Project description:Background and aimsClinical management of critical limb-threatening ischaemia (CLTI) is focused on prevention and treatment of atherosclerotic arterial occlusions. The role of microvascular pathology in disease progression is still largely unspecified and more importantly not utilized for treatment. The aim of this explorative study was to characterize the role of the microvasculature in CLTI pathology.MethodsClinical high-resolution imaging of CLTI patients (n = 50) and muscle samples from amputated CLTI limbs (n = 40) were used to describe microvascular pathology of CLTI at the level of resting muscle blood flow and microvascular structure, respectively. Furthermore, a chronic, low arterial driving pressure-simulating ischaemia model in rabbits (n = 24) was used together with adenoviral vascular endothelial growth factor A gene transfers to study the effect of microvascular alterations on muscle outcome.ResultsResting microvascular blood flow was not depleted but displayed decreased capillary transit time (P < .01) in CLTI muscles. Critical limb-threatening ischaemia muscle microvasculature also exhibited capillary enlargement (P < .001) and further arterialization along worsening of myofibre atrophy and detaching of capillaries from myofibres. Furthermore, CLTI-like capillary transformation was shown to worsen calf muscle force production (P < .05) and tissue outcome (P < .01) under chronic ischaemia in rabbits and in healthy, normal rabbit muscle.ConclusionsThese findings depict a progressive, hypoxia-driven transformation of the microvasculature in CLTI muscles, which pathologically alters blood flow dynamics and aggravates tissue damage under low arterial driving pressure. Hypoxia-driven capillary enlargement can be highly important for CLTI outcomes and should therefore be considered in further development of diagnostics and treatment of CLTI.
Project description:AimsThe objective of the present study is to elucidate the pathogenic role of eicosanoids in myocardial infarction (MI). The accumulation of eicosanoid metabolites in ischaemic myocardium has been demonstrated in animal models and patients with MI, and it occurs in parallel with the development of irreversible cardiac damage. However, the key question that remains unanswered is whether cardiac-generated eicosanoids are the cause or the consequence of cardiac cell damage in MI.Methods and resultsWe used a clinically relevant animal model of MI and metabolic profiling to monitor the eicosanoid profile in ischaemic myocardium. We demonstrate that ischaemia induces the generation of prostanoids mainly through the cyclooxygenase (COX)-1 pathway in the myocardium. Cardiac-generated prostanoids, particularly prostaglandin D(2) (PGD(2)), can directly induce apoptosis in cardiac myocytes. This effect involves the up-regulation of the pro-apoptotic gene, Fas ligand (FasL), in a D-type prostanoid receptor-independent manner. The treatment of the MI mice with low-dose aspirin effectively inhibits the ischaemia-induced prostanoid generation and FasL expression in the myocardium, leading to the reduction in cardiac apoptosis following cardiac ischaemia.ConclusionsCardiac ischaemia results in COX-1-mediated generation of prostanoids, which by inducing cardiac myocyte apoptosis, contribute to the cardiac cell loss following MI. The benefits of low-dose aspirin treatment in MI may be attributable, in part, to the inhibition of cardiac prostanoid generation and attenuation of apoptosis. Further understanding of the mechanisms underlying prostanoid-induced cardiac apoptosis may be of significant value in designing new therapeutic strategies to prevent aberrant cell loss following MI and subsequent progression to heart failure.
Project description:BACKGROUND:Peripheral arterial disease is a major health problem, and in about 1% to 2% of patients the disease progresses to critical limb ischaemia (CLI). In a substantial number of patients with CLI, no effective treatment option other than amputation is available and around a quarter of these patients will require a major amputation during the following year. This is an update of the review first published in 2011. OBJECTIVES:To determine the effectiveness and safety of local intramuscular transplantation of autologous adult bone marrow mononuclear cells (BMMNCs) as a treatment for critical limb ischaemia (CLI). SEARCH METHODS:For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 1). SELECTION CRITERIA:We included all randomised controlled trials of CLI in which participants were randomly allocated to intramuscular administration of autologous adult BMMNCs or control (either no intervention or conventional conservative therapy). We excluded studies on patients with intermittent claudication. DATA COLLECTION AND ANALYSIS:Two authors independently selected trials, assessed trials for eligibility and methodological quality, and extracted data. Disagreements were resolved by consensus or by the third author. MAIN RESULTS:Only two small studies, with a combined total of 57 participants, met our inclusion criteria and were finally included. They were classified as having a moderate risk of bias with unclear issues regarding their methods, and according to the GRADE approach, the overall quality of the evidence would be considered as moderate. In one study the effects of intramuscular injections of BMMNCs in the ischaemic lower limbs of patients with CLI were compared with control (standard conservative treatment). No deaths were reported and no significant difference was observed between the two groups for either pain (P = 0.37) or the ankle brachial index (ABI) parameter. However, the treatment group showed a significantly smaller proportion of participants undergoing amputation compared with the control group (P = 0.026).In the other study, following subcutaneous injections of granulocyte colony-stimulating factor (G-CSF) for five days, peripheral blood derived mononuclear cells were collected and then transplanted by intramuscular injections into ischaemic lower limbs. The effects were compared with daily intravenous prostaglandin E1 injections (control group). No deaths were reported. Pain reduction was greater in the treatment group than in the control group (P < 0.001) as was increase in ABI (mean increase 0.13 versus 0.02, P < 0.01). The treatment group experienced a statistically significant increase in pain-free walking distance (PFWD) compared with the control group (mean increase 306.4 m versus 78.6 m, P = 0.007). A smaller proportion of participants underwent amputation in the treatment group compared with the control group (0% versus 36%, P = 0.007). AUTHORS' CONCLUSIONS:The data from the published trials suggest that there is insufficient evidence to support this treatment. These results were based on only two trials which had a very small number of participants. Therefore evidence from larger randomised controlled trials is needed in order to provide adequate statistical power to assess the role of intramuscular mononuclear cell implantation in patients with CLI.
