What is the role of the bone marrow microenvironment in AML?

Acute myeloid leukemia (AML) continues to be associated with relapse and resistance to chemotherapy. The bone marrow microenvironment in AML has been shown to regulate responsiveness to chemotherapy and to support disease progression. This review summarizes some recent experimental insights into the crucial role of the bone marrow microenvironment in AML and persistence after chemotherapy.     

What is the clinical significance of bone loss in primary hyperparathyroidism?

To help determine the clinical significance of the bone loss associated with primary hyperparathyroidism, we studied the prevalence of vertebral fractures in a group of patients with this disorder. From a registry of parathyroidectomies, 206 cases were reviewed, and lateral chest roentgenograms were studied for the presence of fractures. All roentgenograms were interpreted by two of the investigators who were "blinded" to diagnoses. Comparisons of readings were made that assured interrater agreement. A group of patients who underwent cholecystectomy served as controls. Studied in a logistic regression analysis model, controlling for the effects of age, sex, and race, primary hyperparathyroidism was found to be significantly associated with vertebral fractures. Subgroup analyses performed on the patients with hyperparathyroidism failed to identify specific biochemical or clinical markers associated with fractures. Our results suggest that the bone loss of primary hyperparathyroidism is clinically significant, leading not only to decreased bone densities but also to an increased prevalence of fractures.     

Statins, fracture risk, and bone remodeling: What is true?

Besides the action on plasma lipid levels, statins show a series of ancillary effects defined as all of their vascular and nonvascular effects independent from the cholesterol reduction. It has been recently hypothesized that one of these ancillary effects could be the improvement of bone health, due to the interference with bone metabolism. This may potentially represent the rationale for statins' use in the treatment of osteoporosis, the most common disease of the bone. Both experimental observations and clinical studies on this topic generated a number of conflicting results; however, the largest randomized clinical trials, the Scandinavian Simvastatin Survival Study (4S), Long Term Intervention with Pravastatin in Ischemic Disease (LIPID), and Heart Protection Study (HPS), indicate that statins do not prevent or reduce fracture risk.