Maintaining bovine satellite cells stemness through p38 pathway.

Isolating and maintaining the appropriate stem cell for large scale cell culture is essential in tissue engineering or food production. For bovine satellite cells an optimized isolation and purification protocol is lacking and there is also no detailed understanding on the factors that maintain stemness of these cells. Here, we set up a fluorescence-activated cell sorting strategy to enrich bovine satellite cells. We found that p38-MAPK signalling is activated and PAX7 expression is gradually lost during satellite cell proliferation. The p38 inhibitor (SB203580) treatment maintained PAX7 expression but inhibited the fusion of satellite cells in a concentration-dependent way in short-term incubation. The mechanism of p38 inhibition was confirmed by inhibiting canonical p38 signalling, i.e. HSP27. Long-term culture with an appropriate concentration of p38i enhanced the proliferation and PAX7 expression, while the differentiation capacity recovered and was enhanced compared to vehicle control. These studies indicate that bovine satellite cells maintenance depends on cell purity and p38 MAPK signalling. Inhibition of p38 MAPK signaling is a promising strategy to facilitate large scale cell expansion of primary cells for tissue engineering and cultured meat purposes.

Lipid peroxidation in type 2 diabetes: relationship with macrovascular disease?

BACKGROUND: Macrovascular disease is the leading cause of death in diabetes. The increased risk of atherosclerosis in diabetes may be partly explained by increased lipid peroxidation. METHODS: We assessed lipid peroxidation in subjects with type 2 diabetes with (n = 23) and without (n = 23) macrovascular complications versus healthy age-matched controls (n = 13). The diabetic groups were matched for glycemic control (mean HbA1c = 9%), and for age had similar known duration of diabetes. RESULTS: Plasma TBARS were comparable between diabetic subjects with and without macrovascular complications (1.89 +/- 0.32 and 1.81 +/- 0.28 mumol/l) and elevated compared to healthy controls (1.64 +/- 0.26 mumol/l, p = 0.025). Ratios of IgG and IgM antibodies to oxidized vs. native LDL were comparable between diabetic subjects and controls, and also between diabetic subjects with or without macrovascular complications. The lag phase, an index of the resistance of LDL to oxidation, was significantly longer in diabetic patients with macrovascular complications (66 +/- 8 min) vs. those without macrovascular complications and controls (resp. 59 +/- 7 and 56 +/- 7 min, p < 0.05). An explanation may be the frequent use of drugs with possible antioxidant potential, e.g. beta-blocking agents, ACE-inhibitors and calcium entry blockers by these patients. Surprisingly, plasma vitamin E levels were higher in diabetic subjects. CONCLUSIONS: We found no evidence of increased lipid peroxidation in diabetic subjects with macrovascular complications, but an increased resistance to oxidation in this group, probably due to an altered antioxidant status. The increased TBARS level in diabetic subjects contrasts with the other indices of lipid peroxidation and may be related to prevalent hyperglycemia and should therefore be interpreted cautiously.

Breakers of advanced glycation end products restore large artery properties in experimental diabetes.

Glucose and other reducing sugars react with proteins by a nonenzymatic, posttranslational modification process called nonenzymatic glycation. The formation of advanced glycation end products (AGEs) on connective tissue and matrix components accounts largely for the increase in collagen crosslinking that accompanies normal aging and which occurs at an accelerated rate in diabetes, leading to an increase in arterial stiffness. A new class of AGE crosslink "breakers" reacts with and cleaves these covalent, AGE-derived protein crosslinks. Treatment of rats with streptozotocin-induced diabetes with the AGE-breaker ALT-711 for 1-3 weeks reversed the diabetes-induced increase of large artery stiffness as measured by systemic arterial compliance, aortic impedance, and carotid artery compliance and distensibility. These findings will have considerable implications for the treatment of patients with diabetes-related complications and aging.