Low dose chloroquine decreases insulin resistance in human metabolic syndrome but does not reduce carotid intima-media thickness.

BACKGROUND: Metabolic syndrome, an obesity-related condition associated with insulin resistance and low-grade inflammation, leads to diabetes, cardiovascular diseases, cancer, osteoarthritis, and other disorders. Optimal therapy is unknown. The antimalarial drug chloroquine activates the kinase ataxia telangiectasia mutated (ATM), improves metabolic syndrome and reduces atherosclerosis in mice. To translate this observation to humans, we conducted two clinical trials of chloroquine in people with the metabolic syndrome. METHODS: Eligibility included adults with at least 3 criteria of metabolic syndrome but who did not have diabetes. Subjects were studied in the setting of a single academic health center. The specific hypothesis: chloroquine improves insulin sensitivity and decreases atherosclerosis. In Trial 1, the intervention was chloroquine dose escalations in 3-week intervals followed by hyperinsulinemic euglycemic clamps. Trial 2 was a parallel design randomized clinical trial, and the intervention was chloroquine, 80 mg/day, or placebo for 1 year. The primary outcomes were clamp determined-insulin sensitivity for Trial 1, and carotid intima-media thickness (CIMT) for Trial 2. For Trial 2, subjects were allocated based on a randomization sequence using a protocol in blocks of 8. Participants, care givers, and those assessing outcomes were blinded to group assignment. RESULTS: For Trial 1, 25 patients were studied. Chloroquine increased hepatic insulin sensitivity without affecting glucose disposal, and improved serum lipids. For Trial 2, 116 patients were randomized, 59 to chloroquine (56 analyzed) and 57 to placebo (51 analyzed). Chloroquine had no effect on CIMT or carotid contrast enhancement by MRI, a pre-specified secondary outcome. The pre-specified secondary outcomes of blood pressure, lipids, and activation of JNK (a stress kinase implicated in diabetes and atherosclerosis) were decreased by chloroquine. Adverse events were similar between groups. CONCLUSIONS: These findings suggest that low dose chloroquine, which improves the metabolic syndrome through ATM-dependent mechanisms in mice, modestly improves components of the metabolic syndrome in humans but is unlikely to be clinically useful in this setting.Trial registration ClinicalTrials.gov (NCT00455325, NCT00455403), both posted 03 April 2007.

Common sense treatment for common lipid disorders.

Dyslipidemia is a common, major modifiable risk factor for cardiovascular disease. Screening for lipid disorders is simple, and available treatments decrease disease risk. However, secondary causes of dyslipidemia are probably underappreciated, and severe lipid elevations should be referred to a lipid specialist. Patients usually respond to lifestyle modifications and drug therapy guided by a stepwise approach supported by the results of clinical trials, but several misconceptions may interfere with treatment strategies.

Prevention of bone loss after withdrawal of tamoxifen.

OBJECTIVE: Tamoxifen has antiestrogenic effects in the breast and estrogenlike activity in the skeletons of postmenopausal women. We hypothesized that postmenopausal women with breast cancer would experience a rapid decline in bone mineral density (BMD) after stopping tamoxifen, similar to that seen with estrogen withdrawal. The objective of this study was to assess, in a randomized, double-blind, placebo-controlled trial, whether administration of alendronate (70 mg weekly) would prevent bone loss associated with tamoxifen discontinuation. METHODS: Postmenopausal women with breast cancer were randomly assigned to receive alendronate or placebo for 1 year within 3 months after withdrawal of tamoxifen therapy. We initiated a randomized, double-blind, placebo-controlled trial of alendronate (70 mg weekly) in an effort to prevent bone loss associated with discontinuation of tamoxifen therapy. Patients treated with aromatase inhibitors were excluded from the study. BMD at the spine, hip, and forearm was measured at baseline and at 12 months. Analyses employed repeated-measures analysis of variance. RESULTS: Patient accrual was considerably limited by the substantial increase in use of aromatase inhibitors during the enrollment period. The study patients (N = 11) had similar baseline BMD T-scores in the alendronate (n = 6) and placebo (n = 5) subgroups. After 1 year, tamoxifen withdrawal was associated with a significant decline in BMD at the femoral neck, which appeared to be prevented by weekly administration of alendronate (-5.2% versus 0.1%; P = .02). Levels of urinary N-telopeptide, a marker of bone turnover, increased by 48% in study subjects in the placebo group (P < .01), whereas weekly alendronate treatment was associated with a 52% decline (P < .01) in this bone resorption marker. CONCLUSION: Differences in BMD and bone turnover were evident despite the small sample size. These data suggest that postmenopausal women with breast cancer completing tamoxifen therapy warrant an evaluation of their skeletal health and that bisphosphonate therapy may be useful in preventing bone loss associated with discontinuation of tamoxifen.