Upright water-based exercise to improve cardiovascular and metabolic health: a qualitative review.

Research regarding the benefits of exercise for cardiovascular and metabolic health is extensive and well-documented. However, weight-bearing exercise may not be suitable for individuals with orthopaedic or musculoskeletal limitations, excess adiposity or other medical conditions. Water-based exercise may provide an attractive alternative to land-based exercise for achieving improved health and fitness in these populations. Although swimming is a popular form of water-based exercise it requires specific skills and is often undertaken at intensities that may not be safely prescribed in patient populations. Therefore upright, water-based exercise has been suggested as a viable water-based alternative. However, surprisingly little is known about the effects of upright water-based exercise on improvements in cardiovascular and metabolic health. Limited evidence from water-based studies indicate that regular deep or shallow water exercise can exert beneficial effects on cardiorespiratory fitness, strength, and body fat distribution. However, the impacts of water-based exercise on lipid profile, bodyweight, and carbohydrate metabolism are still unclear. Further studies are warranted to establish the effects of non-swimming, water-based exercise on cardiometabolic risks in humans.

Thiols stabilize cobblestone morphology of cultured mesothelial cells.

Cellular thiols including GSH (glutathione) and L-Cys (L-cysteine) are essential for cell signalling, growth and differentiation. L-Cys is derived from the extracellular thiol pool and is the rate-limiting compound for intracellular GSH biosynthesis. The present study investigated the effect of thiol-supplemented medium on cell growth, phenotype and total GSH of cultured hPMCs (human peritoneal mesothelial cells). Cells were cultured in medium M199 supplemented with 2% serum, with 'plus' or without 'minus' L-Cys and compared with medium supplemented with either ß-ME (ß-mercaptoethanol) (0.25 mmol/l) or the receptor tyrosine kinase ligand EGF (epidermal growth factor, 100 ng/ml). ß-ME produced a disproportionate increase in total GSH compared with L-Cys and other thiols tested [(procysteine (2-oxothiazolidine-4-carboxylic acid) or NAC (N-acetyl-L-cysteine)], while growth and morphology were identical. Cell behaviour of primary hPMCs is characterized by the transition of fibroblastoid to cobblestone morphology during early passage. L-Cys and ß-ME promoted a rapid MET (mesenchymal-to-epithelial transition) within 3 days of culture, confirmed by the presence of cobblestone cells, intact organelles, abundant microvilli, primary cilia and cortical actin. In contrast, EGF produced a biphasic response consisting of delayed growth and retention of a fibroblastoid morphology. During a rapid log phase of growth, MET was accompanied by rapid catch-up growth. Thiols may stabilize the epithelial phenotype by engaging redox-sensitive receptors and transcription factors that modulate differentiation. These data may benefit researchers working on thiol-mediated cell differentiation and strategies to regenerate damage to serosal membranes.

Formaldehyde scavenging from peritoneal dialysis solutions using reduced aminothiol compounds.

BACKGROUND: Aldehydes were identified in clinical solutions, including peritoneal dialysis (PD) and cryoprotection solutions, which were used to freeze cells, tissues and embryos. Aldehydes are associated with increased cellular injury and may contribute to peritoneal membrane damage that occurs in patients on peritoneal dialysis. Recently, it was demonstrated that aldehydes could be 'scavenged' from these solutions by using aminothiol compounds. Although aldehydes were removed during the scavenging process, the kinetics of scavenging and the products formed were not characterized. METHODS: Proton nuclear magnetic resonance (NMR) spectroscopy was used to investigate formaldehyde scavenging from an artificial PD solution supplemented with aminothiol compounds, cysteamine or l-cysteine. Artificial PD solutions were formulated on the basis of commercial PD solutions and consisted of 132 mmol/L NaCl, 0.25 mmol/L MgCl2, 1.25 mmol/L CaCl2, and buffered with lactate (4.0 mmol/L) and lacked d-glucose. Formaldehyde scavenging was a two-step process involving an intermediate step followed by the formation of stable thiazolidine compounds. These included the derivatives of cysteamine and l-cysteine; thiazolidine and thiazolidine-4-carboxylic acid, respectively. CONCLUSION: Scavenging with aminothiol compounds masked the destructive carbonyl group (C = O) of formaldehyde and formed a compound that has antioxidant properties. The addition of aminothiol compounds may improve the biocompatibility of commercial PD solutions.

Cultured peritoneal mesothelial cells exhibit apical primary cilia.

This study examined primary cilia on cultured human and rabbit peritoneal mesothelial cells (PMC) and investigated factors that influence ciliary expression. Primary cilia were examined with indirect immunocytochemistry, laser scanning confocal microscopy and scanning electron microscopy. Ciliary expression was evaluated in cultures with or without l-cysteine (0.25 mM) or exposure to Ca(2+)-free Krebs-Ringer solution supplemented with EGTA, 0.5 mM. This treatment disrupted cell monolayer integrity. Cilia were counted and normalized to total cell counts using NIH image. Primary cilia were identified on both human and rabbit PMC. Cells treated with l-cysteine expressed significantly more cilia compared with monolayers deprived of l-cysteine. Exposure to Ca(2+)-free Krebs-Ringer solution significantly reduced cilia (5.9+/-1.0%, n=7). Although ciliary expression could be augmented with l-cysteine, approximately 60% of human PMC and 84% of rabbit PMC did not exhibit cilia. Together, these data show that monolayers of PMC express apical cilia that can be augmented with l-cysteine, independently of increased cell density.