Day: January 22, 2024

Categories : COVID Immune SystemTags :

Overactive Complement System Causes Long Covid

On By ModernMedia
Photo by Andrea Piacquadio: https://www.pexels.com/photo/woman-in-gray-tank-top-3812757/

A new study from the University of Zurich (UZH) has revealed that the complement system plays an important role in Long Covid, a common sequela of SARS-CoV-2 infection. The findings, published in Science, show that the complement system ends up damaging tissue and blood cells even after the original infection has ended.

A significant proportion of individuals infected with SARS-CoV-2 develop long-lasting symptoms with a wide range of manifestations. The causes and disease mechanisms of Long Covid are still unknown, and there are no diagnostic tests or targeted treatments.

Part of the immune system active for too long

A team of researchers led by Onur Boyman, professor of immunology at UZH and Director of the Department of Immunology at the University Hospital Zurich (USZ), has implicated the complement system. It is part of the innate immune system and normally helps to fight infections and eliminate damaged and infected body cells.

“In patients with Long Covid, the complement system no longer returns to its basal state, but remains activated and, thus, also damages healthy body cells,” says Boyman.

Continued activation of complement system damages tissue and blood cells

The researchers followed 113 COVID patients for up to one year after their acute SARS-CoV-2 infection and compared them with 39 healthy controls.

After six months, 40 patients had active Long Covid disease.

More than 6500 proteins in the blood of the study participants were analysed both during the acute infection and six months later.

“The analyses of which proteins were altered in Long Covid confirmed the excessive activity of the complement system. Patients with active Long Covid disease also had elevated blood levels indicating damage to various body cells, including red blood cells, platelets and blood vessels,” explains Carlo Cervia-Hasler, a postdoctoral researcher in Boyman’s team and first author of the study.

Bioinformatics recognises protein patterns

The measurable changes in blood proteins in active Long Covid indicate an interaction between proteins of the complement system, which are involved in blood clotting and the repair of tissue damage and inflammation.

In contrast, the blood levels of Long Covid patients who recovered from the disease returned to normal within six months.

Active Long Covid is therefore characterised by the protein pattern in the blood.

The blood markers were discovered using bioinformatics methods in collaboration with Karsten Borgwardt during his time as a professor at ETH Zurich.

“Our work not only lays the foundation for better diagnosis, but also supports clinical research into substances that could be used to regulate the complement system. This opens up new avenues for the development of more targeted therapies for patients with Long Covid,” Onur Boyman said.

Source: University of Zurich

Categories : Neurodegenerative Diseases NeurologyTags :

Researchers Shine a Light on the Mechanism Behind Guillain-​Barré Syndrome

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Source: CC0

Patients with Guillain-​Barré syndrome (GBS) face a rare and heterogeneous disorder of the peripheral nervous system that is often triggered by preceding infections and causes severe muscle weakness. In Europe and the USA, around 1 to 2 cases per 100 000 people occur every year.

Although GBS is considered an autoimmune disease, the underlying mechanisms remain largely unknown, making an accurate diagnosis and effective treatment a challenge.

A recent study published in the journal Nature, has revealed a pivotal aspect of GBS pathophysiology.

The work, led by Daniela Latorre, an SNSF PRIMA group leader at the Institute of Microbiology at ETH Zurich, investigated autoimmune factors that are potentially responsible for this illness in close collaboration with clinical scientists at the University Hospital Zurich and the Neurocenter of Southern Switzerland (EOC) in Lugano.

GBS usually begins with weakness and tingling in the legs, which can then spread to the arms and upper body, making it difficult to walk or move. In severe cases, paralysis can affect respiration.

Autoreactive T cells target peripheral nerves

By employing sensitive experimental approaches, Latorre’ s group was able to reveal that in GBS patients, specific cells of the immune system known as T lymphocytes invade the nerve tissue and target the insulating covering of nerve fibres called myelin.

Normally, T lymphocytes play a vital role in our immune system by identifying and eliminating threats like infections and abnormal cells.

However, in rare cases, they can mistakenly attack the body’s own tissues, leading to autoimmune diseases.

“We found that these autoreactive T lymphocytes were exclusive to patients with a type of GBS characterised by nerve demyelination and showed a specific disease-associated signature, distinguishing them from healthy individuals,” Latorre explains.

These findings mark the first evidence of the contribution of autoreactive T lymphocytes to the disease in humans.

Furthermore, the researchers identified T lymphocytes reactive to both self-antigens of peripheral nerves (myelin) and viral antigens in a subset of post-viral GBS patients, supporting a direct link between disease development and triggers of a preceding infection.

Current treatments are effective for many GBS patients, but they lack specificity, and around 20% of patients remain severely disabled or die. Overall, the work of the research team offers novel insights into our understanding of GBS, opening avenues for further investigations on larger patient groups to decipher immune mechanisms in different GBS variants. This new knowledge could lead to targeted therapies for specific GBS subtypes, potentially improving patient care.

Source: ETH Zurich

Categories : Neurology PaediatricsTags :

1 in 3 Children with Bacterial Meningitis will Suffer Lasting Neurological Disabilities

On By ModernMedia
Photo by Ben Wicks on Unsplash

One in three children who fall ill from bacterial meningitis go on to live with permanent neurological disabilities due to the infection. This is according to a new epidemiological study led by Karolinska Institutet and published in JAMA Network Open. This marks the first time that researchers have identified the long-term health burden of bacterial meningitis.

The bacterial infection can currently be cured with antibiotics, but it often leads to permanent neurological impairment. And since children are often affected, the consequences are significant.

“When children are affected, the whole family is affected. If a three-year-old child has impaired cognition, a motor disability, impaired or lost vision or hearing, it has a major impact. These are lifelong disabilities that become a major burden for both the individual and society, as those affected need health care support for the rest of their lives,” says Federico Iovino, associate professor in Medical Microbiology at the Department of Neuroscience, Karolinska Institutet, and one of the authors of the current study.

