Senolytics

Senolytics are a group of biologically active compounds capable of selectively eliminating senescent cells, i.e., aging cells that have lost the ability to divide but remain metabolically active. In recent years, senolytics have become one of the most intensively developed research directions in aging processes and longevity medicine. Senescent cells accumulate in the body with age and under the influence of chronic inflammation, oxidative stress, UV radiation, or DNA damage. Their excessive accumulation is linked to the development of age-related diseases, including atherosclerosis, type 2 diabetes, osteoarthritis, organ fibrosis, and skin aging. Senolytics represent a promising therapeutic strategy aimed at improving tissue function and extending healthspan.

Senolytics - what are they?

Senolytics are substances that recognize and eliminate senescent cells by activating mechanisms leading to their apoptosis, i.e., programmed cell death. The term “senolytic” comes from the combination of the Latin word senescere (“to grow old”) and the Greek lysis (“dissolution”, “destruction”).

Senescent cells initially perform a protective function – they prevent the proliferation of damaged or potentially cancerous cells. The problem arises in the case of their chronic persistence in tissues. These cells secrete numerous pro-inflammatory factors, proteases, and cytokines collectively referred to as SASP (Senescence-Associated Secretory Phenotype). SASP induces chronic, low-grade inflammation, referred to as inflammaging, which is recognized as one of the key mechanisms of biological aging.

The most well-known senolytics include:

dasatinib,
quercetin,
fisetin,
navitoclax,
piperlongumine,
certain plant flavonoids.

Modern medicine treats senolytics as a potential element of geroprotective therapies, i.e., those aimed at slowing down the processes of biological aging.

Senolytics - how do they act on senescent cells?

Senescent cells exhibit increased resistance to apoptosis due to the activation of so-called pro-survival pathways (SCAPs – Senescent Cell Anti-Apoptotic Pathways). Senolytics work by blocking these defense mechanisms, which leads to the selective removal of aging cells without significantly damaging healthy tissues.

The most important mechanisms of action of senolytics include:

inhibition of proteins from the BCL-2 family,
modulation of the PI3K/AKT pathway,
influence on tyrosine kinases,
reduction of NF-κB pro-inflammatory signaling,
induction of mitochondrial stress in senescent cells.

Of particular importance is the fact that senescent cells possess a distinct metabolism and an increased requirement for anti-apoptotic mechanisms. As a result, senolytics can act relatively selectively.

Preclinical studies have shown that the removal of senescent cells can lead to:

improved tissue regeneration,
reduction of chronic inflammation,
improvement of blood vessel function,
increased insulin sensitivity,
improvement of skin and subcutaneous tissue condition,
delay in the development of degenerative diseases.

In dermatology and aesthetic medicine, senescence processes are considered one of the key mechanisms of skin aging. Senescent fibroblast cells limit the production of collagen and elastin, intensifying the loss of firmness and the degradation of the extracellular matrix.

Senolytics - connection with the removal of senescence

The removal of senescent cells is referred to as "senescence clearance" or antisenescence therapy. This strategy differs from classic anti-aging methods because it does not focus solely on stimulating regeneration, but on eliminating the biological source of chronic inflammation and tissue dysfunction.

Two main therapeutic approaches are distinguished:

Strategy	Mechanism of action
Senolytics	Elimination of senescent cells
Senomorphics	Inhibition of SASP secretion without cell elimination

In the practice of biological aging, both approaches can complement each other.

In experimental studies, the removal of senescent cells has been associated with:

extending the lifespan of laboratory animals,
improving physical performance,
reduction of organ fibrosis,
improving cognitive functions,
reduction of osteoporosis,
improving tissue healing.

There is also growing interest in the impact of antisenescence therapies on the skin. Skin aging is associated with the accumulation of senescent fibroblasts, keratinocytes, and endothelial cells. The elimination of these cells can support repair processes, improve the quality of the collagen matrix, and limit the degradation of skin support fibers.

In aesthetic and regenerative medicine, procedures supporting the reduction of oxidative stress and chronic inflammation, which indirectly influence the limitation of cellular senescence, are currently used. These include, among others:

biostimulating therapies,
fractional laser therapy,
regenerative mesotherapy,
procedures stimulating collagen remodeling,
antioxidant therapies,
regenerative treatments using platelet-rich plasma and exosomes.

Senolytics - current state of scientific research

Research on senolytics currently remains at the stage of intensive preclinical development and early clinical trials. Most data comes from animal models, but the first results of human studies are considered promising.

Particular interest has been generated by studies from the Mayo Clinic team and the Scripps Research Institute, which showed that intermittent administration of a combination of dasatinib and quercetin can reduce the number of senescent cells in patients with idiopathic pulmonary fibrosis and diabetic kidney disease.

Currently, the potential of senolytics is being analyzed in the context of:

neurodegenerative diseases,
cardiovascular diseases,
osteoarthritis,
pulmonary fibrosis,
frailty syndrome in the elderly,
metabolic diseases,
skin aging.

However, researchers emphasize several significant limitations:

lack of long-term safety data,
risk of damaging beneficial senescent cells,
possibility of hematological adverse effects,
complexity of the biology of aging,
difficulty in determining optimal dosing regimens.

A significant issue also remains the fact that cellular senescence partly serves a protective anti-cancer function. Overly aggressive elimination of such cells could disrupt natural DNA damage control mechanisms.

Modern gerontology increasingly views aging not as a single process, but as a complex network of biological disorders including, among others, mitochondrial dysfunction, epigenetics, chronic inflammation, telomere shortening, and cellular senescence.

Senolytics - natural and synthetic examples

Senolytics can be divided into natural and synthetic compounds.

Natural senolytics

Plant polyphenols with anti-inflammatory and antioxidant effects attract the most interest.

Fisetin

A flavonoid present in, among others:

strawberries,
apples,
onions,
grapes.

In experimental studies, it showed the ability to reduce senescence markers and extend the lifespan of mice.

Quercetin

A natural flavonoid occurring in, among others:

capers,
red onions,
kale,
blueberries.

Most commonly studied in combination with dasatinib.

Curcumin

The active substance of turmeric with strong anti-inflammatory effects, capable of modulating SASP and oxidative stress.

Synthetic senolytics

Dasatinib

A drug from the tyrosine kinase inhibitor group originally used in the treatment of leukemias. One of the best-studied senolytics.

Navitoclax

A BCL-2 protein inhibitor showing high efficacy in eliminating senescent cells, however, it is associated with a risk of side effects, especially thrombocytopenia.

Piperlongumine

A compound of natural origin with potentially strong senolytic activity through the induction of oxidative stress in aging cells.

Despite the dynamic development of this field, there are currently no approved senolytic therapies routinely used in anti-aging prophylaxis. Most substances remain the subject of clinical and experimental research.