Treatment Of Limb Ischemia Research Articles

Magnetically Controlled Strategies for Enhanced Tissue Vascularization

AbstractTissue vascularization plays a critical role in the regeneration and repair of damaged tissues. However, in certain instances of tissue injury, the pace and effectiveness of vascularization can be limited. Innovative strategies leveraging magnetic fields and magnetic nanoparticles (MNPs) are devised to enhance the efficacy of tissue vascularization. This review explores the potential of magnetic field‐assisted strategies in augmenting tissue vascularization and repair. Direct application of static or dynamic magnetic fields, alone or in combination with MNPs, offers a means to modulate cellular behaviors and gene expression, thereby promoting angiogenesis and tissue regeneration. Techniques such as cell labeling, gene delivery using MNPs, and magnetic targeting have shown promise in efficiently repairing various ischemic tissue injuries by enhancing tissue vascularization. These strategies have broad applications in bone and skin tissue regeneration, limb ischemia treatment, myocardial injury treatment, and diabetic wound therapy. By summarizing recent advancements in magnetically controlled strategies, this review aims to shed light on their future prospects in tissue regeneration and clinical treatment.

Assessment of Efficacy and Complications of Endovascular Interventions for Critical Limb Ischemia in Germany: A Nationwide Study.

Endovascular interventional radiological procedures have become the mainstay for the treatment of critical limb ischemia (CLI) due to arterial stenosis or occlusion. Open surgical or endovascular procedures, such as percutaneous transluminal angioplasty (PTA) or stenting can be used as a treatment strategy. The aim is to evaluate the success and major complication rates of interventional radiology treatments for CLI in Germany in 2021, and to compare these results with internationally published data. Data for PTA and stenting in CLI for 2021 was obtained from the quality management system of the German Society of Interventional Radiology (DeGIR). 16 393 PTA procedures, 701 stenting procedures, and 8110combined procedures were documented for 2021. Data was analyzed for technical and clinical success rates, as well as major complication rates documented mainly as major bleeding, distal embolization, and aneurysm formation. PTA had technical and clinical success rates of 96.3 % and 92.33 %, respectively. Stenting had technical and clinical success rates of 98.7 % and 96.15 %, respectively. PTA and stenting combined had success rates of 98.71 % and 96.91 %, respectively. The major complications were mainly: major bleeding (PTA: 0.40 %; stenting: 1.28 %; PTA and stenting: 0.54 %), distal embolization (PTA: 0.48 %; stenting: 1 %; PTA and stenting: 0.96 %), and aneurysm formation (PTA: 0.19 %; stenting: 0.43 %; PTA and stenting: 0.19 %). All procedures showed high technical and clinical success rates, while the complication rates were low. Interventional radiologists in Germany perform effective and safe treatment for CLI, achieving outcomes that tend to surpass internationally published data. · German interventional radiologists provide safe and effective critical limb ischemia treatment.. · Major complications occurred at maximum in 1.28 % of cases.. · Outcomes tend to surpass international data, indicating strong performance.. · Bastian M, Scheschenja M, Wessendorf J et al. Assessment of Efficacy and Complications of Endovascular Interventions for Critical Limb Ischemia in Germany: A Nationwide Study. Fortschr Röntgenstr 2024; 196: 1161 - 1165.

Poly(ethylenimine)-Cyclodextrin-Based Cationic Polymer Mediated HIF-1α Gene Delivery for Hindlimb Ischemia Treatment.

