Extracellular Vesicles: Evolving Factors in Stem Cell Biology

Stem cells are proposed to continuously secrete trophic factors that potentially serve as mediators of autocrine and paracrine activities, associated with reprogramming of the tumor microenvironment, tissue regeneration, and repair. Hitherto, significant efforts have been made to understand the level of underlying paracrine activities influenced by stem cell secreted trophic factors, as little is known about these interactions. Recent findings, however, elucidate this role by reporting the effects of stem cell derived extracellular vesicles (EVs) that mimic the phenotypes of the cells from which they originate. Exchange of genetic information utilizing persistent bidirectional communication mediated by stem cell-EVs could regulate stemness, self-renewal, and differentiation in stem cells and their subpopulations. This review therefore discusses stem cell-EVs as evolving communication factors in stem cell biology, focusing on how they regulate cell fates by inducing persistent and prolonged genetic reprogramming of resident cells in a paracrine fashion. In addition, we address the role of stem cell-secreted vesicles in shaping the tumor microenvironment and immunomodulation and in their ability to stimulate endogenous repair processes during tissue damage. Collectively, these functions ensure an enormous potential for future therapies

PenQuest Volume 1, Number 2

Table of Contents for this Volume: Untitled by Julie Ambrose Night by Judith Gallo Untitled by Judy Gozdur the shamans by Charles Riddles Untitled by Jerry Connell Untitled by Laura Woods Untitled by LEMA Wicked Bird by Laura Jo Last Untitled by Rick Dentos Untitled by Jeni Moody Untitled by Bettie W. Kwibs Untitled by Joann Stagg The Protector Stood by Laura Jo Last Visions of Salome by Charles Riddles Untitled by Thomas Tutten Kennesaw Line by Don Ova-Dunaway Stone Blood by Mary Ellen C. Wofford Untitled by Roger Whitt Jr. Untitled by C. Wingate Untitled by Doug Dorey Untitled by Karen Blumberg Untitled by Beverly Oviatt Untitled by Virginia Shrader The Crapulous Credo of Charles C. by Charles Riddles the brave and the true by David Reed Untitled by Charles Gutierrez Canoe Creek by Patricia Kraft Untitled by Linda Bobinger The Man in the Iron Lung by Patricia Kraft Untitled by Roger Whitt, Jr. Childish Things by Kathleen Gay Untitled by Joseph Avanzini The Lover by Mary S. Aken Untitled by Ann Harrington And He Taketh Away by David Reed Untitled by Mary Graham Untitled by Melody A. Cummons Untitled by Karen Blumberg To The Poets by Judith Gallo Untitled by Ann Harringto

Cholestatic liver injury associated with whey protein and creatine supplements

We present a case of acute cholestatic liver injury associated with the combination of whey protein and creatine supplements. The difficulty of diagnosing drug-induced liver injury is emphasized. The patient is a healthy, 27-year-old man who presented with painless jaundice. He had no occupational exposures to solvents, was not taking prescription medications, and did not use recreational drugs or alcohol. He was an enthusiastic weight-lifter and had been taking creatine for 8 to 9 months and whey protein supplements for 4 weeks prior to the development of symptoms. Laboratory tests revealed elevated total bilirubin (54.7 mg/dL) and alkaline phosphatase (436 U/L), minimally elevated transaminases, and a creatinine of 3.1 mg/dL. Serologic work-up was negative for viral hepatitis and autoimmune liver disease, and Wilson's disease was ruled out. Magnetic resonance cholangiopancreatogram was unremarkable, but a liver biopsy showed marked cholestasis with ductular proliferation. He had dramatic clinical improvement with intravenous fluids and discontinuation of the nutritional supplements. In patients with acute liver injury, clinicians should inquire about dietary supplement usage and consider immediate discontinuation of all unnecessary products. We describe a case of profound jaundice related to a commonly used and reportedly safe combination of such supplements

The association between physical activity and both incident coronary artery calcification and ankle brachial index progression: the multi-ethnic study of atherosclerosis.

ObjectiveBoth coronary artery calcification (CAC) and the ankle brachial index (ABI) are measures of subclinical atherosclerotic disease. The influence of physical activity on the longitudinal change in these measures remains unclear. To assess this relation we examined the association between these measures and self-reported physical activity in the Multi-Ethnic Study of Atherosclerosis (MESA).MethodsAt baseline, the MESA participants were free of clinically evident cardiovascular disease. We included all participants with an ABI between 0.90 and 1.40 (n = 5656). Predictor variables were based on self-reported measures with physical activity being assessed using the Typical Week Physical Activity Survey from which metabolic equivalent-minutes/week of activity were calculated. We focused on physical activity intensity, intentional exercise, sedentary behavior, and conditioning. Incident peripheral artery disease (PAD) was defined as the progression of ABI to values below 0.90 (given the baseline range of 0.90-1.40). Incident CAC was defined as a CAC score >0 Agatston units upon follow up with a baseline score of 0 Agatston units.ResultsMean age of participants was 61 years, 53% were female, and mean body mass index was 28 kg/m(2). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, intentional exercise was protective for incident peripheral artery disease (Relative Risk (RR) = 0.85, 95% Confidence Interval (CI): 0.74-0.98). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, there was a significant association between vigorous PA and incident CAC (RR = 0.97, 95% CI: 0.94-1.00). There was also a significant association between sedentary behavior and increased amount of CAC among participants with CAC at baseline (Δlog (Agatston Units + 25) = 0.027, 95% CI 0.002, 0.052).ConclusionsThese data suggest that there is an association between physical activity/sedentary behavior and the progression of two different measures of subclinical atherosclerotic disease