Modulation of blood pressure by central melanocortinergic pathways.

BACKGROUND: Weight gain and weight loss are associated with changes in blood pressure through unknown mechanisms. Central melanocortinergic signaling is implicated in the control of energy balance and blood pressure in rodents, but there is no information regarding such an association with blood pressure in humans. METHODS: We assessed blood pressure, heart rate, and urinary catecholamines in overweight or obese subjects with a loss-of-function mutation in MC4R, the gene encoding the melanocortin 4 receptor, and in equally overweight control subjects. We also examined the effects of an MC4R agonist administered for 7 days in 28 overweight or obese volunteers. RESULTS: The prevalence of hypertension was markedly lower in the MC4R-deficient subjects than in the control subjects (24% vs. 53%, P=0.009). After the exclusion of subjects taking antihypertensive medications, blood-pressure levels were significantly lower in MC4R-deficient subjects than in control subjects, with mean (+/-SE) systolic blood pressures of 123+/-14 mm Hg and 131+/-12 mm Hg, respectively (P=0.02), and mean diastolic blood pressures of 73+/-10 mm Hg and 79+/-7 mm Hg, respectively (P=0.03). As compared with control subjects, MC4R-deficient subjects had a lower increase in heart rate on waking (P=0.007), a lower heart rate during euglycemic hyperinsulinemia (P<0.001), and lower 24-hour urinary norepinephrine excretion (P=0.04). The maximum tolerated daily dose of 1.0 mg of the MC4R agonist led to significant increases of 9.3+/-1.9 mm Hg in systolic blood pressure and of 6.6+/-1.1 mm Hg in diastolic blood pressure (P<0.001 for both comparisons) at 24 hours, as compared with placebo. Differences in blood pressure were not explained by changes in insulin levels; there were no significant adverse events. CONCLUSIONS: Results of our genetic and pharmacologic studies implicate melanocortinergic signaling in the control of human blood pressure through an insulin-independent mechanism.

Early changes in biochemical markers of bone formation predict BMD response to teriparatide in postmenopausal women with osteoporosis.

UNLABELLED: The relationship between early changes in biochemical markers of bone turnover and the subsequent BMD response to daily teriparatide therapy in women with postmenopausal osteoporosis was studied. Changes in five biochemical markers, obtained from a subset of women enrolled in the Fracture Prevention Trial, were examined. Early increases in the PICP and the PINP were the best predictors of BMD response to teriparatide in this analysis. INTRODUCTION: Early reductions in biochemical markers of bone turnover with antiresorptive therapy negatively correlate with subsequent increases in BMD. We undertook this analysis to determine if early changes in biochemical markers with teriparatide therapy predict subsequent increases in BMD. MATERIALS AND METHODS: In the Fracture Prevention Trial, 1637 postmenopausal women with osteoporosis were randomized to receive daily, self-administered, subcutaneous injections of placebo, teriparatide 20 microg/day, or teriparatide 40 microg/day. Serum concentrations of two bone formation markers (bone-specific alkaline phosphatase [bone ALP] and the carboxy-terminal extension peptide of procollagen type 1 [PICP]) and urinary concentrations of two bone resorption markers (free deoxypyridinoline [DPD] and N-terminal telopeptide [NTX]) were assessed in a trial population subset (n = 520) at baseline and at 1, 3, 6, and 12 months. We also assessed serum concentrations of another bone formation marker, the amino-terminal extension peptide of procollagen type 1 (PINP), in a subset of 771 women at baseline and 3 months. Lumbar spine (LS) BMD was measured by DXA at baseline and 18 months. Femoral neck BMD was measured at baseline and 12 months. RESULTS AND CONCLUSION: Baseline bone turnover status correlated positively and significantly with BMD response. The highest correlations occurred for the LS BMD response to teriparatide 20 microg/day. Among all studied biochemical markers, increases in PICP at 1 month and PINP at 3 months correlated best with increases in LS BMD at 18 months (0.65 and 0.61, respectively; p < 0.05). The relationships between these two biochemical markers and the LS BMD response were stronger than the corresponding relationships for the femoral neck BMD response. Using receiver operator curve analysis, we determined that the increases in PICP at 1 month and PINP at 3 months were the most sensitive and accurate predictors of the LS BMD response.

