# Age-Dependent Systemic Regulation of C1q/TNF-Related Protein 3 and Progranulin in Patients with Cystic Fibrosis: Biomarkers or Therapeutic Targets?

## TL;DR

This study explores how two proteins, CTRP3 and PGRN, change with age in cystic fibrosis patients and their potential as biomarkers.

## Contribution

The study reveals age-dependent regulation of CTRP3 and PGRN in CF patients and their inverse correlation with BMI and lung function.

## Key findings

- Adult CF patients had lower CTRP3 and higher PGRN compared to healthy controls.
- Pediatric CF patients had higher CTRP3 and PGRN than adults.
- PGRN reliably differentiated CF patients from controls but not those with liver disease.

## Abstract

Background/Objectives: C1q/TNF-related protein 3 (CTRP3), progranulin (PGRN), and chemerin are adipokines that participate in systemic inflammation. This study systematically examined adipokine levels in cystic fibrosis patients of different ages to evaluate their role in inflammatory, metabolic, and hepatic processes. Thirty-seven pediatric and thirty-three adult CF patients were enrolled to assess the potential of these adipokines as biomarkers. Methods: Anthropometric and physiological data, pulmonary function (forced expiratory volume, FEV1; vital capacity, VC), and liver fibrosis score FIB-4 were assessed. Liver stiffness was measured by transient elastography. Serum samples from 40 healthy adult volunteers served as the control group. Serum concentrations of chemerin, CTRP3, and PGRN were quantified by enzyme-linked immunosorbent assay (ELISA). Results: Compared with healthy controls, adults with CF had markedly lower circulating CTRP3 levels, whereas PGRN concentrations were significantly higher. Among CF patients, both CTRP3 and PGRN were higher in the pediatric group than in adults, while chemerin did not vary with age. The presence of cystic fibrosis-related liver disease (CFLD) did not significantly alter adipokine levels relative to CF patients without liver disease. Receiver operator characteristic (ROC) analysis showed that circulating PGRN could reliably differentiate CF patients from controls; none of the three adipokines predicted the presence of CFLD. CTRP3 and PGRN were inversely correlated with age, BMI, and pulmonary function. Conclusions: Overall, our data support systemic PGRN as a potential biomarker for CF and indicate an age-dependent regulation of circulating CTRP3 and PGRN. Both proteins were inversely associated with BMI, inflammatory markers, liver fibrosis, and pulmonary capacity.