Expression and functional role of adenosine receptors in regulating inflammatory responses in human synoviocytes

Background and purpose:

Adenosine is an endogenous modulator, interacting with four G-protein coupled receptors (A₁, A_2A, A_2B and A₃) and acts as a potent inhibitor of inflammatory processes in several tissues. So far, the functional effects modulated by adenosine receptors on human synoviocytes have not been investigated in detail. We evaluated mRNA, the protein levels, the functional role of adenosine receptors and their pharmacological modulation in human synoviocytes.

Experimental approach:

mRNA, Western blotting, saturation and competition binding experiments, cyclic AMP, p38 mitogen-activated protein kinases (MAPKs) and nuclear factor (NF)-κB activation, tumour necrosis factor α (TNF-α) and interleukin-8 (IL-8) release were assessed in human synoviocytes isolated from patients with osteoarthritis.

Key results:

mRNA and protein for A₁, A_2A, A_2B and A₃ adenosine receptors are expressed in human synoviocytes. Standard adenosine agonists and antagonists showed affinity values in the nanomolar range and were coupled to stimulation or inhibition of adenylyl cyclase. Activation of A_2A and A₃ adenosine receptors inhibited p38 MAPK and NF-κB pathways, an effect abolished by selective adenosine antagonists. A_2A and A₃ receptor agonists decreased TNF-α and IL-8 production. The phosphoinositide 3-kinase or G_s pathways were involved in the functional responses of A₃ or A_2A adenosine receptors. Synoviocyte A₁ and A_2B adenosine receptors were not implicated in the inflammatory process whereas stimulation of A_2A and A₃ adenosine receptors was closely associated with a down-regulation of the inflammatory status.

Conclusions and implications:

These results indicate that A_2A and A₃ adenosine receptors may represent a potential target in therapeutic modulation of joint inflammation.     

Antibody-dependent Lymphocyte-mediated Cytotoxicity in Man: No Requirement for Lymphocytes with Membrane-bound Immunoglobulin

Normal human lymphocytes, depleted of B-lymphocytes by passage through nylon-wool columns, manifested intact antibody-dependent cell-mediated cytotoxicity. Similar findings were made with lymphocytes from four hypo-gammaglobulinaemic patients lacking B-lymphocytes. It is concluded that antibody-induced cell-mediated cytotoxicity in man is independent of B-lymphocytes, as identifiable by membrane-bound immunoglobulin.     

Developments in hepatitis C therapy during 2000-2002

Hepatitis C virus (HCV) is a human hepatotropic virus with an estimated worldwide prevalence of 170 million cases, including approximately 4 million cases in the US. It is a major cause of liver disease and is the most common indication for liver transplantation in the US. The majority of infected individuals are eligible for therapy. Since it is difficult to predict who will have progressive disease, those with significant inflammation or fibrosis on histologic examination of liver biopsy are generally offered treatment. The following chapter is an overview of the patent literature during 2000-mid-2002, and discusses the potential of various treatment modalities for HCV.     

Plasma growth hormone response to growth hormone-releasing hexapeptide (GH-RP-6) in children with short stature

Eighteen children with short stature were evaluated for growth hormone (GH) reserve after pharmacological tests and a single iv injection of GH-RP-6. These children were divided into two groups: 10 were diagnosed as having idiopathic GH deficiency by classical stimulation tests (group A) and the remaining 8 (group B) were considered growth-retarded children with normal GH secretion, following conventional stimulation, but reduced endogenous GH secretion. The results were compared with a group of 12 normal children. As a group, patients in group A showed a lower GH response to GH-RP-6, while patients in group B had a similar response as normal controls. However, on an individual basis, a considerable degree of overlapping in responses among the three groups was evident. These data indicate that, on an individual basis, GH-RP-6 testing is not of diagnostic value in children suspected of having idiopathic GH deficiency.GH deficiency, GH-RP-6, short stature C Dieguez, PO Box 563, 15705 Santiago de Compostela, Spain     

