Pharmacogenetics in cardiovascular diseases: State of the art and implementation-recommendations of the French National Network of Pharmacogenetics (RNPGx)

The use of genomic markers to predict drug response and effectiveness has the potential to improve healthcare by increasing drug efficacy and minimizing adverse effects. Polymorphisms associated with inter-individual variability in drug metabolism, transport, or pharmacodynamics of major cardiovascular drugs have been identified. These include single nucleotide polymorphisms (SNP) affecting clinical outcomes in patients receiving antiplatelet agents, oral anticoagulants and statins. Based on clinical evidence supporting genetic testing in the management of cardiovascular diseases using these drug classes, this short review presents clinical guidance regarding current pharmacogenetics implementation in routine medical practice.

Lyn tyrosine kinase regulates androgen receptor expression and activity in castrate-resistant prostate cancer

Castrate-resistant prostate cancer (CRPC) progression is a complex process by which prostate cells acquire the ability to survive and proliferate in the absence or under very low levels of androgens. Most CRPC tumors continue to express the androgen receptor (AR) as well as androgen-responsive genes owing to reactivation of AR. Protein tyrosine kinases have been implicated in supporting AR activation under castrate conditions. Here we report that Lyn tyrosine kinase expression is upregulated in CRPC human specimens compared with hormone naive or normal tissue. Lyn overexpression enhanced AR transcriptional activity both in vitro and in vivo and accelerated CRPC. Reciprocally, specific targeting of Lyn resulted in a decrease of AR transcriptional activity in vitro and in vivo and prolonged time to castration. Mechanistically, we found that targeting Lyn kinase induces AR dissociation from the molecular chaperone Hsp90, leading to its ubiquitination and proteasomal degradation. This work indicates a novel mechanism of regulation of AR stability and transcriptional activity by Lyn and justifies further investigation of the Lyn tyrosine kinase as a therapeutic target for the treatment of CRPC.

Invasive Geotrichum clavatum fungal infection in an acute myeloid leukaemia patient: a case report and review

Invasive Geotrichum clavatum fungal infections are extremely rare and unusual, occurring nearly exclusively in patients experiencing prolonged neutropenia during the treatment for acute myeloid leukaemia. Several groups of cases of fatal G. clavatum infection were reported in France between 2011 and 2012, but the ecological niche has not yet been identified. We report a case of a 32-year-old patient with acute myeloid leukaemia who developed G. clavatum sepsis with primary peritonitis, hepatic nodular lesions, and multivisceral failure during aplasia after induction followed by salvage chemotherapy. He was treated with voriconazole and is still alive 1 year after with controlled disease. We then discuss the epidemiological, clinical, and therapeutic features of these serious fungal infections compared to the published data.

Design and discovery of soluble epoxide hydrolase inhibitors for the treatment of cardiovascular diseases

INTRODUCTION

Cardiovascular diseases are a leading cause of death in developed countries. Increasing evidence shows that the alteration in the normal functions of the vascular endothelium plays a major role in the development of cardiovascular diseases. However, specific agents designed to prevent endothelial dysfunction and related cardiovascular complications are still lacking. One emerging strategy is to increase the bioavailability of epoxyeicosatrienoic acids (EETs), synthesized by cytochrome P450 epoxygenases from arachidonic acid. EETs are endothelium-derived hyperpolarising and relaxing factors and display attractive anti-inflammatory and metabolic properties. Genetic polymorphism studies in humans, and experiments in animal models of diseases, have identified soluble epoxide hydrolase (sEH), the major enzyme involved in EET degradation, as a potential pharmacological target.

AREAS COVERED

This review presents EET pathway and its functions and summarises the data supporting the development of sEH inhibitors for the treatment of cardiovascular and metabolic diseases. Furthermore, the authors present the different chemical families of sEH inhibitors developed and their effects in animal models of cardiovascular and metabolic diseases.

EXPERT OPINION

Several generations of sEH inhibitors have now been designed to treat endothelial dysfunction and cardiovascular complications for a variety of diseases. The safety of these drugs remains to be carefully investigated, particularly in relation to carcinogenesis. The increasing knowledge of the biological role of each of the EET isomers and of their metabolites may improve their pharmacological profile. This, in turn, could potentially lead to the identification of new pharmacological agents that achieve the cellular effects needed without the deleterious side effects.