Hindlimb ischemia is a common disease worldwide featured by the sudden decrease in limb perfusion, which usually causes a potential threat to limb viability and even amputation or death. Revascularization has been defined as the gold-standard therapy for hindlimb ischemia. Considering that vascular injury recovery requires cellular adaptation to the hypoxia, hypoxia-inducible factor 1 α (HIF-1α) is a potential gene for tissue restoration and angiogenesis. In this manuscript, effective gene delivery vector PEI-β-CD (PC) was reported for the first application in the hindlimb ischemia treatment to deliver HIF-1α plasmid in vitro and in vivo. Our in vitro finding demonstrated that PC/HIF-1α-pDNA could be successfully entered into the cells and mediated efficient gene transfection with good biocompatibility. More importantly, under hypoxic conditions, PC/HIF-1α-pDNA could up-regulate the HUEVC cell viability. In addition, the mRNA levels of VEGF, Ang-1, and PDGF were upregulated, and transcriptome results also demonstrated that the cell-related function of response to hypoxia was enhanced. The therapeutic effect of PC/HIF-1α-pDNA was further estimated in a murine acute hindlimb ischemia model, which demonstrated that intramuscular injection of PC/HIF-1α-pDNA resulted in significantly increased blood perfusion and alleviation in tissue damage, such as tissue fibrosis and inflammation. The results provide a rationale that HIF-1α-mediated gene therapy might be a practical strategy for the treatment of limb ischemia.

Factors Associated with Therapeutic Outcomes in the Treatment of Nontraumatic Acute Upper Limb Ischemia at a Tertiary Care Center in South India: A Prospective Analysis

Abstract Background: The outcomes of acute upper extremity ischemia (AUEI) demonstrated lower rates of limb loss (0%–3.1%) and mortality (~6%) compared to acute lower extremity ischemia. However, AUEI still is a challenge for a vascular surgeon as delays in diagnosis and treatment are likely to result in severe functional disability, even in the absence of overt tissue loss. Objectives: The objectives of this study are to determine the association of factors affecting the clinical outcomes of acute upper limb ischemia treatment. Methodology: A single-center prospective observational study was done between July 2021 and July 2023 on patients with AUEI who came to our emergency medicine department at a tertiary care center in South India. The demography, risk factors, duration of ischemia, time from onset of complaints, and primary intervention chosen were recorded. Functional improvement on subsequent follow-up intervals was analyzed to describe the surgical outcome. Results: Of 53 patients with AUEI, 31 (58.5%) had atrial fibrillation. In 81.1% of patients, thrombosis was the primary cause of acute limb ischemia. Most patients belonged to the 2A Rutherford classification (47.2%), followed by 2B (26.4%). Regardless of the severity of ischemia, the patients (n = 10) who arrived after 36 h had a higher rate of amputation (5; 50%). Lower levels of preoperative serum lactate dehydrogenase and serum glutamic-oxaloacetic transaminase were associated with better postoperative outcomes (P = 0.007) and lesser amputation rates (P = 0.017). Lower grades of ischemia, prompt intervention, and early consultation were all linked to better postoperative functional outcomes (P = 0.026). Conclusion: At our facility, AUEI due to cardiac or noncardiac emboli, thrombosis, or both was a significant cause of inhospital morbidity. An important risk factor for worse outcomes was hypertension. The availability of appropriate interventional care, and the timing of presentation after the onset of symptoms are thus significant modifiable factors in lowering the rates of amputation.

Sex-Related Disparities in Acute Limb Ischemia Treatment Outcomes

Although a substantial impetus behind disparities research in healthcare exists, those that are sex-related within vascular surgery outcomes are largely unexplored. Consequently, published guidelines lack specificity when it comes to treating male and female patients with vascular disease. Disparities related to patients suffering from chronic limb-threatening ischemia have been broached, although no extensive studies assessing disparities in acute limb ischemia treatment outcomes have come to the forefront. In this study, our aim is to identify and quantify sex-related disparities as they pertain to interventions for acute limb ischemia. Using the TriNetX global research network, we conducted a multicenter query across 48 healthcare organizations spanning five countries for patients treated for acute limb ischemia. We determined the number of male and female patients that received one of the following interventions: open revascularization, percutaneous mechanical thrombectomy, or catheter-directed thrombolysis and/or adjunctive endovascular procedures. Propensity score matching was performed to account for comorbidities. Risk of adverse outcomes within 30 days was calculated for each sex, including re-intervention, major amputation, and death. Risk of adverse outcomes was then compared between treatment groups of the same sex and between sexes. Type I errors were reduced through utilization of the Holm-Bonferroni method to correct P-values. Within our study we noted several important findings. Females were more likely to receive catheter-directed thrombolysis and/or adjunctive endovascular procedures (p = 0.001) than males. There were no significant differences in the rates of open revascularization or percutaneous mechanical thrombectomy between males and females. Overall, females were more likely to die within 30 days (p < 0.0001) and greater number of males required reintervention within 30 days (p < 0.0001). Analyzing outcomes within individual treatment groups, females undergoing open revascularization or catheter-directed thrombolysis and/or adjunctive endovascular intervention demonstrated a profound increase in mortality within 30 days of intervention (p = 0.0072 and p = 0.0206, respectively), but these differences were not reflected in the percutaneous mechanical thrombectomy group. Limb salvage rates in females were higher than males overall although there were no significant sex differences within any treatment groups specifically. In conclusion, there was a significantly higher risk of death in females across all treatment groups in the studied timeframe. Limb salvage rates were higher for females in the OR treatment group, while males were more likely to require a reintervention across all treatment groups. By evaluating these disparities, we can provide greater insight into personalized treatment for patients presenting with acute limb ischemia.

