Occurrence of various age-related diseases increase in aged animals.
Aging is characterized by chronic systemic inflammation accompanied by cellular senescence, immunosenescence, and organ dysfunction.
A chronic low-grade pro-inflammatory state known as “inflammaging” accelerates age-related diseases such as obesity, diabetes, vascular diseases, and certain types of cancer.

Senescent cells drive age-related tissue dysfunction partially by inducing a chronic senescence-associated secretory phenotype (SASP) associated with various diseases.
Cellular senescence is a state of permanent cell proliferation arrest induced by persistent DNA damage and other stress-induced signals.
Many senescent cells secret a wide spectrum of bioactive factors, including:
・inflammatory cytokines 
・chemokines 
・growth factor 
・matrix metalloproteases 
・lipids 
・nucleotides 
・extracellular vesicles 
・soluble factor 
termed SASP.
The SASP has been proposed as the underlying cause of inflammaging and comprises various soluble factors, including proinflammatory mediators and matrix-degrading molecules characterized by the release of pro-inflammatory cytokines.
Inflammaging is characterized by increased blood levels of several inflammatory biomarkers, including CRP, IL-6, IL-8, and TNF-α.

Age-related changes in body composition and physical fitness
(physical frailty, physical inactivation, ectopic lipid disposition, visceral adiposity, insulin resistance and SASP) are among the most apparent and unavoidable effects of aging, and cause metabolic dysfunction.
Various metabolic dysfunctions and aberration of hormone secretion are reported in aged dogs, cats and horses.

Age-related diseases have many causes, and there are no specific nutritional, environmental and pharmacological interventions for the age-related diseases.
As prevention of the severe diseases is required, early diagnosis of the age-related diseases is very important.
Development of new diagnostic biomarkers for inflammaging could lead to early diagnosis and prevention of age-related disease.
In aged animals, the incidence of age-related diseases is inevitable.
However, the extension of healthy life years and the ability to stay healthy until old age are standard medical requirements.
Therefore, the early diagnosis of inflammaging could be a significant step towards preventing various age-related diseases in animals.
Serum amyloid A (SAA) is used as acute phase protein for acute inflammation in cats, and SAA is reported to be potentially useful as chronic inflammation marker (inflammaging marker) in obese cats.

The critical role diet plays in either exacerbating or mitigating the inflammatory state associated with aging.
Nutrition is a key factor that can influence the degree of inflammaging through various mechanisms, including:
・the modulation of gut microbiota 
・antioxidant intake 
・fatty acid profiles 
Proper nutritional strategies could potentially attenuate the proinflammatory environment by enhancing the body's ability to counteract oxidative stress and improving metabolic health.
Investigating the impact of specific nutrients, dietary patterns, and feeding regimes on the onset and progression of inflammaging can provide valuable insights, leading to the development of dietary interventions aimed at promoting healthier aging in animals.

Various phytochemicals have been developed as senolytic drugs.
Resveratrol, a natural polyphenol found in plants such as peanuts, grapes, and strawberries, modulates the expression of pro- and anti-apoptotic factors, neutralizes free radical species, affects mitochondrial function, chelates redox-active transition-metal ions, and prevents protein aggregation.
Resveratrol inhibits the SASP through the SIRT1/NF-κB signaling pathway and delayed aging.
Early diagnosis of the SASP by detecting various pro-inflammatory cytokines and inflammatory markers is possible.
In age-related obesity cats, SAA can be good diagnostic marker at early stage of inflammaging.
Aging is inevitable in animals, however, delaying the onset of age-related diseases through adequate interventions in the early stage of the SASP is possible.
Moreover, stem-cell therapy is effective for prevention of severity of some kinds of age-related diseases in dogs and cats.

Age-related diseases become more common as animals live longer, and alleviation of inflammaging can prevent severe age-related diseases.
More research on inflammaging may reduce incidence of age-related diseases in animals.

In recent years, the lifespan of companion animals such as dogs and cats has increased substantially.
In clinical practice, veterinarians are encountering a growing number of patients with age-related conditions, including chronic kidney disease, neoplasia, diabetes mellitus, cardiovascular disorders, and obesity.
A recurring observation in daily practice is that, by the time clinical signs become apparent, disease progression is often already well advanced.
When animals present with symptoms such as reduced appetite, weight loss, or decreased activity, diagnostic evaluation frequently reveals that organ damage has already occurred.

The concept of inflammaging, which has gained increasing attention in recent years, provides a compelling explanation for these observations in clinical practice.
With advancing age, animals experience a persistent state of low-grade chronic inflammation, which is believed to underpin many age-associated diseases.
In other words, many diseases are not sudden in onset, but are thought to arise along a continuum of chronic inflammatory processes that develop and progress over an extended period of time.

If this subclinical state of chronic inflammation—present before the onset of overt symptoms—can be identified, many diseases could shift from conditions treated after onset to those amenable to intervention before they develop.

However, in current clinical practice, it remains challenging to detect such chronic inflammatory states during routine care.
Conventional blood tests often reveal no marked abnormalities, and at stages when animals appear clinically well to their owners, it is difficult for veterinarians to clearly demonstrate or explain the presence of underlying pathology.

Against this background, serum amyloid A (SAA), particularly when measured with high sensitivity as VET-SAA, is expected to have significant clinical potential—not only as a marker of acute inflammation, but also as an indicator of chronic inflammation, namely the state of inflammaging.

To date, animal health has been assessed primarily based on parameters such as appetite, activity, body weight, and routine laboratory findings.

However, by incorporating regular evaluation of inflammatory status alongside these conventional measures, it may become possible to enable earlier interventions, including lifestyle guidance, nutritional management, weight control, and periodontal care.

This development should not be regarded merely as the addition of a new diagnostic parameter; rather, it has the potential to drive a fundamental shift in the conceptual framework of veterinary medicine—from a treatment-centered approach to one focused on prevention and long-term health management.
In clinical practice, increasing emphasis is expected to be placed on a new model of care in which animals are not brought to veterinary clinics only after disease onset, but instead undergo regular monitoring of inflammatory status while still clinically healthy, with the aim of maintaining overall health.

Such a transition toward wellness-oriented veterinary medicine is likely to become increasingly important in the future.

I believe that veterinary medicine is evolving from a model focused on treating disease to one aimed at preventing its onset, and that the first step in this transition is the early detection of inflammation.
With the broader adoption of tests such as VET-SAA in clinical practice, I expect veterinary medicine to progress significantly—from diagnosing disease to proactively managing health.
I believe that the concept of inflammaging, together with the development of biomarkers that enable its assessment in clinical practice, will form a new foundation for extending the healthy lifespan of animals.
From a clinical veterinarian’s perspective, I strongly hope that continued collaboration between research and clinical practice will further advance this field.

Veterinarian; Doctor of Veterinary Medicine (DVM), PhD
•Director, Seijo Kobayashi Veterinary Clinic (over 30 years).
•Vice Chair, Tokyo Veterinary Medical Association (for 10 years from 2012).
•Since 2018, has focused on hospital management in an administrative role, contributing to advancements in animal healthcare, innovation in veterinary hospital management, and strategic advisory support for pet-related businesses.