Medical Bulletin 22/August/2026

Here are the top medical news for today:

Nicotine Directly Damages Blood Vessels, Raising Heart Attack and Stroke Risk: Study

A new review published in Nature Reviews Cardiology has mapped how nicotine can damage blood vessels, tracing its effects from receptor activation to processes that may contribute to atherosclerosis, plaque rupture, heart attacks and strokes.

The review examined mechanistic, biomarker, preclinical and clinical evidence across major nicotine-containing products. Researchers found that nicotine can directly affect two key types of cells in blood vessel walls: endothelial cells lining the vessels and vascular smooth muscle cells surrounding them.

In endothelial cells, nicotine suppresses prostacyclin, a substance that helps blood vessels relax, while increasing endothelin-1, a powerful vessel-constricting hormone. At the same time, nicotine acts on smooth muscle cells, disrupting potassium channels and calcium regulation. Together, these effects can promote blood-vessel constriction, impaired vascular function and conditions that favour clot formation.

The researchers also outlined a hierarchy of cardiovascular harm across nicotine products. Combustible products, including cigarettes and waterpipes, were associated with the highest cardiovascular risk. They were followed by heated tobacco products, e-cigarettes and oral nicotine products such as pouches and chewing tobacco. Complete abstinence was identified as the only risk-free option.

The authors emphasized that eliminating combustion may reduce cardiovascular harm compared with conventional smoking, but does not eliminate the effects associated with nicotine exposure.

The review also highlights nicotine's strong dependence-forming potential and calls for more consistent regulation across nicotine products rather than separate rules for individual categories.

The researchers recommend stronger measures to prevent nicotine initiation, particularly among young people, alongside taxation, restrictions on flavours and improved evidence-based cessation support.

Importantly, the review does not suggest that every nicotine product carries identical risk. Instead, it indicates that cardiovascular harm exists on a continuum, with combustible products posing the greatest danger and non-combustible products still carrying potential cardiovascular risks.

REFERENCE: Münzel, T., Kuntic, M., Keaney, J.F. et al. Nicotine-containing products and the cardiovascular system: mechanisms and global health implications. Nat Rev Cardiol (2026). https://doi.org/10.1038/s41569-026-01331-6

Pomegranate-Derived Compound Improves Heart Function by Up to 80% in Study

A compound produced by the body after consuming foods such as pomegranates, walnuts and some berries may offer a new treatment approach for heart failure with preserved ejection fraction (HFpEF), according to researchers at King’s College London.

The study, funded by the British Heart Foundation, is set to be published in Science Advances.

The compound, urolithin A, was found to improve the heart’s ability to relax, reduce scarring and limit harmful enlargement of heart muscle in experimental models.

Heart failure with preserved ejection fraction accounts for roughly half of heart failure cases. In this condition, the heart can still pump blood normally but becomes stiff and has difficulty relaxing and filling between beats. Patients may experience breathlessness, fatigue and reduced exercise capacity, while treatment options remain relatively limited.

Researchers discovered that urolithin A activates PKG1α, a protein involved in blood-vessel function and heart-muscle relaxation. The compound targets a specific amino acid on this protein, triggering a pathway that may improve cardiovascular function.

In animal models, urolithin A improved measures of heart function by up to 80% compared with untreated models. It also increased heart-tissue relaxation, reduced fibrosis and limited enlargement of heart muscle cells.

The researchers then tested the compound in engineered human heart tissue derived from human stem cells. Urolithin A significantly improved the tissue's ability to relax, providing additional evidence that the biological mechanism could potentially be relevant to human heart function.

Urolithin A has already been studied in humans and has shown a favourable safety profile. However, the new findings are still preclinical.

Researchers stress that there is currently not enough evidence to recommend eating pomegranates or taking urolithin A to treat heart failure. Clinical trials in people will be needed to determine whether the benefits seen in animals and engineered heart tissue translate into actual improvements for patients.

REFERENCE: Jie Su et al. ,Targeting PKGIα Cys42 attenuates cardiac dysfunction in heart failure with preserved ejection fraction.Sci. Adv.12,eaec8088(2026).DOI:10.1126/sciadv.aec8088

Researchers Explain Why Walking Becomes Increasingly Difficult With Age

Ageing was associated with a “safety-first” walking strategy in older adults, with the body prioritizing stability over speed and energy efficiency, according to researchers from Flinders University and the University of Canberra.

The study, published in Gait & Posture, analyzed movement data from 107 healthy adults aged 26 to 86 years to examine how ageing affects the ankle and muscles involved in walking.

Researchers found that older adults were more likely to activate opposing muscles around the ankle at the same time, a pattern known as co-contraction. This makes the ankle joint stiffer and can improve stability when the foot contacts the ground.

However, the increased stiffness also means muscles work harder without generating as much forward movement, potentially making walking more tiring.

Older participants also produced less push-off power with each step. This was associated with shorter strides and slower walking speeds, helping explain why longer-distance walking may become more physically demanding with age.

The researchers suggest these changes reflect a broader “safety-first” strategy adopted by the nervous system. By prioritizing stability over performance, the body may help reduce the risk of losing balance, but this can come at the cost of movement efficiency and endurance.

The study also highlights potential implications for fall prevention. Reduced ability to recover from trips or slips, combined with changes in muscle coordination, may contribute to greater fall risk and reduced confidence on uneven surfaces.

Researchers say exercise programs for older adults should focus not only on strength but also on balance, coordination and movement control. Activities such as tai chi, lower-leg strengthening and exercises that challenge coordination may help support mobility and independence.

Further research is needed to determine whether targeted exercise can counter these age-related changes and improve walking efficiency, stability and fall recovery in older adults.

REFERENCE: Cody Lindsay, Ceridwen R. Radcliffe, Maarten A. Immink. Ageing alters ankle mechanics and muscle co-contraction patterns across the gait cycle. Gait, 2026; 128: 110202 DOI: 10.1016/j.gaitpost.2026.110202