Viability and diagnostic potential of tissues obtained through cryobiopsy

Background

Transbronchial lung cryobiopsy is primarily used for diagnosing interstitial lung diseases and tumors, providing larger tissue samples with reduced tissue crushing than traditional biopsies. However, freezing during cryobiopsy may damage cells, potentially affecting diagnostic methods that require live cells, such as flow cytometry (FCM). We aimed to determine the extent of freezing-related cell damage in cryobiopsies using cells cultured in vitro.

Methods

To investigate the relationship between freezing duration and sample volume, Jurkat cells underwent freezing for durations ranging from 2 to 6 s, with 1-s intervals, using either 1-mm- or 1.7-mm cryoprobes. FCM was conducted to assess both cell viability (2, 4, and 6 s) and cell-surface molecule expression (3 and 6 s) over varying freezing times. Additionally, we describe a clinical case involving a 70-year-old man suspected of malignant lymphoma, in which tissue samples were obtained via both forceps biopsy and cryobiopsy methods to compare the pathological and cytological features between the methods.

Results

Harvested cell count increased with freezing duration, with a notable increase in viable cell percentage. Moreover, cells distant from the cryoprobe exhibited higher survival rates under milder freezing conditions. FCM revealed significantly higher marker expression levels in viable cryobiopsy samples than in non-viable samples. The clinical case demonstrated that cryobiopsy yields a significant proportion of live cells (>90%), with cytological findings consistent with those of non-frozen samples.

Conclusions

Cryobiopsy may be beneficial for histopathological diagnosis, providing sufficient viable cells for FCM, and can be used for diagnosing malignant lymphomas and other pulmonary conditions.