Safety and efficacy of injection of exosomes derived from human umbilical cord mesenchymal stem cells in the treatment of limb ischemia: an in-vivo evaluation in mice

article: Safety and efficacy of injection of exosomes derived from human umbilical cord mesenchymal stem cells in the treatment of limb ischemia: an in-vivo evaluation in mice - Minerva Biotechnology and Biomolecular Research 2022 December;34(4):170-9 - Minerva Medica - Journals

EE307 Orbital Atherectomy System (OAS) with Angioplasty for Critical Lower LIMB Ischemia Treatment. Budget IMPACT Analysis: From a Modelling Approach to a Hospital Reality in Italy

Critical limb ischemia (CLI) is a clinical syndrome of ischemic pain at rest or tissue loss, such as non-healing ulcers or gangrene, related to Peripheral Artery Disease (PAD). CLI has a high short-term risk of limb amputation.Mortality after amputation is extremely high and is increased in diabetic patients. An Endovascular first approach is recommended based on a lower procedural risk.

Stem Cell Therapy in Limb Ischemia: State-of-Art, Perspective, and Possible Impacts of Endometrial-Derived Stem Cells.

As an evidence-based performance, the rising incidence of various ischemic disorders has been observed across many nations. As a result, there is a growing need for the development of more effective regenerative approaches that could serve as main therapeutic strategies for the treatment of these diseases. From a cellular perspective, promoted complex inflammatory mechanisms, after inhibition of organ blood flow, can lead to cell death in all tissue types. In this case, using the stem cell technology provides a safe and regenerative approach for ischemic tissue revascularization and functional cell formation. Limb ischemia (LI) is one of the most frequent ischemic disease types and has been shown to have a promising regenerative response through stem cell therapy based on several clinical trials. Bone marrow-derived mononuclear cells (BM-MNCs), peripheral blood CD34-positive mononuclear cells (CD34+ PB-MNCs), mesenchymal stem cells (MSCs), and endothelial stem/progenitor cells (ESPCs) are the main, well-examined stem cell types in these studies. Additionally, our investigations reveal that endometrial tissue can be considered a suitable candidate for isolating new safe, effective, and feasible multipotent stem cells for limb regeneration. In addition to other teams’ results, our in-depth studies on endometrial-derived stem cells (EnSCs) have shown that these cells have translational potential for limb ischemia treatment. The EnSCs are able to generate diverse types of cells which are essential for limb reconstruction, including endothelial cells, smooth muscle cells, muscle cells, and even peripheral nervous system populations. Hence, the main object of this review is to present stem cell technology and evaluate its method of regeneration in ischemic limb tissue.

