RESUMEN
Youth living with HIV (YLH) experience multiple disease-related stresses along with the same structural and developmental challenges faced by their uninfected peers; alcohol use among YLH represents a risk behavior by virtue of potential effects on youth health and increased likelihood of engaging in unprotected sex while drinking alcohol. Research aimed at better understanding the interplay of individual- and neighborhood-level influences on alcohol use for YLH is needed to inform interventions. This study examined whether socioeconomic disadvantage (SED) and social support influence, independently and through interaction, alcohol use in YLH. Data from the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) consisted of YLH across 538 neighborhoods in the United States who acquired HIV behaviorally. Neighborhood-specific data were compiled from the 2010 U.S. Census Bureau and matched with individual-level data from the ATN (N = 1,357) to examine effects that contribute to variation in frequency of alcohol use. Other drug use, being male, being non-Black, and older age were associated with greater alcohol use. Higher social support was negatively associated with alcohol use frequency. A cross-level interaction indicated that the association found between decreasing social support and increasing alcohol use frequency was weakened in areas with lower SED. Implications are discussed.
Asunto(s)
Consumo de Bebidas Alcohólicas/epidemiología , Infecciones por VIH , Pobreza , Características de la Residencia , Apoyo Social , Adolescente , Adulto , Femenino , Humanos , Masculino , Puerto Rico/epidemiología , Trastornos Relacionados con Sustancias/epidemiología , Estados Unidos/epidemiología , Adulto JovenRESUMEN
Background: The ability to create tissues using pluripotent stem cells to repair or replace tissue lost due to damage, i.e. regenerative medicine, is developing very rapidly in many fields of human medicine. For veterinarians, regenerative medicine has focused mainly in the use of stem cells for arthritis and tendon ligament repair, indicating a need for treating musculoskeletal injuries. Our objective is to review the available approaches being used to derive pluripotent stem cells and discuss their potential use for regenerative medicine in the horse. Review: Adult adipose- and bone marrow-derived mesenchymal stem cells (MSC) are being used in practice to treat injuries in horses. However, there is scarce scientific evidence of their effectiveness and little is known of the mechanisms by which such cell preparations improve the healing process. For instance, although early healing response of articular cartilage injury was improved by treatment with injection of MSC, they did not enhance the long-term tissue response, indicating that cell proliferation was attenuated. Better protocols for the isolation and clinical testing of equine MSC are required to confirm healing properties. In contrast to MSC, embryonic stem cells (ESC) derived from the inner-cell- mass (ICM) of blastocyst stage embryos carry the ability to proliferate indefinitely in vitro and, given appropriate and favorable conditions, can differentiate into any tissue in the body. Parthenogenesis (PG) and somatic cell nuclear transfer (SCNT) are used to obtain a genetic match to the host animal and, thereby, eliminate the risk of inducing immune rejection of the grafted tissue. However, apart from the typical markers of pluripotency, equine ESC also express markers of trophoblastic tissues, indicating that they are different and possibly less able to differentiate than the ESC lines obtained in other species. Consequently, further studies are underway to identify conditions to obtain fully pluripotent ESC lines from equine SCNT embryos. To overcome the limitations of ESC lines derived from equine embryos, induced pluripotent stem cells (iPSC) were derived using a piggyBac transposon-based method to deliver transgenes containing the reprogramming factors Oct4, Sox2, Klf4 and c-Myc, expressed in a temporally controlled fashion. Our established fetal-derived iPSC lines express hallmark pluripotency markers, display a stable karyotype after prolonged culture, and are able to form teratomas in immunodeficient mice containing tissues from all three embryonic layers. By establishing a protocol for deriving stable iPSC lines in the horse, we expect that new opportunities will be shortly developed for regenerative therapies in this species. Conclusion: It is possible to derive autologous pluripotent stem cells in horses by using both ESC and iPSC-derived approaches. Although ESC lines are generally the gold standard of pluripotency, further research is required to improve the proliferative and pluripotency characteristics for clinical applications. On the other hand, equine iPSC show excellent stability during prolonged in vitro culture and have the capacity to differentiate into the three germ layers in vivo, suggesting that they could soon be used in pre-clinical trials. Therefore, further studies need to be performed to establish reliable protocols for assessing the regenerative properties of iPS and ESC for equine muscle-skeletal injuries.