By analyzing data from the Swedish quality register on bacterial meningitis between 1987 and 2021, the researchers have been able to compare just over 3500 people who contracted bacterial meningitis as children with just over 32 000 matched controls from the general population, with an average follow-up time of over 23 years.

The results show that those diagnosed with bacterial meningitis consistently have a higher prevalence of neurological disabilities such as cognitive impairment, seizures, visual or hearing impairment, motor impairment, behavioural disorders, or structural damage to the head.

The risk was highest for structural head injuries – 26 times greater, hearing impairment – almost eight times greater, and motor impairment almost five times greater.

About one in three people affected by bacterial meningitis had at least one neurological impairment compared to one in ten among controls.

“This shows that even if the bacterial infection is cured, many people suffer from neurological impairment afterwards,” says Federico Iovino.

With the long-term effects of bacterial meningitis identified, Federico Iovino and his colleagues will now move forward with their research.

“We are trying to develop treatments that can protect neurons in the brain during the window of a few days it takes for antibiotics to take full effect. We now have very promising data from human neurons and are just entering a preclinical phase with animal models. Eventually, we hope to present this in the clinic within the next few years,” says Federico Iovino.

Source: Karolinska Institutet

Categories : Medical IndustryTags :

GEMS is Again Recognised as a Top Employer 2024 in South Africa

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The 2024 Top Employers have been announced and GEMS (Government Employees Medical Scheme) has again been recognised as a Top Employer in South Africa. 

Being certified as a Top Employer showcases an organisation’s dedication to a better world of work and exhibits this through excellent HR policies and people practices. 

GEMS Principal Officer, Dr Stan Moloabi says this of the accolade, “The Scheme takes immense pride in this achievement as we believe in the adage, ‘batho pele’– people first.” He adds, “It is our focus on investing in our more than 400 employees that enables us to fulfil our mission to provide all members with equitable access to affordable and comprehensive healthcare; promoting member wellbeing.”

The Top Employers Institute programme certifies organisations based on the participation and results of their HR Best Practices Survey. This survey covers six HR domains consisting of 20 topics including People Strategy, Work Environment, Talent Acquisition, Learning, Diversity, Equity & Inclusion, Wellbeing and more.

To the Scheme, it is heartwarming that it is the third year in a row that it has received this recognition.

Top Employers Institute CEO David Plink says: “Exceptional times bring out the best in people and organisations. And we have witnessed this in our Top Employers Certification Programme this year: exceptional performance from the certified Top Employers 2024. These employers have always shown that they care for the development and well-being of their people. By doing so, they collectively enrich the world of work. We are proud to announce and celebrate this year’s group of leading people-oriented employers: the Top Employers 2024.” 

The programme has certified and recognised over 2 300 Top Employers in 121 countries/regions across five continents. 

Categories : Ageing Diet and NutritionTags :

Meat Builds Muscle Proteins Better than Equivalent Vegan Dishes

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Photo by Jose Ignacio Pompe on Unsplash

Older adults require more protein but eat less than younger people, making it a challenge for them to maintain muscle mass. Eating a meal with meat ensures that muscle proteins are built faster than a vegan meal with the same amount of protein. This study, published in The Journal of Nutrition, was the first to compare the speed at which muscle proteins are being made after eating a complete meal with animal or plant proteins.

Every two to three months the proteins in human muscle are completely renewed. In order to make muscle proteins, we need protein from food, for example from animal sources such as meat, cheese and yoghurt, or from plant products such as beans, nuts and soymilk. Previous research on protein powders showed that animal proteins have better muscle-building properties than plant proteins. “But in reality, we do not get our proteins in powder form, but through complete meals,” says study author and PhD student Philippe Pinckaers. “Those meals contain different types of protein and other nutrients such as fibres, fats and carbohydrates. These nutrients affect how proteins are released from the diet and influences the making of muscle proteins.”

To investigate how muscles respond after eating a complete meal, Pinckaers asked 16 participants aged over 65 to come to the lab twice for a dinner meal.

Dining out in the lab

On one day, the participants sat down to a meal with quinoa with chickpeas, broad beans, soy beans and soy sauce was on the menu, while on the other day the menu consisted of a beef tartlet, potatoes, green beans, apple sauce and herb butter. Both meals had similar amounts of protein, fat, carbohydrates and calories. Prior to the meals, participants were administered an infusion of special amino acids.

“The amino acids administered via the infusion were marked, as it were with a flag,” Pinckaers explains. “We took small pieces of muscle tissue from the participants and were able to measure the amount of ‘flags’ in them. If more flags are measured, it means that muscle proteins are built up faster, which is beneficial for muscles. In this way, we found that after eating a meal with animal protein, muscle protein was built up faster than after eating a vegan meal. This means that a vegan meal does not have the same capacity to make muscle proteins as a meal that includes animal proteins.” This difference arises partly because plant-based foods are harder to digest, and because they naturally contain fewer essential amino acids.

Context is key  

The results do not mean that everyone should eat meat or other animal products, clarifies professor of exercise science and lead researcher Luc van Loon. “Healthy people can very well compensate for the lower quality of plant proteins by eating more of them.” For elderly or frail patients it is a bit more complicated. “Elderly people actually need more protein in order to reach the same level of muscle protein synthesis, when compared to young individuals. However, they actually eat less. Also, patients with reduced appetite or who do not exercise much, for example during hospitalisation, may have trouble consuming a sufficient amount of protein. For them, it is therefore important to choose protein sources that stimulate the making of muscle proteins as much as possible. The best sources in this situation would be proteins from animal products.”

Source: Maastricht University