The impact of cord blood stem cell transplantation on the functional status of living-donor kidney allografts

Abstract

Standard immunosuppressive therapy (SIST) remains the cornerstone in preventing early rejection episodes in kidney transplantation. However, long-term graft survival rates have seen limited improvement over the past three decades. Recent research suggests that stem cells possess immunomodulatory properties, contribute to the reduction of ischemia-reperfusion injury, and enhance graft function.

The present study aimed to evaluate the effect of cord blood stem cell (CBSC)-enhanced induction immunosuppression on the functional outcomes of kidney allografts during the first post-transplantation year.

Methods. This prospective study included 45 recipients of living-donor kidney transplants, who were divided into two groups: Group I (n = 20) received CBSC in combination with SIST, while Group II (n = 25) received SIST alone. Graft function was assessed over three post-transplant periods: Period I (days 1–7), Period II (days 8–89), and Period III (days 90–360).

Parameters assessed included serum creatinine levels, estimated glomerular filtration rate (eGFR), daily urine output, urinary neutrophil gelatinase-associated lipocalin (NGAL) levels, and protocol biopsies at 3 and 12 months post-transplantation.

Results. CBSC administration in Group I was well tolerated without adverse events. During the first week, daily urine output in Group I was significantly higher (9,400 ± 950 mL) compared to Group II (7,545 ± 750 mL; p < 0.01). Normalization of serum creatinine occurred within 2–3 days in Group I, whereas in Group II it occurred by days 5–7. At 12 months, the mean eGFR was significantly better in Group I (98.2 mL/min/1.73 m²) compared to Group II (61.4 mL/min/1.73 m²; p < 0.01).

Urinary NGAL levels on days 1 and 3 post-transplant were substantially lower in Group I (79.4 and 28.4 pg/mL, respectively) versus Group II (375 and 121 pg/mL; p < 0.01), indicating reduced tubular injury. No opportunistic infections were recorded in Group I during the 12-month follow-up. In contrast, two cases of cytomegalovirus infection were documented in Group II.

Protocol biopsies at 3 and 12 months showed no pathological findings in Group I. In Group II, 10% of biopsies revealed glomerulitis and peritubular capillaritis with C4d deposition, and one patient exhibited lymphocytic tubulitis.

Conclusions. The addition of CBSC to SIST appears to mitigate ischemia-reperfusion injury and accelerates early recovery of graft function, with improved eGFR and reduced tubular injury markers observed within the first year post-transplant. These findings support the potential of CBSC in enhancing transplant outcomes. Further research is warranted to define optimal dosing strategies, administration frequency, and long-term immunological impacts.