Acute on Chronic Limb Ischemia Treatment: Case Series

ABSTRACT&#x0D; &#x0D; BACKGROUND: Acute on chronic limb ischemia is a condition caused by acute disruption in chronic vessel disease. The major cause is peripheral arterial disease or embolism. Treating the acute phase while considering the origin of disease is important to treat acute on chronic limb ischemia.&#x0D; CASE DESCRIPTION: 3 cases were described on this serial case report. The first and second case represent acute on chronic limb ischemia conditions with history of intermittent claudication (IC) and signs of acute limb ischemia (ALI) upon arrival. They were both treated with surgical intervention for ALI. Despite of adequate surgical intervention, both cases showed suboptimal limb recovery. Both patients were referred for further evaluation of chronic vessel disease with angiography. Third case represent chronic limb ischemia as end point of treatment from the first and second case. Patient with worsening IC despite adequate medical and exercise treatment underwent angiography examination. Angiography result found two sites of total occlusion of right common iliac artery and superficial femoral artery. Angioplasty and primary stenting were done on common iliac artery. Drug coated balloon and stenting was also performed on superficial femoral artery.&#x0D; CONCLUSION: Patients with acute on chronic limb ischemia need to be treated during acute phase and the remaining chronic vessel disease. Consideration and care should be taken when managing similar cases for optimal treatment.&#x0D; &#x0D; KEYWORDS: Acute on chronic limb ischemia, Thrombectomy, Angioplasty, Drug-coated Balloon.

PH/Thermosensitive dual-responsive hydrogel based sequential delivery for site-specific acute limb ischemia treatment.

Acute limb ischemia (ALI) is the most severe manifestation of peripheral artery disease, accompanied by pH/temperature-microenvironment changes in two different phases. In the acute phase, temperature and pH are significantly decreased, and reactive oxygen species (ROS) are excessively generated owing to the sharp reduction of blood perfusion. Afterwards, in the chronic phase, although the temperature gradually recovers, angiogenesis is delayed due to chronic vascular injury, skeletal muscle cell apoptosis and endothelial cell dysfunction. Current therapeutic strategies mainly focus on recanalization; however, their effects on scavenging ROS in the acute phase and promoting angiogenesis in the chronic phase are quite limited. Herein, an injectable pH and temperature dual-responsive poloxamer 407 (PF127)/hydroxymethyl cellulose (HPMC)/sodium alginate (SA)-derived hydrogel (FHSgel), encapsulating melatonin and diallyl trisulfide-loaded biodegradable hollow mesoporous silica nanoparticles (DATS@dHMSNs), is developed, which can intelligently respond to the different phases of ALI. In the acute phase of ischemia, the decreased pH results in the rapid release of melatonin to scavenge excessive ischemia-induced ROS. On the other hand, in the chronic repair phase, the recovered temperature triggers the sustained release of DATS@dHMSNs from the FHSgel, thus generating hydrogen sulfide (H2S) to enhance the angiogenesis and microcirculation reconstruction of ischemic limbs.

ROS-responsive nanoparticle-mediated delivery of CYP2J2 gene for therapeutic angiogenesis in severe hindlimb ischemia.

With critical limb ischemia (CLI) being a multi-factorial disease, it is becoming evident that gene therapy with a multiple bio-functional growth factor could achieve better therapeutic outcomes. Cytochrome P450 epoxygenase-2J2 (CYP2J2) and its catalytic products epoxyeicosatrienoic acids (EETs) exhibit pleiotropic biological activities, including pro-angiogenic, anti-inflammatory and cardiovascular protective effects, which are considerably beneficial for reversing ischemia and restoring local blood flow in CLI. Here, we designed a nanoparticle-based pcDNA3.1-CYP2J2 plasmid DNA (pDNA) delivery system (nanoparticle/pDNA complex) composed of a novel three-arm star block copolymer (3S-PLGA-po-PEG), which was achieved by conjugating three-armed PLGA to PEG via the peroxalate ester bond. Considering the multiple bio-functions of CYP2J2-EETs and the sensitivity of the peroxalate ester bond to H2O2, this nanoparticle-based gene delivery system is expected to exhibit excellent pro-angiogenic effects while improving the high oxidative stress and inflammatory micro-environment in ischemic hindlimb. Our study reports the first application of CYP2J2 in the field of therapeutic angiogenesis for CLI treatment and our findings demonstrated good biocompatibility, stability and sustained release properties of the CYP2J2 nano-delivery system. In addition, this nanoparticle-based gene delivery system showed high transfection efficiency and efficient VEGF expression in vitro and in vivo. Intramuscular injection of nanoparticle/pDNA complexes into mice with hindlimb ischemia resulted in significant rapid blood flow recovery and improved muscle repair compared to mice treated with naked pDNA. In summary, 3S-PLGA-po-PEG/CYP2J2-pDNA complexes have tremendous potential and provide a practical strategy for the treatment of limb ischemia. Moreover, 3S-PLGA-po-PEG nanoparticles might be useful as a potential non-viral carrier for other gene delivery applications.

