Background and purpose: Current therapies for muscular dystrophy are based on corticosteroids. Significant side effects associated with these therapies have prompted several studies aimed at identifying possible alternative strategies. As inflammation and defects of nitric oxide (NO) generation are key pathogenic events in muscular dystrophies, we have studied the effects of combining the NO donor isosorbide dinitrate (ISDN) and the non‐steroidal anti‐inflammatory drug ibuprofen.Experimental approach: α‐Sarcoglycan‐null mice were treated for up to 8 months with ISDN (30 mg·kg−1) plus ibuprofen (50 mg·kg−1) administered daily in the diet. Effects of ISDN and ibuprofen alone were assessed in parallel. Drug effects on animal motility and muscle function, muscle damage, inflammatory infiltrates and cytokine levels, as well as muscle regeneration including assessment of endogenous stem cell pool, were measured at selected time points.Key results: Combination of ibuprofen and ISDN stimulated regeneration capacity, of myogenic precursor cells, reduced muscle necrotic damage and inflammation. Muscle function in terms of free voluntary movement and resistance to exercise was maintained throughout the time window analysed. The effects of ISDN and ibuprofen administered separately were transient and significantly lower than those induced by their combination.Conclusions and implications: Co‐administration of NO and ibuprofen provided synergistic beneficial effects in a mouse model of muscular dystrophy, leading to an effective therapy. Our results open the possibility of immediate clinical testing of a combination of ISDN and ibuprofen in dystrophic patients, as both components are approved for use in humans, with a good safety profile.
1 December 2010 in Bioorganic & Medicinal Chemistry
Endothelial dysfunction is a crucial event in the early pathogenesis of cardiovascular diseases and is linked to magnesium (Mg) deficiency. Indeed, in endothelial cells, low Mg levels promote the acquisition of a pro-inflammatory and pro-atherogenic phenotype. This paper investigates the mechanisms by which Mg deficiency promotes oxidative stress and affects endothelial behavior in human umbilical vascular endothelial cells (HUVECs). Our data show that low Mg levels trigger oxidative stress initially by increasing NAPDH oxidase activity and then by upregulating the pro-oxidant thioredoxin-interacting protein TXNIP. The overproduction of reactive oxygen species (ROS) activates NF-κB, leading to its increased binding to the inducible nitric oxide synthase (iNOS) promoter, with the consequent increase in iNOS expression. The increased levels of nitric oxide (NO) generated by upregulated iNOS contribute to disrupting endothelial cell function by inhibiting growth and increasing permeability. In conclusion, we provide evidence that multiple mechanisms contribute to generate a pro-oxidant state under low-Mg conditions, ultimately affecting endothelial physiology. These data add support to the notion that adequate Mg levels play a significant role in preserving cardiovascular health and may suggest new approaches to prevent or manage cardiovascular diseases.
Cytokinins are phytohormones critically involved in the regulation of plant growth and development. They also affect the proliferation and differentiation of animal cells, thus representing new tools to treat diseases that involve dysfunctional cell growth and/or differentiation. Recently, by performing structure-function studies on human cells, we found that only N6-isopentenyladenosine and its benzyl analogue N6-benzyladenosine suppress the clonogenic activity and the growth of different neoplastic cells. We here broaden our studies on bladder carcinoma T24 cells, because, due to the high recurrence rate of bladder cancer, new active molecules are sought to contrast the growth of this tumor. Early events induced by N6-isopentenyladenosine and N6-benzyladenosine are the alteration of T24 cell morphology and the disorganization of the actin cytoskeleton. After 24 h N6-isopentenyladenosine and N6-benzyladenosine inhibit growth by arresting the cells in the G0/G1 phase of the cell cycle. We also show that the two compounds induce apoptosis, an event linked to the activation of caspase 3. Since DNA damage is a prime factor resulting in cell cycle arrest and apoptosis, it is noteworthy that we do not detect any genotoxic effect upon treatment of T24 cells with N6-isopentenyladenosine and N6- benzyladenosine. Because the disruption of actin filaments leads to G1 arrest and is also implicated in apoptosis, we hypothesize that cytoskeletal rearrangement might be responsible for triggering the antiproliferative and proapotpotic effects of N6-isopentenyladenosine and N6- benzyladenosine in T24 cells.