Effect of oral monthly ibandronate on bone microarchitecture in women with osteopenia-a randomized placebo-controlled trial.

UNLABELLED: We have examined the effect of oral monthly ibandronate on distal radius and tibia microarchitecture with high-resolution peripheral quantitative tomography compared with placebo, in women with osteopenia, and found that ibandronate did not significantly affect trabecular bone but improved cortical density and thickness at the tibia. METHODS: We have examined the effect of ibandronate on bone microarchitecture with peripheral high-resolution quantitative computed tomography (HR-pQCT) in a randomized placebo-controlled trial among 148 women with osteopenia. Patients received either oral 150 mg monthly ibandronate or placebo over 24 months. Bone microarchitecture was assessed at baseline, 6, 12, and 24 months, using HR-pQCT at the distal radius and tibia; areal bone mineral density (aBMD) was measured with DXA at the spine, hip, and radius. RESULTS: At 12 months, there was no significant difference in trabecular bone volume at the radius (the primary end point) between women on ibandronate (10.8 ± 2.5%) and placebo (10.5 ± 2.9%), p = 0.25. There was no significant difference in other radius trabecular and cortical microarchitecture parameters at 12 and 24 months. In contrast, at the tibia, cortical vBMD in the ibandronate group was significantly greater than in the placebo group at 6, 12, and 24 months, with better cortical thickness at 6, 12, and 24 months. With ibandronate, aBMD was significantly increased at the hip and spine at 12 and 24 months but at the radius was significantly superior to placebo only at 24 months. Most of the adverse events related to ibandronate were expected with bisphosphonate use, and none of them were serious. CONCLUSION: We conclude that 12 months of treatment with ibandronate in women with osteopenia did not affect trabecular bone microarchitecture, but improved cortical vBMD at the tibia at 12 and 24 months, and preserved cortical thickness at the tibia.

Fcγ receptor type IIIA polymorphism influences treatment outcomes in patients with rheumatoid arthritis treated with rituximab.

OBJECTIVE: To assess the association between a single nucleotide polymorphism in the gene of FCGR3A and the response to treatment with rituximab (RTX) in rheumatoid arthritis (RA). METHODS: SMART is a randomised open trial assessing two strategies of re-treatment in patients responding to 1 g infusion of RTX with methotrexate on days 1 and 15 after failure, intolerance or contraindication to tumour necrosis factor (TNF) blockers. Among the 224 patients included, 111 could be genotyped and were included in an ancillary study of SMART. Univariate and multivariate analyses adjusted on disease activity score on 28 joints were performed to assess whether FCGR3A-158V/F polymorphism was associated with European League Against Rheumatism response at week 24. RESULTS: Among the 111 patients, 90 (81%) were responders of whom 30 (27%) were good responders. V allele carriage was significantly associated with a higher response rate (91% of responders vs 70%, OR 4.6 (95% CI 1.5 to 13.6), p=0.006). These results were also confirmed in rheumatoid factor-positive patients (93% vs 74%, p=0.025). In multivariate analysis, V allele carriage was independently associated with response to RTX (OR 3.8 (95% CI 1.2 to 11.7), p=0.023). CONCLUSION: The 158V/F polymorphism of FCGR3A seems to influence the response to RTX in patients with RA after failure, intolerance or contraindication to TNF blockers.

Five-year mortality in patients with diabetic foot ulcer during 2009-2010 was lower than expected.

AIM: Mortality rates are decreasing in patients with diabetes. However, as this observation also concerns patients with diabetic foot ulcer (DFU), additional data are needed. For this reason, our study evaluated the 5-year mortality rate in patients with DFU during 2009-2010 and identified risk factors associated with mortality. METHODS: Consecutive patients who attended a clinic for new DFU during 2009-2010 were followed until healing and at 1 year. Data on mortality were collected at year 5. Multivariate Cox proportional-hazards model was used to identify mortality risk factors. RESULTS: A total of 347 patients were included: mean age was 65±12 years, diabetes duration was 16 [10; 27] years; 13% were on dialysis; and 7% had an organ transplant. At 5 years, 49 patients (14%) were considered lost to follow-up. Total mortality rate at 5 years was 35%, and 16% in patients with neuropathy. On multivariate analyses, mortality was positively associated with: age [hazard ratio (HR): 1.05 (1.03-1.07), P<0.0001]; duration of diabetes [HR: 1.02 (1.001-1.03], P=0.03]; PEDIS perfusion grade 2 vs. 1 [HR: 2.35 (1.28-4.29), P=0.006)]; PEDIS perfusion grade 3 vs. 1 [HR: 3.14 (1.58-6.24), P=0.001); and ulcer duration at year 1 [HR 2.09 (1.35-3.22), P=0.0009]. CONCLUSION: Mortality rates were not as high as expected despite the large number of comorbidities, suggesting that progress has been made in the health management of these patients. In particular, patients with neuropathic foot ulcer had a survival rate of 84% at 5 years.