Quantitative proteomic analysis of cyclosporine-induced toxicity in a human kidney cell line and comparison with tacrolimus

The calcineurin-inhibitors (CNIs) cyclosporine (CsA) and tacrolimus (TAC) remain the pillars of modern immunosuppression regimens used in solid organ transplantation. Nephrotoxicity is an adverse effect that limits their successful use. The precise molecular mechanisms underlying this nephrotoxicity remain unclear. Using SILAC together with LC-MALDI-TOF/TOF, we investigated the CNIs-induced proteomic perturbations in renal cells. Among the 495 proteins quantifiable in both forward and reverse SILAC, 69 displayed CsA-induced perturbations: proteins involved in ER-stress/protein folding, apoptosis, metabolism/transport or cytoskeleton pathways were up-regulated, while cyclophilin B as well as nuclear and RNA-processing proteins were down-regulated. Co-administration of CsA with the antioxidant N-acetylcysteine significantly decreased lipid peroxidation and also partially corrected the CsA-induced unfolded protein response. TAC toxicity profile was apparently different from that of CsA, especially without perturbation of cyclophilins A and B, up-regulation of ER-chaperones nor down-regulation of a number of nuclear proteins. These results provide a new insight and are consistent with recent data regarding the molecular mechanisms of CNIs-induced nephrotoxicity. Our findings offer new directions for future research aiming to identify specific biomarkers of CsA nephrotoxicity.

Regulation of osteoprotegerin pro- or anti-tumoral activity by bone tumor microenvironment

Tumor development in bone is often associated with fractures, bone loss and bone pain, and improvement is still needed in therapeutic approaches. Bone tumors are related to the existence of a vicious cycle between bone resorption and tumor proliferation in which the molecular triad osteoprotegerin (OPG)/receptor activator of NF-kappaB (RANK)/RANK ligand (RANKL) plays a pivotal role. RANKL, a member of the TNF superfamily, is one of the main inducers of bone resorption. Its soluble receptor OPG represents a promising therapeutic candidate as it prevents bone lesions and inhibits associated tumor growth. However, its therapeutic use in bone tumors remains controversial due to its ability to bind and inhibit another member of the TNF superfamily, TNF related apoptosis inducing ligand (TRAIL), which is a potent inducer of tumor cell apoptosis. Through its heparin binding domain, OPG is also able to bind proteoglycans present in the bone matrix. This paper is an overview of the involvement of the micro-environment, as represented by the balance of RANKL/TRAIL and the presence of proteoglycans in the regulation of OPG biological activity in bone tumors.

Stability of antibiotics in portable pumps used for bronchial superinfection: guidelines for prescribers

OBJECTIVES

The aims of this study were (1) to collect data on the stability of antibiotics in portable pumps for the treatment of bronchial superinfection in patients with cystic fibrosis and (2) to provide guidelines for prescribers.

METHODS

The stability over 72 hours, in portable pumps stored at 35 degrees C, of piperacillin plus tazobactam, ticarcillin plus clavulanic acid, cefsulodin, cefepime, and aztreonam was checked at 3 different concentrations. Stability was assessed through visual examination, pH measurements, and direct measurements of drug concentrations by using high-performance liquid chromatography. All parameters were measured at time 0, time 0 plus 24 hours, and time 0 plus 72 hours.

RESULTS

Degradation rates for penicillin plus beta-lactamase inhibitor combinations remained <10% at time 0 plus 24 hours for all drugs, but the rate for piperacillin reached 12% for the highest concentration tested. The cephalosporins cefepime and cefsulodin had significant respective degradation rates of 18% and 28% at time 0 plus 24 hours and 60% and 68.5% at time 0 plus 72 hours, which were linked to the storage temperature. Aztreonam seemed to be stable over 72 hours.

CONCLUSIONS

This work provides data on drug stability that were lacking, allowing recommendations for physicians to optimize the safety and efficacy of antibiotic treatment of patients with cystic fibrosis. Piperacillin plus tazobactam and ticarcillin plus clavulanic acid infusions must be limited to 24 hours, and patients receiving cefepime or cefsulodin must wear a cold pack close to the ambulatory drug-delivery device during the infusion.

RANKL, RANK, osteoprotegerin: key partners of osteoimmunology and vascular diseases

1997 saw the identification of a novel set of proteins within the tumor necrosis factor (TNF)/TNF receptor families that are required for the control of bone remodeling. Therefore, these receptors, receptor activator of nuclear factor kappa B (RANK), osteoprotegerin (OPG) and their ligand RANK ligand (RANKL) became the critical molecular triad controlling osteoclastogenesis and pathophysiologic bone remodeling. However, the establishment of the corresponding knock-out and transgenic mice revealed unexpected results, most particularly, the involvement of these factors in the vascular system and immunity. Thus, the OPG/RANK/RANKL molecular triad appears to be associated with vascular calcifications and plays a pivotal function in the development of the immune system through dendritic cells. OPG/RANK/RANKL thus constitute a molecular bridge spanning bone metabolism, vascular biology and immunity. This review summarizes recent knowledge of OPG/RANK/RANKL interactions and activities as well as the current evidence for their participation in osteoimmunology and vascular diseases. In fine, the targeting of the OPG/RANK/RANKL axis as novel therapeutic approaches will be discussed.

