[Vol 39] Medi-Scene: Your Weekly Health News Update

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MediScene Vol 391. Asymptomatic covid-19 could be safer, t-cell study suggests

A small UK study has found that “cellular immunity” to the pandemic SARS-CoV-2 virus is present after six months in people who had mild or asymptomatic Covid-19 infections – suggesting they might have some level of protection for at least that time. Paul Moss, a professor of haematology at Britain’s Birmingham University who co-led the study, “While our findings cause us to be cautiously optimistic about the strength and length of immunity generated after SARS-CoV-2 infection, this is just one piece of the puzzle. There is still a lot for us to learn before we have a full understanding of how immunity to Covid-19 works.” The study, which has not yet been peer-reviewed by other experts but was published online on bioRxiv, analysed the blood of 100 patients six months after they had had either mild or asymptomatic Covid-19. It found that while some of the patients’ antibody levels had dropped, their T-cell response – another key part of the immune system – remained robust. The study also found the size of T-cell response differed, and was considerably higher in people who had had symptomatic Covid-19 than those who had no symptoms when infected. Charles Bangham, chair of immunology at Imperial College London said, “These results provide reassurance that, although the titre of antibody to SARS-CoV-2 can fall below detectable levels within a few months of infection, a degree of immunity to the virus may be maintained. However, the critical question remains: do these persistent T-cells provide efficient protection against re-infection?”

2. Biodegradable patch developed to monitor glucose by Anna University

To reduce medical waste from glucose test strips, researchers from Anna University have developed a biodegradable material, a cellulose derivative-based polymer, for detecting glucose and alcohol level from sweat. Due to the highly flexible and transparent nature of the material, it could be used as a wearable non-invasive sensor and can be attached to a smart watch to display the concentration of glucose and alcohol in the sweat. It can also be connected to an app, which can send an alert if the alcohol consumption is higher than a set limit. “The lowest detection limit found for glucose is 0.4 mM (millimolar) whereas for that of ethanol it was found to be 0.34 mM (millimolar),” researchers said in their article, “Non-Invasive, Non-Enzymatic, Biodegradable and Flexible Sweat Glucose Sensor and Its Electrochemical Studies”, published in Chemistryselect, an European journal published in September 2020. Preethi Ramadoss, lead researcher from Anna University said, “The cellulose material completely degrades within 15 days. It is a very easily available material at low cost. The available disposable test strips are made of plastics and not degradable. The lancets which contain blood can also transmit infectious diseases like HIV, Hepatitis B and it poses serious environmental risk. The material is also antibacterial, hence it can be safely used on sensitive skin without causing any infections.” Since the new material functions as a working electrode, they have to print just two electrodes on top of it without adding any inorganic compounds like zinc oxide.

3. New cause of inflammation identified in HIV patients

In a major study, researchers have identified the important factors which could be contributing to the chronic inflammation in people living with HIV. While current antiretroviral treatments for HIV are highly effective, data has shown that people living with HIV appear to experience accelerated aging and have shorter lifespans by up to five to 10 years compared to people without HIV. These outcomes have been associated with chronic inflammation, which could lead to the earlier onset of age-associated diseases, such as atherosclerosis, cancers, or neurocognitive decline.In a major study, researchers have identified the important factors which could be contributing to the chronic inflammation in people living with HIV. While current antiretroviral treatments for HIV are highly effective, data has shown that people living with HIV appear to experience accelerated aging and have shorter lifespans — by up to five to 10 years — compared to people without HIV. These outcomes have been associated with chronic inflammation, which could lead to the earlier onset of age-associated diseases, such as atherosclerosis, cancers, or neurocognitive decline. Nina Lin from the Boston University in the US said, “Our study set out to identify a possible association between HIV latently infected cells with chronic inflammation in people with HIV who have suppressed viral loads. Our findings suggest that novel treatments are needed to target the inflammation persistent in people living with HIV. Current antiretroviral drugs prevent new infection, but they do not prevent HIV RNA production, which our results point as a potential key factor driving inflammation in people living with HIV.”

4. Research shows molecular link between cancer risk and meat diet

An international team of researchers has identified a direct molecular link between meat and dairy diets and the development of antibodies in the blood that increase the chances of developing cancer. This connection may explain the high incidence of cancer among those who consume large amounts of dairy products and red meat, similar to the link between high cholesterol and an increased risk of heart disease. According to the study, published in the journal BMC Medicine, Neu5Gc is a sugar molecule found in the tissues of mammals but not in poultry or fish. While it is known that these antibodies increase the risk of cancer, especially colorectal cancer, no direct link has been found between the antibodies and meat and dairy consumption. Study author Vered Padler-Karavani from the Tel Aviv University in Israel, “We found a significant correlation between high consumption of Neu5Gc from red meat and cheeses and increased development of those antibodies that heighten the risk of cancer.” The research team members measured the amount of Neu5Gc sugar in a variety of dairy and meat foods common in the French diet and calculated the daily Neu5Gc intake of 19,621 adults aged 18 and over, who reported all of their food intake online over a period of several days. Based on these findings and the quantification of Neu5Gc sugar in various food products from France, the team created an index called the Glycemic index. This index ranks foods whose excessive consumption can lead to an increase in the antibodies – and possibly to an increase in the risk of cancer. They found a significant correlation between high consumption of Neu5Gc from red meat and cheeses and increased development of those antibodies that heighten the risk of cancer. “We were able to find a molecular link thanks to the accuracy of the methods used to measure the antibodies in the blood and the detailed data from the French diet questionnaires,” the study authors noted.

