Hirudin promotes angiogenesis by modulating the cross-talk between p38 MAPK and ERK in rat ischemic skin flap tissue

Hirudin promotes cerebral angiogenesis and exerts neuroprotective effects in MCAO/R rats by activating the Wnt/β-catenin pathway

OBJECTIVE

Hirudin has shown potential in promoting angiogenesis and providing neuroprotection in ischemic stroke; however, its therapeutic role in promoting cerebrovascular angiogenesis remains unclear. In this study, we aimed to investigate whether hirudin exerts neuroprotective effects by promoting angiogenesis through the regulation of the Wnt/β-catenin signaling pathway.

METHODS

An in vitro model of glucose and oxygen deprivation/reperfusion (OGD/R) was established using rat brain microvascular endothelial cells (BMECs). The effects of hirudin on OGD/R cell viability were assessed using the cell counting kit-8 (CCK-8) assay. The angiogenic potential of hirudin was evaluated using Transwell and tube formation assays. In vivo, a middle cerebral artery occlusion/reperfusion (MCAO/R) model was created in rats. The neuroprotective effects of hirudin were assessed using the modified neurological severity score (mNSS), Hematoxylin and eosin (H&E) staining, 2,3,5-Triphenyltetrazolium chloride (TTC) staining, and immunofluorescence staining. Dickkopf-1 (DKK1), a specific inhibitor of this pathway, was introduced in order to investigate the role of the Wnt/β-catenin pathway. The effects of hirudin on the Wnt/β-catenin pathway were examined through immunohistochemistry, western blotting, and reverse transcription quantitative polymerase chain reaction (RT-qPCR).

RESULTS

Hirudin significantly improved BMEC survival and enhanced both cell migration and tube formation in the OGD/R model. In the MCAO/R model, hirudin reduced the mNSS score, alleviated pathological damage, decreased infarction volume, and increased the expression of key angiogenic factors, including CD34, vascular endothelial growth factor (VEGF), and angiopoietin-2 (Ang-2). In addition, hirudin activated the Wnt/β-catenin pathway, leading to elevated levels of Wnt3a and β-catenin.

CONCLUSION

Hirudin has substantial neuroprotective effects associated with the promotion of angiogenesis in the ischemic penumbra. This mechanism is mediated by the regulation of the Wnt/β-catenin pathway.

Novel drug delivery systems for hirudin-based product development and clinical applications

Hirudin, a natural biological polypeptide macromolecule secreted by the salivary glands of medicinal leech, is a specific thrombin inhibitor with multiple favourable bioactivities, including anti-coagulation, anti-fibrotic, and anti-tumour. Despite several anticoagulants have been widely applied in clinic, hirudin shows advantages in reducing the incidence of bleeding side effects by virtue of its high specificity in binding to thrombin. As a result, hirudin has been tested in clinical practice to prevent and treat several complex diseases. However, the application of this polypeptide macromolecule is compromised by its low bioavailability and bioactivity due to poor serum stability and susceptibility to protease degradation in vivo. To overcome these drawbacks, several studies have proposed novel drug delivery systems (NDDSs) to prevent the degradation and increase the targeting efficiency of hirudin. This systematic review summarises the clinical research on hirudin, including its classification and bioactivities, and highlights the opportunities and challenges in the clinical use of hirudin. The NDDSs designed to enhance the bioavailability and bioactivity of hirudin are discussed to explore its application in the treatment of related diseases. This review may considerably contribute to the advancement of delivery science and technology, particularly in the context of polypeptide-based therapeutics.

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.

Intracerebral hirudin injection alleviates cognitive impairment and oxidative stress and promotes hippocampal neurogenesis in rats subjected to cerebral ischemia

