Systemic tranexamic acid promotes bone healing in a rat model of femur fracture

The emerging role of tranexamic acid and its principal target, plasminogen, in skeletal health

The worldwide burden of skeletal diseases such as osteoporosis, degenerative joint disease and impaired fracture healing is steadily increasing. Tranexamic acid (TXA), a plasminogen inhibitor and anti-fibrinolytic agent, is used to reduce bleeding with high effectiveness and safety in major surgical procedures. With its widespread clinical application, the effects of TXA beyond anti-fibrinolysis have been noticed and prompted renewed interest in its use. Some clinical trials have characterized the effects of TXA on reducing postoperative infection rates and regulating immune responses in patients undergoing surgery. Also, several animal studies suggest potential therapeutic effects of TXA on skeletal diseases such as osteoporosis and fracture healing. Although a direct effect of TXA on the differentiation and function of bone cells in vitro was shown, few mechanisms of action have been reported. Here, we summarize recent findings of the effects of TXA on skeletal diseases and discuss the underlying plasminogen-dependent and -independent mechanisms related to bone metabolism and the immune response. We furthermore discuss potential novel indications for TXA application as a treatment strategy for skeletal diseases.

The effects of hydroxychloroquine-induced oxidative stress on fracture healing in an experimental rat model

OBJECTIVES

The purpose of this study was to investigate whether hydroxychloroquine (HCQ) sulfate causes oxidative stress (OS) and its effect on fracture healing in an experimental rat model.

MATERIALS AND METHODS

In this experimental study, open diaphyseal femur fractures were induced in 24 eight-week-old male rats (mean weight: 225±25 g; range, 200 to 250 g) and then fixed with K-wire. The rats were divided into four groups: HCQ-2, control-2 (C-2), HCQ-4, and control-4 (C-4). During the study period, rats in the HCQ groups received an HCQ solution (160 mg/kg/day), whereas rats in the control groups received saline. The HCQ-2 and C-2 groups were sacrificed on the 14th day, and the HCQ-4 and C-4 groups were sacrificed on the 28th day. After sacrifice, malondialdehyde levels induced by OS were calculated for each rat, and fracture healing was evaluated radiographically, histomorphometrically, histopathologically, and immunohistochemically.

RESULTS

Malondialdehyde levels were higher in the HCQ groups than in the control groups (p<0.05). Hydroxychloroquine caused OS in rats. The ratio of total callus diameter to femur bone diameter was lower in HCQ groups compared to control groups (p<0.05). No differences were observed when comparing radiological and histological healing results between the control and HCQ groups. Alkaline phosphatase levels were lower in the HCQ-4 group than the C-4 group at week four (p<0.05), although osteocalcin and osteopontin levels did not differ between groups (p>0.05). Oxidative stress had no adverse effects on histologic healing outcomes and osteoblast functions. Cathepsin K and tartrate-resistant acid phosphatase-5b levels were higher in the HCQ-4 group than in the C-4 group (p<0.05). While the number and function of osteoclasts increased due to OS in callus tissue, a decrease in the number of chondrocytes was observed.

CONCLUSION

Hydroxychloroquine-induced OS increases the number and function of osteoclasts and decreases the number of hypertrophic chondrocytes and endochondral ossification but has no significant effect on mid-late osteoblast products and histological fracture healing scores.

Effects of repeated intravenous doses of tranexamic acid on closed tibial fracture healing: Experimental study based on the rat model

OBJECTIVE

The aim of this study was to assess the effects of tranexamic acid on fracture healing in the rat tibia closed fracture model.

METHODS

Sixty-four male Sprague-Dawley rats were included in this study, where closed fracture and intramedullary nailing were performed on their right tibial diaphyses. They were divided into 2 main groups, the experimental group, which was given weekly tranexamic acid injections, and the control group, which received no additional treatment. Eight rats from each group were sacrificed and evaluated for fracture healing at the first experimental group and control group, second experimental group and control group, third experimental group and control group, and fourth experimental group and control group weeks. Fracture healing was radiologically assessed according to the "Spencer Index" and "Lane and Sandhu Scoring System," and histologically evaluated according to the scoring system devised by Huo et al. Results: According to the Spencer Index, the mean union score was statistically significantly higher in the E3 group than in the third con- trol group (P = .014). Furthermore, the mean union score was statistically significantly higher in the fourth experimental group compared to the fourth control group (P=.047). According to the Lane and Sandhu Scoring System, only the mean union scores of the E3-4 groups were statistically significantly higher than the mean union scores of the C3-4 groups (P=.048). There was no histological difference between groups in terms of union, according to the criteria defined by Huo et al (P > .05).

