As populations age, scientists are looking more closely at a hidden biological process that may help explain why some older adults remain mobile and independent while others experience a rapid decline in strength, balance, and endurance. A systematic review by A. Boshnjaku, R. Obërtinca, M. Hoxha, and colleagues examines whether five inflammation-related biomarkers—CRP, high-sensitivity CRP, interleukin-6, interleukin-10, and tumor necrosis factor-alpha—are linked to physical performance in older adults living in the community. Published in BMC Geriatrics, the review focuses on a question with major implications for healthy aging: can signals circulating in the blood reveal who is at greater risk of losing physical function?

The study centers on chronic, low-grade inflammation, a biological condition often associated with aging and commonly described as “inflammaging.” Unlike the intense inflammation triggered by an infection or injury, inflammaging can persist quietly over years. It may be influenced by immune-system changes, excess body fat, physical inactivity, chronic disease, and cellular stress. Although inflammation is essential for repairing tissue and fighting pathogens, prolonged activation can affect muscle metabolism, blood-vessel function, nervous-system signaling, and energy production. These changes could, in theory, make everyday movements such as walking, rising from a chair, or climbing stairs increasingly difficult.

C-reactive protein, or CRP, is one of the most widely used indicators of systemic inflammation. It is produced primarily by the liver in response to inflammatory signals, especially interleukin-6. Standard CRP testing is useful for detecting relatively pronounced inflammatory activity, while high-sensitivity CRP, known as hs-CRP, can measure much lower concentrations. That distinction matters in research on older adults, where subtle inflammatory differences may exist even when there is no obvious acute illness. However, neither CRP nor hs-CRP identifies a single disease or proves that inflammation itself caused a decline in physical ability.

The review also considers three signaling proteins known as cytokines. Interleukin-6, or IL-6, can promote inflammation but also participates in muscle adaptation and energy regulation, making its effects highly dependent on timing, tissue, and physiological context. Tumor necrosis factor-alpha, or TNF-α, is a potent inflammatory mediator that can influence muscle protein breakdown and interfere with insulin signaling. Interleukin-10, or IL-10, generally acts as an anti-inflammatory regulator, helping restrain excessive immune activation. Examining these markers together offers a more nuanced picture than relying on a single laboratory value.

Physical performance is a crucial measure of aging because it reflects how effectively multiple systems work together. Muscle strength alone does not determine whether a person can remain independent. Walking speed, repeated chair stands, balance, grip strength, endurance, and composite tests such as the Short Physical Performance Battery can reveal the combined effects of the muscular, cardiovascular, neurological, and skeletal systems. For people living outside hospitals and care facilities, these measures may also provide a practical snapshot of resilience in everyday life. A small difference in performance can translate into a major difference in fall risk, mobility, and the ability to manage daily activities.

By bringing together evidence from studies of community-dwelling older adults, the authors address an important gap between laboratory research and real-world aging. Older people living independently are not a uniform group: some have multiple chronic conditions, while others remain highly active; some take anti-inflammatory medications, and others do not. Diet, smoking, obesity, socioeconomic conditions, sleep, recent infections, and exercise can all alter cytokine levels and physical performance. A systematic review can help determine whether associations between biomarkers and function appear consistently across this complex population or whether they vary substantially from one study to another.

The review’s importance lies not only in asking whether inflammatory markers are associated with poorer performance, but also in highlighting the limitations of interpreting such relationships. A high biomarker level may be a consequence of frailty, reduced activity, obesity, or an undiagnosed illness rather than the original cause of decline. Conversely, a single blood sample may fail to capture fluctuations in inflammation over time. Differences in laboratory methods, cutoff values, participant health, medication use, and performance tests can make studies difficult to compare. These issues are central when translating population-level associations into decisions about an individual patient.

The findings may ultimately support a broader approach to healthy aging in which inflammation is considered alongside strength, nutrition, cardiovascular health, cognition, and social environment. The biomarkers discussed in the review are not presented as standalone tests that can predict the future with certainty. Instead, they may help researchers understand why physical function changes and identify biological pathways that could be targeted through exercise, weight management, treatment of chronic disease, or other interventions. The study also underscores the need for longitudinal research capable of separating cause from consequence and for standardized testing that can connect laboratory signals with meaningful improvements in daily life.

