Dr. Michael Snyder on Continuous Glucose Monitoring and Deep Profiling for Personalized Medicine

0:50:02 Michael Snyderneeds contextmoderate

Serum creatinine levels are known to increase over time with aging.

"like there's a molecule called creatinine, which is a marker of kidney function, and we discovered that's known to go up over time" (said at 0:50:02)

Creatinine is a widely used marker of kidney function, and cross-sectional population surveys (such as NHANES III) demonstrate that mean serum creatinine concentrations increase modestly across older age strata in both men and women. However, physiologically, the age-related decline in glomerular filtration rate (GFR) is not accompanied by a proportional surge in serum creatinine because age-related loss of muscle mass (sarcopenia) simultaneously reduces endogenous creatinine production. Consequently, serum creatinine levels remain relatively stable or rise only slightly with normal aging, making serum creatinine alone an insensitive indicator of renal functional decline in older adults.

context: Assessment of renal function in the old. Special considerations. (Clinics in laboratory medicine 1993) · cited 64x in the literature
"Mean serum creatinine values, however, fail to increase with age because creatinine production, which is dependent on muscle mass, falls at nearly the same rate as the renal clearance of creatinine." (abstract, results, passage verified)
pubmed
supports: Serum creatinine levels in the US population: third National Health and Nutrition Examinat… (American journal of kidney diseases : the official journal of the National Kidney Foundation 1998) · cited 578x in the literature
"Mean serum creatinine levels increased with age among both men and women in all three ethnic groups, with total US mean levels ranging from 0.88 to 1.10 mg/dL in women and 1.00 to 1.29 mg/dL in men." (abstract, results, passage verified)
pubmed full study (doi)

1:06:56 Michael Snyderneeds contextmoderate

The human gut contains more immune cells than any other part of the body.

"you have more immune cells in your gut than anywhere else in your body, and it's because they're actually in this interplay with your microbiome that's in, you know, in your colon, in your feces." (said at 1:06:56)

In traditional immunology literature, gut-associated lymphoid tissue (GALT) is frequently described as the largest immune organ in the human body, housing a massive concentration of mucosal lymphocytes, plasma cells (producing the majority of the body's IgA), and myeloid cells that actively interact with the gut microbiome. However, comprehensive quantitative cellular censuses (such as Sender et al., PNAS 2023) indicate that by absolute total cell count, the bone marrow (which houses most neutrophils and precursors) and secondary lymphoid tissues like lymph nodes and the spleen contain a larger absolute number of immune cells than the gastrointestinal tract proper.

supports: Initiating mechanisms of food allergy: Oral tolerance versus allergic sensitization. (Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 2007) · cited 74x in the literature
"This important job is fulfilled by cells of the gut-associated lymphoid tissue, the largest immunologic organ in the body." (abstract, background, passage verified)
pubmed full study (doi)
context: The total mass, number, and distribution of immune cells in the human body. (Proceedings of the National Academy of Sciences of the United States of America 2023) · cited 296x in the literature
"Lymphocytes constitute 40% of the total number of immune cells and 15% of the mass and are mainly located in the lymph nodes and spleen. Neutrophils account for similar proportions of both the number and total mass of immune cells, with most neutrophils residing in the bone marrow." (abstract, results, passage verified)
pubmed full study (doi)
supports: Does Massive Bowel Resection in Newborns Affect Further Immunity in Children? (Children (Basel, Switzerland) 2024) · cited 1x in the literature
"The massive resection of the small intestine leading to short bowel syndrome (SBS) deprives an organism of many immunocompetent cells concentrated in gut-associated lymphoid tissue, the largest immune organ in humans." (abstract, background, passage verified)
pubmed full study (doi)

Dr. Michael Snyder on Continuous Glucose Monitoring and Deep Profiling for Personalized Medicine

Needs context

Serum creatinine levels are known to increase over time with aging.

The human gut contains more immune cells than any other part of the body.