Histopathological and immunohistochemical investigation of the local and systemic effects of tranexamic acid on the healing of the Achilles tendon in rats

The impact of N-acetylcysteine on early periods of tendon healing: histopathologic, immunohistochemical, and biomechanical analysis in a rat model

PURPOSE

This study aimed to evaluate the early effects of N-acetylcysteine, which has antioxidant, inflame-modulatory, and cytoprotective properties, on tendon healing.

MATERIALS AND METHODS

Thirty-five male Wistar Hannover rats were divided into five groups: first-week treatment (Group 1T), first-week control (Group 1C), third-week treatment (Group 3T), third-week control (Group 3C), and native tendons (Group N). Bilateral Achilles tenotomy was performed on all rats except Group N. After tenotomy, 150 mg/kg N-acetylcysteine was administered daily intraperitoneally to treatment groups, while isotonic saline was given to the control groups. Tendons were evaluated histopathologically, immunohistochemically, and biomechanically after sacrifice in the first and third weeks.

RESULTS

No significant differences were observed in the first week (p > 0.05). Movin and Bonar scores (lower scores reflect improved histologic healing) were significantly lower in Group 3T than in Group 3C (p = 0.002). Collagen type-I/type-III ratios were higher in Group 3T compared to Group 3C (p = 0.001). Fmax (N) values were similar across Group 3T, Group 3C, and Group N (p = 0.772). However, cross-sectional areas (mm2) were significantly smaller in Group 3T than in Group 3C (p = 0.001), with the smallest areas observed in native tendons. Thus, tensile strength (MPa, load per unit area) and toughness (J/103 mm3, energy absorbed per unit volume) were significantly higher in Group 3T than in Group 3C (p = 0.001).

CONCLUSION

N-acetylcysteine supplied some improved results on early markers of tendon healing. Although our findings support the potential of NAC as a therapeutic adjunct in tendon injuries, further studies are needed to evaluate the long-term effects and underlying mechanisms.

The effects of tranexamic acid on the histopathology of defect healing in an in vivo porcine model after gastric and colonic endoscopic submucosal dissection

Introduction

There is limited data on the histopathological effects of hemostatic agents (HAs) used during endoscopic submucosal dissection (ESD). We used an in vivo porcine model to compare the tissue effects of tranexamic acid (TXA) and adrenaline (epinephrine) compared to controls.

Methods

Standard ESD, using a 2 mm flash-knife, was performed in three pigs. Four resections were performed in the stomach and rectum of each pig. Injectate contained 4% succinylated gelatin solution and indigo carmine, plus either TXA, adrenaline, or neither. Pigs were euthanized after 7 days and evaluated by two blinded pathologists.

Results

Twenty-four defects were analyzed. Within each animal no significant histopathological changes were noted between the defects, but differences were noted between the animals. In the stomachs of the TXA and adrenaline pigs, pathology revealed a clear ulcer in the mucosa/submucosa with abundant granulation tissue, while the muscular layer was unaffected. In the control pig's stomach, the lesions were deeper, transmurally distributed, with inflammation of the muscular and adventitia layers accompanied by severe inflammation and necrosis. Fewer differences were noted in the rectum.

Conclusion

For ESD, HAs such as TXA and adrenaline may have protective effects on the depth and extent of injury to the underlying tissue.

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.

Utilization of Tranexamic Acid in Surgical Orthopaedic Practice: Indications and Current Considerations

Tranexamic acid (TXA) is a lysine analog that exhibits an anti-fibrinolytic effect by directly preventing the activation of plasminogen as well as inhibiting activated plasmin from degrading fibrin clots, thereby promoting hemostasis and reducing the duration and quantity of blood loss. The aims of this study were to summarize the indications, routes of administration, safety, and clinical outcomes of TXA use throughout the different subspecialities in orthopedic surgery. Given that orthopedic procedures such as TKA, THA, fracture fixation, and various spine surgeries involve significant intraoperative blood loss, TXA is indicated in providing effective perioperative hemostasis. Additionally, use of TXA in orthopedic trauma has been indicated as a measure to reduce blood loss especially in a group with potential for hemodynamic compromise. TXA has been implicated in reducing the risk of blood transfusions in orthopedic trauma, joint surgery, and spine surgery, although this effect is not seen as prominently in sports medicine procedures. There remains disagreement in literature as to whether TXA via any route of administration can improve other clinically significant outcomes such as hospital length of stay and total operative time. Procedures that rely extensively on clarity on visualization of the surgical field such as knee and shoulder arthroscopies can greatly benefit from the use of TXA, thereby leading to less intraoperative bleeding, with better visual clarity of the surgical field. While most studies agree thrombosis due to TXA is unlikely, new research in cells and animal models are evaluating whether TXA can negatively impact other aspects of musculoskeletal physiology, however with conflicting results thus far. As of now, TXA remains a safe and effective means of promoting hemostasis and reducing intraoperative blood loss in orthopedic surgery.