Gradients in the in vivo intestinal stem cell compartment and their in vitro recapitulation in mimetic platforms

peer-reviewedIntestinal tissue, and specifically its mucosal layer, is a complex and gradient-rich environment. Gradients of soluble factor (BMP, Noggin, Notch, Hedgehog, and Wnt), insoluble extracellular matrix proteins (laminins, collagens, fibronectin, and their cognate receptors), stromal stiffness, oxygenation, and sheer stress induced by luminal fluid flow at the crypt-villus axis controls and supports healthy intestinal tissue homeostasis. However, due to current technological challenges, very few of these features have so far been included in in vitro intestinal tissue mimetic platforms. In this review, the tightly defined and dynamic microenvironment of the intestinal tissue is presented in detail. Additionally, the authors introduce the current state-of-the-art intestinal tissue mimetic platforms, as well as the design drawbacks and challenges they face while attempting to capture the complexity of the intestinal tissue’s physiology. Finally, the compositions of an “idealized” mimetic system is presented to guide future developmental efforts

Barriers to HIV Medication Adherence: Examining Distinct Anxiety and Depression Symptoms among Women Living with HIV Who Experienced Childhood Sexual Abuse

Experiencing sexual violence in childhood or adolescence is highly prevalent among some women living with HIV, often resulting in anxiety and depression symptoms in adulthood. Anxiety and depression have been associated with HIV medication nonadherence, yet little research has assessed distinct components of anxiety and depression as risk factors of HIV medication nonadherence. The current study examined distinct symptom components of anxiety and depression as predictors of HIV medication nonadherence among women living with HIV and childhood sexual abuse enrolled in a coping intervention. This secondary analysis included a sample of 85 women living with HIV and childhood sexual abuse and being prescribed antiretroviral medication who completed measures on anxiety, depression, and medication adherence. Results from a logistic regression analysis suggest that distinct components of anxiety may be related to medication nonadherence among this population. Targeted mental health interventions for this population may increase adherence to antiretroviral medication

Can behavioral theory inform the understanding of depression and medication nonadherence among HIV-positive substance users?

Medication adherence is highly predictive of health outcomes across chronic conditions, particularly HIV/AIDS. Depression is consistently associated with worse adherence, yet few studies have sought to understand how depression relates to adherence. This study tested three components of behavioral depression theory—goal-directed activation, positive reinforcement, and environmental punishment—as potential indirect effects in the relation between depressive symptoms and medication nonadherence among low-income, predominantly African American substance users (n = 83). Medication nonadherence was assessed as frequency of doses missed across common reasons for nonadherence. Non-parametric bootstrapping was used to evaluate the indirect effects. Of the three intermediary variables, there was only an indirect effect of environmental punishment; depressive symptoms were associated with greater nonadherence through greater environmental punishment. Goal-directed activation and positive reinforcement were unrelated to adherence. Findings suggest the importance of environmental punishment in the relation between depression and medication adherence and may inform future intervention efforts for this population