Medical Bulletin 22/February/2024

Here are the top medical news highlights for the day:

Research discovers microplastics in every human placenta

In a study published on February 17 2024 in the journal Toxicological Sciences, a team led by Matthew Campen, PhD, Regents' Professor in the UNM Department of Pharmaceutical Sciences, reported finding microplastics in all 62 of the placenta samples tested, with concentrations ranging from 6.5 to 790 micrograms per gram of tissue.

Microplastics are present in virtually everything we consume, from bottled water to meat and plant-based food.Additionally, research has shown that these particles have infiltrated the human body, with microplastics detected in organs and tissues.

While microplastics are already present in our bodies, it is unclear what health effects they might have. Traditionally, plastics have been assumed to be biologically inert, but some microplastics are so small, measured in nanometers,and are capable of crossing cell membranes.

“The growing concentration of microplastics in human tissue might explain puzzling increases in some types of health problems, such as inflammatory bowel disease and colon cancer in people under 50, as well as declining sperm counts,” said Campen.

For the study, Campen and his team, in collaboration with scientists from Baylor College of Medicine and Oklahoma State University, investigated donated placental tissue. They utilized saponification to chemically process the samples, breaking down fats and proteins to create a soap-like substance. Subsequently, each sample was subjected to ultracentrifugation, resulting in a plastic nugget settling at the bottom of a tube. Employing pyrolysis, the researchers heated the plastic pellet in a metal cup to 600 degrees Celsius, capturing gas emissions as various types of plastic combusted at specific temperatures.

The findings showed that the most prevalent polymer in placental tissue was polyethylene, which is used to make plastic bags and bottles. It accounted for 54% of the total plastics. Polyvinyl chloride (better known as PVC) and nylon each represented about 10% of the total, with the remainder consisting of nine other polymers.

The concentration of microplastics in placentas is particularly troubling, said Campen, because the tissue has only been growing for eight months (it starts to form about a month into a pregnancy). “Other organs of your body are accumulating over much longer periods of time.”

“It’s only getting worse, and the trajectory is it will double every 10 to 15 years. So, even if we were to stop it today, in 2050 there will be three times as much plastic in the background as there is now. And we’re not going to stop it today.” concluded Campen.

Reference: Marcus A Garcia, Rui Liu, Alex Nihart, Eliane El Hayek, Eliseo Castillo, Enrico R Barrozo, Melissa A Suter, Barry Bleske, Justin Scott, Kyle Forsythe, Jorge Gonzalez-Estrella, Kjersti M Aagaard, Matthew J Campen. Quantitation and identification of microplastics accumulation in human placental specimens using pyrolysis gas chromatography mass spectrometry. Toxicological Sciences, 2024; DOI: 10.1093/toxsci/kfae021

Red light has the potential to decrease blood glucose levels, study suggests

A study published in the Journal of Biophotonics indicates that red light has been shown to decrease blood glucose levels by 27.7% after glucose intake, as well as reduce maximum glucose spiking by 7.5%.

Mitochondria, the cellular powerhouse, utilizes oxygen and glucose to generate the energy-rich nucleoside adenosine triphosphate (ATP), vital for cellular processes. Previous research has demonstrated that long-wavelength light ranging from approximately 650 to 900 nanometers, spanning the visible to near-infrared spectrum, can enhance mitochondrial ATP production. This, in turn, decreases blood glucose levels and promotes improved health and longevity in animals. Additionally, researchers discovered that red light at 670 nanometers stimulated energy production within mitochondria, resulting in heightened glucose consumption.

To study the effects of 670 nm red light on blood glucose levels, the researchers enlisted 30 healthy participants. These participants were randomly assigned to two groups: 15 in the 670 nm red light group and 15 in the placebo (no light) group. Excluding individuals with known metabolic conditions and those taking medication, the participants underwent an oral glucose tolerance test. They were then instructed to monitor their blood glucose levels every 15 minutes for the following two hours.

The findings revealed that people who received red light exposure 45 minutes before drinking glucose exhibited a reduced peak blood glucose level and reduced total blood glucose during the two hours.

