May 8, 2023
Literature Review
1) Plastics in the blood - what is the story? In the journal Nanomaterials: "Humans are continuously exposed to polymeric materials such as in textiles, car tires and packaging. Unfortunately, their break down products pollute our environment, leading to
widespread contamination with micro- and nanoplastics (MNPs). The blood–brain barrier (BBB) is an important biological barrier that protects the brain from harmful substances. In our study we performed short term uptake studies in mice with orally administered polystyrene micro-/nanoparticles (9.55 µm, 1.14 µm, 0.293 µm). We show that nanometer sized particles—but not bigger particles—reach the brain within only 2 h after gavage. To understand the transport mechanism, we performed coarse-grained molecular dynamics simulations on the interaction of DOPC bilayers with a polystyrene nanoparticle in the presence and absence of various coronae. We found that the composition of the biomolecular corona surrounding the plastic particles was critical for passage through the BBB. Cholesterol molecules enhanced the uptake of these contaminants into the membrane of the BBB, whereas the protein model inhibited it. These opposing effects could explain the passive transport of the particles into the brain." (Kopatz V. et. al. 2023)
This is a really BIG deal! If these nano plastics are in the brain, an immunologically conserved space, then there is a strong possibility that glial immune cells may: 1) recognize these particles as foreign invaders and mount an innate response to them leading to local inflammation 2) recognize them adaptively and develop antibodies against these neoantigens leading to possible molecular mimicry issues or worse true autoimmunity in the brain 3) begin an inflammatory based neuronal degradation process that could lead to amyloid and tau plaque formation = neuro-degeneration. This is all hypothetical, but it is truly a frightening possibility.
Reduce your exposure to plastics in all their forms. A clean environment is a massive net positive for human health.
2) Fascinating study using dogs that can sniff for Covid in children. Without getting into the social side of why this is likely not a great idea, the fact that the dogs could sniff out a covid case with a sensitivity of 83% and specificity of 90%. It blows the mind that a dog can sniff out either a 200 nanometer virion or some metabolic response given off by the child who is sick. (Glaser et. al. 2023)
Ok, maybe one comment. I do have a vision of a line of children in school 6 feet apart with dogs sniffing their ankles randomly sitting down next to possibly sick children. I wonder what the response is from the other kids who "aren't" looking per the study. Ah, the social struggles of childhood do not need our help causing more division. Also, as I have said for years, kids are not the problem with this disease. Have the dogs work in nursing homes and elder care facilities.
3) Brain Cancer - a single CT can raise the risk of cancer of the brain in children if the exposure occurs before age 22 years. The risk is very small at 1 cancer per 10,000 CT scans of the head and neck. However, if you are that one it is an issue. Multiple CT's raise risk further. The simple answer to this rare issue is this. Only obtain a head CT if it is absolutely necessary. (Hauptmann et. al. 2023)
4) A critical part of healing from mental health problems remains to be movement and exercise. From the journal JAMA Pediatrics we see: a meta-analysis looking at the association with physical activity and depressive symptoms. There is a clear correlation between mood and physical activity. This is most definitely multi factorial in cause and effect. Exercise is a pleiotropic intervention touching metabolic, hormonal, immune and neurological actions. Other than nutrition, exercise is the other great lever to pull on for mental health that is relatively controllable. (Recchia et. al. 2023)
5) Aging has a gut microbiome signature! From the journal Nature Aging, "Centenarians are an excellent model to study the relationship between the gut microbiome and longevity. To characterize the gut microbiome signatures of aging, we conducted a cross-sectional investigation of 1,575 individuals (20–117 years) from Guangxi province of China, including 297 centenarians (n = 45 with longitudinal sampling). Compared to their old adult counterparts, centenarians displayed youth-associated features in the gut microbiome characterized by an over-representation of a Bacteroides-dominated enterotype, increase in species evenness, enrichment of potentially beneficial Bacteroidetes and depletion of potential pathobionts. Health status stratification in older individuals did not alter the directional trends for these signature comparisons but revealed more apparent associations in less healthy individuals. Importantly, longitudinal analysis of centenarians across a 1.5-year period indicated that the youth-associated gut microbial signatures were enhanced with regard to increased evenness, reduction in interindividual variation and stability of Bacteroides, and that centenarians with low microbial evenness were prone to large microbiome instability during aging. These results together highlight a youth-related aging pattern of the gut microbiome for long-lived individuals." (Pang et. al. 2023)
That's all this week,
Dr. M
