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Pulmonary fibrosis has been linked molecularly and pathophysiologically by abnormal telomere maintenance.

Short telomere lengths are commonly found in both the familial and sporadic forms, telomerase mutations being the most common identifiable genetic cause of the disease.
Telomeres are repeated nucleotide sequences that cap the ends of chromosomes and protect them from damage. Telomeres are eroded with cell division and shorten with age. Telomere integrity is mediated by the telomerase complex, a specialized polymerase that adds sequences to the ends of chromosomes. Mutations in the genes encoding telomerase (TERT and TERC) cause pulmonary fibrosis through low telomerase activity, accelerated telomere shortening and exhaustion of lung stem cells.
Mutations in TERT or TERC account for only 19% of familial pulmonary fibrosis cases, and it is likely that additional environmental, genetic and epigenetic factors contribute to telomere erosion and to disease phenotype.
Identification of short telomeres has potential clinical implications in pulmonary fibrosis: it may be a marker for an increased predisposition toward the development of the disease, it might affect risk stratification as it has been associated with lower survival rates and post‑transplant complications that reflect the syndromic nature of this molecular defect.
Keywords: pulmonary fibrosis, short telomere lengths, telomerase mutations

Neural Respiratory Drive measurement for COPD assessment and monitoring

Currently there is an unmet need for more objective assessments that could determine COPD severity. Ideally such objective assessments could also anticipate COPD exacerbations in order to decrease the need for repeated hospital admissions. In this review we outline how patients' neural respiratory drive (NRD) may be determined using the electromyography of the diaphragm as an objective measurement of COPD severity. Respiratory muscle NRD is indeed less influenced by patients' voluntary effort limitation than for example when testing for exercise tolerance in which case the patients themselves decide when to stop. Exercise tolerance tests are better correlated with muscle weakness rather than COPD severity per se. NRD would also be less dependent upon patients' subjective perception of the severity of their breathlessness. A key further advantage is that recent studies showed that the diaphragm electromyography measurements using electrodes placed on the skin are correlated with those obtained using specific electrodes, therefore this method is non-invasive and more acceptable for routine clinical practice. Thus, NRD measurements could be used in COPD in a similar way as electrocardiography is used to evaluate and monitor ischemic heart disease. NRD measurements could therefore complement more established instruments such as lung function tests, FEV1, exercise tolerance tests, the BODE index etc. in COPD. This could lead to better COPD management and reduce the acute exacerbations which are amongst the most common causes of repeated hospital admissions and consume significant resources.
Keywords: COPD, dyspnea, biomarker, exacerbation, exercise, diaphragm, fatigue, respiratory drive