Anabolic and catabolic bone effects of human parathyroid hormone (1-34) are predicted by duration of hormone exposure.

Parathyroid hormone (PTH)(1-34), given once daily, increases bone mass in a variety of animal models and humans with osteoporosis. However, continuous PTH infusion has been shown to cause bone loss. To determine the pharmacokinetic profile of PTH(1-34) associated with anabolic and catabolic bone responses, PTH(1-34) pharmacokinetic and serum biochemical profiles were evaluated in young male rats using dosing regimens that resulted in either gain or loss of bone mass. Once-daily PTH(1-34) or 6 PTH(1-34) injections within 1 h, for a total daily dose of 80 microg/kg, induced equivalent increases in proximal tibia bone mass. In contrast, 6 PTH(1-34) injections/day over 6 h for a total dose of 80 microg/kg/day or 3 injections/day over 8 h for a total of 240 microg/kg/day decreased tibia bone mass. The PTH(1-34) pharmacokinetics of the different treatment regimens were distinctive. The magnitude of the maximum serum concentrations (Cmax) of PTH(1-34) and area under the curve (AUC) did not predict the catabolic bone outcome. Compared to the anabolic pharmacokinetic profile of a transient increase in PTH(1-34) with rapid decreases in serum calcium and phosphate, the catabolic regimen was associated with PTH(1-34) concentrations remaining above baseline values during the entire 6-h dosing period with a trend toward an increase in serum calcium and a prolonged decrease in phosphate. The pharmacokinetic profiles suggest that the anabolic or catabolic response of bone to PTH(1-34) is determined primarily by the length of time each day that serum concentrations of PTH(1-34) remain above baseline levels of endogenous PTH and only secondarily by the Cmax or AUC of PTH(1-34) achieved.

Population exposure-response model to support dosing evaluation of ixekizumab in patients with chronic plaque psoriasis.

Ixekizumab (LY2439821), a humanized immunoglobulin G subclass 4 (IgG4) monoclonal antibody that selectively binds and neutralizes interleukin (IL) 17A has demonstrated efficacy in the treatment of psoriasis. A population pharmacokinetics-pharmacodynamics model was developed using NONMEM 7.2 to describe the temporal relationship between ixekizumab concentrations and absolute Psoriasis Area and Severity Index (PASI) scores from a phase 2 dose-finding study in chronic plaque psoriasis. The objective was to inform dose-selection for further development. The primary endpoint, PASI 75 (75% or greater improvement from baseline PASI score) was then derived from each individual's absolute PASI score. The population pharmacokinetics of ixekizumab was characterized by a two-compartment model, while the exposure-response relationship was characterized using an indirect response model that described the pharmacological effects of ixekizumab and placebo in the form of inhibition of the formation of psoriatic skin lesions. PASI 75 responder status at the Week 12 primary endpoint was found to be a significant covariate on the concentration producing half maximal effect (EC50 ). While the results suggested patient may have different levels of sensitivity to ixekizumab, it is possible that nonresponder patients assigned to lower doses of ixekizumab may potentially become responders to ixekizumab if given doses that yield adequate exposures.

Combination of a Beta adrenoceptor modulator and a norepinephrine-serotonin uptake inhibitor for the treatment of obesity.

We report the novel combination of a selective beta adrenoceptor modulator and a norepinephrine-serotonin uptake inhibitor (sibutramine) with potential for the treatment of obesity. The synthesis and characterization of 6-[4-[2-[[(2S)-3-(9H-carbazol-4-yloxy)-2-hydroxypropyl]amino]-2-methylpropyl]phenoxy]pyridine-3-carboxamide (LY377604), a human ß3-adrenergic receptor agonist and ß1- and ß2-adrenergic receptor antagonist with no sympathomimetic activity at the ß1- and ß2-adrenergic receptors, is reported. Some in vivo data in both rats and humans is presented.