Day: July 27, 2023

Categories : Diseases, Syndromes and Conditions VaccinesTags : Leave a comment

More Monkeypox Antibodies with Childhood Smallpox Vaccination

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Mpox (monkeypox) virus. Source: NIH

In a study published in Cell Host & Microbe, scientists studied the sensitivity of MPXV, the virus that causes mpox (formerly monkeypox) to neutralising antibodies (NAbs) generated after infection with the virus and/or vaccination with IMVANEX. They found that those who had been born before 1980 had more antibodies in response to either IMVANEX vaccination or mpox infection, highlighting the lasting protection of smallpox vaccination.

The IMVANEX vaccine has been used as pre- and post-exposure prophylaxis in high-risk populations, but its effectiveness is not yet well characterised. To analyse the sensitivity of the virus, a team of scientists led by Pasteur Institut developed two cellular tests to quantify neutralising antibodies, using either the attenuated virus as a vaccine (MVA) or an MPXV strain isolated in a recently infected individual.

In 2022-2023, an unprecedented epidemic of 87 000 cases of mpox occurred in non-endemic areas, affecting people with no direct link to travel in Central or West Africa, where the virus has historically been present. MPXV is mainly transmitted to humans by rodents, with human-to-human transmission occurring via respiratory droplets or close contact. Symptoms are less severe than those of smallpox, and the case-fatality rate is lower. MPXV is still circulating at very low levels in non-endemic areas, which is why it is important to improve characterisation and analyse the immune response of people infected with the virus or vaccinated with IMVANEX, the third-generation vaccine currently available, initially developed for smallpox.

The large number of sera analysed provided good statistical power, meaning that the analysis could be narrowed to subgroups of patients based on various criteria such as age.

The study demonstrated the role of complement, already known for other poxviruses, and the neutralising activity of the antibodies generated by infection or vaccination. Robust levels of anti-MVA antibodies were detected after infection, vaccination with the historic smallpox vaccine, or administration of IMVANEX or another MVA-based vaccine candidate. MPXV was minimally sensitive to neutralisation in the absence of complement. The addition of complement from sera enhanced detection of individuals with antibodies and increased their level of anti-MPXV antibodies. Four weeks after infection, anti-MVA and -MPXV NAbs were observed in 94% and 82% of individuals, respectively. Two doses of IMVANEX generated anti-MVA and -MPXV NAbs that were detectable in 92% and 56% of vaccinees, respectively.

The highest level of antibodies was found in individuals born before 1980 (who had therefore been vaccinated for smallpox), whether after infection or after administration of IMVANEX, highlighting the impact of historic smallpox vaccination on immune responses to infection or administration of IMVANEX. This suggests that a sort of hybrid immunity was generated in infected individuals who were vaccinated in childhood.

The number of MPXV infections has been constantly on the rise since mass vaccination for smallpox was discontinued in the 1980s. “The neutralisation assays developed in connection with this research may help define correlates of protection against infection or disease severity. The assays can also be used to conduct epidemiological surveys, assess the duration of protection conferred by previous infection or by authorised and candidate vaccines, and analyse the use of immunotherapeutic intervention. The assays represent useful tools to understand the mechanisms of multiplication of MPXV and its effects on public health, and to optimsze patient treatment,” commented Olivier Schwartz, Head of the Institut Pasteur’s Virus and Immunity Unit and last author of the study.

Source: Institut Pasteur

Categories : Cardiovascular Disease Metabolic DisordersTags : Leave a comment

SGLT-2 Inhibitors Reduce HF Hospitalisation Risk in Type 2 Diabetes

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A study published in Annals of Internal Medicine has suggested that the new sodium-glucose co-transporter 2 inhibitors (SGLT-2i) may be viable as a first-line treatment in patients with type 2 diabetes (T2D), with reduced odds of hospitalisation for heart failure compared to those receiving metformin.

In cardiovascular outcome trials among adults with T2D, SGLT-2i have shown therapeutic promise, including reduced risk of hospitalisation for heart failure compared to placebo. However, SGLT-2i have mainly been evaluated as a second-line treatment, as metformin is generally given as a first-line, antidiabetic treatment.

