Inflamm-aging in Senior Horses

Senior horses have low-grade systemic inflammation know as inflamm-aging. This is similar to what occurs in senior humans. A published study¹ provides insights into physiological changes associated with inflamm-aging in the senior horse.

Background

Researchers said that age correlated with numerous inflammatory cytokines and fatty acids. “Cytokines are signaling proteins that help control inflammation in your body. They allow your immune system to mount a defense if germs or other substances that can make you sick enter your body. Too many cytokines can lead to excess inflammation and conditions like autoimmune diseases,” according to information from Cleveland Clinic.²

Researchers studied 42 senior horses that were managed similarly. They evaluated the relationships between inflamm-aging and measures of circulating nutrients, body composition, age, and PPID.

Inflamm-aging Research

The researchers tested the horses’ serum levels of various vitamins, minerals, inflammatory markers, and fatty acids approximately 2 hours after eating. Specific blood cell types were evaluated to assess their cytokine production profile when stimulated. The researchers also measured various haematological and biochemical blood parameters.

Researchers collected body condition scores and body weights. Researchers used ultrasound to obtain body fat content for all 42 horses. The gold standard deuterium oxide method was used for a subset of 10 horses.

Muscle scoring was undertaken using a previously published scoring system. (Editor’s note: This was not the recently published MASS system explained in the article Equine Muscle Mass: Detecting and Monitoring Changes.) Researchers also evaluated pituitary function to determine horses’ PPID status.

Results

Results showed various relationships between inflammatory markers and the other variables measured. However, researchers noted no relationship between body composition and inflammatory markers.

As folate and certain fatty acids increased, so did inflammation. However, the researchers suggest that in some cases (including with folate), this might have been a compensatory effect (i.e., certain anti-inflammatory compounds may have been released from tissues into the bloodstream in an effort to moderate the elevated systemic inflammation).

Researchers did not find relationships between inflamm-aging and PPID. However, horses positive for PPID were more likely to have low vitamin B12 levels.

Final Words

The researchers noted that, “In summary, inflamm-aging exhibited relationships with various other parameters examined, particularly with certain fatty acids. This exploratory study provides insights into physiological changes associated with inflamm-aging in the senior horse.”

The positive correlation between age and both vitamin E and selenium may suggest either a protective effect in which horses with higher levels of vitamin E and selenium tend to live longer, or an inability of senescent cells to uptake these nutrients, thereby leaving them sequestered in circulation.