Day: June 22, 2022

Retinal Cells a Haven for Ebola and Other Viruses

Credit: National Eye Institute

A specific cell within the retina, the retinal pigment epithelial cell, appears to be particularly good at housing Ebola and other viruses, according to new research published in the journal Frontiers in Virology.

“Inflammation of the eye, known as uveitis, is very common following infection with Ebola and we know the cells within the iris, at the front of the eye, as well as the retina have the capacity to play a major role in uveitis and act as hosts for microorganisms,” explained study senior author Professor Justine Smith at Flinders University.

“However, what we didn’t know was which out of the two was most responsible in the case of Ebola.”

“Patients with Ebola eye disease have characteristic retinal scars”

Professor Justine Smith

The study used cells from human eyes donated from the South Australia Eye Bank to investigate the ability of iris and retinal pigment epithelial cells to be infected by Ebola.

Cells were infected with Ebola virus, Reston virus (a type of ebolavirus that does not cause disease in humans) or Zika virus (another type of virus, but one that also can cause uveitis), while some were left uninfected for the duration of the trial.

While both types of cells allow replication of the Ebola virus, it was the retinal cells that showed much higher levels of infection.

“We also found similar results when looking at the cells infected with Reston virus and Zika virus,” said Professor Smith.

“Patients with Ebola eye disease have characteristic retinal scars, suggesting the retinal pigment epithelium is involved in the disease, so this finding is consistent with what eye doctors are seeing in the clinic.

“These retinal cells are good at eating things – called phagocytosis – and they play an essential part in the visual cycle by recycling our photoreceptors, so it makes sense that these cells would be a receptive haven for Ebola, as well as other viruses.”

The researchers say the study demonstrates an important target cell for Ebola infection in the eye and suggests the potential for these cells to be monitored during acute viral infection to identify patients at highest risk of uveitis.

“Amongst other issues, including pain and blurred vision, uveitis can ultimately lead to vision loss, so it’s important we find ways to diagnose it as early as possible to enable swift treatment,” said Professor Smith.

Source: Flinders University

Females ‘Significantly’ More Likely to Experience Long COVID

Photo by Stephen Andrews on Unsplash

A new study published in Current Medical Research and Opinion has revealed that females are “significantly” more likely to suffer from Long COVID than males and will experience substantially different symptoms.

Long COVID is a syndrome in which complications persist more than four weeks after the initial infection of COVID, sometimes for many months.

In a review of studies, researchers observed females with Long COVID are presenting with a variety of symptoms including ear, nose, and throat issues; mood, neurological, skin, gastrointestinal and rheumatological disorders; as well as fatigue.

Male patients, however, were more likely to experience endocrine disorders such as diabetes and kidney disorders.

“Knowledge about fundamental sex differences underpinning the clinical manifestations, disease progression, and health outcomes of COVID is crucial for the identification and rational design of effective therapies and public health interventions that are inclusive of and sensitive to the potential differential treatment needs of both sexes,” the authors explained.

“Differences in immune system function between females and males could be an important driver of sex differences in Long COVID syndrome. Females mount more rapid and robust innate and adaptive immune responses, which can protect them from initial infection and severity. However, this same difference can render females more vulnerable to prolonged autoimmune-related diseases.”

In their review, researchers gathered a total sample size amounting to 1 393 355 unique individuals.

While the number of participants sounds large, only 35 of the 640 634 total articles in the literature provided sex disaggregated data in sufficient details about symptoms and sequalae of COVID disease to understand how females and males experience the disease differently.

The findings showed that, with the initial onset of COVID, female patients were far more likely to experience mood disorders such as depression, ear, nose, and throat symptoms, musculoskeletal pain, and respiratory symptoms. Male patients, on the other hand, were more likely to suffer from renal disorders.

The authors note that this synthesis of the available literature is among the few to break down the specific health conditions that occur as a result of COVID-related illness by sex. Plenty of studies have examined sex differences in hospitalisation, ICU admission, ventilation support, and mortality. But the research on the specific conditions that are caused by the virus, and its long-term damage to the body, have been understudied when it comes to sex.