Cerebral ischemia starts with cerebral blood flow interruption that causes severely limited oxygen and glucose supply, eliciting a cascade of pathological events, such as excitotoxicity, oxidative stress, calcium dysregulation, and inflammatory response, which could ultimately result in neuronal death. Hirudin has beneficial effects in ischemic stroke and possesses antioxidant and anti-inflammatory properties. Therefore, we investigated the biological functions of hirudin and its related mechanisms in cerebral ischemia. The ischemia-like conditions were induced by transient middle cerebral artery occlusion (MCAO). To investigate hirudin roles, intracerebroventricular injection of 10 U hirudin was given to the rats. Cognitive and motor functions were examined by beam walking and Morris water maze tests. 2,3,5-triphenyl tetrazolium chloride-stained brain sections were used to measure infarct volume. Oxidative stress was determined by assessment of oxidative stress markers. The proliferated cells were labeled by BrdU and Nestin double staining. Western blotting was performed to measure protein levels. Hirudin administration improved cognitive and motor deficits post-ischemia. Hirudin reduced brain infarction and neurological damage in MCAO-subjected rats. Hirudin alleviated oxidative stress and enhanced neurogenesis in ischemic rats. Hirudin facilitated the promotion of phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and serine-threonine kinase. In sum, hirudin alleviates cognitive deficits by attenuating oxidative stress and promoting hippocampal neurogenesis through the regulation of ERK1/2 and serine-threonine kinase in MCAO-subjected rats.

Current Status of Experimental Animal Skin Flap Models: Ischemic Preconditioning and Molecular Factors

Skin flaps are necessary in plastic and reconstructive surgery for the removal of skin cancer, wounds, and ulcers. A skin flap is a portion of skin with its own blood supply that is partially separated from its original position and moved from one place to another. The use of skin flaps is often accompanied by cell necrosis or apoptosis due to ischemia-reperfusion (I/R) injury. Proinflammatory cytokines, such as nuclear factor kappa B (NF-κB), inhibitor of kappa B (IκB), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and oxygen free radicals are known causative agents of cell necrosis and apoptosis. To prevent I/R injury, many investigators have suggested the inhibition of proinflammatory cytokines, stem-cell therapies, and drug-based therapies. Ischemic preconditioning (IPC) is a strategy used to prevent I/R injury. IPC is an experimental technique that uses short-term repetition of occlusion and reperfusion to adapt the area to the loss of blood supply. IPC can prevent I/R injury by inhibiting proinflammatory cytokine activity. Various stem cell applications have been studied to facilitate flap survival and promote angiogenesis and vascularization in animal models. The possibility of constructing tissue engineered flaps has also been investigated. Although numerous animal studies have been published, clinical data with regard to IPC in flap reconstruction have never been reported. In this study, we present various experimental skin flap methods, IPC methods, and methods utilizing molecular factors associated with IPC.

Leech Therapy Protects Free Flaps against Venous Congestion, Thrombus Formation, and Ischemia/Reperfusion Injury: Benefits, Complications, and Contradictions

The use of free cutaneous or myocutaneous flaps in some surgeries, especially in reconstructive surgeries, is routine and imperative; nevertheless, it is controversial because of fear of flap loss due to tissue congestion and partial or complete necrosis. Different mechanisms are discussed in this process, and based on the involved mechanisms, various agents and approaches are suggested for flap salvage. Among these agents and strategies, leech therapy (hirudotherapy) can be a valuable complementary treatment; however, in this way, full attention should be given to all beneficial and harmful aspects to reach the best results. This study included a literature review of the essential complications following free tissue transfer and explained the effects of leech therapy for the respective complications. Based on the review of the literature, the essential complications following free tissue transfer were (I) venous obstruction and congestion, (II) delay in blood flow reestablishment, (III) ischemia/reperfusion injuries, and (IV) thrombus formation. Leech therapy can protect free flaps against the mentioned complications as a complementary treatment. Leech therapy is an appropriate complement, however, not a definite approach for flap salvage. Therefore, in some patients, other alternative methods or even flap removal may be a better option.

Superiority of Adipose-derived CD34 + Cells over Adipose-derived Stem Cells in Promoting Ischemic Tissue Survival

BACKGROUND

Tissue ischemia usually leads to necrosis and is a threatening condition associated with reconstructive surgery. Promoting the survival of ischemic tissue is critical for improving clinical outcomes. Although various solutions based on stem cells have been reported, there are still limitations to clinical translation. The aim of this study was to develop an effective method to promote the survival of ischemic tissue.

METHODS

Adipose-derived CD34 + and CD34- cells were obtained by magnetic bead sorting from the stromal vascular faction (SVF). Adipose-derived stem cells (ADSCs) were collected by subculture. The angiogenic capacities of CD34 + cells, CD34- cells and ADSCs were evaluated in vitro by comparing mRNA and protein expression. Random axial flaps in nude mice were used to evaluate the efficacy of these cells in protecting tissue from necrosis. The effect of these cells in preventing inflammation was also evaluated.

