In search of an ideal drug for safer treatment of obesity: The false promise of pseudoephedrine.

Obesity is a major public health problem worldwide. Only relatively few treatment options are, at present, available for the management of obese patients. Furthermore, treatment of obesity is affected by the widespread misuse of drugs and food supplements. Ephedra sinica is an old medicinal herb, commonly used in the treatment of respiratory tract diseases. Ephedra species contain several alkaloids, including pseudoephedrine, notably endowed with indirect sympathomimetic pharmacodynamic properties. The anorexigenic effect of pseudoephedrine is attributable primarily to the inhibition of neurons located in the hypothalamic paraventricular nucleus (PVN), mediating satiety stimuli. Pseudoephedrine influences lipolysis and thermogenesis through interaction with ß3 adrenergic receptors and reduces fat accumulation through down-regulation of transcription factors related to lipogenesis. However, its use is associated with adverse events that involve to a large extent the cardiovascular and the central nervous system. Adverse events of pseudoephedrine also affect the eye, the intestine, and the skin, and, of relevance, sudden cardiovascular death related to dietary supplements containing Ephedra alkaloids has also been reported. In light of the limited availability of clinical data on pseudoephedrine in obesity, along with its significantly unbalanced risk/benefit profile, as well as of the psychophysical susceptibility of obese patients, it appears reasonable to preclude the prescription of pseudoephedrine in obese patients of any order and degree.

Paricalcitol for secondary hyperparathyroidism in renal transplantation.

Secondary hyperparathyroidism contributes to post-transplant CKD mineral and bone disorder. Paricalcitol, a selective vitamin D receptor activator, decreased serum parathyroid hormone levels and proteinuria in patients with secondary hyperparathyroidism. This single-center, prospective, randomized, crossover, open-label study compared the effect of 6-month treatment with paricalcitol (1 µg/d for 3 months and then uptitrated to 2 µg/d if tolerated) or nonparicalcitol therapy on serum parathyroid hormone levels (primary outcome), mineral metabolism, and proteinuria in 43 consenting recipients of renal transplants with secondary hyperparathyroidism. Participants were randomized 1:1 according to a computer-generated sequence. Compared with baseline, median (interquartile range) serum parathyroid hormone levels significantly declined on paricalcitol from 115.6 (94.8-152.0) to 63.3 (52.0-79.7) pg/ml (P<0.001) but not on nonparicalcitol therapy. At 6 months, levels significantly differed between treatments (P<0.001 by analysis of covariance). Serum bone-specific alkaline phosphatase and osteocalcin decreased on paricalcitol therapy only and significantly differed between treatments at 6 months (P<0.001 for all comparisons). At 6 months, urinary deoxypyridinoline-to-creatinine ratio and 24-hour proteinuria level decreased only on paricalcitol (P<0.05). L3 and L4 vertebral mineral bone density, assessed by dual-energy x-ray absorption, significantly improved with paricalcitol at 6 months (P<0.05 for both densities). Paricalcitol was well tolerated. Overall, 6-month paricalcitol supplementation reduced parathyroid hormone levels and proteinuria, attenuated bone remodeling and mineral loss, and reduced eGFR in renal transplant recipients with secondary hyperparathyroidism. Long-term studies are needed to monitor directly measured GFR, ensure that the bone remodeling and mineral effects are sustained, and determine if the reduction in proteinuria improves renal and cardiovascular outcomes.

The potential of endothelin antagonism as a therapeutic approach.

Endothelin (ET) is a pivotal physiological regulator of blood pressure through its effects on blood vessels, heart, lung and kidneys, and the ET system can be overactive in disorders such as pulmonary hypertension, heart failure and renal disease. Such observations stimulated interest among scientists and pharmaceutical companies that have set up high-throughput screens to search for antagonists of ET receptors. The emerging compounds have been tested in animals with exciting results, leading to great hope that such inhibitors could be translated into human drugs with desirable therapeutic activities and few side effects. This review will describe the most relevant results obtained in experimental animals in a wide variety of disease conditions and focus on the data of selected compounds that have been employed in clinical trials.

Combined treatment with mycophenolate mofetil and an angiotensin II receptor antagonist fully protects from chronic rejection in a rat model of renal allograft.

Antigen-dependent and antigen-independent factors have been implicated in the pathophysiology of chronic allograft rejection, but their relative role is not well established. In the Fisher 344-->Lewis rat kidney transplant model, we sought (1) to compare the relative efficacy of the novel immunosuppressant, mycophenolate mofetil (MMF), with that of the AT1 receptor blocker, losartan, in preventing the development of chronic graft rejection when given for 52 wk; (2) to examine whether combining MMF with losartan affords better protection than each of the drugs alone. For comparison, the effect of cyclosporine (CsA) to control chronic graft rejection was also assessed. Administration of MMF alone or losartan alone to the kidney allografted rats resulted in a partial decrease in the amount of proteinuria, preservation of glomerular and tubulo-interstitial graft structure, limitation of intragraft cell infiltration, and improvement of graft survival compared with corresponding parameters in untreated, transplanted control rats. Combined treatment with MMF and losartan completely prevented the development of proteinuria, largely reduced glomerular and tubulointerstitial injury, and suppressed intragraft cell infiltration, and all animals survived at the end of the follow-up. Similarly, CsA treatment largely prevented graft injury but failed to achieve 100% animal survival. We have shown that MMF synergizes with the angiotensin II receptor antagonist, losartan, in simultaneously targeting complementary pathways of chronic allograft rejection. Combining MMF and angiotensin II receptor blocker offers superior long-term renoprotection as compared with CsA. Together, these findings provide the basis to prevent chronic injury and progressive dysfunction after renal transplantation.