Tag Archives: aging

Stem Cell Aging and Loss of Tissue Maintenance Because of Inflammaging

Early and mid-life inflammation ia a mediator of lifelong defects in tissue maintenance and regeneration due to the inflammation aging the stem cells. Inflammation damages the extracellular matrix, DNA, and epigenetic mechanisms, all of which contribute to aging and age-related diseases.

A schematic of stem cell inflammaging (from Bogeska et al, 2022)

Inflammaging, defined as an age-related increase in the levels of pro-inflammatory markers in blood and tissues, is a strong risk factor for multiple diseases that are highly prevalent, and frequent causes of disabilities in elderly individuals but are pathophysiologically uncorrelated, i.e., everything from cancer, to skin diseases, to heart disease, and neurodegeneration. And remember, as I’ve discussed in previous blogs, inflammation in the skin can can lead to systemic inflammation.

Inflammation can wreak havoc on the body, including the skin, through a number of key mechanisms. Let’s have a look at how inflammation can damage tissue, such as by degrading the extracellular matrix, and can damage cells at the molecular level through genetic and epigenetic mechanisms. Genetic refers to how damage occurs to the DNA, and epigenetic refers to how damage occurs “above” the DNA, such as the mechanisms that control the expression of DNA – i.e., affecting how the DNA makes RNA and proteins. Inflammation can also cause misfolding in proteins, resulting in a number of dysfunctional pathways in the body, including the control of epigenetics such as protein-based epigenetics. You read that right – proteins can be inherited and dysfunctional proteins in an adult can be inherited as dysfunctional proteins in the offspring. That’s one reason why genetics and heredity don’t mean the same thing.

Inflammaging is a process induced by chronic inflammatory cytokine signaling that promotes accelerated damage to the extracellular matrix (ECM), stem-cell aging, and precancer stem-cell generation. Multiple different sterile and infection-associated inflammatory stimuli have been shown to provoke primitive stem cells (HSCs) to exit their long-term quiescent state and enter into active proliferation. In other words, inflammation, whether it is sterile inflammation or infection-related inflammation, drives stem cells into a state where they multiply. Therefore, chronic inflammation will induce the constant multiplication of stem cells. And every time a cell multiplies itself, mutations and consequent aging processes will occur. As I’ve said before, one of the most dangerous things a cell can do is to multiply itself. 

As scientists have recently published, their work demonstrates that inflammatory stimuli can provoke a long-lasting inhibitory effect on tissue regeneration that extends far beyond the duration of the original inflammatory event, via the progressive and irreversible attrition of the functional stem cell pool. They argue that prophylactic anti-inflammatory interventions may effectively delay or prevent the evolution of age-associated pathologies, but that such treatments may hold limited capacity to rejuvenate an already aged stem cell system. 

In other words, it is important to reduce inflammation even during our younger years, not just during our aged period, in order to reduce stem cell aging processes. This means eating a plant-forward diet, full of lots of fruits and vegetables, as well as using sunscreen during long sun exposures, as well as using skin products that are not inflammatory – rather using skin care products that reduce inflammation and those that help to maintain or build the skin’s barrier function.

Finally, Some Good Genetics Research on Aging Processes – Implications for the Skin

Professor Doctor Andreas Beyer, Ph.D., at the University of Cologne, Institute for Genetics in Germany, along with his research team has discovered that as we age, a critical process in our cells, called gene transcription, speeds up. This process involves making a copy of a specific DNA strand into the form of RNA. When the process occurs too fast, more errors are made. The RNA is then used for a number of things, including making the backbone of proteins. Posttranslational modifications then finish the making of proteins. If the protein’s backbone is error ridden, the protein loses function. Likewise, posttranslational modification (PTM) depends on other proteins, and if they are error ridden, then error ridden PTM will also lead to dysfunctional proteins.

What does this mean for our health? Dr. Beyer says, for example, “Our study is saying that, for instance, having a healthy diet or, this caloric restriction intervention, would improve the quality of the transcription of the RNA production in the cell. And this would then have beneficial effects for the cells in the long run.” The evidence for his statement; mice and worms following a low-calorie diet were assessed to gauge the impact on cell transcription during the aging process. In both scenarios, transcription’s pace was observed to be more measured, resulting in fewer errors.

To validate their experiment’s applicability to humans, they conducted assessments using blood samples from both young and elderly humans. Prof. Dr. Argyris Papantonis, Ph.D., at the University of Gottingen in Germany, one of the principal investigators, remarked, “And when we compared the young cells to the very old cells, in vitro, we got exactly the same results.”

Skin aging is characterized by the accumulation of macromolecular and molecular damage within cells, impaired ability of stem and progenitor cells to promote tissue regeneration, and restore the loss of normal physiology. Chronological aging and photo-aging are two processes of skin aging that although related, have different clinical manifestations and pathogenesis. Chronological aging appears as we age and is affected by factors such as ethnicity, individual epigenetics and exposome, and skin site. It is mainly characterized by dry skin, dullness, lack of elasticity, sagging, discoloration, and fine wrinkles. Histological features include epidermal atrophy, reduction in the number of dermal fibroblasts and collagen fibers, slackening, thinness, and functional disorganization of the cells and matrix. The primary causes are: first, the stem cell dysfunction of keratinocytes, decreased regenerative ability of stem cells in the basal layer of the epidermis leading to a decline in skin renewal and repair ability, ultimately causing aging, and second, due to the accumulation of damage and aging skin dysfunction, fibroblasts lose the ability to reshape the extracellular matrix or have a reduced ability to synthesize and secrete collagen or viscous proteins. Third, aging fibroblasts alter intracellular homeostasis through certain paracrine mechanisms Now we know an important basis for these aging associated deficits is an increase in the speed of making transcripts (RNA made from DNA), and the resulting dysfunction of proteins.

As I have written, proteins being affected by our exposome is the largest factor in diseases, including cancer. A big portion of your exposome is diet. So eat well and ignore David Sinclair, your processing of transcripts in the skin will be renormalized..