A Biodegradable Hemostatic Gelatin/Polycaprolactone Composite for Surgical Hemostasis

Multi-functional dual-layer nanofibrous membrane for prevention of postoperative pancreatic leakage

Postoperative pancreatic leakage due to pancreatitis in patients is a life-threatening surgical complication. The majority of commercial barriers are unable to meet the demands for pancreatic leakage due to poor adhesiveness, toxicity, and inability to degrade. In this study, we fabricated mitomycin-c and thrombin-loaded multifunctional dual-layer nanofibrous membrane with a combination of alginate, PCL, and gelatin to resolve the leakage due to suture line disruption, promote hemostasis, wound healing, and prevent postoperative tissue adhesion. Electrospinning was used to fabricate the dual-layer system. The study results demonstrated that high gelatin and alginate content in the inner layer decreased the fiber diameter and water contact angle, and crosslinking allowed the membrane to be more hydrophilic, making it highly biodegradable, and adhering firmly to the tissue surfaces. The results of in vitro biocompatibility and hemostatic assay revealed that the dual-layer had a higher cell proliferation and showed effective hemostatic properties. Moreover, the in vivo studies and in silico molecular simulation indicated that the dual layer was covered at the wound site, prevented suture disruption and leakage, inhibited hemorrhage, and reduced postoperative tissue adhesion. Finally, the study results proved that dual-layer multifunctional nanofibrous membrane has a promising therapeutic potential in preventing postoperative pancreatic leakage.

Hydrophobic Polystyrene-Modified Gelatin Enhances Fast Hemostasis and Tissue Regeneration in Traumatic Brain Injury

Hemostatic sealant is required to deal with blood loss, especially in the scenario of traumatic brain injury (TBI), which presents high rates of morbidity and disability. Hemostasis in surgery with traditional gelatin-based sealants often leads to blood loss and other issues in brain because of the hydrophilic gelatin swelling. Herein, hydrophobic effects on the hemostasis in TBI surgery are studied by tuning the chain length of polystyrene (PS) onto methylacrylated gelatin (Gel-MA). The hydrophobicity and hemostatic efficiency can be tuned by controlling the length of PS groups. The platelet activation of modified sealants Gel-MA-2P, Gel-MA-P, and Gel-MA-0.5P is as much as 17.5, 9.1, and 2.1 times higher than Gel-MA in vitro. The hemostatic time of Gel-MA-2P, Gel-MA-P, and Gel-MA-0.5P groups is 2.0-, 1.6-, and 1.1-folds faster than that in Gel-MA group in TBI mice. Increased formation of fibrins and platelet aggregation can also be observed in vitro by scanning electron microscopy. Animal's mortality is lowered by 46%, neurologic deficiency is reduced by 1.5 times, and brain edema is attenuated by 10%. Protein expression is further investigated to exhibit toxic iron-related processes caused by delayed hemostasis and activation of platelets via PI3K/PKC-α signaling. The hydrophobic Gel-MA has the potential in hemostatic TBI and promotes nervous system recovery in brain with the potentials in clinics.

Effects of a Thermosensitive Antiadhesive Agent on Single-Row Arthroscopic Rotator Cuff Repair

BACKGROUND

Postoperative stiffness after rotator cuff repair is a common complication that can lead to poor outcomes and patient discomfort. The application of an antiadhesive agent at the time of repair recently became an option for clinicians, but little information is available on its effects.

PURPOSE

To evaluate and compare retear rates, the incidence of postoperative stiffness, and the clinical outcomes of patients who underwent cuff repair with or without the application of an antiadhesive agent.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among 296 patients who underwent arthroscopic rotator cuff repair surgery, we compared the outcomes of those injected with a thermosensitive gel antiadhesive agent into the subacromial space (112 cases) versus noninjected controls (184 cases). Retear rates in the 2 groups were determined by magnetic resonance imaging at 1 year after surgery. Shoulder joint range of motion and functional scores were evaluated serially.

RESULTS

The rate of retear was significantly lower in the injection group (20/112 cases; 17.9%) than the control group (53/184 cases; 28.8%) (P = .034). Postoperative stiffness was not significantly different between the 2 groups (P = .710). Among the data regarding range of motion, only forward flexion at 6 months after surgery showed superior results in the injection group. Functional scores showed conflicting results: The control group had better visual analog scale scores for pain (injection vs control: 2.17 vs 1.68 at 6 months; 1.82 vs 1.28 at 12 months), American Shoulder and Elbow Surgeons scores (79.89 vs 89.64 at 12 months), and simple shoulder test scores (8.70 vs 10.06 at 12 months), whereas the injection group had better Constant-Murley scores (injection vs control: 59.49 vs 55.60 at 3 months; 77.35 vs 71.98 at 6 months; 87.28 vs 81.56 at 12 months).

CONCLUSION

The tendon healing rate was significantly higher in the group receiving an antiadhesive agent than in the control group. No intergroup difference was seen in the occurrence of postoperative stiffness. However, the pain-related functional score showed inferior results in the injection group at 12 months. The biological action of antiadhesive agents in rotator cuff repair should be further evaluated.

Research status and development potential of composite hemostatic materials

Through the discussion of the coagulation mechanism of compositehemostatic materials, the future development potential of hemostatic materials is proposed.

Effects of Yak skin gelatin on platelet activation

Studies have shown that gelatin is not only a good hemostatic material, but also a food additive with potentially broad use. Yak skin gelatin is a new gelatin resource, but its oral coagulant effects have not been studied. Given the central role of platelets in hemostasis, in this study we examined the pharmacodynamical differences between different molecular Yak skin gelatins on platelet activation. The hemostatic effects of Yak skin gelatins with different molecular weight distributions were evaluated for bleeding time (BT), clotting time (CT), and platelet activity by measuring the contents of P-selectin, platelet membrane glycoprotein Ia/IIa (GP Ia/IIa), platelet membrane glycoprotein IIb/IIIa (GP IIb/IIIa), and platelet membrane glycoprotein IV (GP IV). Intragastric administration of Yak skin gelatin resulted in a significant reduction in CT and BT, and an increase in the contents of P-selectin, GP Ia/IIa, GP IIb/IIIa, and GP IV in all groups in comparison with the control group. The strongest activation of platelets by Yak skin gelatin was observed with size between 0.1 μm and 0.22 μm, and activation may have been in response to improving GP IIb/IIIa and GP IV levels. When measuring the levels of an established indicator of platelet activation, platelet activation-dependent granule membrane protein (CD62P), its promotion was observed for all molecular weight ranges of Yak skin gelatins. In brief, Yak skin gelatin has hemostatic effects, and Yak skin gelatin fractions between 0.1 μm and 0.22 μm are the primary effectors of hemostasis via promoting platelet membrane glycoprotein activities and strengthening platelet function.

Chitosan-Based Composite Materials for Prospective Hemostatic Applications

Effective hemostasis is vital to reduce the pain and mortality of patients, and the research and development of hemostatic materials are prerequisite for effective hemostasis. Chitosan (CS), with good biodegradability, biocompatibility and non-toxicity, has been widely applied in bio-medicine, the chemical industry, the food industry and cosmetics. The excellent hemostatic properties of CS have been extensively studied. As a result, chitosan-based composite hemostatic materials have been emerging. In this review, the hemostatic mechanism of chitosan is briefly discussed, and then the progress of research on chitosan-based composite hemostatic materials with multiple forms such as films, sponges, hydrogels, particles and fibers are introduced. Finally, future perspectives of chitosan-based composite hemostatic materials are given. The objective of this review is to provide a reference for further research and development of effective hemostatic materials.