Graphene supports in vitro proliferation and osteogenic differentiation of goat adult mesenchymal stem cells: potential for bone tissue engineering

Current treatments for bone loss injuries involve autologous and allogenic bone grafts, metal alloys and ceramics. Although these therapies have proved useful, they suffer from inherent challenges, and hence, an adequate bone replacement therapy has not yet been found. We hypothesize that graphene may be a useful nanoscaffold for mesenchymal stem cells and will promote proliferation and differentiation into bone progenitor cells. In this study, we evaluate graphene, a biocompatible inert nanomaterial, for its effect on in vitro growth and differentiation of goat adult mesenchymal stem cells. Cell proliferation and differentiation are compared between polystyrene‐coated tissue culture plates and graphene‐coated plates. Graphitic materials are cytocompatible and support cell adhesion and proliferation. Importantly, cells seeded on to oxidized graphene films undergo osteogenic differentiation in fetal bovine serum‐containing medium without the addition of any glucocorticoid or specific growth factors. These findings support graphene's potential to act as an osteoinducer and a vehicle to deliver mesenchymal stem cells, and suggest that the combination of graphene and goat mesenchymal stem cells provides a promising construct for bone tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd.     

Positive and negative effects of glitazones in carcinogenesis: Experimental models vs. clinical practice

Diabetes increases cancer risk, which may be modulated by careful choice of treatment. Experimental reports showed efficacy of glitazones in various in vitro and in vivo models of carcinogenesis, but procarcinogenic effects in some models were reported too, and, similarly, data on cancer incidence in glitazone users are inconsistent. This review summarizes oncostatic effects of glitazones in preclinical and clinical studies and brings a brief summary of their impact on cancer risk in diabetic patients, with a focus on the association between pioglitazone use and bladder cancer.     

Human epithelial growth factor receptor 2[Ile655Val] polymorphism and risk of breast fibroadenoma.

Studies on the association between the Ile to Val polymorphism at codon 655 of the human epithelial growth factor receptor 2 (HER-2) gene and susceptibility to breast cancer have been reported for almost all ethnic populations, with both positive or negative conclusions. No study, however, has yet been focused on the possible association between this gene and its predisposition to benign breast lesions, especially on risk for fibroadenoma. We aimed to study the association of the single nucleotide polymorphism V655 HER-2 gene polymorphism with histologically verified breast fibroadenoma risk. We conducted a molecular epidemiological case-control study of 70 breast fibroadenoma cases without cellular atypia and 172 healthy female controls. We found that the Val variant allele and genotype frequency of this polymorphism is higher in cases with fibroadenoma; however, this difference was not significant (allele Val 655: 27.86 and 22.67% in fibroadenoma and controls, respectively; genotype Ile/Val: 35.71 and 38.37% and Val/Val: 10.0 and 3.49% in fibroadenoma and controls, respectively). Applying logistic regression analysis, we found an increased risk of fibroadenoma formation in carriers of the Val allele (odds ratio = 1.17; 95% confidence interval = 0.67-2.05), in which the highest risk was associated with homozygous genotype (odds ratio = 3.07; 95% confidence interval = 0.97-9.72), but this risk was not significant. Stratification by age (cut-off 45 years) revealed the highest risk of fibroadenoma among young women homozygous for the Val allele (odds ratio = 3.30). The risk, however, was slightly increased (odds ratio = 1.24) among older carriers of the aberrant allele in their genotype as well, but it was not significant. In spite of insignificant differences, our results indicate that HER-2 Ile655Val polymorphism, especially in a homozygous form might play some role in the etiology of breast fibroadenoma formation. The significance of this susceptibility, however, will have to be verified by larger studies.     

Longitudinal in vivo MRI of alterations in perilesional tissue after transient ischemic stroke in rats

Spontaneous restoration of function after stroke is associated with remodelling of functional neuronal networks in and around the ischemic lesion. However, the spatiotemporal profile of structural alterations in (peri)lesional tissue in relation to post-stroke recovery of neuronal function remains largely to be elucidated.We performed neurological testing in combination with in vivo serial T₂-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to assess functional recovery in relation to longitudinal changes in tissue integrity from 3 h up to 9 weeks after experimental unilateral stroke in rats (n = 7). Subsequently, to evaluate perilesional neuronal connectivity, we conducted manganese-enhanced MRI after MnCl₂ injection in cortical tissue at the boundary of the lesion at 10 weeks post-stroke (n = 5). All animals showed significant improvement of neurological function over time. Normalization of tissue T₂ and fractional diffusion anisotropy (FA) after significant subacute change was observed in cortical and subcortical lesion borderzones between 3 and 9 weeks post-stroke. Progressive FA increase above baseline levels was detected in perilesional white matter areas (n = 4). In these animals particularly, significant manganese enhancement appeared within the neuronal network around the chronic lesion, including areas that were part of the lesion at day 3 post-stroke. This longitudinal multi-parametric MRI study suggests that resolution of early ischemic damage and reorganization of white matter in perilesional tissue is chronically accompanied by preservation or restoration of neuronal connectivity, which may significantly contribute to post-stroke functional recovery.     

In vivo study of propolis supplementation effects on antioxidative status and red blood cells

In vivo study has been conducted on 47 healthy women and men in order to investigate whether daily intake of powdered propolis extract during 30 days has any influence on the following blood parameters: activity of superoxide dismutase, glutathione peroxidase and catalase, concentration of plasma malondialdehyde, total cholesterol, low- and high-density lipoprotein cholesterol, triglycerides, glucose, uric acid, ferritin and transferrin, together with routine red blood cell parameters.

The effect of daily propolis intake seems to be time and gender related. For the men test group after the initial 15 days of propolis treatment, 23.2% (p = 0.005) decrease in concentration of malondialdehyde was observed. After 30 days of treatment, statistically significant (p = 0.010) 20.9% increase in superoxide dismutase activity and change in some of the red blood cell parameters were detected. For the women test group, the propolis treatment did not induce a change in any of the measured parameters.     

Correspondence between altered functional and structural connectivity in the contralesional sensorimotor cortex after unilateral stroke in rats: a combined resting-state functional MRI and manganese-enhanced MRI study

This study shows a significant correlation between functional connectivity, as measured with resting-state functional magnetic resonance imaging (MRI), and neuroanatomical connectivity, as measured with manganese-enhanced MRI, in rats at 10 weeks after unilateral stroke and in age-matched controls. Reduced interhemispheric functional connectivity between the contralesional primary motor cortex (M1) and ipsilesional sensorimotor cortical regions was accompanied by a decrease in transcallosal manganese transfer from contralesional M1 to the ipsilesional sensorimotor cortex after a large unilateral stroke. Increased intrahemispheric functional connectivity in the contralesional sensorimotor cortex was associated with locally enhanced neuroanatomical tracer uptake, which underlines the strong link between functional and structural reorganization of neuronal networks after stroke.