mushrooms produce a wide range of bioactive polysaccharides, different from each other in chemical structure and biological effects. In the last years, the idea to develop functional foods or drugs containing fungal polysaccharides is attracting great attention. Fruiting bodies of Basidiomycetes Ganoderma lucidum are commonly used in Oriental medicine to treat several disorders. G. lucidum polysaccharides - mainly ß-glucans and heteroglycans - have numerous biological properties such as antitumour and immunomodulatory activities. This report shows, by gene expression analyses and bioenergetic assays, immunomodulatory properties and capacity to improve glucose metabolism of a water-soluble heteroglycan extracted from mycelium of an Italian isolate of G. lucidum. The findings suggest the use of the heteroglycan as probiotic or ingredient in functional foods, being easy to produce and disperse in a food matrix thanks to its water-solubility. Heteroglycan could exert protective effects in pro-inflammatory conditions and benefits for people characterised by suppressed immune response.

The Effects of Vaccinium myrtillus Extract on Hamster Pial Microcirculation during Hypoperfusion-Reperfusion Injury.

INTRODUCTION: The present study was aimed to assess the in vivo hamster pial microvessel alterations due to 30 min transient bilateral common carotid artery occlusion (BCCAO) and reperfusion (60 min); moreover, the neuroprotective effects of Vaccinium myrtillus extract, containing 34.7% of anthocyanins, were investigated. MATERIALS AND METHODS: Two groups of male hamsters were used: the first fed with control diet and the other with Vaccinium myrtillus supplemented diet. Hamster pial microcirculation was visualized by fluorescence microscopy through an open cranial window. Pial arterioles were classified according to Strahler's method. RESULTS: In age-matched control diet-fed hamsters, BCCAO caused a decrease in diameter of all arterioles. At the end of reperfusion, the reduction of diameter in order 3 arterioles was by 8.4 ± 3.1%, 10.8 ± 2.3% and 12.1 ± 1.1% of baseline in the 2, 4 and 6 month control diet-fed hamsters, respectively. Microvascular permeability and leukocyte adhesion were markedly enhanced, while perfused capillary length (PCL) decreased. The response to acetylcholine and papaverine topical application was impaired; 2'-7'-dichlorofluoresceine-diacetate assay demonstrated a significant ROS production. At the end of BCCAO, in age-matched Vaccinium myrtillussupplemented diet-fed hamsters, the arteriolar diameter did not significantly change compared to baseline. After 60 min reperfusion, order 3 arterioles dilated by 9.3 ± 2.4%, 10.6 ± 3.1% and 11.8 ± 2.7% of baseline in the 2, 4 and 6 month Vaccinium myrtillus supplemented diet-fed hamsters, respectively. Microvascular leakage and leukocyte adhesion were significantly reduced in all groups according to the time-dependent treatment, when compared with the age-matched control diet-fed hamsters. Similarly, the reduction in PCL was progressively prevented. Finally, the response to acetylcholine and papaverine topical application was preserved and there was no significant increase in ROS production in all groups. CONCLUSIONS: In conclusion, Vaccinium myrtillusextract protected pial microcirculation during hypoperfusion-reperfusion, preventing vasoconstriction, microvascular permeability, leukocyte adhesion, reduction in PCL and preserving the endothelium function.

Effects of bone marrow mesenchymal stem cells (BM-MSCs) on rat pial microvascular remodeling after transient middle cerebral artery occlusion.