Treatment of Limb Ischemia with Conducted Effects of Catheter-Based Endovascular Ultrasound

Ultrasound (US) is known to stimulate endogenous shear-dependent pathways, and can lower microvascular resistance through mediators that are conducted downstream from US exposure. We hypothesized that endovascular US, already in use for thrombolysis in humans, can improve tissue perfusion in the setting of acute limb ischemia through downstream-conducted effects. Models of severe peripheral arterial disease were developed in mice and in rhesus macaques. An endovascular US catheter (2.3 MHz, 0.5–1.1 MPa) was used to expose the limb adductor in mice for 10 min or the femoral artery distal to stenosis in macaques for 15 min. Quantitative contrast-enhanced ultrasound perfusion imaging was performed to assess flow augmentation in the adductor muscle of mice and the calf muscle of macaques. Microvascular blood flow in the ischemic limb relative to the contralateral control limb was reduced to 22 ± 8% in mice and 36 ± 20% in macaques. US produced immediate 2.3- and 3-fold increases (p < 0.05) in the murine and macaque ischemic limbs, respectively. In macaques, perfusion in the ischemic limb was increased to a normal level. We conclude that non-cavitating US produced by endovascular catheters that are used to enhance thrombolysis in humans can reduce vascular resistance and increase limb perfusion in the setting of acute ischemia.

Navigating between the science and art of acute limb ischemia treatment

The diagnosis and treatment of acute limb ischemia (ALI) has long been a fierce adversary that has evolved over the last several decades with scientific advancements in endovascular therapy.History and physical examination remain the mainstay of diagnosis enhanced by detailed imaging to guide therapy. Many endovascular tools are available for prompt restoration of flow that compliment traditional surgical options. These devices incorporate the mechanical removal of thrombus and the chemical dissolution of thrombus . Medical decision-making for ALI patients must take into account the patient characteristics, anatomic variables, mechanism of ischemia, degree of ischemia, and operator skill to employ the right strategy for the right patient. This moving target challenges scientific study, making the therapeutic bedside decision making an artform. We present an overview of the field, supportive data, and a treatment algorithm that hopefully captures this delicate balance.

ROS-responsive capsules engineered from EGCG-Zinc networks improve therapeutic angiogenesis in mouse limb ischemia

The successful treatment of limb ischemia requires that promote angiogenesis along with microenvironment improvement. Zinc ions have been reported to stimulate angiogenesis, but application was limited to the toxicity concerns. We hypothesized that zinc based metal-EGCG capsule (EGCG/Zn Ps) can achieve sustained release Zn2+ resulting in reduced toxicity and improve angiogenesis as well as the improvement of microenvironment by ROS scavenging of EGCG. The surface morphology, zeta potential, infrared absorbance peaks and zinc ion release profile of the EGCG/Zn Ps were measured. In vitro, EGCG/Zn showed significantly antioxidant, anti-inflammatory and induced cell migration effect. In addition, EGCG/Zn Ps enabled the sustained release of zinc ions, which reduced cytotoxicity and enhanced the secretion of vascular endothelial growth factor (VEGF) in vitro and in vivo. In mouse models of limb ischemia, EGCG/Zn Ps promoted angiogenesis and cell proliferation in ischemic tissues. Moreover, EGCG/Zn Ps group exhibited the most significant recovery of limb ischemic score, limb temperature and blood flow than other groups. In conclusion, EGCG/Zn Ps is a safe and promising approach to combine the merit of Zn2+ and EGCG, thus enabling the direct application to limb ischemia.

