Biomedical subjects

Michael S Rutenberg

Publications and source records attributed to Michael S Rutenberg.

3 recordsLinked to original sources

PubMed2004

Stem cell plasticity, beyond alchemy.

Cell plasticity is a central issue in stem cell biology. Differentiated somatic nuclei have the flexibility to dedifferentiate when transferred into oocytes or when fused to pluripotent embryonic stem cells. Recent publications also claim that somatic stem cells can convert into developmentally unrelated cell types both in vivo and ex vivo without such drastic cell manipulations. Some of these claims are still controversial, making it difficult for us to determine the reality of somatic stem cell plasticity. Indeed, we have heard enough about the "potentials" of cell plasticity; how much do we know about mechanisms? A fundamental issue in current stem cell biology is to understand the mechanisms underlying cell plasticity. In this short review, we overview three research fields related to cell plasticity: nuclear transfer, transdifferentiation, and cell fusion, with an emphasis on studies of molecular mechanisms underlying cell plasticity.

Adult↗

PubMed2004

Cell fusion and reprogramming: resolving our transdifferences.

Bone marrow-derived cells (BMDCs) can contribute to the regeneration of diverse adult tissues, including brain, liver and heart, following bone marrow transplantation. These unexpected events were initially considered a result of transdifferentiation of BMDCs, supporting the emerging idea of extended plasticity of adult stem cells. Although studies have now clearly demonstrated that spontaneous cell fusion, rather than transdifferentiation, was the primary cause for unexpected cell fate-switches of BMDCs into hepatocytes, Purkinje cells and cardiac myocytes in vivo.

Animals↗

PubMed2004

Differential metabolic effects of saturated versus polyunsaturated fats in ketogenic diets.

Ketogenic diets (KDs) are used for treatment of refractory epilepsy and metabolic disorders. The classic saturated fatty acid-enriched (SAT) KD has a fat:carbohydrate plus protein ratio of 4:1, in which the predominant fats are saturated. We hypothesized that a polyunsaturated fat-enriched (POLY) KD would induce a similar degree of ketosis with less detrimental effects on carbohydrate and lipid metabolism. Twenty healthy adults were randomized to two different weight-maintaining KDs for 5 d. Diets were 70% fat, 15% carbohydrate, and 15% protein. The fat contents were 60 or 15% saturated, 15 or 60% polyunsaturated, and 25% monounsaturated for SAT and POLY, respectively. Changes in serum beta-hydroxybutyrate, insulin sensitivity (S(I)), and lipid profiles were measured. Mean circulating beta-hydroxybutyrate levels increased 8.4 mg/dl in the POLY group (P = 0.0004), compared with 3.1 mg/dl in the SAT group (P = 0.07). S(I) increased significantly in the POLY group (P = 0.02), whereas total and low-density lipoprotein cholesterol increased significantly in the SAT group (both P = 0.002). These data demonstrate that a short-term POLY KD induces a greater level of ketosis and improves S(I), without adversely affecting total and low-density lipoprotein cholesterol, compared with a traditional SAT KD. Thus, a POLY KD may be superior to a classical SAT KD for chronic administration.

3-Hydroxybutyric Acid↗