In a new study, researchers from the Brigham compared cardiovascular outcomes among adults with T2D who initiated first-line treatment with either metformin or SGLT-2i. For the study, 8613 patients treated with SGLT-2i were matched to 17 226 patients treated with metformin. The authors found that patients receiving SGLT-2i showed a similar risk for myocardial infarction, stroke, and all-cause mortality, and a lower risk for hospitalization for heart failure compared with patients who received metformin. The risk for adverse events was similar except for an increased risk for genital infections compared with those receiving metformin.

“Our results suggest that SGLT-2i may be considered as first-line treatment for patients with T2D and cardiovascular disease or who are at increased risk for cardiovascular events,” said lead author HoJin Shin, BPharm, PhD, of the Division of Pharmacoepidemiology and Pharmacoeconomics. “However, more evidence from randomised clinical trials or observational studies will help us to identify patients who would benefit most from using SGLT-2i as first-line type 2 diabetes treatment.”

Source: EurekAlert!

Categories : Genetics Medical Research & TechnologyTags : Leave a comment

New CRISPR Discovery Targets Infected Cells

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CRISPR-Cas9 is a customisable tool that lets scientists cut and insert small pieces of DNA at precise areas along a DNA strand. This lets scientists study our genes in a specific, targeted way. Credit: Ernesto del Aguila III, National Human Genome Research Institute, NIH

German and US scientists have discovered a CRISPR system in cells that shuts them down entirely to protect against viral replication, instead of merely chopping out foreign DNA that it comes across. It does this by shredding any DNA or RNA it comes across, causing the cell to become senescent and not become a virus factory. The newly identified CRISPR system is described in two papers published in Nature.

“With this new system, known as Cas12a2, we’re seeing a structure and function unlike anything that’s been observed in CRISPR systems to date,” says Jackson, assistant professor in Utah State’s Department of Chemistry and Biochemistry.

CRISPR, (Clustered Regularly Interspaced Short Palindromic Repeats) has taken science by storm with its gene-editing potential. Study of CRISPR DNA sequences and CRISPR-associated (Cas) proteins, which are actually bacterial immune systems, is still a young field.

Identified as a distinct immune system within the last five years, the Class 2, type V Cas12a2 is somewhat similar to the better-known ‘molecular scissors’ of CRISPR-Cas9, which binds to target DNA and cuts it, effectively shutting off a targeted gene. But CRISPR-Cas12a2 binds a different target than Cas9, and that binding has a very different effect.

Using cryo-electron microscopy, the team captured the CRISPR-Cas12a2 in a naturally occurring defensive strategy called abortive infection, a natural resistance strategy used by bacteria and archaea to limit the spread of viruses and other pathogens by preventing replication in the cell.

The team observed Cas12a2 in the act of cutting double-stranded DNA, bending it 90° to expose the backbone of the helix to cut it, a phenomenon that a phenomenon that elicits audible gasps from fellow scientists,” Jackson says.

Since the difference between a healthy cell and a malignant cell or infected cell is genetic, if Cas12a2 could be harnessed, “the potential therapeutic applications are significant.”

“If Cas12a2 could be harnessed to identify, target and destroy cells at the genetic level, the potential therapeutic applications are significant,” he says.

Source: Utah State University

Categories : Ageing Cardiovascular DiseaseTags : Leave a comment

Rethink Preventative Aspirin for Older Adults, Researchers Say

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Photo by cottonbro studio: https://www.pexels.com/photo/person-holding-white-round-medication-pill-4661296/

Low-dose aspirin is used as primary prevention for ischaemic stroke, but its protective effect weighed against the increased risk of bleeding events is controversial. A new secondary analysis of daily aspirin in older people found that, in this population, aspirin failed to reduce the risk for ischaemic stroke but increased it for intracranial bleeding. The findings were presented in JAMA Network Open.

