An inflammation clock

Here are six 2022 papers that either cited the second study of Variable aging measurements, or provided further evidence for its findings. Let’s start with a citing study:

“This study aimed to investigate expression patterns and prognostic values of the inflammatory aging clock (iAge) in glioblastoma (GBM), and its relations with stem cells. Similar to epigenetic clocks and transcriptomic clocks, iAge could track multifaceted aging phenotypes and have clinical significance in translation medicine.

iAge was positively correlated with chronological age, and highly associated with immune cells and inflammatory activities. iAge could serve as a prognostic biomarker for overall survival, and could precisely predict GBM stem cells stemness.

We identified the physiological importance and function of iAge in GBM, and provided novel insights into how iAge is a critical event for development of GBM.” “Inflammatory aging clock: A cancer clock to characterize the patients’ subtypes and predict the overall survival in glioblastoma”

Beginning with a human osteoporosis study, five papers investigated cytokine CXCL9, which the iAge study found to be “clearly actionable as shown by our experiments in CXCL9 where we can reverse aging phenotypes.”

“We assessed whether levels of CXCL9 and CXCL10 were elevated in human serum samples of older adults who had incident hip fractures. Our findings revealed higher serum levels of CXCL9 in pre-fracture blood samples of men with subsequent hip fractures, compared with their non-fracture controls. There was no such difference in CXCL9 serum levels between cases and controls in women.

Serum CXCL9 improved the prediction of osteoporotic hip fracture in men. The association between CXCL10 and hip fracture risk was not statistically significant in either sex.

While our epidemiologic findings are supported by experimental data providing the mechanistic pathway for CXCL9 in regulating osteoclast recruitment, further studies are needed to confirm validity of our findings and determine their generalizability to other study populations. Underlying biological mechanisms that limit our findings to men but not women require further investigation.” “CXCL9 Predicts the Risk of Osteoporotic Hip Fracture in a Prospective Cohort of Chinese Men—A Matched Case–Control Study”

Two immune-mediated skin diseases, with a vitiligo review:

“Current findings emphasize the critical role of immune cells and their mediators in the immunopathogenesis of vitiligo. IFN-γ [interferon gamma] is the primary cytokine mediator that activates the JAK/STAT pathway, causing keratinocytes to produce the key chemokines CXCL9 and CXCL10.

Interactions between immune and non-immune cells finally result in apoptosis of melanocytes. Additional investigations of these pathways may provide an opportunity for finding possible therapeutic targets, as there are currently no targeted biological drugs available for treatment of vitiligo.” “Current Concepts of Vitiligo Immunopathogenesis”

and a study of psoriasis:

“CXCL9 is an important chemokine involved in T cell recruitment, and is up-regulated in plasma of patients with psoriasis. Increased CXCL9 expression can aggravate the progression of psoriasis.

cxcl9 expression

IL-1β and CXCL9 were up-regulated and CLDN8 was down-regulated in psoriasis with statistically significant differences. Identification of potential key molecular markers and signaling pathways provides potential research directions for further understanding molecular mechanisms of psoriasis.” “Identification of potential key molecules and signaling pathways for psoriasis based on weighted gene co-expression network analysis”

Two lung-related studies, first, an editorial for a human lung transplant study that isn’t freely available:

“CXCL9 and CXCL10 are chemokines that bind to the shared receptor CXCR3, potentiating T cells, mononuclear cells, and natural killer (NK) cells. Previous studies demonstrated that presence of these chemokines in bronchoalveolar lavage samples preceded development of chronic lung allograft dysfunction (CLAD).

Acute rejection and acute lung injury are known risk factors to the development of CLAD, yet this study found that increased risk was dependent on the presence of CXCL9/CXCL10 plasma elevation. Early identification of patients at risk, possibly during the active inflammatory phase, rather than once abnormal wound healing pathways dominate resulting in irreversible injury, provides an attractive opportunity for intervention.” “CXCL9 and CXCL10 plasma levels: Potential keys to unlocking CLAD risk”

and a study of smoking effects:

“We collected blood samples from 78 healthy male volunteers aged 18–60, including non-smokers (n = 30), current smokers (n = 30), and ex-smokers (n = 18). Expression levels of CXCL9/MIG [monokine induced by IFN-γ] and sIL-6R significantly increased after smoking, and continued to increase after quitting smoking.

cxcl9 smoking

Changes in related cytokines after smoking cessation are mainly restorative, while some cytokines further strengthen the trend of smoking-related changes.” “Effects of Smoking on Inflammatory-Related Cytokine Levels in Human Serum”


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