“It is clear that light affects the way mitochondria function and this impacts our bodies at a cellular and physiological level. Our study has shown that we can use a single, 15-minute exposure to red light to reduce blood sugar levels after eating.” said Dr Michael Powner, Senior Lecturer in Neurobiology in the School of Health & Psychological Sciences at City and also lead author of the study.

“Sunlight has a balance between red and blue, but we now live in a world where blue light is dominant because, although we do not see it, LED lights are dominant in blue and have almost no red in them. This reduces mitochondrial function and ATP production. Hence our internal environments are red-starved. Long-term exposure to blue light is potentially toxic without red. Blue light on its own impacts badly on physiology and can drive disrupted blood sugars that may in the long run contribute to diabetes and undermine health spans.” concludedProfessor Glen Jeffery, Professor of Neuroscience in the UCL Institute of Ophthalmology.”

While the study has only been done in healthy individuals, it has the potential to impact diabetes control going forward, as it could help to reduce potentially damaging glucose spikes in the body after meals

Reference: https://doi.org/10.1002/jbio.202300521

Oocytes cleverly evade toxic proteins to maintain long-term female fertility

Researchers at the Centre for Genomic Regulation (CRG) in Barcelona have discovered a new mechanism which explains how oocytes remain in pristine conditions for decades without succumbing to the wear and tear that would cause other cell types to fail. The research published in the journal Cell,represents a new frontier to explore the unexplained causes of infertility.

Oocytes are immature egg cells that develop in almost all female mammals before birth. The propagation of future generations depends on this finite reserve of cells surviving for many years without incurring damage and can last almost half a century, the average time between birth and menopause.

The researchers studied protein aggregates, which are clusters of misfolded or damaged proteins known for their toxic effects. These aggregates accumulate in the cytoplasm and are associated with various neurodegenerative diseases. Cells typically manage them by enzymatically breaking them down or segregating them during cell division. However, oocytes, responsible for contributing their entire cytoplasm to an embryo after fertilization, reduce their metabolic activity to minimize the generation of harmful by-products that could compromise maternal DNA and future reproductive success. As a result, oocytes are particularly sensitive to misfolded or damaged proteins.

Dr.Böke's team, led by Dr. Gabriele Zaffagnini, extensively examined thousands of immature oocytes, mature eggs, and early embryos from adult mice. Using special dyes and live-cell imaging, they observed protein aggregate behavior in real-time. Electron microscopy provided nanoscopic insights within cells, culminating in the identification of EndoLysosomal Vesicular Assemblies (ELVAs). These structures, approximately 50 per oocyte, move throughout the cytoplasm, capturing and neutralizing protein aggregates. ELVAs are dubbed a "superorganelle" due to their diverse cellular components operating cohesively as a single unit.

The study’s findings revealed a crucial moment during the oocyte maturation stage which is when an oocyte converts into a mature egg, preparing for ovulation and possible fertilisation. During this stage, the researchers observed ELVAs moving towards the cell's surface and breaking down the protein aggregates, essentially deep-cleaning the cytoplasm.

“An oocyte must donate all its cytoplasm to the embryo at fertilisation, so it cannot afford for garbage to accumulate, which would pose an existential risk for its function. In that sense, ELVAs are like a sophisticated waste disposal network or clean-up crew, patrolling the cytoplasm to ensure no aggregates are freely floating. ELVAs keep these aggregates in a confined environment until the oocyte is ready to dispose of them in one fell swoop. It’s an effective and energy-efficient strategy,” saidDr.Zaffagnini, postdoctoral researcher at the Centre for Genomic Regulation.

Reference: Gabriele Zaffagnini, Shiya Cheng, Marion C. Salzer, Barbara Pernaute, Juan Manuel Duran, Manuel Irimia, Melina Schuh, Elvan Böke. Mouse oocytes sequester aggregated proteins in degradative super-organelles. Cell, 2024; DOI: 10.1016/j.cell.2024.01.031