New Molecule Protects Cardiomyocytes
Heat shock transcription factor 1, identified through the death-trap method, proved itself to be an effective protector of cardiomyocytes in tests undertaken by researchers from the University of Tokyo Graduate School of Medicine and the Yamaguchi University Graduate School of Medicine in Japan and reported in this week’s issue of the journal Circulation (Circulation. 2003;108:3024–3030OpenUrl).
When the researchers, led by Yunzeng Zou, MD, PhD, of the University of Tokyo Graduate School of Medicine, attempted to induce cell death with hydrogen peroxide in COS7 cells, the overexpression of heat shock transcription factor 1 prevented the cells from dying. When the hearts of transgenic mice overexpressed an active form of heat shock transcription factor 1, they more quickly overcame the negative effects of ischemia followed by ST-segment elevation induced by reperfusion and had infarcts of smaller size than did normal mice under similar conditions. Protein kinase B/Akt was more strongly activated and Jun N-terminal kinase and caspase 3 were less activated in the hearts of the transgenic mice than in the hearts of the normal mice.
C-Reactive Protein Associated With Atrial Fibrillation
C-reactive protein—a marker of inflammation—is associated with atrial fibrillation and may even predict the risk of developing the condition in the future, said researchers from the Cleveland Clinic, University of Washington, Wake Forest University School of Medicine in Winston-Salem, NC, and the University of Vermont who took part in the Cardiovascular Health Study. They reported their results in this week’s issue of Circulation (Circulation. 2003;108:3006–3010OpenUrl).
In this large cohort study of the association between C-reactive protein and atrial fibrillation, researchers led by Ronnier J. Aviles, MD, now of the National Heart, Lung and Blood Institute in Bethesda, Md, measured the level of the protein and cardiovascular health status of 5806 subjects enrolled in the Cardiovascular Health Study. The patients were then followed up for a mean of 6.9 years.
At baseline, 315 subjects had atrial fibrillation. Those with higher levels of C-reactive protein were more likely to have atrial fibrillation than those with lower levels and were more likely to develop atrial fibrillation in the future, according to the researchers.
C-Reactive Protein, Blood Pressure, and Future Heart Problems
Increasing levels of C-reactive protein and blood pressure are both independent predictors of the risk of developing cardiovascular disease, said researchers from the Women’s Health Study in a report in this week’s issue of the journal Circulation (Circulation. 2003;108:2993–2999OpenUrl). In addition, the researchers reported that the predictive value of the 2 factors is additive.
In this study, the researchers led by Gavin J. Blake, MD, MPH, from the Center for Cardiovascular Disease and Prevention and the Donald W. Reynolds Center for Cardiovascular Research at the Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass, monitored 15 215 women prospectively for a median of 8.1 years. In their prospective analyses, elevated levels of C-reactive protein and increasing levels of blood pressure were independent determinants of future cardiovascular events. In fact, C-reactive protein levels were predictive of cardiovascular events at all blood pressure levels.
Inflammation May Play a Role in Hypertension
High levels of inflammation, represented by increasing levels of C-reactive protein, are associated with an increased risk of developing hypertension, said researchers from the Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass, in the December 10, 2003, issue of The Journal of the American Medical Association (JAMA. 2003;290:2945–2951OpenUrlCrossRefPubMed).
In the study, the researchers led by Howard D. Sesso, ScD, MPH, studied 20 525 women subjects in the Women’s Health Study, measured C-reactive protein levels at the beginning of the study, and monitored them for a median of 7.8 years. During that time, 5365 of the women became hypertensive, and the researchers found a positive correlation between increasing levels of the protein and the development of hypertension. The authors wrote, “These data suggest that inflammation may have a potentially important role in the development of hypertension.”
Long Flight Associated With Blood Clot Risk
The risk of developing blood clots during air flights may be increased for people with certain genetic predispositions and for those who are in the air longer than 8 hours, according to researchers in studies published in this month’s issue of the Archives of Internal Medicine (Arch Intern Med. 2003;163:2771–2774; 2003;163:2759–2764).
In one study, Ida Martinelli, MD, PhD, of the University of Milano in Italy, and her colleagues performed DNA analysis and blood tests on 210 people who developed venous thromboembolism and 210 who did not. In their studies, the Italian researchers looked for genetic factors and levels of blood components that are known to increase the risk of these kinds of blood clots. In the month before suffering the venous thromboembolism, 31 of the subjects who had the problem had traveled by air. By contrast, only 16 of the subjects who not developed thromboembolism had traveled by air.
Dr Martinelli and her colleagues found that 102 of the patients who had had a venous thromboembolism had genetic and blood factors associated with an increased risk of the problem. Only 26 of the controls had such genetic or blood factors. The risk of venous thromboembolism in subjects who had flown and also had the genetic and blood risk factors was 16 times that of patients who did not fly and lacked the other risk factors, she and her colleagues concluded. Women who took oral contraceptives and had flown within a month were at a 13-fold higher risk of developing thromboembolism than women who did not have those risk factors.
In an accompanying article, Thomas Schwarz, MD, of the University of Dresden Medical School in Germany, and his colleagues studied 964 passengers who had been on airline flights longer than 8 hours and compared them with 1213 subjects who had not flown. A total of 27 airline passengers developed venous thrombosis, whereas 12 controls did. Of these, 20 passengers and 10 controls had venous thrombosis isolated to the calf muscle. Dr Schwarz and his colleagues concluded that long-haul flights do present an increased risk for deep venous thrombosis in those patients with risk factors for the problem.