Potential consequences of screening of occupational silica dust exposed workers for early detection of silicosis/silico-tuberculosis using a novel biomarker, club cell protein-16, with possible intervention by repurposing metformin

Abstract

Earlier, a study conducted by the Indian Council of Medical Research – National Institute of Occupational Health (ICMR-NIOH), India, evidenced that CC16 may be used as a proxy marker and screening tool for early detection and progression of silica-induced lung damage. Once CC16 indicates early silicosis, it needs to be confirmed by chest radiography. Next, ICMR-NIOH and ICMR-National Institute of Virology (ICMR-NIV) jointly developed a semi-quantitative and point-of-care CC16 detection kit using lateral flow immune chromatography. The said test can be done from one drop of blood collected through a finger prick. All trained peripheral healthcare workers can screen the silica dust-exposed workers periodically, under the national silicosis control program. Once early silicosis is detected, their sputum may be examined periodically by CB-NAAT/True-NAT for early detection of silicotuberculosis. The serum CC-16 detection kit is the first of its kind for early detection of silicosis through periodic screening, which is approved by the Indian Council of Medical Research, Ministry of Health, Govt. of India. Unless silicosis is controlled, elimination of TB appears to be difficult in India as there is a huge burden of silicosis including sub-radiological silicosis in India and considering the fact that silicosis is a stronger risk factor for lung tuberculosis due to its progressive declining effect of lung immunity. Since occupational silica dust exposure facilitates progressive fibrosis of lung tissue, a clinical trial using metformin may be the need of the day as animal experiments have already shown metformin's anti-fibroblastic effect in silica-induced animals.