Diabetic Limb Salvage With Endovascular Revascularisation and Free Tissue Transfer: Long-Term Follow up

Combining vascular bypass surgery with free flap coverage is one of the treatment methods for complex soft tissue defects in the ischaemic lower limb. Endovascular revascularisation has become the first line treatment for limb ischaemia in many centres. Surgeons now perform free tissue transfer after angioplasty. The early and long-term limb salvage rate in diabetic patients who had undergone infrapopliteal endovascular revascularisation and free flap reconstruction are assessed. This was retrospective study of all consecutive diabetic patients who had undergone endovascular revascularisation with free flap reconstruction for lower limb salvage between 2008 and 2014. They were followed up for at least 2 years or to death (mean follow up 39 ± 17 months). Cox regression analysis was used to analyse variables influencing outcome. There were 55 patients who had undergone 60 procedures. Five patients had undergone the procedure to the contralateral leg. All tissue lesions were Wagner–Meggit classification Grades 3 or 4. Thirty-six patients had TASC C lesions and 24 patients with TASC D lesions. Combined below knee triple vessel disease was seen in 30% of the cases, 28% involved both the anterior and posterior tibial artery, 7% and 2% involved the anterior tibial or the posterior tibial and the peroneal arteries. The free flap success rate was 95%. The peri-operative mortality was 1.7%. Twenty-one cases required surgical re-intervention. Mean length of hospital admission was 32 ± 9 days. One and five year amputation free survival rates were 94% and 68%, patient survival rates were 95% and 67%, limb salvage rates were 93% and 91% and respectively. The results show that excellent early and late limb salvage can be achieved with free tissue transfer based on endovascular revascularisation of infrapopliteal arteries. This can be a further treatment option in diabetic patients with complex soft tissue defects.

Analysis of Biological Properties of Human Adult Mesenchymal Stem Cells and Their Effect on Mouse Hind Limb Ischemia

Background: Due to their self-renewal, proliferation, differentiation, and angiogenesis-inducing capacity, human adipose mesenchymal stem cells (AMSC) have potential clinical applications in the treatment of limb ischemia. AMSC from healthy donors have been shown to induce neovascularization in animal models. However, when cells were obtained from donors suffering from any pathology, their autologous application showed limited effectiveness. We studied whether liposuction niche and obesity could determine the regenerative properties of cells meaning that not all cell batches are suitable for clinical practice. Methods: AMSC obtained from 10 donors, obese and healthy, were expanded in vitro following a good manufacturing practice-like production protocol. Cell viability, proliferation kinetics, morphological analysis, phenotype characterization, and stemness potency were assessed over the course of the expansion process. AMSC selected for having the most suitable biological properties were used as an experimental treatment in a preclinical mouse model of hind limb ischemia. Result: All cell batches were positively characterized as mesenchymal stem cells, but not all of them showed the same properties or were successfully expanded in vitro, depending on the characteristics of the donor and the extraction area. Notably, AMSC from the abdomen of obese donors showed undesirable biological properties. AMSC with low duplication times and multilineage differentiation potential and forming large densely packed colonies, were able, following expansion in vitro, to increase neovascularization and repair when implanted in the ischemic tissue of mice. Conclusion: An extensive AMSC biological properties study could be useful to predict the potential clinical efficacy of cells before in vivo transplantation. Thus, peripheral ischemia and possibly other pathologies could benefit from stem cell treatments as shown in our preclinical model in terms of tissue damage repair and regeneration after ischemic injury.

Does the new vascular management of acute limb ischemia have effective results with lower treatment costs.

Aim To compare hospital costs of acute limb ischemia treatment in two periods of time and to show evidence of long-term repercussions on reducing costs during successful treatment. Methods Retrospective analysis of data obtained from 100 patients' medical history in the period 2000-2016 at the Clinic of Vascular Surgery Sarajevo: group A - 60 patients with acute limb ischemia in the period 2005-2016 and group B - 40 patients with acute limb ischemia (ALI) in the period 2000-2005. From 2000 to 2005 conservative treatment method was used, invasive diagnostic and surgical procedures were often delayed for a shorter or longer period of time. During the period from 2005 to 2016, the management model and safe practice included emergency diagnostic procedures, colour-Doppler, arteriography, emergency surgery (embolectomy by Fogharty and if necessary, vascular by-pass). Results Better health service for the patients with acute limb ischemia was offered in the period 2005-2016, which relied on proven medical treatment trends. The largest share of the total costs of each patient included costs of hospital bed with significant difference between the period 2005-2016 and 2000-2005, mean of 1398.71 KM and 2480.45KM, respectively (p<0.0001), indicating rationalization of time that patients spend at the Vascular Clinic. Conclusion This trend of money/fund savings is an example of good practice, effectiveness and efficiency in the treatment of ALI and as such was used in patients with other vascular diseases.