[Treatment of bronchial superinfections: data related to stability of antibiotics in portable pumps]

INTRODUCTION

Given many data about the stability of antibiotics in portable pump (elastomer) are lacking, this study was designed to make a point about available data and to evaluate the stability of antibiotics when exposed to temperature within 35 degrees C (average temperature measured in real conditions of use).

MATERIAL AND METHODS

First, to collect information about the stability of antibiotics in portable pump and to confront them with the local antibiotics protocols dedicated to the treatment of bronchial superinfection in patients with cystic fibrosis; second, to evaluate the stability of piperacillin associated with tazobactam at 35 degrees C.

RESULTS

While measured concentrations in tazobactam did not show significant variation during the study, piperacillin measurements showed a major reduction of concentration (up to 33%), both time and concentration related to.

DISCUSSION

Such information must be pointed out to prescribers and patients to ensure a cold accumulator is placed in the pump carrying-bag and to limit the duration of infusion to 24 h with a single pump.

CONCLUSION

This experimental program will keep on going with the stability study of both ticarcillin and cefsulodin in portable pump.

Evaluation of vasospasm secondary to subarachnoid hemorrhage with technetium-99m-hexamethyl-propyleneamine oxime (HM-PAO) tomoscintigraphy

Vasospasm of intracranial vessels is difficult to diagnose on clinical ground alone. Still, a clear diagnosis is important because it can impact on surgical timing; and also because it can help evaluate new treatments. Fifteen patients with sub-arachnoid hemorrhage secondary to aneurysm rupture were submitted to a total of 26 tomographic technetium-99m-hexamethyl-propyleneamine oxime (99mTc-HM-PAO) brain examinations that were correlated with temporally close (generally less than 24 hr) angiography or transmission computed tomography (TCT). Nine of 10 angiographically confirmed episodes of spasm and 6 of 6 infarcts seen on angiography or TCT were correctly diagnosed with 99mTc-HM-PAO. One normal scintigraphic exam was angiographically doubtful, one positive 99mTc-HM-PAO study was normal on angiography (sub-radiologic spasm?), one technically poor scintigraphy was positive for spasm on angiograms, and eight exams were normal for spasm with all modalities. We had agreement between tests in 23 of 26 series of exams (88%) obtained in 15 patients. We think that 99mTc-HM-PAO tomography should be useful for the evaluation of patients with suspected vasospasm.

Dipyridamole testing compared to exercise stress for thallium-201 imaging in patients with left bundle branch block

Because of numerous reports of false positive results with thallium-201 (Tl-201) stress testing in patients with left bundle branch block, the authors decided to evaluate another mode of coronary vasodilatation, dipyridamole, for the diagnosis of coronary atheromatosis. Nine patients were prospectively studied with stress and dipyridamole Tl-201 scintigraphy; both tests were performed within three to 79 days of one another. Five of the patients also had coronary angiograms (four within one year, one five years earlier). Four of the patients had normal results with both tests (two normal angiograms, two not performed); two had reversible septal defects with stress-induced coronary vasodilatation but normal dipyridamole studies (only one had an angiogram, which was normal); one patient had a fully reversible septal defect with stress and a fixed defect with dipyridamole (normal angiogram); one had a partially reversible septal stress defect which was fixed with dipyridamole; and one had a normal stress study but a reversible septal defect with dipyridamole (an angiogram performed five years earlier showed 30 to 40% stenosis of the anterior descending artery). Because it seems that dipyridamole produces fewer false positive results, it should be used instead of stress testing to induce coronary vasodilatation in patients with left bundle branch block.

Spontaneous resolution of severe right ventricular dysfunction in right ventricular infarction: documentation by radionuclide studies

A case of inferior myocardial infarction complicated by severe arrhythmias and right heart failure is presented. Radionuclide studies performed near the acute phase and one month later illustrate the reversibility of right heart dysfunction caused by infarction. Signs of right ventricular involvement in acute inferior myocardial infarction are noted in about 40% of cardiac blood-pool studies: right ventricular dilatation with a significantly decreased ejection fraction, and ventricular wall motion abnormalities. Follow-up studies in the recovery period show good recovery of right ventricular function.