Research news in brief

Sex differences in how blood pressure affects dementia risk

Differences in how blood pressure affects the risk of dementia in men and women may provide clues to help slow the rapid growth of the disease, according to research published in BMC Medicine. To examine sex differences in major cardiovascular risk factors for dementia, the researchers used the UK Biobank, a large-scale biomedical database that recruited 502 489 Britons aged 40–69 years (free from dementia at study initiation) between 2006 and 2010. They found that current smoking status, diabetes, high levels of body fat, having had a prior stroke, and low socio-economic status were all associated with a greater risk of dementia to a similar degree in women and men. But when it came to blood pressure, the relationship with dementia risk between the sexes was different. The study showed that both low and high blood pressure were associated with a greater risk of dementia in men, but for women the risk of dementia increased as blood pressure went up. Although the reason for this wasn’t clear, the authors proposed some possible explanations. “Biological differences between women and men may account for the sex differences we saw in the relationship between blood pressure and the risk of dementia,” the authors reported. “But there may also be differences in medical treatment for hypertension. For example, women are less likely to take medication as prescribed by their healthcare provider than men and may be taking more medications and experiencing more side effects. Our study suggests that a more individualised approach to treating blood pressure in men compared to women may result in even greater protection against the development of dementia. It also shows the importance of ensuring sufficient numbers of women and men are recruited into studies and that the data for women and men should be analysed separately.”

Towards a universal influenza vaccine for Indigenous populations

Researchers have identified specific influenza targets that could be used to better protect Indigenous people from experiencing severe influenza disease through a universal, T cell-based vaccine. In a study published in Nature Communications, Peter Doherty Institute for Infection and Immunity (Doherty Institute) researchers took a deep-dive look into how the immune system can protect Aboriginal and Torres Strait Islander people from severe influenza disease. The research team particularly focused on killer T cells and proteins called human leucocyte antigens (HLAs), important in determining immune responses to different pathogens. HLA proteins vary across individuals and ethnicities. A specific HLA protein, named HLA-A*24:02, can be linked to more severe (or even fatal) outcomes of influenza. It is also highly prevalent in Aboriginal and Torres Strait Islander people, as well as many other Indigenous populations around the world. Using state-of-the-art antigen discovery technology at Monash University, the researchers identified small fragments of influenza (peptide antigens) that were subsequently screened and then fragments which formed protective targets for killer CD8 T cells that are presented by HLA-A*24:02 were identified. “We propose that a universal influenza vaccine could be developed using these targets to promote optimal killer CD8 T cell response in the context of HLA-A*24:02,” the researchers wrote. “This could provide much better global protection and help prevent severe influenza disease and death in populations who are at higher risk. These findings are a significant step forward in understanding the immune profile of Aboriginal and Torres Strait Islander people and enable us to put that in context with the other determinants contributing to a higher risk of severe influenza. It is critical that future T cell-based influenza vaccines are designed to also protect ethnic populations who experience a high burden of disease.”

New therapy shows promise in future treatment of multiple myeloma

A preclinical study, published in Molecular Cell, has found multiple myeloma is highly sensitive to a newly developed experimental therapy. Multiple myeloma is a type of blood cancer that originates in plasma cells, immune cells in the bone marrow that normally produce protective antibodies. These abnormal plasma cells proliferate rapidly and do not produce productive antibodies thus reducing the body’s ability to fight infection. About 2000 Australians are diagnosed with multiple myeloma each year. The researchers explored the effects of new drugs that inhibit two closely related enzymes called P300 and CBP. P300 and CBP have long been suspected to work together to support cancer cell growth; however, there have been no drugs developed that can inhibit their activity until very recently, and their exact role in cancer was not completely understood. The new experimental therapy works by specifically turning off many important cancer-causing genes, lowering rates of transcription in the cancerous plasma cells and leading to their death. “Currently this experimental therapy is being tested in the laboratory only, we hope that these results might spur efforts to start testing in patients,” the authors wrote.

Long term health woes more likely to hit COVID-19 survivors

One in seven (14%) adults with coronavirus disease 2019 (COVID-19) developed at least one new condition that required medical care during the post-acute phase of illness, which is 5% higher than adults with no COVID-19 in 2020, according to a US study published by The BMJ. The post-acute phase in this study started 21 days (or 3 weeks) after initial infection. US researchers set out to evaluate the excess risk of developing new clinical conditions after the acute phase of COVID-19. Using health insurance records, they identified 266 586 adults (aged 18–65 years) diagnosed with COVID-19 from 1 January to 31 October 2020 and examined whether these individuals were diagnosed with at least one of 50 conditions up to 6 months after initial infection. Individuals were matched to three comparison groups with no COVID-19 infection from 2020, 2019, and a group diagnosed with other viral lower respiratory infections. Differences between groups, such as age, sex, area of residence and medical history were taken into account. The results show that 14% of adults with COVID-19 had at least one new condition that required medical attention after the acute phase of illness. This was 5% higher than in the 2020 comparison group and 1.65% higher than individuals diagnosed as having viral lower respiratory tract illness. The risk for specific conditions in the 4 months after the acute phase of COVID-19 – including chronic respiratory failure, heart rhythm problems, amnesia, diabetes, anxiety and fatigue – was greater than in all three comparison groups. While the overall absolute risk was small (an extra 0.02–2.26 per 100 people developing specific types of conditions compared with the 2020 comparison group), it persisted up to 6 months after initial infection. Risk increased with age, pre-existing conditions, and admission to hospital for COVID-19. However, younger adults (aged 50 years and under), those with no pre-existing conditions and those who recovered at home were also at risk for new conditions several months after initial infection. The researchers point out that this was an observational study.