Capture of Cancerous Cells and Overall Survival in Rats using Ex-vivo Extracorporeal Device in
Multiple Onco-dialysis Cycles

Introduction: 

The micrometastatic cascade involves the progression of cancer cells from the primary tumor to distant organs. Capture and elimination of circulating tumor cells (CTCs) may potentially delay metastasis; however, demonstrating this in ex-vivo models remains highly challenging. Here, we demonstrate cancer cell capture, safety, and overall survival in rats using an ex-vivo extracorporeal device across multiple onco-dialysis cycles.

Methods: 

In this animal observational study (IAEC/2025-26/M2/15), 12 White Wistar Albino rats were subjected to onco-dialysis using the miniature OncoMetastat device containing anti-EpCAM antibody-coated glass beads. For safety evaluation, rats were anesthetized, and 1 ml of blood was obtained from the retro-orbital artery, heparinized, and exposed to the device. Subsequently, 0.3 ml of blood was re-injected through the tail vein, and the animals were monitored for changes in temperature and signs of anaphylactic shock. DAPI-pre-stained MCF-7 cells (0.5 × 10⁶) were injected via the rat tail vein (n=6). After 15 minutes, 1 ml of blood was withdrawn from the retro-orbital artery, heparinized, circulated through the OncoMetastat device, and 0.3 ml was recirculated into the rats. Glass beads were analyzed for cancer cell capture across cycles I–III, with 48 hours of rest between cycles. Animals were monitored for 14 days for overall survival (OS) and subsequently sacrificed for histopathological evaluation.

Results: 

Eleven of the 12 rats demonstrated safety following exposure to the onco-dialysis device. A total of 23 cells were captured across three rats over three cycles. In Rat 1, 9, 5, and 1 cells were captured in cycles I, II, and III, respectively, with a mean of 5.0 cells. In Rat 2, 3, 2, and 1 cells were captured across cycles I–III, respectively. In Rat 3, 1, 1, and 0 cells were captured across cycles I–III, respectively. The mean distribution of captured cells across all rats was 7.67/ml. Overall survival was observed in both groups, although one rat in the control group experienced mortality. All rats in the test group survived the 14-day observation period. Histopathological evaluation revealed normal tissues in device-exposed rats.

Conclusion: 

This study demonstrates the safety and capture of cancer cells using an ex-vivo extracorporeal device across multiple onco-dialysis cycles in rats, with all test-group animals surviving the 14-day observation period and showing normal tissue histopathology.