RESULTS

Our data suggest that CD34 + cells expressed higher levels of angiogenetic factors and lower levels of inflammatory factors than the other cell types. More vessel branches were formed when human umbilical vein endothelial cells (HUVECs) were treated with conditioned medium from CD34 + cells than conditioned medium from the other cell types. Compared to ADSCs, CD34 + cells showed significantly higher efficacy in promoting tissue survival. More CD31 + cells and higher levels of angiogenic factors were observed in tissues from the CD34 + group than in those from the other groups. Lower levels of the proinflammatory factors TNF-α and IL-1b and higher levels of anti-inflammatory factors were found in the CD34 + group than in the other groups.

CONCLUSION

Adipose-derived CD34 + cells showed better efficacy in improving ischemic tissue survival than ADSCs by reducing tissue inflammation and promoting angiogenesis. CD34 + cells can be obtained easily and may be suitable for clinical applications.

Effect of p-cymene and rosmarinic acid on gastric ulcer healing - Involvement of multiple endogenous curative mechanisms

BACKGROUND

p-Cymene and rosmarinic acid are secondary metabolites found in several medicinal plants and spices. Previous studies have demonstrated their anti-inflammatory, antioxidant, and cytoprotective effects.

PURPOSE

To evaluate their gastroduodenal antiulcer activity, gastric healing and toxicity in experimental models.

METHODS

Preventive antiulcer effects were assessed using oral pre-treatment on HCl/ethanol-induced gastric lesions and cysteamine-induced duodenal lesions models. Gastric healing, the underlining mechanisms and toxicity after repeated doses were carried out using the acetic acid-induced gastric ulcer rat model and oral treatment for 14 days.

RESULTS

In the HCl/ethanol-induced gastric ulcer and cysteamine-induced duodenal injury, p-cymene and rosmarinic acid (50-200 mg/kg) decreased significantly the ulcer area, and so prevented lesions formation. In the acetic acid-induced ulcer model, both compounds (200 mg/kg) markedly reduced the ulcerative injury. These effects were related to an increase in the levels of reduced glutathione (GSH) and interleukin (IL)-10, and due to a decrease in malondialdehyde (MDA), IL-1β, tumor necrosis factor (TNF)-α, total and mitochondrial reactive oxygen species (ROS) levels. Downregulation of factor nuclear kappa B (NFκB) and enhanced expression of suppressor of cytokine signaling (SOCS)3 were also demonstrated. Furthermore, positive vascular endothelial growth factor (VEGF), metalloproteinase (MMP)-2, and cyclooxygenase (COX-2)-stained cells were increased in treated groups. Treatment also upregulated the platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor (TGF)-β and epidermal growth factor receptor (EGFR) in gastric tissues. In isolated gastric epithelial cells this healing effect seems to be linked to a modulation of apoptosis, proliferation, survival and protein phosphorylation, such as the extracellular signal-regulated kinases (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK). Oral toxicity investigation for 14 days revealed no alterations in heart, liver, spleen, and kidneys weight nor the biochemical and hematological assessed parameters. p-Cymene and rosmarinic acid also protected animals from body weight loss maintaining feed and water intake.

CONCLUSIONS

Data altogether suggest low toxicity, antiulcer and gastric healing activities of p-cymene and rosmarinic acid. Antioxidant and immunomodulatory properties seem to be involved in the curative effect as well as the induction of different factors linked to tissue repair.

Pharmacological Activities and Mechanisms of Hirudin and Its Derivatives - A Review

Hirudin, an acidic polypeptide secreted by the salivary glands of Hirudo medicinalis (also known as "Shuizhi" in traditional Chinese medicine), is the strongest natural specific inhibitor of thrombin found so far. Hirudin has been demonstrated to possess potent anti-thrombotic effect in previous studies. Recently, increasing researches have focused on the anti-thrombotic activity of the derivatives of hirudin, mainly because these derivatives have stronger antithrombotic activity and lower bleeding risk. Additionally, various bioactivities of hirudin have been reported as well, including wound repair effect, anti-fibrosis effect, effect on diabetic complications, anti-tumor effect, anti-hyperuricemia effect, effect on cerebral hemorrhage, and others. Therefore, by collecting and summarizing publications from the recent two decades, the pharmacological activities, pharmacokinetics, novel preparations and derivatives, as well as toxicity of hirudin were systematically reviewed in this paper. In addition, the clinical application, the underlying mechanisms of pharmacological effects, the dose-effect relationship, and the development potential in new drug research of hirudin were discussed on the purpose of providing new ideas for application of hirudin in treating related diseases.

