Hematopoietic and T-lymphopoiesis-stimulating effects of a fluorinated pyrazolopiperidine β-cyclodextrin complex in...

Cyclophosphamide is widely used in oncology, autoimmune disorders, and transplantation-related conditioning or post-transplant immunosuppression. However, its therapeutic value is limited by hematopoietic and lymphoid toxicity, including leukopenia, neutropenia, anemia, thrombocytopenia, bone marrow suppression, thymic injury, and prolonged impairment of T-cell recovery. These effects may occur after pulsed intravenous administration, high-dose regimens used in transplantation or severe refractory disease, and continuous low-dose/metronomic exposure. Therefore, there is a medical need for pharmacological agents capable of compensating cyclophosphamide-induced hematopoietic and lymphopoietic suppression without causing uncontrolled stimulation of early progenitor cells.

To evaluate the hematopoietic and T-lymphopoiesis-stimulating activity of BIV under cyclophosphamide-induced hematopoietic and T-lymphopoietic suppression.

Cyclophosphamide-induced hematopoietic- and T-lymphopoiesis-suppressive models were established on laboratory albinos rats and C57BL6/J mice. Peripheral blood hematological indices in rats were measured using hematology analyzers. Hematopoietic stem cells, thymocyte subsets, Th_act, T_reg, T_mem, CTL cell populations, and erythroid cells from the bone marrow, thymus, and spleen were analyzed by flow cytometry. Statistical analysis was performed using one-way ANOVA (p < 0.05).

In rats with CPh-induced hematopoietic suppression, BIV supported partial recovery of erythrocyte and hemoglobin parameters and improved leukopoietic indices under CPh-induced hematopoietic suppression. The β-cyclodextrin complex of 5-benzyl-7-(o-fluorobenzylidene)-2,3-bis(o-fluorophenyl)-3,3a,4,5,6, 7-hexahydro-2H-pyrazolo[4,3-c]pyridine (BIV) demonstrated a consistent moderate activity in restoring the overall level of CD3ε+CD19- T lymphocytes in the bone marrow and thymus. In the bone marrow, BIV uniformly increased the reduced levels of CD3ε+CD19- T lymphocytes and CD3ε+CD44⁺ T_mem memory T cells to physiological normal values. In the spleen, BIV restored the decreased levels of CD25+FoxP3+ T_reg regulatory lymphocytes and CD28⁺CD44⁺ T_mem memory T cells to physiological normal levels, while reducing the elevated levels of CD3ε+CD8a+ CTL cytotoxic T lymphocytes and CD4⁺CD25⁺ Th_act activated helper T cells to values corresponding to the physiological norm.

BIV demonstrated notable hematopoietic- and T-lymphopoiesis-modulating activity. The compound partially restored erythropoiesis as well as central and peripheral T-lymphopoiesis, while providing balanced regulation of cytotoxic, regulatory, and memory T-cell subsets in cyclophosphamide-induced T-lymphopoiesis-suppressive models. Several evaluated T-lymphocyte subpopulations approached or returned to physiological control levels under the experimental conditions, although full translational validation requires further pharmacological and toxicological investigation.