The study, published in The American Journal of Human Genetics on May 2nd, reveals that the length of telomeres in white blood cells, also known as leukocytes, varies greatly among different sub-Saharan African populations. Additionally, researchers found that the length of leukocyte telomeres is negatively linked to the prevalence of malaria and is only partially influenced by genetic factors.ned by genetic factors.”We emphasize the impact of genetic and environmental factors on LTL, and we have revealed a potential connection between malaria and the shortening of LTL in sub-Saharan Africa,” says Sarah Tishkoff of the University of Pennsylvania, a co-senior author on the study. “The correlation between malaria and LTL seems to be more significant than any other known exposure or behavior that has been studied in large-scale research.”Telomeres are repetitive DNA sequences that protect the ends of chromosomes from damage. LTL varies greatly from person to person, with aAfricans generally have longer LTL than non-Africans, but it shortens with age and can predict aging-related diseases and mortality. LTL is a trait that is mostly inherited and the variation at birth determines it throughout life. However, most studies on LTL have focused on European populations, which limits our understanding of the genetic and environmental factors affecting LTL and its impact on telomere-related diseases.
One area of limited understanding is the influences of genetics, environment, and evolution on the considerable differences in LTL among sub-Saharan African populations. Genetic factors are the primary explanation for the variation in LTL, but it’s possible that environmental factors also play a role. An example of an environmental factor that could impact LTL is exposure to malaria caused by Plasmodium falciparum. Recent research has indicated a connection between malaria infection and LTL, making it a notable environmental factor to consider.
Although there is evidence suggesting a correlation between malaria infection and telomere shortening, the studies are based on individual, acute infection cases where participants were at risk of contracting malaria. Therefore, the relationship between malaria infection and LTL remains an area that requires additional exploration.The impact of repeated malaria exposure on the length of leukocyte telomeres (LTL) remains uncertain, especially in populations residing in regions where malaria is rampant. It is also not clear whether longer LTL at birth in malaria-prone areas or in regions with a high pathogen burden could confer selective advantages. To address these uncertainties, Tishkoff and co-author Abraham Aviv of Rutgers University conducted a study on LTL in various environmental settings across Africa, including highly malaria-endemic regions. The researchers extracted DNA from blood cells, genotyped individuals, and measured LTL.The study included 1,818 adults from Tanzania, Botswana, Ethiopia, and Cameroon, who were ethnically diverse. The findings showed that there was a significant difference in LTL (leukocyte telomere length) across different populations. The San hunter-gatherers from Botswana had the longest telomeres, while the Fulani pastoralists from Cameroon had the shortest telomeres. Genetic factors accounted for about half of the variation in LTL among individuals.
Additionally, the study found that adults living in regions with high malaria prevalence had shorter LTL compared to those living in regions with low malaria prevalence. These findings highlight the potential impact of malaria prevalence on LTL.The impact of malaria on LTL is greater than previously thought. Malaria may lead to a shorter LTL due to the destruction and replacement of red blood cells. According to Tishkoff, erythrocytes outnumber leukocytes by a large margin and make up the majority of somatic cells in the body. As a result, the telomere length reserves of the hematopoietic system are mainly used to maintain the massive pool of erythrocytes in the human body.The researchers suggest that a long-term study involving children and adults living in areas with high and low levels of malaria transmission would provide more valuable insights. They propose that the impact of malaria on the shortening of telomeres in hematopoietic cells occurs primarily during childhood, even though the data on telomere length are based on adults. The next step in testing the relationship between malaria and telomere length is to study the dynamics of telomere length in children who were born and raised in high malaria areas compared to those in low or non-malaria areas. This study was funded by the National Institutes of Health.The study was funded by the National Institutes of Health, an American Diabetes Association Pathway to Stop Diabetes grant, and the Center of Excellence in Environmental Toxicology (CEET) at the University of Pennsylvania.
Â