CONCLUSION

This study showed us that repeated intravenous administrations of tranexamic acid had no negative effect on fracture heal- ing in the rat tibia fracture model. Although tranexamic acid demonstrated better radiological healing in the late period, it had no effect on histological union.

Peri-articular administration of tranexamic acid is an alternative route in total knee arthroplasty: a systematic review and meta-analysis

Background

As an antifibrinolytic agent, tranexamic acid (TXA) is increasingly used in total knee arthroplasty (TKA) to reduce blood loss. The administration of intravenous and intra-articular TXA has been well explored, but the most efficient way to administer TXA remains in question. Peri-articular injection (PAI) of TXA is a recently mentioned method. A meta-analysis of the efficacy of PAI TXA in patients after TKA should be performed.

Methods

A systematic search was performed within PubMed, Embase, and the Cochrane Library up to November 8, 2021. Two authors independently screened studies for eligibility and extracted data for analysis. The primary outcome was haemoglobin change. The secondary outcomes were haematocrit change, total drainage volume, thromboembolic events, and blood transfusion.

Results

A total of ten studies were included in this meta-analysis. The results indicated that there was a significant decrease in haemoglobin change when using PAI TXA compared with no TXA (mean difference − 1.05; 95% CI − 1.28 to − 0.81; P < 0.00001; I² = 0%), but it had no significant differences compared with IA and IV (mean difference − 0.01; 95% CI − 0.17 to − 0.14; P = 0.85; I² = 39%). There were no significant differences between the TXA < 1.5 g subgroup (0.10, 95% CI − 0.27 to 0.46; P = 0.60; I² = 0%) and the TXA ≥ 1.5 g subgroup (0.18, 95% CI − 0.12 to 0.48; P = 0.24; I² = 74%). In addition, the combined group (PAI plus IV or IA) was superior to the IV or IA group in terms of haemoglobin change (mean difference − 0.51; 95% CI − 0.76 to − 0.27; P < 0.0001; I² = 19%). Regarding haematocrit change, the pooled result showed it was significantly less in the PAI group than the non-TXA group. Similarly, comparing it against the IV subgroup, the result revealed a difference in favour of the PAI group, with a mean difference of − 1.89 g/dL (95% CI − 2.82 to − 0.95; P < 0.0001; I² = 67%). For total drainage volume, the pooled result was in favour of PAI TXA over no TXA (297 ml, 95% CI − 497.26 to − 97.23; P = 0.004; I² = 87%), but it had no significant difference compared with IA and IV (mean difference − 37.98; 95% CI − 115.68 to 39.71; P = 0.34; I² = 95%). There was no significant difference in thromboembolic events (OR 0.74; 95% CI 0.25 to 2.21; P = 0.59; I² = 0%). Blood transfusion was not significantly different between the PAI group and the non-TXA group (OR 0.50; 95% CI 0.23 to 1.06; P = 0.07; I² = 21%), and there was no significant difference between PAI and the other two TXA injection methods (OR 0.72; 95% CI 0.41 to 1.25; P = 0.24; I² = 19%).

Conclusion

PAI has comparable effects to IV and IA injections. PAI is an alternative injection route of TXA for patients who have undergone TKA.

Effect of Local Tranexamic Acid on the Quality of Bone Healing in a Rat Spinal Fusion Model

Introduction

The use of the antifibrinolytic agent tranexamic acid has positive effects on bleeding control, but our knowledge is still limited regarding how fibrinolysis suppression changes the process of bone formation and the quality of bone. Because of the several side effects of systemic tranexamic acid, topical usage has been established in several procedures. This study aimed to investigate the effect of local tranexamic acid on vertebral fusion by using macroscopic, radiologic, and microscopic techniques. We also attempted to determine the safe dose range in case some doses had negative effects on fusion.

Methods

Twenty-eight Wistar albino rats underwent intertransverse fusion. All rats were randomized into four groups: groups treated with local tranexamic acid doses of 1 mg/kg (D1), 10 mg/kg (D10), and 100 mg/kg (D100) and the control group with no drug (D0). At the end of the eighth week, all rats were sacrificed for evaluation in terms of palpation, mammography, and histopathologic analysis.