[Effect of natural hirudin on revascularization of ischemic skin flaps in rats by Micro-CT]

OBJECTIVE

To investigate the effect of natural hirudin on revascularization of ischemic skin flap in rats using Micro-CT and three-dimensional (3D) reconstruction.

METHODS

Thirty-two Sprague Dawley rats were prepared a ischemic skin flap (8.0 cm×1.8 cm) model on the back and randomly divided into hirudin group and control group (16 rats in each group). At immediate and within 3 days after operation, the rats were treated with hypodermic injection of natural hirudin 0.3 mL (including natural hirudin 6 ATU) every day in hirudin group and the equal amount of normal saline in control group. At 6 days after operation, the survival rate of skin flap was evaluated, histological changes were observed by HE staining, and the volemia, length of blood vessels, and number of blood vessels were analyzed with Micro-CT 3D reconstruction.

RESULTS

Both groups of rats survived to the end of the experiment without infection. Different degrees of necrosis occurred in the distal part of the skin flaps in both groups at 6 days after operation, but the flap survival rate of the hirudin group (72.11%±8.97%) was significantly higher than that of control group (58.94%±4.02%) ( t=3.280, P=0.008). Histological observation showed that the histological hierarchy of the hirudin group was clearer than that of the control group, with more microangiogenesis and less inflammatory response and inflammatory cell infiltration. Micro-CT 3D reconstruction showed that the flap vessels in the hirudin group were more and denser, and the volemia, length of blood vessels, and number of blood vessels were significantly higher than those in the control group ( P<0.05).

CONCLUSION

Natural hirudin can reduce the inflammation of tissue, promote the regeneration and recanalization of blood vessels in ischemic skin flap, so as to improve the survival rate of the flap.

Vaccarin hastens wound healing by promoting angiogenesis via activation of MAPK/ERK and PI3K/AKT signaling pathways in vivo

Purpose

To explore the potential role and unclear molecular mechanisms of vaccarin in wound healing.

Methods

Rats’ skin excision model to study the effects of vaccarin on wound healing in vivo . Hematoxylin and eosin staining was performed to evaluate Histopathologic characteristics. Immunohistochemistry was employed to assess the effects of vaccarin in accelerating angiogenesis. Western blot was used to evaluate relative protein expressed levels.

Results

Vaccarin could significantly promote wound healing and endothelial cells and fibroblasts proliferation in the wound site. Immunohistochemistry and Western blot studies showed that the nodal proteins and receptor (bFGFR) related to angiogenesis signaling pathway were activated, and the microvascular density in the wound site was markedly higher than that in the control group.

Conclusions

The present study was the first to demonstrate that vaccarin is able to induce angiogenesis and accelerate wound healing in vivo by increasing expressions of p-Akt, p-Erk and p-bFGFR. This process is mediated by MAPK/ERK and PI3K/AKT signaling pathways.

TIR/BB-loop mimetic AS-1 protects vascular endothelial cells from injury induced by hypoxia/reoxygenation

Morphological and functional abnormalities of vascular endothelial cells (VECs) are risk factors of ischemia-reperfusion in skin flaps. Signaling pathway mediated by interleukin-1 receptor (IL-1R) is essential to hypoxia/reoxygenation (H/R) injury of VECs. While the TIR/BB-loop mimetic (AS-1) disrupts the interaction between IL-1R and myeloid differentiation primary-response protein 88 (MyD88), its role in the VECs dysfunction under H/R is unclear. In this study, we first showed that there was an infiltration of inflammatory cells and the apoptosis of VECs by using a skin flap section from patients who received flap transplantation. We then showed that the H/R treatment induced apoptosis and loss of cell migration of endothelial cell line H926 were attenuated by AS-1. Furthermore, our data suggested that AS-1 inhibits the interaction between IL-1R and MyD88, and subsequent phosphorylation of IκB and p38 pathway, as well as the nuclear localization of NF-KB subunit p65/p50. Thus, this study indicated that the protective role of AS-1 in H/R induced cellular injury may be due to the AS-1 mediated down-regulation of IL-1R signaling pathway.

