Effect of hirudin on arterialized venous flap survival in rabbits

Hirudin enhances perforator flap survival: Clinical application report and mechanistic exploration

BACKGROUND AND PURPOSE

Hirudin, a potent anticoagulant, is used in traditional Chinese medicine (TCM) to treat thrombotic conditions and prevent postoperative thrombosis. Coagulation-related vascular complications are a common cause of perforator flaps failure. This study explores hirudin's potential to enhance flap growth by mitigating coagulation-related issues.

MATERIALS AND METHODS

Patients were divided into GroupⅠ(hirudin group) and GroupⅡ(control). Laboratory tests covered red blood cell count (RBC), hematocrit (HCT), platelet count (PLT), monocyte count (MONO), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), and D-Dimer. Clinical parameters, including capillary refill time (CRT), flap swelling, and survival status, were evaluated. Animal experiments used Sprague-Dawley (SD) rats to establish random skin flaps. The experimental side received hirudin injection, while the control side received saline. Flaps were photographed to calculate survival rate, and CD31 immunohistochemical (IHC) analysis was performed to calculate microvessel density (MVD).

RESULTS

The study, with 29 patients, found significant CRT differences between groups on postoperative days 2 and 6 (p = 0.027; p = 0.019), favoring GroupⅠ. Swelling severity varied significantly over time; GroupⅡhad more pronounced swelling. GroupⅠshowed superior flap growth with fewer complications, statistically significant (p = 0.033). Specific lab indicators (MONO, PT, and FIB) were significant at certain times. In animal experiments, the experimental side consistently had higher flap survival and slightly increased CD31 expression at various times, with higher MVD on days 2 and 6.

CONCLUSIONS

Hirudin enhances flap survival through diverse mechanisms, supporting its role as a complementary approach in perforator flap surgeries.

Tetrandrine promotes the survival of the random skin flap via the PI3K/AKT signaling pathway

Flaps are mainly used for wound repair. However, postoperative ischemic necrosis of the distal flap is a major problem, which needs to be addressed urgently. We evaluated whether tetrandrine, a compound found in traditional Chinese medicine, can prolong the survival rate of random skin flaps. Thirty-six rats were randomly divided into control, low-dose tetrandrine (25 mg/kg/day), and high-dose tetrandrine (60 mg/kg/day) groups. On postoperative Day 7, the flap survival and average survival area were determined. After the rats were sacrificed, the levels of angiogenesis, apoptosis, and inflammation in the flap tissue were detected with immunology and molecular biology analyses. Tetrandrine increased vascular endothelial growth factor and Bcl-2 expression, in turn promoting angiogenesis and anti-apoptotic processes, respectively. Additionally, tetrandrine decreased the expression of Bax, which is associated with the induction of apoptosis, and also decreased inflammation in the flap tissue. Tetrandrine improved the survival rate of random flaps by promoting angiogenesis, inhibiting apoptosis, and reducing inflammation in the flap tissue through the modulation of the PI3K/AKT signaling pathway.

Emerging prospects of protein/peptide-based nanoassemblies for drug delivery and vaccine development

Proteins have been widely used in the biomedical field because of their well-defined architecture, accurate molecular weight, excellent biocompatibility and biodegradability, and easy-to-functionalization. Inspired by the wisdom of nature, increasing proteins/peptides that possess self-assembling capabilities have been explored and designed to generate nanoassemblies with unique structure and function, including spatially organized conformation, passive and active targeting, stimuli-responsiveness, and high stability. These characteristics make protein/peptide-based nanoassembly an ideal platform for drug delivery and vaccine development. In this review, we focus on recent advances in subsistent protein/peptide-based nanoassemblies, including protein nanocages, virus-like particles, self-assemblable natural proteins, and self-assemblable artificial peptides. The origin and characteristics of various protein/peptide-based assemblies and their applications in drug delivery and vaccine development are summarized. In the end, the prospects and challenges are discussed for the further development of protein/peptide-based nanoassemblies.

Effect of memantine on the survival of an ischemic random skin flap and the underlying mechanism

BACKGROUND

Skin flap transplantation is a common wound repair method in orthopedic surgery, but skin flap necrosis remains problematic. Memantine, an excitatory amino acid receptor antagonist, is currently used in the treatment of moderate to severe Alzheimer's disease, due to its ability to promote angiogenesis and reduce oxidative stress. This study investigated the effect of memantine on the survival of random skin flaps in Sprague-Dawley (SD) rats.

MATERIALS AND METHODS

Thirty six male SD rats were divided into control, high-dose (20 mg/kg per day), and low-dose (10 mg/kg per day) groups and underwent a McFarland flap procedure. Seven days later, the survival of the flap was evaluated, The microvascular density and neutrophil density were measured by hematoxylin and eosin staining. Lead angiography was used to detect angiogenesis, and laser Doppler was used to detect blood perfusion. Expression levels of vascular endothelial growth factor (VEGF), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, Toll-like receptor (TLR) 4, nuclear factor kappa B(NF-κB) and Mitogen-activated protein kinase（MAPK）were detected by immunohistochemistry. Oxidative stress was evaluated by measuring the levels of malondialdehyde (MDA) and superoxide dismutase (SOD).

RESULTS

Compared with the control group, the flap survival area of memantine group, especially the high-dose group, was larger, VEGF expression, microvascular density, angiogenesis, blood perfusion, and superoxide dismutase in the flap were higher in the Memantine-H group than in the Memantine-L and control groups (P < 0.01). In addition, levels of neutrophil density, IL-1β, IL-6, TNF-α, TLR4, NF-κB, MAPK and malondialdehyde decreased significantly in the Memantine-H group (P < 0.01).

CONCLUSIONS

Memantine can promote the survival of skin flap in rats by improving the blood supply, promoting angiogenesis, inhibiting the inflammatory response, and reducing ischemia-reperfusion injury.