Project description:Critical limb ischaemia (CLI) is the most advanced form of peripheral artery disease (PAD) and it is often associated with foot gangrene, which may lead to major amputation of lower limbs, and also with a higher risk of death due to fatal cardiovascular events. Matrix metalloproteinases (MMPs) seem to be involved in atherosclerosis, PAD and CLI. Aim of this study was to evaluate variations in MMP serum levels in patients affected by CLI, before and after lower limb surgical revascularisation through prosthetic or venous bypass. A total of 29 patients (7 females and 22 males, mean age 73·4 years, range 65-83 years) suffering from CLI and submitted to lower extremity bypass (LEB) in our Institution were recruited. Seven patients (group I) underwent LEB using synthetic polytetrafluoroethylene (PTFE) graft material and 22 patients (group II) underwent LEB using autogenous veins. Moreover, 30 healthy age-sex-matched subjects were also enrolled as controls (group III). We documented significantly higher serum MMPs levels (P < 0·01) in patients with CLI (groups I and II) with respect to control group (group III). Finally, five patients with CLI (17·2%) showed poor outcomes (major amputations or death), and enzyme-linked immunosorbent assay (ELISA) test showed very high levels of MMP-1 and MMP-8. MMP serum levels seem to be able to predict the clinical outcomes of patients with CLI.
Project description:A reduction in blood supply to any limb causes ischaemia, pain and morbidity. Critical limb ischaemia is the most serious presentation of peripheral vascular disease. One in five patients with critical limb ischaemia will die within six months of diagnosis and one in three will require amputation in this time. Improving blood flow to the limb, via the administration of angiogenic agents, could relieve pain and avoid amputation. Herein, chitosan is combined with β-glycerophosphate to form a thermoresponsive formulation (chitosan/β-GP) that will flow through a syringe and needle at room temperature but will form a gel at body temperature. The chitosan/β-GP hydrogel, with or without the angiogenic molecule desferrioxamine (DFO), was injected into the mouse hind limb, following vessel ligation, to test the ability of the formulations to induce angiogenesis. The effects of the formulations were measured using laser Doppler imaging to determine limb perfusion and CD31 staining to quantify the number of blood vessels. Twenty-eight days following induction of ischaemia, the chitosan/β-GP and chitosan/β-GP + 100 µM DFO formulations had significantly (p < 0.001 and p < 0.05, respectively) improved blood flow in the ischaemic limb compared with an untreated control. Chitosan/β-GP increased vessel number by 1.7-fold in the thigh of the ischaemic limb compared with an untreated control, while chitosan/β-GP + 100 µM DFO increased vessel number 1.8-fold. Chitosan/β-GP represents a potential minimally invasive treatment for critical limb ischaemia.
Project description:Background & objectivesPlatelet concentrate contains a rich cocktail of growth factors that support growth and proliferation of cells. The primary goal of this study was to investigate the safety of platelet lysate (PL) in patients with critical limb ischaemia (CLI) not suitable for standard revascularization. Data on the preliminary efficacy are also presented.MethodsSeven patients (18-70 yr) with CLI classified in the Rutherford grades 3-5, with history of intermittent claudication for more than eight weeks and were not suitable for standard revascularization, underwent autologous intramuscular injections of PL. These patients were examined physically alongside other parameters such as TcPO2, toe pressure, and ankle brachial index, at baseline and were followed up for 12 months.ResultsThe procedure was well tolerated with no serious adverse or any adverse events reported during follow up. Although not the primary aim of this report, preliminary data showed significant clinical improvement in Rutherford stage, ankle-brachial index and toe pressure which persisted for a year.Interpretation & conclusionsIntramuscular injection of PL was well tolerated with no major adverse events reported in our study participants. With the observed satisfactory safety data, preliminary efficacy data of PL should be further validated.
Project description:Adipose-derived regenerative cell (ADRC) is a promising alternative source of autologous somatic stem cells for the repair of damaged tissue. This study aimed to assess the safety and feasibility of autologous ADRC implantation for therapeutic angiogenesis in patients with critical limb ischaemia (CLI). A clinical pilot study-Therapeutic Angiogenesis by Cell Transplantation using ADRCs (TACT-ADRC) study-was initiated in Japan. Adipose tissue was obtained by ordinary liposuction method. Isolated ADRCs were injected into the ischaemic limb. We performed TACT-ADRC procedure in five patients with CLI. At 6 months, no adverse events related to the TACT-ADRC were observed. No patients required major limb amputation, and ischaemic ulcers were partly or completely healed during the 6-month follow-up. In all cases, significant clinical improvements were seen in terms of rest pain and 6-min walking distance. Numbers of circulating CD34+ and CD133+ cells markers of progenitor cell persistently increased after ADRC implantation. The ratio of VEGF-A165b (an anti-angiogenic isoform of VEGF) to total VEGF-A in plasma significantly decreased after ADRC implantation. In vitro experiments, cultured with ADRC-conditioned media (CM) resulted in increased total VEGF-A and decreased VEGF-A165b in C2C12 cells, but not in macrophages. ADRC-CM also increased CD206+ cells expression and decreased TNF-α in macrophages. Autologous ADRC implantation was safe and effective in patients with CLI and could repair damaged tissue via its ability to promote angiogenesis and suppress tissue inflammation.