A trial comparing local pain after subcutaneous injection of epoetin-beta versus darbepoetin-alpha in healthy volunteers.

BACKGROUND: The aim of this study was to compare local pain experienced with subcutaneous (s.c.) injection of epoetin-beta vs. darbepoetin-alpha. METHODS: 40 healthy volunteers were enrolled into this single-blind, crossover study. After receiving an injection of placebo, individuals were randomized to receive s.c. injections of epoetin-beta 6,000 IU (0.3 ml) or darbepoetin-alpha 30 mg (0.3 ml), with a 1-week washout period between injections. Local pain was evaluated using a Visual Analog Scale (VAS) and a 6-item Verbal Rating Scale (VRS) immediately after (T0) and 1 h after injection (T1). RESULTS: The respective mean (standard deviation) and median (range) VAS values at T0 were 1.2 (1.7) and 0.5 (0.0 - 6.9) for epoetin-beta vs. 2.8 (2.4) and 1.9 (0.0 - 9.0) for darbepoetin-alpha (p < 0.0001). At T0, VRS scores demonstrated that 51% of individuals experienced no pain after epoetin- injection compared with 16% of those receiving darbepoetin-alpha. The percentage of individuals perceiving moderate or important pain was significantly greater with darbepoetin-alpha (38%) compared with epoetin-beta (5%, p = 0.0005) and placebo (14%). Pain evaluation at T1 showed no difference between treatment groups. Local tolerance was excellent except for a small hematoma with epoetin- at T1 and with darbepoetin-alpha at T0 which persisted at T1. CONCLUSION: In healthy volunteers, s.c. injection of epoetin-beta was significantly less painful than with darbepoetin-alpha and comparable with placebo. No significant pain was apparent at T1 in any group.

Characterisation of Kv4.3 in HEK293 cells: comparison with the rat ventricular transient outward potassium current.

OBJECTIVE: The Shal (or Kv4) gene family has been proposed to be responsible for primary subunits of the transient outward potassium current (Ito). More precisely, Kv4.2 and Kv4.3 have been suggested to be the most likely molecular correlates for Ito in rat cells. The purpose of the present study was to compare the properties of the rat Kv4.3 gene product when expressed in a human cell line (HEK293 cells) with that of Ito recorded from rat ventricular cells. METHODS: The cDNA encoding the rat Kv4.3 potassium channel was cloned into the pHook2 mammalian expression vector and expressed into HEK293. Patch clamp experiments using the whole cell configuration were used to characterise the electrophysiological parameters of the current induced by Kv4.3 in comparison with the rat ventricular myocyte Ito current. RESULTS: The transfection of HEK293 cells with rat Kv4.3 resulted in the expression of a time- and voltage-dependent outward potassium current. The current activated for potentials positive to -40 mV and the steady-state inactivation curve had a midpoint of -47.4 +/- 0.3 mV and a slope of 5.9 +/- 0.2 mV. Rat ventricular Ito current was activated at potentials positive to -20 mV and inactivated with a half-inactivation potential and a Boltzmann factor of -29.1 +/- 0.7 mV and 4.5 +/- 0.5 mV, respectively. The time course of recovery from inactivation of rat Kv4.3 expressed in HEK293 cells and of Ito recorded from native rat ventricular cells were exponentials with time constants of 213.2 +/- 4.1 msec and 23. +/- 1.5 msec, respectively. Pharmacologically, Ito of rat myocytes showed a greater sensitivity to 4-aminopyridine than Kv4.3 since half-maximal effects were obtained with 1.54 +/- 0.13 mM and 0.14 +/- 0.02 mM on Kv4.3 and Ito, respectively. In both Kv4.3 and Ito, 4-aminopyridine appears to bind to the closed state of the channel. Finally, although a higher level of expression was observed in the atria compared to the ventricle, the distribution of the Kv4.3 gene across the ventricles appeared to be homogeneous. CONCLUSION: The results of the present study show that Kv4.3 channel may play a major role in the molecular structure of the rat cardiac Ito current. Furthermore, because the distribution of Kv4.3 across the ventricle is homogeneous, the blockade of this channel by specific drugs may not alter the normal heterogeneity of Ito current.

