SARS-CoV-2 infection can lead to severe bone loss during the acute and post-recovery phases, finds a study.

This is caused due to inflammatory activation of bone resorption cells, said researchers from the University of Hong Kong. The findings, published in the journal Nature Communications, provide insights into the possible long-term complications of COVID-19.

COVID survivors were so far known to experience debilitating, lingering symptoms that affect the heart, brain, lungs and other parts of the body. However, the full spectrum of clinical manifestations, especially the influence of SARS-CoV-2 infection on bone metabolism, has yet to be fully understood.

To study the effects of COVID infection on bone metabolism, the experimental subjects were intranasally challenged with SARS-CoV-2 and then their bone tissues were collected serially after the infection.

Using three-dimensional micro-computerised tomography scans, the research team identified that SARS-CoV-2 infection had induced severe bone loss from 20 per cent to 50 per cent progressively, in particular to the trabecular bone, in the long bones and lumbar vertebrae.

This effect extended from the acute phase to the chronic phase of infection. The pathological osteopenia - in which the protein and mineral content of bone tissue is reduced - was found to be associated with the inflammatory activation of osteoclasts - a kind of cell responsible for bone resorption.

The team is the first in the world to report the effects of SARS-CoV-2 on bone metabolism using a well-established Syrian experimental model that closely mimics COVID-19 in humans.

The findings indicate that pathological bone loss may be an important but neglected complication, which warrants more extensive investigations during the long-term follow-up of COVID-19 patients.