Results

The manual palpation results presented with lower fusion rates in D10 and D100 groups than in the control group. Radiological examination results were significantly higher in the control group. The histopathologic examination revealed no significant differences between groups in the percent of new bone formation.

Conclusions

Our results showed that local administration of tranexamic acid reduced the quality and stability of fusion without a delay in bone formation. However, doses of 1 mg/kg did not reduce the stability in the palpation test. Our findings suggest that 1 mg/kg dose is a critical threshold above which tranexamic acid reduced the bone healing process of fusion and that surgeons should consider the doses of local tranexamic acid during surgery.

Improving the repair mechanism and miRNA expression profile of tibial defect in rats based on silent information regulator 7 protein analysis of mesenchymal stem cells

The aim of this study was to verify the role of Silent Information Regulator 7 (SIRT7) in improving the repair mechanism of bone marrow mesenchymal stem cells (BMMSCs) and the expression of microribonucleic acid (miRNA). Human BMMSCs were extracted from patients with femoral fractures, and the proliferation activity of human BMMSCs before and after knockout SIRT7 and the expression levels of bone-related genes and proteins were compared. Thirty-two 8-week-old male Sprague-Dawley (SD) rats were randomly divided into a blank group, a chitosan scaffold group, a control group, and a silence information regulator knockout group 7 (n = 8). In addition to the blank group, the chitosan scaffold, the green fluorescent protein (GFP) transfected stem cell composite chitosan scaffold, and the SIRT7 knockout stem cell composite chitosan scaffold were implanted in the other three groups, respectively. The X-rays and small animal in vivo three-dimensional tomography (Micro-CT) were adopted to quantitatively analyze the volume fraction, the number of trabeculae, and the connection density. Compared with the other three groups, the bone defect was formed more in the medullary mesenchymal stem cell knockout group, and the bone volume fraction, number of trabeculae and connection density were significantly increased (P < 0.05). MiR-98-5p can significantly promote the formation of bone molecules and bone structure in rats (P < 0.05). Human BMMSCs combined with chitosan scaffold can accelerate the repair of tibial defects. MiR-98-5p targeting and regulating bone formation gene (CKIP-1) could significantly improve the process of osteogenesis in rats.

The Efficacy and Safety of Tranexamic Acid Treatment in Orthopaedic Trauma Surgery

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Tranexamic acid (TXA) is a drug used to control hemorrhage by preventing the breakdown of fibrin.

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TXA is a cost-effective treatment for trauma patients across a variety of economic settings.

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Concerns of TXA causing thromboembolic events (TEEs) in orthopaedic trauma patients are not supported by evidence.

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TXA has been shown to reduce blood loss in hip fracture surgery.

Effects of different vardenafil doses on bone healing in a rat fracture model

Objectives

We aimed to investigate the radiological, biomechanical, histopathological, histomorphometric, and immunohistochemical effects of different doses of vardenafil on fracture healing.

Materials and methods

Fifty-one rats were divided into three groups. Group V5 was given 5 mg/kg/day of vardenafil; Group V10 was given 10 mg/kg/day of vardenafil; and the control group was given the same volume of saline. Six rats from each group were sacrificed on Day 14 (early period) and the remaining rats were sacrificed on Day 42 (late period). Callus/femoral volume and bone mineral density were measured using micro- computed tomography. Five femurs from each group in the late period were examined by biomechanical tests. In addition to the histopathological and histomorphometric evaluations, immunohistochemical analyses were performed to examine the levels of inducible nitric oxide synthase (iNOS), transforming growth factor-3 (TGF-β3), and nuclear factor kappa B (NF-κB) proteins.

Results

Both doses of vardenafil increased primary bone volume and maximal bone fracture strength in late period, compared to the control group (p<0.05). Histological healing scores of vardenafil groups were significantly higher in early period (p<0.001). While cartilaginous callus/total callus ratio in early period was higher, callus diameter/femoral diameter ratio in late period was lower in vardenafil groups (p<0.01). The NF-κB immunopositivity in V10 group decreased in early period, compared to control group (p<0.001). The TGF-β3 and iNOS immunopositivity increased in both V5 and V10 groups, compared to the control group in early period, but returned to normal in late period.

Conclusion

During the first period of fracture healing process in which vasodilation is mostly required with increasing inflammation, vardenafil has ameliorating effects on the bone union and supports fracture healing.