“Sex differences in outcomes have been reported during previous coronavirus outbreaks,” the authors added. “Therefore, differences in outcomes between females and males infected with SARS-CoV-2 could have been anticipated. Unfortunately, most studies did not evaluate or report granular data by sex, which limited sex-specific clinical insights that may be impacting treatment.” Ideally, sex disaggregated data should be made available even if it was not the researcher’s primary objective, so other interested researchers can use the data to explore important differences between the sexes.

Greater occupational exposure through traditionally female-dominated jobs may may complicate interpretation the COVID sequelae.

Source: EurekAlert!

Why The Malaria Vaccine Quickly Loses its Effectiveness

Image source: Ekamalev at Unsplash

More than 600 000 people worldwide still die from malaria every year, according to the WHO. The vast majority of fatal cases of malaria are caused by the single-celled pathogen Plasmodium falciparum, which so far has only one approved vaccine against it, and its efficacy, which is already rather low, is also short-lived. A new study in Science Immunology may have the explanation: a lack of cross-reactivity in T helper cells.

The vaccine targets CSP, the quantitatively dominant protein on the surface of the “sporozoites”. Sporozoites are the stage of the malaria pathogen which is transmitted with the bite of the mosquito and enters human blood. “To improve the vaccine, we need to understand which protective antibodies are induced by the immunisation. But the production of such antibodies depends to a large extent on help from the so-called follicular T helper cells,” explained Dr Hedda Wardemann, immunologist and senior author of the study. “They ensure that B cells transform into antibody-producing plasma cells and memory B cells.”

To study the T helper cell response against CSP in detail, Dr Wardemann’s team examined the blood of volunteers infected with killed P. falciparum sporozoites from the vaccine strain. The volunteers were of European descent and had no prior contact with malaria pathogens. The researchers analysed the induced Plasmodium-specific follicular T helper cells at the single cell level. They focused on which sequences of CSP are recognised by the T helper cells’ receptors.

The analyses revealed that the T-cell receptors mainly targeted amino acids 311 to 333 of the CSP. But the researchers were stunned by another finding: there was virtually no cross-reactivity between the individual T-cell clones. “The receptors highly specifically bind only the CSP epitopes of the vaccine strain used. Even deviations of only a single amino acid component were not tolerated in some cases,” Dr Wardemann explained.

The immunologist points out that in the natural population of P. falciparum, sequence polymorphisms occur to a high degree in this region of the CSP. “The specificity of the T-cell clones prevents the constantly recurring natural infections with the pathogen from acting as a natural ‘booster.’ This could possibly explain why the protective effect of the malaria vaccine wears off so quickly,” Dr Wardemann said. The researcher recommends that further development of the vaccine should test whether inducing a broader spectrum of T helper cells could generate longer-lasting immune protection.

Source: German Cancer Research Centre

Parabens in Hair Products May Increase Breast Cancer Risk for Black Women

Parabens, chemicals which are found in widely used hair and personal care products, cause harmful effects in breast cancer cells from Black women, according to a new study presented at ENDO 2022, the Endocrine Society’s annual meeting.

In the US, the lifetime risk of breast cancer is one in eight, and Black women are at a higher risk of getting breast cancer under the age of 40 than any other racial or ethnic group in that country. Breast cancer rates among Black South African women are also on the increase, but the cause remains unexplained and research in this area has been lacking.

“One reason for the higher risk of breast cancer may be exposure to harmful chemicals called endocrine-disrupting chemicals in hair and personal care products,” said lead researcher Lindsey S. Treviño, PhD. “These chemicals mimic the effects of hormones on the body.”

Parabens are endocrine-disrupting chemicals that are commonly used as preservatives in hair and other personal care products. Parabens cause breast cancer cells to grow, invade, spread, and express genes linked to cancer and to hormone action. Research showed that fewer paraben-free options are marketed to Black women.

