Anaemia in chronic heart failure: more awareness is required.

AIMS: To determine the characteristics of anaemic patients, how well anaemia is investigated and its contributing factors in patients with chronic heart failure (CHF). METHODS: Retrospective analysis of longitudinal data collected during routine management of patients admitted with CHF at an Australian tertiary hospital. One thousand and twenty-one patients admitted with CHF between 1997 and 2005 were included. Anaemia was defined as a haemoglobin concentration <110 g/L. Data were compared between anaemic and non-anaemic patients. RESULTS: The prevalence of anaemia among patients with CHF was 20.3% in our study. These patients were more likely to be older, female, and have a higher prevalence of chronic renal failure and peripheral vascular disease. Despite previous studies reporting a higher mortality rate among CHF patients with anaemia, only 60% of patients had basic investigations for anaemia (i.e. iron studies, vitamin B12, folate and thyroid function testing). The cause of anaemia is usually multifactorial with 63.8% of patients having at least two factors contributing to their anaemia. Chronic renal failure, iron deficiency and anaemia of chronic disease were the most common contributors. These factors were not predicted based on abnormalities in mean corpuscular volume. Patients with anaemia had a longer length of stay in hospital. CONCLUSIONS: Anaemia in patients with CHF is common but not well investigated. The aetiology of anaemia is usually multifactorial and not easily predicted. Patients with anaemia and CHF have poorer outcomes. There needs to be more awareness among clinicians about the importance of investigating and treating anaemia in patients with CHF.

Bisperoxovanadium, a phospho-tyrosine phosphatase inhibitor, reprograms myogenic cells to acquire a pluripotent, circulating phenotype.

Satellite cells are the main source of myogenic progenitors in postnatal skeletal muscle, but their use in cell therapy for muscle disorders is limited because these cells cannot be delivered through circulation and they are rapidly exhausted in severe myopathies. The search for alternative donor cells is ongoing, but none of the candidates so far show all the features required for successful colonization and repair of diseased muscle. In this study, we show that bisperoxovanadium, a phospho-tyrosine phosphatase inhibitor, induces myogenic cells to acquire a gene expression profile and a differentiation potential consistent with the phenotype of a circulating precursors, while maintaining their myogenic potential. These effects are mediated, at least in part, by NF-kappaB activation through the Tyr42-IkappaB-alpha phosphorylation, as shown by the expression of the dominant negative mutant form of the p50 NF-kappaB subunit. Moreover, when bisperoxovanadium-treated cells are injected into the femoral artery of alpha-sarcoglican null dystrophic mice, they are able to circulate and to reach muscle tissue; importantly, they contribute to muscle regeneration, as shown by the expression of alpha-sarcoglican in some fibers. Our observations indicate that bisperoxovanadium, or similar compounds, may prove very valuable to obtain and to expand, from committed cells, multipotent cell populations suitable for gene-cell therapy applications and may help to understand the molecular basis of genome reprogramming and "stem-ness."

Protein kinase C theta co-operates with calcineurin in the activation of slow muscle genes in cultured myogenic cells.

Adult skeletal muscle fibers can be divided into fast and slow twitch subtypes on the basis of specific contractile and metabolic properties, and on distinctive patterns of muscle gene expression. The calcium, calmodulin-dependent protein phosphatase, calcineurin, stimulates slow fiber-specific genes (myoglobin (Mb), troponin I slow) in cultured skeletal muscle cells, as well as in transgenic mice, through the co-operation of peroxisome-proliferation-activator receptor gamma co-activator 1alpha (PGC1alpha) myocyte enhancer factor 2 (MEF2), and nuclear factor of activated T cells (NFAT) transcription factors. Specific protein kinase C isoforms have been shown to functionally co-operate with calcineurin in different cellular models. We investigated whether specific protein kinase C isoforms are involved in calcineurin-induced slow skeletal muscle gene expression. By pharmacological inhibition or exogenous expression of mutant forms, we show that protein kinase C theta (the protein kinase C isoform predominantly expressed in skeletal muscle) is required and co-operates with calcineurin in the activation of the Mb promoter, as well as in the induction of slow isoforms of myosin and troponin I expression, in cultured muscle cells. This co-operation acts primarily regulating MEF2 activity, as shown by using reporter gene expression driven by the Mb promoter mutated in the specific binding sites. MEF2 activity on the Mb promoter is known to be dependent on both PGC1alpha and inactivation of histone deacetylases (HDACs) activity. We show in this study that protein kinase C theta is required for, even though it does not co-operate in, PGC1alpha-dependent Mb activation. Importantly, protein kinase C theta regulates the HDAC5 nucleus/cytoplasm location. We conclude that protein kinase C theta ensures maximal activation of MEF2, by regulating both MEF2 transcriptional complex formation and HDACs nuclear export.

In vitro and in vivo studies on transthyretin oligomerization.

The oligomerization of transthyretin has been studied in vitro and in vivo. The results showed that wild-type transthyretin synthesized in vitro in the absence of microsomes did not form dimers and tetramers, but in the presence of microsomes the mature transthyretin which had been translocated into the microsomal lumen formed dimers and a small amount of tetramers which could be detected only by using a cross-linking reagent. Efficiency of tetramer formation depends upon the source of microsomes; in fact the amount of tetramer formed in liver microsomes was much higher than that in pancreas microsomes. Transthyretin synthesized in HepG2 cells appeared after SDS-PAGE analysis in mostly tetrameric form, while that synthesized in transfected COS-1 cells appeared mainly as dimers. Brefeldin A treatment and pulse-chase experiments in HepG2 cells showed that transthyretin tetramer was formed in the endoplasmic reticulum. These results strongly indicate that transthyretin tetramer is formed most efficiently in the endoplasmic reticulum lumen of hepatocytes. Transthyretin without the signal peptide [S(-)] and transthyretin with a mutation that prevents processing of the signal peptide Msc failed to form dimers and tetramers in vitro. In the transfected COS-1 cells, however, S(-) transthyretin did form dimers while Msc transthyretin failed to oligomerize. These results show that the cleavage of the signal peptide and some cellular factors are required for transthyretin oligomerization.