The efficacy and safety of intravenous tranexamic acid in patients with posterior operation of multilevel thoracic spine stenosis: a prospective randomized controlled trial.

BACKGROUND: This study was a randomized controlled trial to evaluate efficacy and safety of the usage of intravenous tranexamic acid during posterior operation of multilevel thoracic spine stenosis for controlling perioperative blood loss. METHODS: Sixty eight patients with multilevel thoracic spine stenosis were randomized into the tranexamic acid group receiving 15 mg/kg body weight before the skin incision was made and 1 mg/kg body weight per hour during operation or the control group receiving the same dose of placebo (0.9% sodium chloride solution) intravenously. Pedicle screw fixation, laminectomy and selective discectomy were performed. Intraoperative and perioperative total blood loss were compared. The necessity and amount for blood transfusion, blood coagulation function, durations of postoperative hospital stays were compared. The complications of tranexamic acid were also investigated such as cardiovascular and cerebrovascular events, lower limb venous thrombosis. RESULTS: There were no statistically significant differences in age, gender, body mass index, ASA status, pathology required surgery, preoperative hemoglobin, operation time, laminectomy segments and discectomy segments between the tranexamic acid and control groups. The intraoperative blood loss (455.9 ± 206.6 ml vs 580.6 ± 224.3 ml, p < 0.05) and total blood loss (675.3 ± 170.3 ml vs 936.8 ± 306.4 ml, p < 0.01) in tranexamic acid group were significant lower than those in control group. The means of blood unit transfused (2.5 ± 1.0 vs 4.7 ± 2.4, p < 0.05) and Hb reduction in 48 h (22.5 ± 3.4 g/L vs 25.3 ± 3.9 g/L, p < 0.01) were significantly lower in tranexamic acid group than that in control group. There were no statistically significant differences in blood coagulation function pre-operation or 48 h post-operation between the tranexamic acid and the control groups. The requirements for patients to receive blood transfusion were fewer and durations of post-operational hospital stays were shorter in the tranexamic acid group, however, the difference did not achieve statistical significance. There was no significant difference in superficial or deep venous thrombosis of lower limbs or deterioration of neurological function between tranexamic acid group and control group. CONCLUSIONS: Application of intravenous tranexamic acid significantly reduces intraoperative and perioperative total blood loss without significant side effects in posterior operation of multilevel thoracic spine stenosis. TRIAL REGISTRATION: At Chinese Clinal Trial Registry. http://www.chictr.org.cn/ , ChiCTR2100054221. Registered on 11/12/2021.

Immortalization of human osteoblasts by transferring human telomerase reverse transcriptase gene.

In the current study, in order to establish an immortalized osteoblast cell line, human mesenchymal stem cells (hMSCs) had been inducted into osteoblasts directionally by an osteo-inductive conditioned medium, then the osteoblasts were steadily transduced by a retroviral vector containing human telomerase reverse transcriptase (hTERT) gene. The expression of hTERT, the telomerase activity, the telomere lengths, the tumorigenesis and the osteogenesis characteristics of transduced cells at different population doublings (PDs) and the primary normal human osteoblast (hOB) were identified. The results demonstrated that hTERT gene had been transferred into human osteoblasts successfully; the transduced cell line-clone5 expressed telomerase activity and divided vigorously and now have undergone more than 120 PDs; The telomere length of clone5 elongated and was stable; Different eras of clone5 (PD 40 and PD 88) both expressed bone-specific markers, such as alkaline phosphatase (ALP), collagen type I, and osteopontin. And the quantitative assay of ALP activity showed that there were no significant differences among untransduced cells, PD 40 and PD 88 clone5 cells. Furthermore, the immortalized cell line was benign in nude mice tumor formation and soft agar colony formation assay.