Rheumatic manifestations in HIV-1 infected in-patients and literature review

OBJECTIVE

To report the rate and spectrum of the rheumatic manifestations of human immunodeficiency virus (HIV) since the advent of highly active anti-retroviral therapy (HAART).

METHODS

A retrospective record review of 888 inpatients with HIV for rheumatic manifestations was performed from January 1995 to March 2006. We then searched the 888 records for rheumatic diseases using International Classification Diagnostic (ICD) Codes. The medical records of the cases of HIV with the rheumatic conditions were then reviewed. A computer-assisted search of Medline/Pubmed for the medical literature from January 1981 to August 2007 using the keywords HIV, acquired immune-deficiency syndrome, rheumatic manifestations, combining with text words like systemic lupus erythematosus (SLE). Only English language literature was included.

RESULTS

The demographic data of 888 cases of HIV included men (64%) and women (36%) with a mean age of 41.5+/-10.2 years. Race consisted of Black (70%), White (22.8%), Hispanic (6.5%), and others (1.1%). Rheumatic manifestations were present in 80 (9%) with arthritis/arthralgia 49 (5.5%), septic arthritis 9 (1%), and osteomyelitis 8 (0.9%), connective tissue diseases (CTDs) 6 (0.7%) (SLE 3, rheumatoid arthritis 1, polymyositis 1, and systemic sclerosis 1), avascular necrosis 6 (0.7%) (hips 3, knees 2, and shoulder 1). There were no cases of seronegative spondyloarthritis or Sjögren's syndrome.

CONCLUSIONS

There was an association of HIV with rheumatic conditions in 9%, including CTDs and avascular necrosis. In addition, there were no cases of the seronegative spondyloarthritis subsets. This change in spectrum from prior reports suggests the rheumatic manifestations of HIV have changed, perhaps related to HAART.

A combination of a PPAR-gamma agonist and an angiotensin II receptor blocker attenuates proinflammatory signaling and stimulates expression of Smad7 in human peritoneal mesothelial cells

BACKGROUND

Human peritoneal mesothelial cells (HPMCs) have been shown to regulate the inflammatory response and the subsequent peritoneal extracellular matrix accumulation (ECM) induced by bio-incompatible peritoneal dialysis solutions. Recently, attention has been given to the possible antiinflammatory effect exhibited by angiotensin receptor blockers (ARB) or PPAR-gamma agonists in several tissues including glomerular. As no data on the potential role of these commonly used drugs in reducing peritoneal fibrosis exist, we examined the in vitro effects of an ARB (losartan) and a PPAR-gamma agonist (rosiglitazone) on inflammatory and profibrotic pathways in cultured HPMCs subjected to high glucose.

METHODS

HPMCs were incubated for 48 hours with 3 different concentrations of glucose: 5 mM (G5), 50 mM (G50) and 100 mM (G100), as well as G50 with either losartan (5 or 10 microM) and/or rosiglitazone (1 or 10 microM). IL-6, IL-8, VEGF and TGF-beta1 in the supernatants were measured by cytokine multiplex assays or ELISA. Smad7, the inhibitor of the TGF/Smad signaling pathway, was measured using immunocytochemistry.

RESULTS

All the measured cytokines increased in proportion to increased concentration of glucose. Unexpectedly, this effect was not inhibited, but rather further enhanced, by rosiglitazone and losartan separately. However, only the combination of the two drugs had an inhibitory effect on TGF- beta1 and IL-6, while the expression of inhibitory Smad7 was increased.

CONCLUSION

We conclude that high glucose exposure stimulates an inflammatory response in HPMCs in a dose-dependent manner. Rosiglitazone and losartan appear to have synergetic effects which could decrease fibrosis by inhibiting inflammation and regulating the TGF/Smad signaling pathway, but further studies are needed to elucidate the complex pathways modulated by these drugs.

Reverse cholesterol transport and cholesterol efflux in atherosclerosis

Reverse cholesterol transport (RCT) is a pathway by which accumulated cholesterol is transported from the vessel wall to the liver for excretion, thus preventing atherosclerosis. Major constituents of RCT include acceptors such as high-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I), and enzymes such as lecithin:cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), hepatic lipase (HL) and cholesterol ester transfer protein (CETP). A critical part of RCT is cholesterol efflux, in which accumulated cholesterol is removed from macrophages in the subintima of the vessel wall by ATP-binding membrane cassette transporter A1 (ABCA1) or by other mechanisms, including passive diffusion, scavenger receptor B1 (SR-B1), caveolins and sterol 27-hydroxylase, and collected by HDL and apoA-I. Esterified cholesterol in the HDL is then delivered to the liver for excretion. In patients with mutated ABCA1 genes, RCT and cholesterol efflux are impaired and atherosclerosis is increased. In studies with transgenic mice, disruption of ABCA1 genes can induce atherosclerosis. Levels of HDL are inversely correlated with incidences of cardiovascular disease. Supplementation with HDL or apoA-I can reverse atherosclerosis by accelerating RCT and cholesterol efflux. On the other hand, pro-inflammatory factors such as interferon-gamma (IFN-gamma), endotoxin, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), can be atherogenic by impairing RCT and cholesterol efflux, according to in vitro studies. RCT and cholesterol efflux play a major role in anti-atherogenesis, and modification of these processes may provide new therapeutic approaches to cardiovascular disease. Further research on new modifying factors for RCT and cholesterol efflux is warranted.