Comparative effects of glibenclamide, tedisamil, dofetilide, E-4031, and BRL-32872 on protein kinase A-activated chloride current in guinea pig ventricular myocytes.

The modulation of the protein kinase A-activated chloride current (PKA-I[Cl]) may lead to modification of the cardiac action potential shape. The purpose of this study was to evaluate the effects of glibenclamide, tedisamil, dofetilide, E-4031, and BRL-32872 on the PKA-I(Cl). Experiments were conducted by using the patch-clamp technique in guinea pig ventricular myocytes. PKA-I(Cl) was activated by application of 1 microM isoproterenol and was inhibited by 1 microM propranolol, 10 microM acetylcholine, or 1 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS). The sulfonylurea receptor inhibitor, glibenclamide, inhibited PKA-I(Cl) at micromolar concentration. Among class III antiarrhythmic agents, tedisamil induced a dose-dependent inhibition of PKA-I(Cl) with a half effective concentration (EC50) of 7.15 microM (Hill coefficient, 0.54). This effect may contribute to action potential widening induced by tedisamil. In contrast, the selective inhibitors of the rapid component of the delayed rectifier K current (I[Kr]), dofetilide, and E-4031, as well as BRL-32872, that blocks I(Kr) and the L-type calcium current, did not significantly affect the amplitude of PKA-I(Cl), even at high concentrations (10-30 microM). These results demonstrate that compounds such as glibenclamide and tedisamil that are known to block the adenosine triphosphate (ATP)-sensitive K current also affect PKA-I(Cl). Furthermore it appears that blockade of PKA-I(Cl) is not a common feature for all class III antiarrhythmic agents.

hKv4.3 channel characterization and regulation by calcium channel antagonists.

Relative expression pattern of short and long isoforms of hKv4.3 channels was evaluated by RT-PCR and RPA. Electrophysiological studies were performed in HEK293 cells transfected with short or long hKv4.3 cDNA. The long variant L-hKv4.3 was the only form present in lung, pancreas, and small intestine. The short variant S-hKv4.3 was predominant in brain whereas expression levels of the two isoforms were similar in cardiac and skeletal muscles. Properties of the ionic channels encoded by L-hKv4.3 and S-hKv4.3 cDNAs were essentially similar. Cadmium chloride and verapamil inhibited hKv4.3 current (with EC50s of 0.110 +/- 0.004 mM and 492.9 +/- 15.1 microM, respectively). Verapamil also accelerated current inactivation. Another calcium channel antagonist nicardipine was found inactive. In conclusion, this study confirms that both isoforms underlie the transient outward potassium current. Moreover, calcium channel inhibitors markedly affect hKv4.3 current, an effect which must be considered when evaluating transient outward potassium channel properties in native tissues.

cDNA sequence and characterization of the gene that encodes human myotrophin/V-1 protein, a mediator of cardiac hypertrophy.

The predominant response of the heart to sustained increased work load is development of ventricular hypertrophy, principally as a result of hypertrophy of cardiomyocytes. The molecular mechanisms and factors involved in cardiomyocyte hypertrophy are poorly understood. Myotrophin is a novel 12-kilodalton protein recently implicated as a factor associated with and able to induce cardiac hypertrophy. Cloning of rat myotrophin revealed that this protein is identical to the functionally undefined rat, murine and chicken V-1 proteins. Although human myotrophin has been purified to homogeneity, its gene has not been characterized. In this report we describe the cloning, expression, purification and characterization of the human homolog of myotrophin/V-1 protein. Sequence analysis indicators high homology (>90%) between all species at both the nucleotide and amino acid levels, and Southern blot analysis of genomic DNA from diverse species verifies that myotrophin/V-1 is a highly conserved gene. Northern analysis indicates wide-spread expression of a single human transcript, and examination of mRNA distribution in 50 human tissues by dot blot analysis indicates ubiquitous expression with relatively high expressioon in adult and fetal heart. We verify that recombinant human myotrophin produces cardiomyocyte hypertrophy, and we demonstrate for the first time that elevated levels of myotrophin/V-1 protein mRNA are expressed in human dilated cardiomyopathic hearts. We report the novel findings that myotrophin expression is elevated in ischemic hearts, and that myotrophin expression correlates positively with ventricular mass in a hypoxic rat model of induced right ventricular hypertrophy.