Editor's Choice – Diabetic Limb Salvage With Endovascular Revascularisation and Free Tissue Transfer: Long-Term Follow up

Combining vascular bypass surgery with free flap coverage is one of the treatment methods for complex soft tissue defects in the ischaemic lower limb. Endovascular revascularisation has become the first line treatment for limb ischaemia in many centres. Surgeons now perform free tissue transfer after angioplasty. The early and long-term limb salvage rate in diabetic patients who had undergone infrapopliteal endovascular revascularisation and free flap reconstruction are assessed. This was retrospective study of all consecutive diabetic patients who had undergone endovascular revascularisation with free flap reconstruction for lower limb salvage between 2008 and 2014. They were followed up for at least 2 years or to death (mean follow up 39±17 months). Cox regression analysis was used to analyse variables influencing outcome. There were 55 patients who had undergone 60 procedures. Five patients had undergone the procedure to the contralateral leg. All tissue lesions were Wagner-Meggit classification Grades 3 or 4. Thirty-six patients had TASC C lesions and 24 patients with TASC D lesions. Combined below knee triple vessel disease was seen in 30% of the cases, 28% involved both the anterior and posterior tibial artery, 7% and 2% involved the anterior tibial or the posterior tibial and the peroneal arteries. The free flap success rate was 95%. The peri-operative mortality was 1.7%. Twenty-one cases required surgical re-intervention. Mean length of hospital admission was 32±9 days. One and five year amputation free survival rates were 94% and 68%, patient survival rates were 95% and 67%, limb salvage rates were 93% and 91% and respectively. The results show that excellent early and late limb salvage can be achieved with free tissue transfer based on endovascular revascularisation of infrapopliteal arteries. This can be a further treatment option in diabetic patients with complex soft tissue defects.

Encapsulation of macrophages enhances their retention and angiogenic potential

Cell therapies to treat critical limb ischaemia have demonstrated only modest results in clinical trials, and this has been partly attributed to poor cell retention following their delivery directly into the ischaemic limb. The aim of this study was to determine whether alginate encapsulation of therapeutic pro-angio/arteriogenic macrophages enhances their retention and ultimately improves limb perfusion. A reproducible GMP-compliant method for generating 300 µm alginate capsules was developed to encapsulate pro-angio/arteriogenic macrophages. Longitudinal analysis revealed no detrimental effect of encapsulation on cell number or viability in vitro, and macrophages retained their pro-angio/arteriogenic phenotype. Intramuscular delivery of encapsulated macrophages into the murine ischaemic hindlimb demonstrated increased cell retention compared with injection of naked cells (P = 0.0001), and that this was associated both enhanced angiogenesis (P = 0.02) and arteriogenesis (P = 0.03), and an overall improvement in limb perfusion (P = 0.0001). Alginate encapsulation of pro-angio/arteriogenic macrophages enhances cell retention and subsequent limb reperfusion in vivo. Encapsulation may therefore represent a means of improving the efficacy of cell-based therapies currently under investigation for the treatment of limb ischaemia.

The Role of Recombinant Human Cyclophilin A in the Antitumor Immune Response.

Cyclophilin A (CypA) is a multifunctional protein that exhibits an isomerase activity and exists in the intracellular and secretory forms. Secretory CypA promotes regeneration of the hematopoietic and the immune systems of an organism by stimulating stem cell migration from the bone marrow. New approaches based on CypA are currently being developed for the treatment of limb ischemia, neutralization of the side effects of Cyclosporine A (CsA) therapy, etc. However, the role of CypA in the antitumor immune response is still unexplored. In this work, we used the model experimental system of lymphoma EL-4 rejection in B10.D2(R101) mice and showed that recombinant human CypA (rhCypA) stimulates the antitumor immune response via early recruitment of granulocytes to the tumor cell localization site and rapid accumulation of effector T-killers