Previous studies have shown that the pial microcirculation remodeling improves neurological outcome after middle cerebral artery occlusion (MCAO), accompanied by higher expression of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), modulating in vivo angiogenesis. This study was aimed to assess the effects of bone marrow mesenchymal stem cells (BM-MSCs) infused after MCAO on rat pial microcirculation. Animals were subjected to 2 h MCAO followed by BM-MSCs infusion into internal carotid artery. Pial microcirculation was observed at different reperfusion times by fluorescence microscopy. Geometric characteristics of arteriolar networks, permeability increase, leukocyte adhesion, perfused capillary density, VEGF, and endothelial nitric oxide synthase (e-NOS) expression were evaluated. Green fluorescent protein (GFP)-BM-MSCs were used to evaluate their distribution and cell phenotype development during reperfusion. BM-MSCs stimulated a geometric rearrangement of pial networks with formation of new anastomotic vessels sprouting from preexistent arterioles in the penumbra at 7-14-28 days of reperfusion. At the same time VEGF and eNOS expression increased. GFP-BM-MSCs appear to be involved in endothelial and smooth muscle cell programming in the infarcted area. In conclusion, transient MCAO induced pial vascular remodeling characterized by arteriolar anastomotic arcades (originated from preexistent arterioles in penumbra area) able to overlap the ischemic core supplying blood to the neuronal tissue. BM-MSCs appear to accelerate angiogenic processes facilitating new vessel formation; this mechanism was promoted by an increase in VEGF and eNOS expression.

Pial microvascular responses induced by transient bilateral common carotid artery occlusion in Zucker rats.

This study was aimed to assess the in vivo geometric and functional characteristics of lean Zucker (ZL) and obese Zucker rat (ZO) pial microvascular networks and to evaluate the vascular responses to cerebral hypoperfusion-reperfusion. Rat pial microcirculation was observed by fluorescence microscopy through a closed cranial window. Bilateral common carotid artery occlusion (BCCAO) lasted 30 min and reperfusion 60 min. Arterioles were classified according to Strahler's ordering scheme. Arteriolar diameter was determined by computer assisted-method as well as permeability increase, leukocyte adhesion and perfused capillary length. Neuronal damage was evaluated by TTC staining. ZO rats did not show order 5 vessels; ZO pial arterioles showed high asymmetry in the largest vessels and reduced number of branchings compared with those detected in ZL and Wistar rats. BCCAO and reperfusion caused more severe microvascular damages in ZO compared with ZL and Wistar rats. Vascular responses to acetylcholine and papaverine in ZO rats were significantly reduced compared with Wistar and ZL rats under baseline condition and at the end of reperfusion. Moreover, ZO rats showed more pronounced lesion in the cortex and striatum. Obesity and hyperglycemia could increase vascular remodeling in cerebral networks, with elevated risk of adverse outcome after brain hypoperfusion-reperfusion.

Microvascular responses to aldosterone in hamster cheek pouch microcirculation.

The aim of the present study was to assess the in vivo effects of aldosterone topically applied on the hamster cheek pouch microcirculation under baseline conditions or during ischemia-reperfusion. Male Syrian hamsters were anesthetized, tracheotomized and intubated. They were studied under baseline conditions or submitted to ischemia-reperfusion. Cheek pouch microvessels were visualized by fluorescence microscopy. Microvascular parameters were determined by computerized methods. Under baseline conditions, aldosterone (0.2, 0.5, 2.4 µM/L/2 min) induced dose-dependent constriction of all arterioles within 2.0 ± 0.5 min of administration. Diameter reduction was in the same range in smaller arterioles: A3 ones constricted by 24 ± 3% of baseline (at the highest dose). Aldosterone applied prior to ischemia and at reperfusion caused arteriolar constriction, marked microvascular permeability (0.66 ± 0.03 Normalized Grey Level), reduction in perfused capillary (-70 ± 4% of baseline) and leukocyte adhesion. All changes were statistically significant compared with ischemic animals. Potassium canrenoate (mineralcorticoid receptor inhibitor) prior to aldosterone did not abolish the aldosterone-induced effects, while valsartan (angiotensin II AT1 receptor inhibitor) prior to aldosterone ameliorated microvascular ischemia-reperfusion injury. In conclusion, aldosterone determined dose-dependent arteriolar constriction likely by angiotensin II type-1 receptor activation (non-genomic mechanism) worsening the effects of ischemia-reperfusion on capillary perfusion, while protecting from free radical formation.