Review article: diagnosis and treatment of non-alcoholic fatty liver disease

Background  Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent condition affecting adults and children, leading to significant morbidity. It is often associated with the metabolic syndrome, although multiple pathogenetic mechanisms have been suggested. In the coming decades, it promises to be the leading cause of liver disease in industrial countries.
Aim  To provide a comprehensive, updated review of diagnosis and management of NAFLD and to appraise the evolution of new modalities in these areas.
Methods  An Ovid MEDLINE search was performed to identify pertinent original research and review articles. Selected references in these articles were also evaluated.
Results  The diagnosis of hepatic steatosis and steatohepatitis or non-alcoholic steatohepatitis (NASH) is not yet possible without liver biopsy. This is impractical given the large numbers affected by the condition. Current therapy has focused on improving insulin resistance and mediators of inflammation, factors probably associated with disease progression.
Conclusions  There are no proven non-invasive diagnostic modalities to distinguish NAFLD and NASH, but new biomarker panels are approximating the liver biopsy in accuracy. Therapeutic targets of drug development are in early stages, but a multifaceted approach will probably yield several treatment options in the years to come.     

糖尿病大鼠卵巢组织中细胞色素C、线粒体Ca2+变化与灵芝孢子粉的干预

目的:以卵巢组织中细胞色素C、线粒体Ca2 和性激素水平为观察指标,观察灵芝孢子粉对2型糖尿病大鼠卵巢组织的保护作用。方法:实验于2006-06/08在佳木斯大学黑龙江省小儿神经康复重点实验室完成。①实验对象:Wistar雌性大鼠50只,随机分为对照组10只,2型糖尿病模型组20只,灵芝孢子粉组20只。②实验方法:大鼠禁食16～18h,自由饮水,模型组及灵芝孢子粉组大鼠经尾静脉一次性按25mg/kg注射2%链脲佐菌素,正常对照组尾静脉注射等量柠檬酸钠-柠檬酸缓冲液。正常饮食喂养2周后,进行糖耐量试验,模型组和灵芝组以糖耐量异常者保留,余去除,并改喂高脂高糖饮食,灵芝孢子粉组另加灵芝孢子粉[250mg/(kg·d)]持续10周,实验结束前一天再次做糖耐量试验。③实验评估:实验结束后,各组动物均禁食12h,乙醚吸入浅麻醉,内眦静脉取血待测血清胰岛素。解剖出卵巢,待测线粒体细胞色素C、线粒体Ca2 含量。结果:选用Wistar雌性大鼠50只,结果分析数量每组8只。①葡萄糖耐量试验:实验开始及实验12周时,模型组大鼠均表现出糖耐量异常的变化(P<0.05),1h血糖增高显著(P<0.05)达到高峰,2h血糖仍较高;对照组大鼠30min血糖达到峰值,2h血糖基本恢复正常。②血清胰岛素和卵巢性激素水平:模型组血清胰岛素明显升高(P<0.05)。而灵芝孢子粉组与对照组比较差异无显著性。模型组雌二醇含量明显降低(P<0.05),卵胞刺激素含量、睾酮含量明显升高(P<0.05),而灵芝孢子粉组与对照组比较差异无显著性。③胞浆细胞色素C、线粒体细胞色素C、线粒体钙变化:模型组卵巢组织胞浆细胞色素C含量明显升高(P<0.05),模型组卵巢组织线粒体细胞色素C含量明显降低(P<0.05),模型组卵巢组织线粒体钙含量明显降低(P<0.05);而灵芝孢子粉组与对照组比较差异均无显著性。结论:灵芝孢子粉可降低糖尿病大鼠血清胰岛素、卵巢组织卵胞刺激素、睾酮、胞浆细胞色素C含量,调节卵巢组织雌二醇、线粒体细胞色素C、钙含量,对糖尿病大鼠卵巢组织具有一定保护作用。