For now, the review places a spotlight on the immune system as a possible contributor to the physical changes associated with later life. Its focus on CRP, hs-CRP, IL-6, IL-10, and TNF-α reflects the growing recognition that aging is not simply the result of muscles becoming weaker, but of interconnected changes across the body. Understanding how these inflammatory signals relate to mobility could help scientists develop more precise strategies for preserving independence—while reminding clinicians and the public that a blood test is most informative when interpreted together with a person’s functional ability, medical history, and lived environment.

Subject of Research: The relationship between inflammatory biomarkers and physical performance in community-dwelling older adults.

Article Title: What is the impact of CRP, hs-CRP, IL-6, IL-10, and TNFα in physical performance in community-dwelling older adults: a systematic review.

Article References: Boshnjaku, A., Obërtinca, R., Hoxha, M. et al. What is the impact of CRP, hs-CRP, IL-6, IL-10, and TNFα in physical performance in community-dwelling older adults: a systematic review. BMC Geriatrics (2026). https://doi.org/10.1186/s12877-026-08080-8

Image Credits: AI Generated

DOI: 10.1186/s12877-026-08080-8

Keywords: aging, older adults, inflammation, CRP, hs-CRP, IL-6, IL-10, TNF-α, physical performance, inflammaging, systematic review

The elephant’s trunk is one of the animal world’s most formidable facial appendages; it is capable of tearing a tree limb from its base and, moments later, carefully lifting a single blade of grass.

Now, this combination of strength and precision is also helping to drive robotics research.

A boneless appendage that can both move heavy logs and peel fruit like a banana, the elephant’s trunk has long been studied by engineers seeking to understand how it can perform both powerful and delicate tasks effectively. Now, in a new study published in PNAS Nexus, researchers have identified the skin, rather than the underlying muscle, as a key factor in the versatility of this pachyderm appendage. 

Lucia Beccai and colleagues at the Istituto Italiano di Tecnologia studied the trunk of an adult Asian elephant that died of natural causes at Zurich Zoo in 2020. They collected 35 samples from different regions of the trunk and analyzed them using biomechanical testing, histology, various imaging techniques, and computational modeling. The team’s analysis revealed a trunk that combines two very different mechanical strategies within a single structure.

One Trunk, Two Skins

The elephant trunk acts as a muscular hydrostat, similar to an octopus tentacle or the human tongue. With no bones and over 100,000 muscles, the trunk can stretch, compress, twist, and bend in any direction. The trunk achieves this flexibility through a combination of muscle power and specialized skin architecture. The study found that the trunk’s outer surface varies in structure depending on location and the types of forces it encounters.

The researchers identified clear differences between the upper and lower surfaces of the trunk, reflecting what scientists call functional anisotropy. The trunk’s upper surface serves as a tough, protective layer, which is over three times stiffer than the underside. In contrast, the trunk’s lower surface remains soft and flexible, allowing the elephant to grip objects with delicacy and precision.

The way elephants use their trunks reflects this structural difference. The upper surface faces the environment and absorbs impacts and abrasions. The underside is used for gripping objects. Its lower stiffness allows it to adapt to the shape of objects and hold them securely. The design of the elephant trunk may offer a solution to a persistent challenge that has stumped soft-robotics engineers in balancing protection and precision by assigning each function to a different layer of skin.

A Lens Made of Tissue

Another significant finding was made beneath the gripping surface. The researchers identified dome-shaped structures known as dermal papillae. Finite element modeling suggested that these structures act as subsurface mechanical lenses, concentrating mechanical stress in regions where sensory nerves are located.

This design could solve an additional problem in robotics: touch sensors are often fragile and require protective coatings that can reduce their sensitivity. The tissue in the elephant trunk appears to protect sensory structures while still allowing mechanical signals to reach them.

The Biomimetic Blueprint

For Beccai’s group, which specializes in soft robotics, the possible design template represents a huge opportunity for their field. A robotic gripping device built on this idea would feature a stiff outer shell over a flexible inner layer, with structures underneath to direct pressure to protected sensors. This setup would keep sensitive electronics shielded while still allowing for mechanical feedback from touch.

This research adds to the growing scientific interest in the elephant trunk as a model for engineering. Another 2024 study in Communications Biology found that the trunk’s dermis is reinforced by tangled collagen fibers, creating skin armor thicker than an armadillo’s shell. Together, these studies show a structure optimized at every level, from the protein fibers in the dermis to the clear split between the upper and lower surfaces.

Today’s robotic hands still struggle to balance durability with sensitivity. The elephant trunk offers biological inspiration for this challenge, providing a model for future engineering designs.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.