Phosphodiesterase 10A Upregulation Contributes to Pulmonary Vascular Remodeling

Phosphodiesterases (PDEs) modulate the cellular proliferation involved in the pathophysiology of pulmonary hypertension (PH) by hydrolyzing cAMP and cGMP. The present study was designed to determine whether any of the recently identified PDEs (PDE7-PDE11) contribute to progressive pulmonary vascular remodeling in PH. All in vitro experiments were performed with lung tissue or pulmonary arterial smooth muscle cells (PASMCs) obtained from control rats or monocrotaline (MCT)-induced pulmonary hypertensive (MCT-PH) rats, and we examined the effects of the PDE10 inhibitor papaverine (Pap) and specific small interfering RNA (siRNA). In addition, papaverine was administrated to MCT-induced PH rats from day 21 to day 35 by continuous intravenous infusion to examine the in vivo effects of PDE10A inhibition. We found that PDE10A was predominantly present in the lung vasculature, and the mRNA, protein, and activity levels of PDE10A were all significantly increased in MCT PASMCs compared with control PASMCs. Papaverine and PDE10A siRNA induced an accumulation of intracellular cAMP, activated cAMP response element binding protein and attenuated PASMC proliferation. Intravenous infusion of papaverine in MCT-PH rats resulted in a 40%–50% attenuation of the effects on pulmonary hypertensive hemodynamic parameters and pulmonary vascular remodeling. The present study is the first to demonstrate a central role of PDE10A in progressive pulmonary vascular remodeling, and the results suggest a novel therapeutic approach for the treatment of PH

Molecular pathology of human prion disease

Human prion diseases are associated with a range of clinical presentations and are classified by both clinicopathological syndrome and aetiology with sub-classification according to molecular criteria. Considerable experimental evidence suggests that phenotypic diversity in human prion disease relates in significant part to the existence of distinct human prion strains encoded by abnormal PrP isoforms with differing physicochemical properties. To date, however, the conformational repertoire of pathological isoforms of wild-type human PrP and the various forms of mutant human PrP has not been fully defined. Efforts to produce a unified international classification of human prion disease are still ongoing. The ability of genetic background to influence prion strain selection together with knowledge of numerous other factors that may influence clinical and neuropathological presentation strongly emphasises the requirement to identify distinct human prion strains in appropriate transgenic models, where host genetic variability and other modifiers of phenotype are removed. Defining how many human prion strains exist allied with transgenic modelling of potentially zoonotic prion strains will inform on how many human infections may have an animal origin. Understanding these relationships will have direct translation to protecting public health

Inflammatory resolution: New opportunities for drug discovery

Treatment of inflammatory diseases today is largely based on interrupting the synthesis or action of mediators that drive the host’s response to injury. Non-steroidal anti-inflammatories, steroids and antihistamines, for instance, were developed on this basis. Although such small-molecule inhibitors have provided the main treatment for inflammatory arthropathies and asthma, they are not without their shortcomings. This review offers an alternative approach to the development of novel therapeutics based on the endogenous mediators and mechanisms that switch off acute inflammation and bring about its resolution. It is thought that this strategy will open up new avenues for the future management of inflammation-based diseases

Gemcitabine alone or in combination with cisplatin in patients with advanced or metastatic cholangiocarcinomas or other biliary tract tumours: A multicentre randomised phase II study- the UK ABC-01 Study

Background: we assessed the activity of gemcitabine (G) and cisplatin/gemcitabine (C/G) in patients with locally advanced (LA) or metastatic (M) (advanced) biliary cancers (ABC) for whom there is no standard chemotherapy. Methods: patients, aged greater than or equal to18 years, with pathologically confirmed ABC, Karnofsky performance (KP) greater than or equal to60, and adequate haematological, hepatic and renal function were randomised to G 1000?mg?m?2 on D1, 8, 15 q28d (Arm A) or C 25?mg?m?2 followed by G 1000?mg?m?2 D1, 8 q21d (Arm B) for up to 6 months or disease progression.Results: in total, 86 patients (A/B, n=44/42) were randomised between February 2002 and May 2004. Median age (64/62.5 years), KP, primary tumour site, earlier surgery, indwelling biliary stent and disease stage (LA: 25/38%) are comparable between treatment arms. Grade 3–4 toxicity included (A/B, % patients) anaemia (4.5/2.4), leukopenia (6.8/4.8), neutropenia (13.6/14.3), thrombocytopenia (9.1/11.9), lethargy (9.1/28.6), nausea/vomiting (0/7.1) and anorexia (2.3/4.8). Responses (WHO criteria, % of evaluable patients: A n=31 vs B n=36): no CRs; PR 22.6 vs 27.8%; SD 35.5 vs 47.1% for a tumour control rate (CR+PR+SD) of 58.0 vs 75.0%. The median TTP and 6-month progression-free survival (PFS) (the primary end point) were greater in the C/G arm (4.0 vs 8.0 months and 45.5 vs 57.1% in arms A and B, respectively).Conclusion: both regimens seem active in ABC. C/G is associated with an improved tumour control rate, TTP and 6-month PFS. The study has been extended (ABC-02 study) and powered to determine the effect on overall survival and the quality of lif