[Effect of natural hirudin on angiogenesis of human microvascular endothelial cells]

Objective

To explore the effect of natural hirudin on proliferation of human microvascular endothelial cells (HMVECs) and its preliminary mechanism of promoting angiogenesis.

Methods

Three-dimensional culture models of HMVECs were established in vitro and observed by inverted phase contrast microscopy after 24 hours of culturing. Then, the three-dimensional culture models of HMVECs were treated with different concentrations (1, 4, and 7 ATU/mL) of the natural hirudin, respectively, and Dulbecco's modified Eagle's medium containing 10% fetal bovine serum as control. The cell proliferations of 4 groups were detected by cell counting kit 8 (CCK-8) method at 24, 48, and 72 hours; the angiogenesis of 4 groups were observed by tube formation assay at 24 hours; the expressions of vascular endothelial growth factor (VEGF) and Notch1 of HMVECs in 4 groups were observed by immunofluorescence staining at 24 hours.

Results

The observation of cells in three-dimensional culture models showed that HMVECs attached to Matrigel well, and the cells formed tube structure completely after 24 hours. The results of CCK-8 test showed that the absorbance ( A) value of 1 and 4 ATU/mL groups were higher than that of control group at each time point ( P<0.05), and A value of 4 ATU/mL group was the highest. The A value of 7 ATU/mL group was significantly lower than those of 1 and 4 ATU/mL groups and control group ( P<0.05). The tube formation assay showed that the tube structure was more in 1 and 4 ATU/mL groups than in 7 ATU/mL group and control group, and in 4 ATU/mL group than in 1 ATU/mL group, showing significant differences ( P<0.05). There was no significant difference between 7 ATU/mL group and control group ( P>0.05). The results of immunofluorescence staining showed that compared with control group, the Notch1 expression was higher in 1 and 4 ATU/mL groups and lower in 7 ATU/mL group; and there was significant difference between 4 and 7 ATU/mL groups and control group ( P<0.05). The VEGF expression was higher in 1, 4, and 7 ATU/mL groups than in control group, in 4 ATU/mL group than in 1 and 7 ATU/mL groups, showing significant differences ( P<0.05).

Conclusion

Natural hirudin can promote angiogenesis at low and medium concentrations, but suppress angiogenesis at high concentrations. Its mechanism may be related to the VEGF-Notch signal pathway.

The effect of hirudin on antagonisting thrombin induced apoptosis of human microvascular endothelial cells1

Purpose

To investigate whether hirudin exerts its antithrombin action to decrease the ratio of Human Microvascular Endothelial Cells (HMVECs) apoptosis.

Methods

Human microvascular endothelial cells (HMVECs) cultured in the third and fifth generations were used. HMVECs were divided into normal group, thrombin group (T group), natrual hirudin group (H group), thrombin + natrual hirudin group (T + H group), AG490 group, thrombin + AG490 group (T + AG490 group), natrual hirudin + AG490 group (H + AG490 group), thrombin + natural hirudin + AG490 (T + H + AG490 group).Apart from the normal group, the other groups were exposed to the relevant drugs for 24 hours.HMVEC apoptosis was assessed by flow cytometric and double Immunofluorescence of phosphorylation of JAK (P-JAK2) and TUNEL assay.

Results

Compared with the normal group, in thrombin group the HMVECs apoptosis rate were significantly increased (P<0.05).The results indicated that the index of apoptosis and the apoptosis rate were improved in cultures treated by natural hirudin (T + H group), relative to cultures with thrombin only (T group). We found that the index of apoptosis and the apoptosis rate in the AG490 + thrombin group were higher than that in the hirudin + thrombin group (P<0.05). Double Immunofluorescence of p-JAK2 and TUNEL assays showed that cells were double positive for P-JAK2 uptake and TUNEL detection liquid binding.

Conclusion

The natural hirudin and JAK2/STATs signal inhibitor AG490 could block the effects of thrombin. Natural hirudin could attenuate HMVECs apoptosis via antagonizing thrombin and it is suggested that this effect may occur by blocking the JAK2/STATs signaling pathway and this signaling pathways appears to be not the only pathway.

