Ethnic Minorities in Cardiovascular Research; New Approach to HIV Vaccine; Post-Mortem SARS Study

Ethnic minority groups must be included in European health research

Despite the knowledge that ethnicity matters in cardiovascular disease, most studies of cardiovascular disease risk have not been designed to yield results that apply to different ethnic groups, report Meghna Ranganathan and Raj Bhopal (of Edinburgh University) in a new study in the international open-access medical journal PLoS Medicine.

To ensure that the results of research studies can be applied to everyone in a multicultural society, it is important that all racial and ethnic groups are included in health research. This need is especially obvious for studies of diseases for which it is known that different risk factors exist in different parts of the population. Cardiovascular disease, the number one killer in most developed countries, is one of them. The disease, which is the underlying cause for heart attacks, strokes, and other serious health threats, is a major cause of death for all ethnic groups, and the risk is especially high in individuals originating from South Asia. In the UK for example, early deaths from coronary heart disease in Indians, Bangladeshis, Pakistanis, and Sri Lankans are about 50% higher than the national average. For Caribbeans and West Africans, on the other hand, the rates are much lower than average.

To examine whether ethnicity was taken into account in cardiovascular disease research, Ranganathan and Bhopal conducted a systematic review of the medical literature. They analyzed in detail 72 large studies that examined cardiovascular disease risk in European and North-American populations.

The results highlight a disconnect between the world of research and the “real world” of increasingly diverse societies: most of the studies did not provide detailed information on the ethnic composition of the broader populations from which the participants were recruited, nor did they state whether minority groups were included or excluded from the study. Many of them did not give details on the ethnic composition of the participants themselves, or on how the participants’ ethnicity was determined. Studies with participants that were representative of diverse populations usually were not large enough to answer the kind of questions necessary to determine differences between different ethnic groups.

However, among the more recent studies, ten were designed to specifically compare white and non-white participants, and five studies focused on non-white minority groups specifically. All fifteen of those studies were done in the US. As the authors conclude, “urgent action is needed in Europe” to ensure that research studies reflect the increasingly multicultural nature of the societies there, and are thus relevant to all of parts of those societies.

Taking an alternative approach to HIV vaccination

Researchers from Baylor College of Medicine have shown that switching off a molecule that helps regulate dendritic cells, specialized white blood cells that activate the immune system, could help the host fight HIV infection.

Increasing evidence suggests the host’s immune system plays an important, but insufficient, role in limiting HIV infection. Most attempts to stimulate an immune response to HIV have been disappointing.

Exploiting the potential of dendritic cells to activate the immune system could help scientists develop an effective host response to prevent or control HIV infection, according to the US study.

Si-Yi Chen and colleagues studied a molecule, SOCS1, which regulates how antigens (small parts of proteins from microbes or tumour cells, which trigger an immune response) are handled by dendritic cells. They have previously found that dendritic cells in which the SOCS1 was turned off were more efficient at stimulating others of the body’s immune cells.

Now Chen and colleagues have found that in mice SOCS1 is part of a pathway that not only controls the production of compounds (cytokines) that stimulate inflammation but also has a critical role in regulating the anti-HIV immune response. Dendritic cells in which SOCS1 was switched off were able to induce a good memory immune response to HIV. In addition, the potency of HIV DNA vaccination was enhanced by co-immunization with an interfering RNA that switched off SOCS1.

The authors suggest that this SOCS1 silencing strategy could help enhance therapeutic and prophylactic vaccines against HIV and other pathogens.

THE FOLLOWING ARTICLE WILL ALSO BE PUBLISHED ONLINE:

Largest post-mortem study of SARS deaths teaches scientists about the disease

Led by John Nicholls of Hong Kong University, researchers from Hong Kong and from Toronto (two of the cities worst affected by the 2003 SARS outbreak) joined forces for a large and detailed study of the bodies of 32 patients who had died from SARS. The results, reported in the international open-access journal PLoS Medicine, suggest ways when and how treatments for this disease might be most effective.

The findings suggest that the SARS virus causes illness and death by attacking cells in the alveolar epithelium, a particular tissue that lines the lung. The virus multiplies mostly within this group of cells, and only for a limited time after infection. Antiviral drugs are likely to be only useful during this initial time window after infection. After less than two weeks, the body’s immune system seems to be able to fight back and prevent the virus from further multiplying, but this does not lead to recovery in all patients. In fact, most of the patients in this study (25 out of 32) died more than two weeks after they fell ill and without signs that the SARS virus was still multiplying in their body. This suggests that disease progression and death is not dependent on continued widespread virus multiplication but that in patients who die the initial damage to the lungs is so severe that they cannot recover. The study also suggests that death from SARS is not due to the virus multiplying outside of the lungs.