5. Flavanols present in apple, berries and tea helps lowering blood pressure

New research shows that a high intake of dietary flavanols, compounds found in plant-based foods, is associated with significantly lower systolic and diastolic blood pressure. Lead author Gunter Kuhnle, Dr rer nat, professor of nutrition and food science, University of Reading, UK said, “The results reinforce the message that dietary interventions, especially those that emphasize fruits and vegetables, can have a beneficial effect on blood pressure.” Flavan-3-ols (flavanols) are a major class of dietary bioactives commonly found in pome fruits, especially apples, as well as berries, cocoa-derived products, red wine, and leafy greens. Dr Gunter Kuhnle further added, “These novel biomarkers allow rigorous and more objective and accurate investigations into associations between actual flavan-3-ol intake and health in observational cohorts at scales relevant to human populations. The English are known for their tea drinking, which makes the population ideal for investigating the impact of flavanols. Participants attended a health examination during which investigators collected nonfasting urine samples and blood pressure data at the same time, so the flavanols were still in the system.” Data on urine samples were adjusted for “specific gravity,” which Kuhnle explained is the level of dilution due to water intake. Participants were divided into those with low or high biomarker concentrations based on the urine samples. Biomarker concentrations were available for 24,152 participants, and 55% were women. Results showed that participants with the highest 10% of flavanol intake had a blood pressure on average 1-3 mm Hg lower than those with the lowest 10% of intake. The differences in effect sizes for the two biomarkers were negligible. Subgroup analyses showed the effect was more pronounced in participants at higher risk of developing CVD, in particular older patients and those with hypertension. Dr Kunhle said, “It essentially supports our assumption that self-reporting doesn’t work for compounds like flavanols. There’s a huge variability in food composition, for example, one cup of tea can have a wide range of flavanol levels depending on the source of the tea leaves and how the beverage is prepared. This can be explained by the magnitude of difference in systolic blood pressure observed, which would not be expected to have a significant impact on individual CVD risk.”  Penny Kris-Etherton, PhD, distinguished professor of nutrition, Penn State, said, “Eating more plant-based foods, including fruits, vegetables, whole grains, legumes, and nuts aligns with American Heart Association current dietary recommendations. And although the literature suggests flavonoids have antioxidant and anti-inflammatory effects, now we’re learning they play a role in controlling blood pressure. We all know that fruits and vegetables are high in potassium, which has a blood pressure-lowering effect, and are also high in dietary nitrates and nitrites, which play a role in achieving healthy endothelium and healthy vasculature, but now we know that fruits and vegetables and plant foods have yet another compound that helps achieve healthy blood pressure, and that’s the flavanols.”

6. Probiotic Blend May Help Patients With GI Symptoms 

A new study shows that a novel five-strain probiotic blend could provide relief for patients with functional gastrointestinal (GI) disorders. Lead study investigator Lucinda A. Harris, MD, MS, from the Mayo Clinic School of Medicine in Scottsdale, Arizona, “The combination improved the patient’s functional GI symptoms and displayed a favorable safety profile. Results of this study are promising, and additional studies would support the novel probiotic blend’s efficacy, safety, and durability of effect. Multiple pathophysiologic processes may cause functional GI symptoms, including altered gut microbiota. The administration of probiotics can impact intestinal microbial balance, thereby contributing to improvement in functional GI symptoms.” Patients were assessed at multiple time points: screening (days –15 to –1), baseline (day 1), day 14, day 30, and a follow-up visit (day 42). The study’s primary efficacy endpoint was patient-reported improvement in overall GI well-being at day 30. Secondary outcomes included changes in GI symptoms, assessed with the 11-point GI Health Symptom Questionnaire. The incidence of treatment-emergent adverse events was assessed during all patient visits. “In addition, we observed a mean decrease in I-FABP [intestinal fatty-acid binding protein] of 32.7% in patients with the highest quartile of baseline I-FABP levels,” Harris reported. David A. Johnson, MD, from the Eastern Virginia Medical School in Norfolk said, “We know that the biome has a role in modulating a number of physiologic processes, so looking at biomic influence for functional disease makes sense. When you do an open-label trial in functional diseases, there’s a high placebo rate response. This effect is less pronounced in longer trials, but shorter trials like this one definitely carry the risk of increased placebo responses. Although promising, a randomized control trial evaluating the microbiome as a response to the treatment intervention would be extremely helpful in defining the true role of effect.”

Reference links:

  1. https://health.economictimes.indiatimes.com/news/industry/t-cell-study-gains-insight-into-covid-19-immunity-asymptomatic-people-could-be-safer/79010474
  2. https://health.economictimes.indiatimes.com/news/medical-devices/anna-university-develops-biodegradable-patch-to-monitor-glucose/78990421
  3. https://health.economictimes.indiatimes.com/news/diagnostics/researchers-identify-new-cause-of-inflammation-in-hiv-patients/78995781
  4. https://health.economictimes.indiatimes.com/news/diagnostics/study-finds-molecular-link-between-meat-diet-cancer-risk/78842775
  5. https://www.medscape.com/viewarticle/939669
  6. https://www.medscape.com/viewarticle/939933

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