Increased survivability of ischemic skin flap tissue in Flk-1+/- mice by Pellino-1 intervention

OBJECTIVE

Reduced skin flap survival due to ischemia is a serious concern during reconstructive cosmetic surgery. The absence of VEGF and its receptors during ischemia may lead to flap failure. We identified Peli1, a 46-kDa protein, as a proangiogenic molecule and is directly regulated by VEGF. Therefore, we hypothesized that Peli1 acts downstream of Flk-1/VEGFR2 and aids in skin flap survival during ischemia.

METHODS

Scratch and matrigel assays were performed to observe cell proliferation, migration, and tube formation in vitro. Western blot analysis was carried out to detect the phosphorylation of Akt (p-Akt) and MAPKAPK2 (p-MK2) in HUVECs. The translational potential of Peli1 pretreatment in the rescue of skin flap tissue was studied in vivo using Flk-1^+/- mice. Animals underwent dorsal ischemic skin flap surgery, and the tissue was collected on day 12 for analysis.

RESULTS

Western blot analysis revealed a direct relationship between Peli1 and VEGF, as demonstrated by loss-of-function and gain-of-function studies. In addition, pretreatment with Ad.Peli1 restored the phosphorylation of Akt and MK2 and improved the migration potential of Flk-1-knockdown cells. Ad.Peli1 pretreatment salvaged the ischemic skin flap of Flk-1^+/- mice by increasing blood perfusion and reducing the inflammatory response and the extent of necrosis.

CONCLUSION

Our findings reveal that Peli1 is a proangiogenic molecule that acts downstream of VEGF-Flk-1 and restores angiogenesis and enhances skin flap survivability.

[Effects of combined natural hirudin and hyperbaric oxygen therapy on survival of transplanted random-pattern skin flap in rats]

Objective

To investigate the effect of natural hirudin combined with hyperbaric oxygen therapy on the survival of transplanted random-pattern skin flap in rats.

Methods

A random-pattern skin flap in size of 10.0 cm×2.5 cm was elevated on the dorsum of 72 Sprague Dawley rats. Then the 72 rats were randomly divided into 4 groups ( n=18) according to the therapy method. At immediate and within 4 days after operation, the rats were treated with normal saline injection in control group, normal saline injection combined with hyperbaric oxygen treatment in hyperbaric oxygen group, the natural hirudin injection in natural hirudin group, and the natural hirudin injection combined with hyperbaric oxygen treatment in combined group. The flap survival was observed after operation, and survival rate was evaluated at 6 days after operation. The skin samples were collected for histological analysis, microvessel density (MVD) measurement, and evaluation of tumor necrosis factor α (TNF-α) expression level by the immunohistochemical staining at 2 and 4 days after operation.

Results

Partial necrosis occurred in each group after operation, and the flap in combined group had the best survival. The survival rate of flap was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, and in combined group than in hyperbaric oxygen group and natural hirudin group ( P<0.05). There was no significant difference between hyperbaric oxygen group and natural hirudin group ( P>0.05). At 2 days, more microvascular structure was observed in hyperbaric oxygen group, natural hirudin group, and combined group in comparison with control group; while plenty of inflammatory cells infiltration in all groups. At 4 days, the hyperbaric oxygen group, natural hirudin group, and the combined group still showed more angiogenesis. Meanwhile, there was still infiltration of inflammatory cells in control group, inflammatory cells in the other groups were significantly reduced when compared with at 2 days. At 2 days, the MVD was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group ( P<0.05); the expression of TNF-α was significantly lower in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group ( P<0.05). There was no significant difference in above indexes between hyperbaric oxygen group, natural hirudin group, and combined group ( P>0.05). At 4 days, the MVD was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, in natural hirudin group and combined group than in hyperbaric oxygen group ( P<0.05). The expression of TNF-α was significantly lower in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, in combined group than in natural hirudin group and hyperbaric oxygen group ( P<0.05).

Conclusion

Hyperbaric oxygen and natural hirudin therapy after random-pattern skin flap transplantation can improve the survival of flaps. Moreover, combined therapy is seen to exhibit significant synergistic effect. This effect maybe related to promotion of angiogenesis and the reduction of inflammation response.

