What do we know about human aging from mouse models?

November 24, 2022November 24, 2022 gettingwell4 4-5 stars Advanced knowledge, Cortisol, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress Control group, Genetic factors, Neurodegenerative disease

Here is a 2021 rodent study and relevant parts from 3 of its 26 citing papers:

“A long line of evidence has established the laboratory mouse as the prime model of human aging. However, relatively little is known about detailed behavioral and functional changes that occur across their lifespan, and how this maps onto the phenotype of human aging.

To better understand age-related changes across the lifespan, we characterized functional aging in male C57BL/6J mice of five different ages (3, 6, 12, 18, and 22 months of age) using a multi-domain behavioral test battery. Assessment of functional aging in humans and mice: age-related patterns were determined based on representative data (Table 2), and then superimposed onto survival rate. (A) Body weight, (B) locomotor activity, (C) gait velocity, (D) grip strength, (E) trait anxiety, (F) memory requiring low attention level, and (G) memory requiring high attention level.

These functional alterations across ages are non-linear, and patterns are unique for each behavioral trait. Physical function progressively declines, starting as early as 6 months of age in mice, while cognitive function begins to decline later, with considerable impairment present at 22 months of age.

Functional aging of male C57BL/6J mice starts at younger relative ages compared to when it starts in humans. Our study suggests that human-equivalent ages of mice might be better determined on the basis of its functional capabilities.”

https://www.frontiersin.org/articles/10.3389/fnagi.2021.697621/full “Functional Aging in Male C57BL/6J Mice Across the Life-Span: A Systematic Behavioral Analysis of Motor, Emotional, and Memory Function to Define an Aging Phenotype”

“Studies in mice show that physical function (i.e., locomotor activity, gait velocity, grip strength) begins to deteriorate around post-natal day (PND) 180, but cognitive functions (i.e., memory) do not exhibit impairment until roughly PND 660. Our results should be considered within the context of behavior changing throughout vole adulthood. Caution should be taken to avoid categorizing the oldest age group in our study as ‘elderly’ or ‘geriatric.'”

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0276897 “Behavioral trajectories of aging prairie voles (Microtus ochrogaster): Adapting behavior to social context wanes with advanced age”

“We used adult mice ranging in age from 5-6 months, not enough to modify experimental autoimmune encephalomyelitis progression. Mice are considered adult after 8 weeks; however, rapid growth for most biological processes is observed until 3 months of age, while past 6 months, mice might be affected by senescence.”

https://www.frontiersin.org/articles/10.3389/fimmu.2022.1036680/full “Age related immune modulation of experimental autoimmune encephalomyelitis in PINK1 knockout mice”

“Locomotor activity and gait velocity of 12 months old male C57BL/6 correlates with an elderly human being aged 60 or older, supporting that the ~15 months old mice we used in our study were aged mice at the time of tissue collection.”

https://www.mdpi.com/1422-0067/23/20/12461 “Genomic Basis for Individual Differences in Susceptibility to the Neurotoxic Effects of Diesel Exhaust”

Do broccoli sprouts treat gout and kidney stones?

November 12, 2022November 12, 2022 gettingwell4 2-3 stars Required further work, Epigenetics, Glutamate, Immune system, Neurochemicals, Stress Control group, DNA methylation, Genetic factors

This 2022 rodent study investigated glucoraphanin’s effects on reducing uric acid:

“Hyperuricemia is a chronic disease characterized by abnormally elevated serum uric acid levels. Sulforaphane could lower uric acid by decreasing urate synthesis and increasing renal urate excretion in hyperuricemic rats.

A hyperuricemia model was established by administering feedstuffs with 4% potassium oxonate and 20% yeast. Forty male Sprague–Dawley rats were randomly divided into the normal control, hyperuricemia, allopurinol, and sulforaphane groups. Animals were treated by oral gavage for six consecutive weeks, and then phenotypic parameters, metabolomic profiling, and metagenomic sequencing were performed.

We identified succinic acid and oxoglutaric acid as critical host-gut microbiome co-metabolites. Sulforaphane improved diversity of microbial ecosystems and functions, as well as metabolic control of the kidney. Sulforaphane exerted its renoprotective effect through epigenetic modification of Nrf2 and interaction between gut microbiota and epigenetic modification in hyperuricemic rats.

Limitations of this study include:

We used glucoraphanin bioactivated with myrosinase for our experiments. Future experiments may directly involve sulforaphane.

Bioinformatics analysis resulted in speculations that require further experimental testing.

Further investigation of interactions between microbiota and the host epigenome is still needed.”

https://www.sciencedirect.com/science/article/pii/S209012322200251X “Sulforaphane-driven reprogramming of gut microbiome and metabolome ameliorates the progression of hyperuricemia”

It was a stretch to label treatment subjects as the “sulforaphane group” by claiming “Glucoraphanin (10 mg/kg) was metabolized to SFN by myrosinase as described in previous studies.” Both this and the referenced 2014 study “(RS)-glucoraphanin purified from Tuscan black kale and bioactivated with myrosinase enzyme protects against cerebral ischemia/reperfusion injury in rats” measured glucoraphanin and myrosinase, but not sulforaphane.