“Black women are more likely to buy and use hair products with these types of chemicals, but we do not have a lot of data about how parabens may increase breast cancer risk in Black women,” Dr Treviño said. “This is because Black women have not been picked to take part in most research studies looking at this link. Also, studies to test this link have only used breast cancer cell lines from White women.”

The new study tested the effects of parabens on breast cancer cells from Black women. Parabens were found to increase the growth of a Black breast cancer cell line but not in the White breast cancer cell line. Parabens increased expression of genes linked to hormone action in breast cancer cell lines from both Black and White women. Parabens also promoted the spread of breast cancer cells, with a bigger effect seen in the Black breast cancer cell line.

“These results provide new data that parabens also cause harmful effects in breast cancer cells from Black women,” Dr Treviño said. 

The study is a part of a community-led project called the Bench to Community Initiative (BCI), which brings together scientists and community members (including breast cancer survivors) to create ways to reduce exposures to harmful chemicals in hair and personal care products in Black women with breast cancer. 

“While this project focuses on Black women, the knowledge we gain about the link between exposure to harmful chemicals in personal care products and breast cancer risk can be used to help all women at high risk of getting breast cancer,” Dr Treviño said.

Source: Endocrine Society

Multivitamins and Dietary Supplements are a ‘Waste of Time’ for Most

Vitamin C pills and orange
Photo by Diana Polekhina on Unsplash

For those who aren’t pregnant, vitamins are a waste of money because the evidence for cardiovascular disease or cancer prevention is lacking, according to researchers at Northwestern University Feinberg School of Medicine.

“Patients ask all the time, ‘What supplements should I be taking?’”

Dr Jeffrey Linder, Northwestern University

The researchers penned an editorial in JAMA that supports new recommendations from the United States Preventive Services Task Force (USPSTF), a national panel which makes evidence-based recommendations on clinical prevention. 

Based on a systematic review of 84 studies, the USPSTF’s new guidelines state there was “insufficient evidence” that taking multivitamins, paired supplements or single supplements can help prevent cardiovascular disease and cancer in otherwise healthy, non-pregnant adults. 

“Patients ask all the time, ‘What supplements should I be taking?’ They’re wasting money and focus thinking there has to be a magic set of pills that will keep them healthy when we should all be following the evidence-based practices of eating healthy and exercising,” said Dr Jeffrey Linder, one of the editorial’s authors.

“The task force is not saying ‘don’t take multivitamins,’ but there’s this idea that if these were really good for you, we’d know by now,” Dr Linder added. 

The task force is specifically recommending against taking beta-carotene supplements because of a possible increased risk of lung cancer, and is recommending against taking vitamin E supplements because it has no net benefit in reducing mortality, cardiovascular disease or cancer.

“The harm is that talking with patients about supplements during the very limited time we get to see them, we’re missing out on counselling about how to really reduce cardiovascular risks, like through exercise or smoking cessation,” Dr Linder said.

No substitute for actual fruits and vegetables

Eating fruits and vegetables is associated with decreased cardiovascular disease and cancer risk, they said, so it is reasonable to think those key vitamins and minerals in pills could prevent disease. But, they explain, whole fruits and vegetables contain a mixture of vitamins, phytochemicals, fibre and other nutrients that probably act synergistically to deliver health benefits. Micronutrients on their own may also have a different effect than when consumed with others in foods.

Dr Linder noted that individuals with vitamin deficiency can still benefit from taking dietary supplements, such as calcium and vitamin D, which have been shown to prevent fractures and perhaps falls in older adults. 

New guidelines do not apply to those who are pregnant

The new USPSTF guidelines do not apply to people who are pregnant or trying to get pregnant, said JAMA editorial co-author Dr Natalie Cameron, a physician at Northwestern. 

“Pregnant individuals should keep in mind that these guidelines don’t apply to them,” said Dr Cameron. “More data is needed to understand how specific vitamin supplementation may modify risk of adverse pregnancy outcomes and cardiovascular complications during pregnancy.” 

Source: Northwestern University