Effects of polyphenol supplementation to in vitro antioxidant potential of citrus juices

Food preparations containing substances with antioxidant activity have considerably aroused the interest of consumers, which has led to the marketing of a number of dietary supplements such as resveratrol, hesperidin or chlorogenic acid. On the other hand, natural antioxidants present in citrus fruit juices, together with dietary supplements, could contribute to an enhancement of their antioxidant properties and, in turn, alter their physiological impacts. The aim of the study was to evaluate the effect of supplementation of freshly squeezed citrus juices with resveratrol, hesperidin and chlorogenic acid on the in vitro antioxidant potential of the juices. The solutions of juices, selected polyphenols and the mixtures of solutions of juices and solution of polyphenols were analyzed to determine total polyphenol concentration using the Fast Blue method and total antioxidant potential by the ABTS method. As a result three different types of interactions were established: synergistic of chlorogenic acid which additionally increased the antioxidant potential by 35 - 38% over theoretical predictions, additive - after addition of resveratrol, and antagonistic - in the case of hesperidin. While the antioxidant potential was substantially higher in the mixture of mandarin juice with chlorogenic acid, the measured total polyphenol concentration decreased. Also a considerable decrease in the concentration of polyphenols was measured in the mixtures of mandarin and orange juices with resveratrol, all these possibly due to the sensitivity to other substances present in juices of the analytical method applied. A correlation between antioxidant potential of all examined solutions and total polyphenol concentration was found (r2 = 0.8879)

Adipose-Derived Stem Cells undergo differentiation after co-culture with porcine Limbal Epithelial Stem Cells

Mesenchymal stem cells (MSCs) are objects of interest in regenerative medicine. They are used for various therapies such as for the regeneration of bone, chondrocytes and other tissues. Adipose derived stem cells (ADSCs) inter alia are particularly easy to access, they are relatively abundant in fat tissue. ADSCs could be differentiated into many types of cells. To date, it has been proven that ADSCs only differentiate into mesodermal cell lineages. In this study, we present the differentiation of ADSCs into the corneal epithelium. Human ADSCs were placed in a co-culture with porcine limbal epithelial stem cells (LESCs). After 14 days of cultivation, total RNA was extracted for the analysis of the molecular markers (expression of genes of interest). The gene expression was assessed by real-time RT-qPCR. The expression of the surface molecular markers of ADSCs is modulated after co-culturing. We have observed the decrease in CD73, CD90 and CD105 mRNA expression, while the expression of mRNA coding for CK3 and CK12 mRNA was increased in ADSCs co-cultured with porcine limbal epithelial stem cells as compared to the control. We conclude that the coculture of LESCs and ADSCs changed ADSCs’ molecular markers gene expression indicating initiation of differentiation towards limbal cells

Characterization of porcine endogenous retrovirus expression in neonatal and adult pig pancreatic islets

BACKGROUND: Pig islets represent an alternative to the current modes of treatment for patients with diabetes. However, the concerns over pathogen transmission including that of PERV limit their immediate, widespread usage in humans. It has been previously demonstrated that PERV copy number and particularly expression levels can vary considerably between individuals and within different tissues of a single animal. In general, expression levels have been found to be particularly low in the pancreas compared to other porcine tissues suggesting a reduced risk associated with the use of this tissue. Data regarding this crucial aspect, however, remain limited and little is known about PERV status of islets themselves, which represent the final product to be transplanted. In addition, comparative analysis of the PERV status of neonatal piglets with adults is important as they are increasingly considered as potential islet donors for xenotransplantation. METHODS: Tissue samples from 51 neonatal piglets (age between 14 and 21 days) and 29 adult pigs were collected from Belgian landrace pigs used for pancreas procurement and islet isolation. Tissue biopsies were used to extract DNA for PERV copy number quantification by qPCR and RNA for PERV expression by qRT-PCR. RESULTS: As expected, PERV expression demonstrated great variation and was significantly lower in pancreas compared to other tissues. More importantly, PERV RNA expression was found to be specifically enriched in pancreatic islets reaching values similar to those found in other tissues such as liver and kidney. Interestingly, this expression was not coupled with the detection of reverse transcriptase in islet cultures or indeed detection of PERV virus. Lung, spleen, and lymph node consistently showed the highest levels of PERV expression. Comparison of PERV in neonatal and adult pigs showed that copy number did not vary significantly from birth to adulthood. PERV expression on the other hand was significantly lower in neonatal pig islets compared to adult islets and did not increase over the period of culture. CONCLUSION: Our study confirms the low level of PERV expression in whole pancreas in a large population of both neonatal and adult pigs (n=80). The level of PERV expression was however higher in the endocrine tissue than in the exocrine cells. There was no correlation between PERV status in donor PBMCs and islet cells, and no evidence of active replication in in vitro regardless of PERV expression in islet cells. Moreover, neonatal pig islets were found to have significantly lower PERV expression compared to adult islets. Neonatal islets have been suggested as the best choice for xenotransplantation in terms of economic and procurement considerations; the PERV status reported here would also potentially support their use

Porcine Endogenous Retroviruses in Xenotransplantation—Molecular Aspects

In the context of the shortage of organs and other tissues for use in human transplantation, xenotransplantation procedures with material taken from pigs have come under increased consideration. However, there are unclear consequences of the potential transmission of porcine pathogens to humans. Of particular concern are porcine endogenous retroviruses (PERVs). Three subtypes of PERV have been identified, of which PERV-A and PERV-B have the ability to infect human cells in vitro. The PERV-C subtype does not show this ability but recombinant PERV-A/C forms have demonstrated infectivity in human cells. In view of the risk presented by these observations, the International Xenotransplantation Association recently indicated the existence of four strategies to prevent transmission of PERVs. This article focuses on the molecular aspects of PERV infection in xenotransplantation and reviews the techniques available for the detection of PERV DNA, RNA, reverse transcriptase activity and proteins, and anti-PERV antibodies to enable carrying out these recommendations. These methods could be used to evaluate the risk of PERV transmission in human recipients, enhance the effectiveness and reliability of monitoring procedures, and stimulate discussion on the development of improved, more sensitive methods for the detection of PERVs in the future

Adjustable high voltage source

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