A human equivalent to this study’s daily glucoraphanin intake of 10 mg / kg weight would be (.162 x 10 mg) x 70 kg = 113 mg. Whether 10 mg was dry or wet weight wasn’t disclosed.

If 10 mg was wet, 113 mg is a little more than twice our model clinical trial’s average glucoraphanin intake of 51 mg fresh weight from eating 30 grams / day of super sprouts. In April 2020’s Understanding a clinical trial’s broccoli sprout amount, a study coauthor said:

“We considered 30 g and 60 g to be 1/2 and 1 portion per day, respectively, of broccoli sprouts. When we carried out tests with consumers, previous to the bioavailability studies, higher amounts per day were not easy to consume and to get eaten by participants.”

Broccoli sprouts activate the AMPK pathway, Part 4

November 8, 2022November 8, 2022 gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Dopamine, Epigenetics, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Stress Brain neurons, Control group, DNA methylation, Genetic factors, Neurodegenerative disease, Prefrontal cortex

Today someone viewed the 2020 Part 3 of Broccoli sprouts activate the AMPK pathway which lacked citations at the time. Checking again, here are three citing 2022 papers, starting with a review:

“Nrf2 is an important transcription factor that regulates expression of a large number of genes in healthy and disease states. Nrf2 regulates expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy, and mitochondrial function in all organs of the human body, and in the peripheral and central nervous systems.

Overall, therapeutic drugs including sulforaphane that target Nrf2 expression and Nrf2/ARE pathway are promising. This article proposes additional research in Nrf2’s role within Parkinson’s disease, Huntington’s disease, and ischemic stroke in preclinical mouse models and humans with age-related neurodegenerative diseases.”

https://www.sciencedirect.com/science/article/pii/S1568163722001982 “Role of Nrf2 in aging, Alzheimer’s and other neurodegenerative diseases” (not freely available) Thanks to Dr. P. Hemachandra Reddy for providing a copy.

One of the Part 3 study’s coauthors contributed to this very detailed review:

“Due to observed overlapping cellular responses upon AMPK or NRF2 activation and common stressors impinging on both AMPK and NRF2 signaling, it is plausible to assume that AMPK and NRF2 signaling may interdepend and cooperate to readjust cellular homeostasis.

The outcome and underlying signaling events of AMPK-NRF2 crosstalk may diverge between:

in vitro and in vivo studies (one cell type in isolation vs inter-organ crosstalk in living organisms);

Different cell types/organs/organisms of different cultivation conditions, genetic background, age or sex;

Different stress-regimens (chronic vs acute, nature of stress (lipotoxicity, redox stress, xenobiotic, starvation, etc));

Different modes of Nrf2 or AMPK activation and inhibition (genetic vs pharmacological, constitutive vs transient/intermittent, systemic vs organ-specific, electrophilic vs PPI, allosteric vs covalent, or pan vs subtype-specific);

Different target genes with distinct promoter and enhancer structure; or

Different timing of activation.

The latter should deserve increased attention as Nrf2 is one of the most cycling genes under control of the circadian clock. Feeding behavior, metabolism and hence AMPK activity follow and substantiate the biological clock, indicating an entangled circadian regulation of metabolic and redox homeostasis.”

https://www.sciencedirect.com/science/article/pii/S089158492200497X “AMPK and NRF2: Interactive players in the same team for cellular homeostasis?”

A third citing paper was a study of lens cells that provided an example of similar metformin effects noted in Part 2 of Broccoli sprouts activate the AMPK pathway:

“Loss of Nrf2 and Nrf2 antioxidant genes expression and activity in aging cells leads to an array of oxidative-induced deleterious responses, impaired function, and aging pathologies. This deterioration is proposed to be the primary risk factor for age-related diseases such as cataracts.

AMPK regulates energy at physiological levels during metabolic imbalance and stress. AMPK is a redox sensing molecule, and can be activated under cellular accumulation of reactive oxygen species, which are endogenously produced due to loss of antioxidant enzymes.

The therapeutic potential of AMPK activation has context-dependent beneficial effects, from cell survival to cell death. AMPK activation was a requisite for Bmal1/Nrf2-antioxidants-mediated defense, as pharmacologically inactivating AMPK impeded metformin’s effect.

Using lens epithelial cell lines (LECs) of human or mouse aging primary LECs along with lenses as model systems, we demonstrated that metformin could correct deteriorated Bmal1/Nrf2/ARE pathway by reviving AMPK-activation and transcriptional activities of Bmal1/Nrf2, resulting in increased antioxidants enzymatic activity and expression of Phase II enzymes. Results uncovered crosstalk between AMPK and Bmal1/Nrf2/antioxidants mediated by metformin for blunting oxidative/aging-linked pathobiology.”

https://www.mdpi.com/2073-4409/11/19/3021/htm “Obligatory Role of AMPK Activation and Antioxidant Defense Pathway in the Regulatory Effects of Metformin on Cellular Protection and Prevention of Lens Opacity”