The researchers analysed data from the ASPREE randomised clinical trial, the first large-scale trial to study the risks and benefits of 100mg daily aspirin in an older population, where increased bleeding risk may alter the balance of risks and benefits of aspirin. This is particularly relevant to intracerebral events because intracranial haemorrhage is harder to treat than ischaemic events and more frequently fatal or disabling. With previous aspirin trials in mostly younger participants, excess intracerebral haemorrhagic events was seen, though usually few in number and non-significant.

Cloud et al. performed a secondary analysis of the ASPREE trial, which included 19 114 older adults, and found a statistically significant 38% increase in intracranial bleeding resulting from a combination of haemorrhagic stroke and other causes of intracerebral haemorrhage among individuals randomised to aspirin. The difference in incidence of ischaemic stroke was not statistically significant.

While aspirin did not cause a statistically significant reduction in ischaemic stroke (hazard ratio [HR], 0.89), there was a a statistically significant 38% increase in intracranial bleeding. Rates of intracranial bleeding from those assigned to aspirin (1.1%) were higher than placebo (0.8%). This came from an increase in a combination of subdural, extradural, and subarachnoid bleeding with aspirin (0.6%) compared with placebo (0.4%). Haemorrhagic stroke was recorded in 0.5% of those assigned to aspirin compared with 0.4% for placebo.

Absolute numbers of haemorrhagic and non-haemorrhagic events were small. Among 1000 individuals taking 100mg/day of low-dose aspirin over five years, there were 2.5 fewer ischaemic strokes at the expense of 3.5 cases of intracranial haemorrhage, but not statistically significant. No difference would be expected for overall stroke incidence or stroke mortality, but haemorrhagic stroke was associated with a mortality rate of nearly a third, compared to 7.7% for ischaemic stroke. Major extracranial haemorrhage was driven by the increased risk of upper gastrointestinal bleeding with aspirin compared with placebo, as previously found (Hazard Ratio, 1.87).

The researchers concluded that “there was no statistically significant benefit from aspirin in preventing stroke or any conventional stroke etiological subtype. However, aspirin significantly increased the overall risk of intracranial bleeding.”

Categories : Exercise Neurodegenerative DiseasesTags : Leave a comment

Could an Alzheimer’s Treatment be Lurking in a Bodybuilder’s Supplement?

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Photo by Jonathan Borba on Unsplash

A safe treatment against Alzheimer’s progression may be hidden in a common bodybuilding supplement. Researchers recently discovered that a muscle-building supplement called beta-hydroxy beta-methylbutyrate (HMB), may help protect memory, reduce plaques and ultimately help prevent the progression of Alzheimer’s disease. The researchers published their results in the journal Cell Reports.

HMB is a safe over-the-counter supplement, which bodybuilders regularly use to enhance exercise-related muscle strength and growth.

“This may be one of the safest and the easiest approaches to halt disease progression and protect memory in Alzheimer’s disease patients,” said Kalipada Pahan, PhD, at RUSH Medical College.

Studies in mouse models of Alzheimer’s have shown that HMB successfully reduces plaques and increases factors for neuronal growth to protect learning and memory, according to neurological researchers at RUSH.

“Understanding how the disease works is important to developing effective drugs to protect the brain and stop the progression of Alzheimer’s disease,” Pahan said.

Previous studies indicate that a family of proteins known as neurotrophic factors are drastically decreased in the brains of people with Alzheimer’s disease and have been found to help in survival and function of neurons, which are cells that receive and send messages from the body to the brain and vice versa.

“Our study found that after oral consumption, HMB enters into the brain to increase these beneficial proteins, restore neuronal connections and improve memory and learning in mice with Alzheimer’s-like pathology, such as plaques and tangles,” Pahan said.

The study findings indicate that HMB stimulates the nuclear hormone receptor PPARα within the brain that regulates the transport of fatty acids, which is key to the success of HMB as a neuroprotective supplement.

“If mouse results with HMB are replicated in Alzheimer’s disease patients, it would open up a promising avenue of treatment of this devastating neurodegenerative disease,” Pahan said.

Source: Rush University Medical Center