No abstract

Disturbance in metallochemical reactions and metal‐protein association are associated with chronic neurodegenerative conditions, such as Alzheimer's and Parkinson's disease, as well as with neurodegeneration triggered by acute cerebral ischaemia. Many neurological diseases have been linked directly or indirectly to perturbed homeostasis of Ca, Fe, Zn, or Cu ions. Consequently, acute or chronic neurodegenerative disorders represent excellent targets for exploiting metal ion chelator approaches. Drug Dev. Res. 56: 300–309, 2002. © 2002 Wiley‐Liss, Inc.

Indomethacin has been suggested for the treatment of Alzheimer's disease (AD), but its use is limited by gastrointestinal and renal toxicity. To overcome this limitation, D-Pharm Ltd. (Rehovot, Israel) developed DP-155 (mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido] hexanoyl}-sn-glycero-3-phosophatidyl choline), a lecithin derivative of indomethacin. Safety was tested by daily oral administration of DP-155 or indomethacin to rats in a dose range of 0.007 to 0.28 mmol/kg. The prevalence of gastrointestinal ulceration was significantly lower (10-fold) for DP-155 than for indomethacin, and the ulcerations were delayed. Signs of renal toxicity, namely reduced urine output and increased urine N-acetyl glycosaminidase to creatinine ratio, were 5-fold lower for DP-155. Indomethacin, but not an equimolar dose of DP-155, reduced urine bicycloprostaglandin E 2 . An equimolar oral dose of DP-155 or indomethacin, administered every 4 h for 3 days, was equally efficacious in reducing the levels of A␤42 in the brains of Tg2576 mice. Indomethacin was the principal metabolite of DP-155 in the serum. After DP-155 oral administration, indomethacin's half-life in the serum and the brain was 22 and 93 h, respectively, compared with 10 and 24 h following indomethacin oral administration. The brain to serum ratio was 3.5 times higher for DP-155 than indomethacin. This finding explains the efficacy of DP-155 in reducing A␤42 brain levels, despite the low systemic blood concentrations of indomethacin derived from DP-155. In conclusion, compared with indomethacin, DP-155 has significantly lower toxicity in the gut and kidney while maintaining similar efficacy to indomethacin in lowering A␤42 in the brains of Tg2576 mice. This superior safety profile highlights DP-155's potential as an improved indomethacin-based therapy for AD.Indomethacin belongs to the nonsteroidal anti-inflammatory drug (NSAID) family. The use of NSAIDs was found to have an inverse correlation with the prevalence and severity of Alzheimer's disease (AD) in epidemiological and clinical studies (in t' Veld et al., 2001). Alzheimer's disease is characterized by three pathological hallmarks: extracellular amyloid ␤ (A␤) plaques, intracellular neurofibrillary tangles (composed of hyperphosphorylated Tau protein), and neuronal and synaptic loss. The pathology development is accompanied by marked inflammatory processes (microglial and astrocytic reaction) (McGeer and McGeer, 1999). Indomethacin inhibits A␤ plaque formation via ␥-secretase inhibition, which is a cyclooxygenase (COX)-independent process (Weggen et al., 2001). In addition, NSAIDs have COX-dependent anti-inflammatory and neuroprotective effects (Halliday et al., 2000;Weggen et al., 2001 ABBREVIATIONS: NSAID, nonsteroidal anti-inflammatory drug; AD, Alzheimer's disease; A␤, amyloid ␤; COX, cyclooxygenase; GI, gastrointestinal; PGE, prostaglandin E; GFR, glomerular filtration rate; DP-155, mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl...

N,N,NЈ,NЈ-Tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN), a transition-metal chelator, was recently found to protect against myocardial ischemia-reperfusion injury. The goals of this study were to investigate the in vivo antiarrhythmic and antifibrillatory potential of TPEN in rats and guinea pigs and to study the in vitro effects of TPEN on calcium homeostasis in cultured newborn rat cardiac cells in normoxia and hypoxia. We demonstrated on an in vivo rat model of ischemia-reperfusion that TPEN abolishes ventricular fibrillation incidence and mortality and decreases the incidence and duration of ventricular tachycardia. To elucidate the mechanism of cardioprotection by TPEN, contraction, synchronization, and intracellular calcium level were examined in vitro. We have shown for the first time that TPEN prevented the increase in intracellular Ca 2ϩ levels (

AimsTo investigate the safety, tolerability and pharmacokinetics of DP-b99 in healthy volunteers. DP-b99 is a newly developed lipophilic, cell permeable derivative of BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N ¢ ,N ¢ -tetraacetic acid), which selectively modulates the distribution of metal ions in hydrophobic milieu, and is in clinical development as a neuroprotectant for cerebral ischaemic stroke. To our knowledge no BAPTA derivative has ever been administered to man. Here we repor t the first human administration of DP-b99 in a phase I, two-part, double-blind, randomized placebo controlled study, with single IV doses of 0.003-1.0 mg kg -1 day -1 DP-b99 (part 1) or multiple ascending doses of 0.03-1.0 mg kg -1 day -1 DP-b99 over 4 days (part 2). MethodsA double-blind, dose escalating tolerability study of DP-b99 in normal (young -aged between 18 and 40 years and elderly -aged between 65 and 85 years) healthy adult male volunteers was conducted. Part 1 of the study investigated single administration of ascending intravenous doses, and part 2 examined the effects of ascending doses given repeatedly over 4 days . Twenty-four young volunteers in part 1 received single dose administrations and 26 young volunteers in part 2 received repeated ascending dose administrations of either intravenous DP-b99 or placebo. Subsequently, 10 elderly volunteers received repeated intravenous DP-b99 (1 mg kg -1 ) or placebo in part 2 over 4 days. Adverse events were identified by either subject self reporting or based upon laboratory parameters (blood chemistry, complete blood cell count, prothrombin time (PT), activated partial thromboplastin (PTT), physical examination, vital signs (blood pressure, pulse rate, respiratory rate, body temperature) and urinalysis. A comprehensive set of cardiovascular parameters was assessed as well (blood pressure, 12 lead-ECG recordings and continuous bedside cardiac monitoring for 6 h on day 1). ResultsThe administration of DP-b99 up to the highest dose of 1.0 mg kg -1 was well tolerated and had an acceptable safety profile up to the highest dose of 1.0 mg kg -1 tested in both study parts. No serious or severe adverse events were encountered. Eight mild to moderate adverse events were observed in six of the seven young subjects treated with four repeated doses of 1.0 mg kg -1 , with reversible phlebitis being the most frequently reported adverse event. The drug was tolerated better at the injection site by the elderly group compared with the younger subjects. No adverse effects were observed in cardiovascular parameters sensitive to trans-membranous calcium concentrations. The pharmacokinetic parameters were derived by noncompar tmental analysis. On day 1 following administration of 1 mg kg -1 the mean half-life of DP-b99 in young volunteers was 3.47 ± 0.90 h and in the elderly was 2.11 ± 0.09 h. On day 4 following the same administration of DP-b99 the mean half-life was 4.36 ± 1.49 and 2.10 ± 1.14 h in the young and elderly, respectively. There was higher systemic G. Rosenberg et al. 860 :1 Br J ...