Increased cardiovascular risk in HIV-infected patients may relate to arterial inflammation
The elevated risk of cardiovascular disease seen in patients infected with HIV appears to be associated with increased inflammation within the arteries, according to a study that will appear in a special issue of JAMA published in conjunction with the International AIDS Conference. The report from Massachusetts General Hospital (MGH) found that levels of inflammation within the aortas of HIV-infected individuals with neither known cardiovascular disease nor elevated traditional risk factors were comparable to those of patients with established cardiovascular disease.
"Several recent studies, including ones that we've done, have found that HIV-infected patients have about twice the risk of heart attack and stroke as non-infected individuals do," says Steven Grinspoon, MD, director of the MGH Program in Nutritional Metabolism and a member of the Neuroendocrine Unit, the study's principal investigator. "These new data suggest a plausible mechanism through which increased arterial inflammation related to activation of the immune system may increase the risk of cardiovascular events in these patients."
While traditional risk factors such as accumulation of abdominal fat, smoking, high blood pressure and elevated cholesterol levels have been thought to contribute to the increased cardiovascular risk in HIV-infected patients, investigators also have theorized that inflammation may play a role as well. Previous evidence suggesting an association was based on measurements of inflammatory markers like C-reactive protein in the bloodstream, but the current study is the first to provide direct evidence of increased inflammation in the arterial walls of patients with HIV.
The investigators, including Ahmed Tawakol, MD, co-director of the MGH Cardiac MR-PET-CT Program, analyzed the results of PET and CT scans of 81 participants: 27 HIV-infected individuals without known cardiovascular disease, all receiving antiretroviral therapy; 27 non-infected controls without atherosclerosis, matched with the HIV group in terms of age, gender and traditional cardiovascular risk factors; and 27 non-infected controls known to have atherosclerosis, matched by gender with the HIV group. All of the PET scans used a radiopharmaceutical called FDG, which accumulates in areas of inflammatory activity. Imaging data for both control groups were selected prospectively from a database of patients who had been scanned for clinical diagnosis of non-HIV related conditions.
The FDG PET scans revealed that levels of inflammation in the aortas of the HIV-infected participants were higher than those seen in control participants without atherosclerosis and were actually comparable to levels seen in control participants with cardiovascular disease. Levels of arterial inflammation in the HIV group were not affected by traditional risk factors or the type of antiviral treatment they received, and increased inflammation was even seen in patients whose viral levels were at undetectable levels. Measurement of circulating inflammatory markers found that levels of soluble CD163, a marker of monocyte activation, were elevated in the HIV group; but no differences were seen in markers of generalized inflammation.
"Activated monocytes part of the innate immune system may be attracted to plaque lesions in the arteries, where they become activated macrophages that release substances contributing, over time, to plaque rupture and heart attack," Grinspoon explains. "Activated macrophages also can release chemical signals that attract more monocytes, setting up a vicious cycle. We previously showed that increased CD163 levels were associated with noncalcified plaque, which is more susceptible to rupture. Our new findings that levels of CD163, but not other inflammatory markers, are related to inflammation signified by the uptake of FDG even among patients without detectible virus suggest that soluble CD163 could be a useful marker of risk-associated inflammation in HIV patients."
A professor of Medicine at Harvard Medical School, Grinspoon stresses that these results do not imply that modification of traditional risk factors is not important in HIV-infected patients but that nontraditional risk factors such as arterial inflammation should also be considered and potentially targeted by new therapies. While FDG-PET scanning would not be appropriate for mass screening of patients, measurement of inflammatory markers like CD163 levels should be explored. His team is currently investigating whether statin treatment might reduce arterial inflammation among HIV-infected patients, the majority of whom demonstrate only modest increases in cholesterol levels.
"Our data also suggest that targeting monocyte activation may be a unique strategy to reduce arterial inflammation in these patients, have implications about the pathogenesis of cardiovascular disease in other inflammatory conditions, and emphasize a new way to look at risk in such patients," Grinspoon adds.
Journal reference: Journal of the American Medical Association
Provided by Massachusetts General Hospital
- HIV infection appears to increases the risk of heart attack Apr 24, 2007 | not rated yet | 0
- Study finds increased presence, severity of coronary artery plaques in HIV-infected men Jan 07, 2010 | not rated yet | 0
- Diabetes drug halts atherosclerosis progression in HIV-infected patients Mar 07, 2012 | not rated yet | 0
- HIV patients at greater risk for bone fractures Aug 28, 2008 | not rated yet | 0
- Low level HIV in bloodstream not linked with inflammation or death Nov 08, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
(AP)—The decade-old law that transformed the battle against HIV and AIDS in developing countries is at a crossroads. The dream of future generations freed from the epidemic is running up against an era ...
HIV & AIDS 7 hours ago | not rated yet | 0
The hunt for an HIV vaccine has gobbled up $8 billion in the past decade, and the failure of the most recent efficacy trial has delivered yet another setback to 26 years of efforts.
HIV & AIDS May 19, 2013 | 5 / 5 (1) | 0
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
HIV & AIDS May 18, 2013 | 5 / 5 (2) | 0
Researchers at the University of Cincinnati (UC) have found that incorporating a peer-referral program for HIV testing into emergency departments can reach new groups of high-risk patients and brings more patients into the ...
HIV & AIDS May 17, 2013 | not rated yet | 0
(HealthDay)—Liver transplants to treat a common type of liver cancer are a viable option for people infected with HIV, according to new research.
HIV & AIDS May 17, 2013 | not rated yet | 0
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
56 minutes ago | not rated yet | 0 |
Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.
42 minutes ago | 4.5 / 5 (2) | 0 |
The level of immunity to the recently circulating H7N9 influenza virus in an urban and rural population in Vietnam is very low, according to the first population level study to examine human immunity to the virus, which was ...
21 minutes ago | not rated yet | 0 |
Researchers at Emory University have identified a protein that stimulates a pair of "orphan receptors" found in the brain, solving a long-standing biological puzzle and possibly leading to future treatments for neurological ...
18 minutes ago | not rated yet | 0 |
In a striking, unexpected discovery, researchers at Albert Einstein College of Medicine of Yeshiva University have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The finding ...
33 minutes ago | 5 / 5 (1) | 0 |
Prostaglandin analogues (PGAs), drugs which lower intraocular pressure, are often the first line of treatment for people with glaucoma, but their use is not without risks. PGAs have long been associated with blurred vision, ...
20 minutes ago | not rated yet | 0