Mutations in potassium channel Kir2.6 cause susceptibility to thyrotoxic hypokalemic periodic paralysis.

Thyrotoxic hypokalemic periodic paralysis (TPP) is characterized by acute attacks of weakness, hypokalemia, and thyrotoxicosis of various etiologies. These transient attacks resemble those of patients with familial hypokalemic periodic paralysis (hypoKPP) and resolve with treatment of the underlying hyperthyroidism. Because of the phenotypic similarity of these conditions, we hypothesized that TPP might also be a channelopathy. While sequencing candidate genes, we identified a previously unreported gene (not present in human sequence databases) that encodes an inwardly rectifying potassium (Kir) channel, Kir2.6. This channel, nearly identical to Kir2.2, is expressed in skeletal muscle and is transcriptionally regulated by thyroid hormone. Expression of Kir2.6 in mammalian cells revealed normal Kir currents in whole-cell and single-channel recordings. Kir2.6 mutations were present in up to 33% of the unrelated TPP patients in our collection. Some of these mutations clearly alter a variety of Kir2.6 properties, all altering muscle membrane excitability leading to paralysis.

Statin alternatives or just placebo: an objective review of omega-3, red yeast rice and garlic in cardiovascular therapeutics.

OBJECTIVE: The aim of this review is to objectively access the trial evidence on the role of omega-3, red yeast rice and garlic in preventing clinical cardiovascular events. Given the large number of clinical trials favoring statin use in cardiovascular disease, it is important to see if evidence is available for these supplements and whether they could replace statin therapy. DATA SOURCE: A PubMed search was conducted using the keywords 'trial, omega-3, red yeast rice, xuezhikang, garlic, cholesterol, cardiovascular, outcomes'; the resulting trials were reviewed together with the references quoted in the papers obtained. STUDY SELECTION: The studies selected are prospective, randomized, placebo-controlled studies with predefined clinical cardiovascular end-points recruiting at least 2000 patients, with a follow-up over 2 years. RESULTS: Modest dose omega-3 fatty acid has been shown in GISSI-P (11 324 patients, follow-up 3.5 years) to produce a reduction in sudden death of 45%, and in cardiac death of 35%, acting probably via an anti-arrhythmic effect. In JELIS (18 645 patients, follow-up 4.6 years), high dose omega-3 given to Japanese patients on a high fish diet and already on statin treatment produced further benefit with a 19% reduction of nonfatal cardiovascular outcomes; fatal cardiac events are not affected. CCSPS (4870 patients, follow-up 4 years), a secondary prevention trial using xuezhikang, a commercial red yeast rice preparation, produced a 46% reduction in nonfatal myocardial infarction and coronary death. There has been no trial to show that garlic reduces clinical cardiovascular outcomes. A rigorous trial with constant assessment of chemicals in the study material in 192 patients found that over a 6-month follow-up, raw garlic and 2 commercial preparations do not significantly affect lipid levels. CONCLUSIONS: Omega-3 in modest doses reduces cardiac deaths, and in high doses reduces nonfatal cardiovascular events. Red yeast rice reduces adverse cardiac events to a similar degree as the statins. It is unlikely that garlic is useful in preventing cardiovascular disease.

Seeking the ideal anti-hypertensive agent: a practical review of the hypertension drug trials.

Numerous trials and meta-analyses have been conducted over the last five years to identify an ideal anti-hypertensive drug. These reports, and the JNC 7 and European hypertension guidelines, have generated some controversy and confusion. A review of the comparative anti-hypertensive drug trials shows that the differences between drugs are minor and not consistently demonstrated by different studies. However, much data have now accumulated on the safety and value of diuretics, beta blockers, calcium-channel blockers (CCBs), angiotensin-converting enzyme inhibitors (ACEIs), and angiotensin receptor blockers (ARBs) in reducing blood pressure and preventing clinical disease. The importance of tight blood pressure control in reducing adverse events has been clearly shown, and clinicians should concentrate on achieving target blood pressure levels, which often requires a combination of anti-hypertensive drugs. The choice of anti-hypertensive drug should be guided by the presence of concomitant clinical disease, as evidence has accumulated on the special efficacy of certain drugs in reducing damage to particular organ systems. In the absence of any associated clinical disease, it is good to initiate anti-hypertensive therapy with diuretics, provided the metabolic parameters are regularly reviewed.