[Progress of monitoring methods and preventions of disorder of blood supplying of expanded flaps]

Objective

To summarize the monitoring methods and preventions of the disorder of blood supplying of expanded flaps, so as to provide some references for improving the survival of expanded flaps.

Methods

The domestic and abroad related literature about the disorder of blood supplying of expanded flaps was reviewed and analyzed.

Results

Handheld Doppler, digital subtraction angiography, computer tomographic angiography, magnetic resonance angiography, and fluorescein angiography can be used as reliable preoperative imaging methods in designing expanded flaps with rich blood supply. Several techniques can be used for monitoring the blood supply of expanded flaps during the early postoperative period including traditional monitoring via physical examination, monitoring via dynamic infrared thermography, near-infrared spectroscopy tissue oximeter, external and implantable Doppler, and more recently developed diffuse correlation spectroscopy. Surgical delay, bloodletting, leech therapy, hyperbaric oxygen, and so on can decrease the risk of necrosis in expanded flaps.

Conclusion

The survival of expanded flap is influenced by many factors. Preoperative design by using handheld Doppler and new imaging technology and postoperative early detection of blood supply can provide references of timely intervention, so that ischemic necrosis of the flaps can be reduced, and the success rate of surgery can be improved.

Spatholobi Caulis extracts promote angiogenesis in HUVECs in vitro and in zebrafish embryos in vivo via up-regulation of VEGFRs

ETHNOPHARMACOLOGICAL RELEVANCE

Spatholobi Caulis is a traditional blood-activating and stasis-dispelling herb medicine, which has been used to treat diseases related to blood stasis syndrome (BSS) by inhibiting platelet aggregation, stimulate hematopoiesis, etc. It has been demonstrated that pro-angiogenesis could improve BSS. However, the pro-angiogenic activity of Spatholobi Caulis was not well elucidated AIM OF STUDY: To determine the potential pro-angiogenic activity of Spatholobi Caulis and elucidate its underlying mechanism. The active fractions of Spatholobi Caulis were further screened.

MATERIAL AND METHODS

Gelatin precipitation and reversed-phase liquid chromatography (RPLC) were used to purify the methanol extracts of Spatholobi Caulis, respectively. The RPLC was also used to prepare fractions. Total flavonoids of purified methanol extracts of Spatholobi Caulis (PSC) were determined using ultraviolet spectrophotometry. The morphological observation of subintestinal vessel plexus (SIVs) and tyrosine kinase inhibitor II (VRI)-induced intersegmental blood vessels (ISVs) loss in transgenic zebrafish Tg(fli-1a: EGFP)y1 were selected to evaluate the pro-angiogenic activity of PSC in vivo. Cell proliferation by MTT assay and cell migration assay were used to evaluate the pro-angiogenesis effect of PSC in human umbilical vein endothelial cells (HUVECs) in vitro. Both zebrafish and HUVECs were used in screening active fractions of PSC. The mechanism of PSC promoting angiogenesis were studied by real-time PCR in zebrafish and western blotting in HUVECs.

RESULTS

Co-treatment PSC dramatically rescued VRI-induced ISVs loss in zebrafish embryos in a dose-dependent manner and 80% of the defective vascular recovered at the concentration of 30μg/ml compared with VRI-only group. PSC also concentration-dependently increased average sprouting number and diameter of SIVs in zebrafish embryo. Real-time PCR assay proved that PSC significantly restored the down regulation of VEGFRs including Flt-1, Kdr and Kdrl induced by VRI in zebrafish (P<0.001). Furthermore, PSC not only promoted proliferation and migration of normal HUVECs but also ameliorated VRI-induced HUVECs cytotoxicity. Western blotting assay showed that co-treatment of PSC increased the expression of VEGFRs and phosphorylation of MAPKs which decreased by VRI treatment. In addition, quality evaluation experiments showed that the content of total flavonoids of PSC reached 56.36% and the main pro-angiogenic fractions of PSC were F3, F4 and F5 both in zebrafish and HUVECs.

CONCLUSIONS

Our data demonstrated that PSC presented pro-angiogenic activity both in zebrafish and HUVECs, and principal pro-angiogenic active components were likely flavonoids. Thus, the current study provided evidence for the clinical usage of Spatholobi Caulis in promoting blood circulation and removing stasis in traditional Chinese medicine (TCM).