Macrophages play a central role in the pathogenesis of atherosclerosis by accumulating cholesterol through increased uptake of oxidized low-density lipoproteins by scavenger receptor CD36, leading to foam cell formation. Here we demonstrate the ability of hexarelin, a GH-releasing peptide, to enhance the expression of ATP-binding cassette A1 and G1 transporters and cholesterol efflux in macrophages. These effects were associated with a transcriptional activation of nuclear receptor peroxisome proliferator-activated receptor (PPAR)gamma in response to binding of hexarelin to CD36 and GH secretagogue-receptor 1a, the receptor for ghrelin. The hormone binding domain was not required to mediate PPARgamma activation by hexarelin, and phosphorylation of PPARgamma was increased in THP-1 macrophages treated with hexarelin, suggesting that the response to hexarelin may involve PPARgamma activation function-1 activity. However, the activation of PPARgamma by hexarelin did not lead to an increase in CD36 expression, as opposed to liver X receptor (LXR)alpha, suggesting a differential regulation of PPARgamma-targeted genes in response to hexarelin. Chromatin immunoprecipitation assays showed that, in contrast to a PPARgamma agonist, the occupancy of the CD36 promoter by PPARgamma was not increased in THP-1 macrophages treated with hexarelin, whereas the LXRalpha promoter was strongly occupied by PPARgamma in the same conditions. Treatment of apolipoprotein E-null mice maintained on a lipid-rich diet with hexarelin resulted in a significant reduction in atherosclerotic lesions, concomitant with an enhanced expression of PPARgamma and LXRalpha target genes in peritoneal macrophages. The response was strongly impaired in PPARgamma(+/-) macrophages, indicating that PPARgamma was required to mediate the effect of hexarelin. These findings provide a novel mechanism by which the beneficial regulation of PPARgamma and cholesterol metabolism in macrophages could be regulated by CD36 and ghrelin receptor downstream effects.

CD36, a type B scavenger receptor expressed on macrophages, appears to play a major role in fatty streak formation through scavenging oxidatively modified lipoproteins in the arterial wall. We tested the hypothesis that EP 80317, a novel CD36 ligand derived from the growth hormone (GH)-releasing peptide family but devoided of any GH releasing activity, exerts anti-atherosclerotic effects in apolipoprotein E-deficient (apoE-/-) mice fed an atherogenic diet from 6 wk of age. Daily subcutaneous injections of EP 80317 (300 microg/kg) or vehicle were initiated at 6, 10, 12, or 14 wk until death at 18 wk. En face analyses of the entire aortic tree revealed a striking reduction (up to 51%) of lesion areas in EP 80317-treated apoE-/- mice compared with controls. Chronic treatment with EP 80317 (12 wk) is also associated with a 30% decrease in total plasma cholesterol, suggesting potential effects of this drug on cholesterol metabolism at the intestine/hepatic levels. EP 80317 exerts both preventive and curative effects on atherosclerotic lesion progression that were shown to be reversible after cessation of treatment. At the macrophage level, EP 80317 reduced oxidized low density lipoproteins internalization and up-regulated genes involved in cholesterol efflux, including peroxisome proliferator-activated receptor gamma (PPARgamma), liver x receptor alpha (LXRalpha), and the ATP binding cassette (ABC) transporters ABCA1 and ABCG1, supporting a role in regulating peripheral cholesterol trafficking. Importantly, the effects of EP 80317 were shown to be CD36 dependent, inasmuch as no anti-atherosclerotic or hypocholesterolemic effects were observed in apoE/CD36 double-deficient mice. In addition, long-term treatment of apoE/CD36 double-deficient mice with EP 80317 did not modulate the expression of genes of the PPARgamma-LXRalpha-ABC transporters pathway. Our results suggest that EP 80317, as a CD36 ligand, might be a prototype for a novel class of anti-atherosclerotic agents.

To gain better understanding of systemic lupus erythematosus (SLE) in Dubai we studied the clinical and immunological manifestations in a cohort of 151 patients attended Rheumatology Clinic in Dubai Hospital between January 2002 and January 2007. We found that the female to male ratio was 20.5:1, with a mean age of 35.5 years (0.9). The mean age at disease onset was 28.9 years (0.8) and mean disease duration 6.7 years (0.4). Five-year survival rate in our cohort was 94%. The commonest clinical manifestations in this cohort were arthritis (88%), haematological abnormalities (61.6%), and malar rash (60.3%). Leucopenia, fever, hair loss and proteinuria were observed in approximately half of the patients. Anaemia was found in 44.3% but only 9.9% had haemolytic anaemia. Photosensitive rash was seen in 43% of patients. Approximately one-third of the patients had serositis and mouth ulcers, 30.5 and 27.2% respectively. Vasculitis was observed in 19.2% of patients. Neuropsychiatric manifestations (15.9%), discoid lupus lesions (12.6%), and brain infarcts (13.2%) were infrequent. Subacute cutaneous lupus (6%) was also uncommon. Anti-nuclear antibodies were detected in 98%, anti-double stranded DNA antibodies in 88.7%, anti-Sm antibodies in 19.7%, anti-RNP in 40.4%, anti-Ro antibodies in 52.3% and anti-La antibodies in 19.8%. Anti-cardiolipin IgM and IgG were detected in 25.3 and 22.4%, respectively. This study suggests that Arabs with SLE residing in Dubai have comparable clinical features to their counterparts in other Arab countries and Western countries. The high prevalence of positive anti-Ro antibodies among our Arab patients probably reflects a character, that is, commonly seen in SLE patients of Middle East origin.

Our results support a role for CD36 signalling in the regulation of mononuclear phagocyte trafficking to atherosclerotic-prone sites and in the associated vascular wall inflammation.

SummaryAimsIn exocrine pancreatic insufficiency (EPI), the quantity and/or activity of pancreatic digestive enzymes are below the levels required for normal digestion, leading to maldigestion and malabsorption. Diagnosis of EPI is often challenging because the characteristic signs and symptoms overlap with those of other gastrointestinal conditions. Additionally, there is no single convenient, or specific diagnostic test for EPI. The aim of this review is to provide a framework for differential diagnosis of EPI vs other malabsorptive conditions.MethodsThis is a non‐systematic narrative review summarising information pertaining to the aetiology, diagnosis and management of EPI.ResultsExocrine pancreatic insufficiency may be caused by pancreatic disorders, including chronic pancreatitis, cystic fibrosis, pancreatic resection and pancreatic cancer. EPI may also result from extra‐pancreatic conditions, including coeliac disease, Zollinger‐Ellison syndrome and gastric surgery. Timely and accurate diagnosis of EPI is important, as delays in treatment prolong maldigestion and malabsorption, with potentially serious consequences for malnutrition, overall health and quality of life. Symptoms of EPI are non‐specific; therefore, a high index of clinical suspicion is required to make a correct diagnosis.