Therapeutic Angiogenesis In Patients Research Articles

Possibilities of Therapeutic Angiogenesis in Patients with Critical Lower Limb Ischemia

Two clinical observations of effective treatment of patients with critical ischemia of the lower extremities using plasma-free lysate autologous platelets. Both patients were male, 73 and 53 years old. Both were diagnosed with total damage to the arteries of the infrainguinal zone. One of them had previously undergone endarterectomy from the femoral artery with subsequent thrombosis. After examination and joint discussion with x-ray endovascular surgeons, they were found inoperable. Due to the ineffectiveness of standard conservative therapy, the patient was offered local administration of plasma-free lysate autologous platelets. After receiving written informed consent, the procedure for collecting venous blood and obtaining plasma-free lysate autologous platelets and the introduction of this drug into the muscles of the leg from the side of ischemia according to the original method. The method for assessing microcirculation was three-phase scintigraphy : before treatment, both patients showed a significant decrease in the inclusion of osteotropic radiopharmaceutical in the soft tissues of the legs. For areas of radiopharmaceutical hyperfixation, relative accumulation coefficients were calculated: for one patient, the calculation results demonstrated the formation of foci of aseptic necrosis. When patients were re-hospitalized after 6 months, there was an improvement in local status and relief of rest pain. According to scintigraphy, a significant improvement in microcirculation was noted; no foci of aseptic necrosis were identified. Thus, the use of plasma-free lysate autologous platelets in combination with complex conservative therapy has demonstrated positive results; this method can be considered as an alternative revascularization ischemic limb.

Therapeutic Potential of Endothelial Colony-Forming Cells in Ischemic Disease: Strategies to Improve their Regenerative Efficacy.

Cardiovascular disease (CVD) comprises a range of major clinical cardiac and circulatory diseases, which produce immense health and economic burdens worldwide. Currently, vascular regenerative surgery represents the most employed therapeutic option to treat ischemic disorders, even though not all the patients are amenable to surgical revascularization. Therefore, more efficient therapeutic approaches are urgently required to promote neovascularization. Therapeutic angiogenesis represents an emerging strategy that aims at reconstructing the damaged vascular network by stimulating local angiogenesis and/or promoting de novo blood vessel formation according to a process known as vasculogenesis. In turn, circulating endothelial colony-forming cells (ECFCs) represent truly endothelial precursors, which display high clonogenic potential and have the documented ability to originate de novo blood vessels in vivo. Therefore, ECFCs are regarded as the most promising cellular candidate to promote therapeutic angiogenesis in patients suffering from CVD. The current briefly summarizes the available information about the origin and characterization of ECFCs and then widely illustrates the preclinical studies that assessed their regenerative efficacy in a variety of ischemic disorders, including acute myocardial infarction, peripheral artery disease, ischemic brain disease, and retinopathy. Then, we describe the most common pharmacological, genetic, and epigenetic strategies employed to enhance the vasoreparative potential of autologous ECFCs by manipulating crucial pro-angiogenic signaling pathways, e.g., extracellular-signal regulated kinase/Akt, phosphoinositide 3-kinase, and Ca2+ signaling. We conclude by discussing the possibility of targeting circulating ECFCs to rescue their dysfunctional phenotype and promote neovascularization in the presence of CVD.

Therapeutic angiogenesis using autologous adipose-derived regenerative cells in patients with critical limb ischaemia in Japan: a clinical pilot study

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.

Electroacupuncture pretreatment promotes angiogenesis via hypoxia-inducible factor 1α and vascular endothelial growth factor in a rat model of chronic myocardial ischemia

Electroacupuncture (EA) pretreatment appears useful in the treatment of chronic myocardial ischemia (CMI). The goal of this study was to investigate the effect of EA preconditioning on the regulation of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) proteins in a CMI model of vascular regeneration. A CMI model was established by subcutaneous injection of isoprinosine hydrochloride (ISO) for 14 days in 45 Wistar rats, which had been randomly divided into a model group (n = 15), a CMI group pretreated with sham EA for 21 days (CMI + Sham group, n = 15) and a CMI group pretreated with verum EA for 21 days (CMI + EA, n = 15) prior to modeling. An additional 15 Wistar rats received 0.9% sodium chloride via intraperitoneal injection for 14 consecutive days (control group). Serum levels of VEGF and HIF-1α were measured by ELISA, while protein expression of VEGF and HIF-1α in the area of myocardial infarction was measured by Western blotting. The area of myocardial infarction and fibrosis of the myocardial tissue in the study groups were visualized by hematoxylin-eosin (HE) staining and Masson staining, respectively. EA pretreatment improved cardiac function by regulating left ventricular end-diastolic diameter and left ventricular end-systolic diameter, left ventricular ejection fraction and the ST segment voltage of the electrocardiogram. EA pretreatment promoted vascular regeneration by increasing serum levels of VEGF and HIF-1α and by increasing protein expression of HIF-1α and VEGF in the infarcted region of the myocardium, leading to a reduction in the area of myocardial infarction on HE staining and reduction of myocardial fibrosis on Masson staining. EA pretreatment promotes protein expression of HIF-1α and VEGF in areas of ischemic myocardium, which may represent useful biomarkers for coronary collateral establishment and offer potential targets for therapeutic angiogenesis in patients with CMI.

Adipose-Derived Mesenchymal Stem Cells in the Treatment of Diabetic Foot Ulcers: A Review of Preclinical and Clinical Studies.

This review provides an outline of the use of adipose-derived mesenchymal stem cells (AMSCs) in the treatment of diabetic foot ulcers (DFUs). A systematic search of PubMed and the Cochrane database was performed on October 2, 2019. Eighteen studies were identified (14 preclinical and 4 clinical). Studies in animal models have demonstrated that AMSCs enhance diabetic wound healing, accelerate granulation tissue formation, and increase reepithelialization and neovascularization. Only 1 randomized control trial has been published so far. Patients (n = 25) with DFUs were treated using an allogeneic AMSC directly on the wound bed as a primary dressing, and improvements were found in complete wound closure in the treatment group (n = 16). Three clinical studies showed that autologous AMSC might be a safe alternative to achieve therapeutic angiogenesis in patients with diabetes and peripheral arterial disease. Based on the available evidence, AMSCs hold promise in the treatment of DFUs. However, this evidence requires confirmation by well-designed trials. Additional studies are also required to understand some issues regarding this treatment for DFUs. For example, the potential application of autologous or allogeneic AMSCs in different types of DFUs, optimal dose/infusion schedules, safety evaluations, and cost-effectiveness.

Establishment of optimal exercise therapy using near-infrared spectroscopy monitoring of tissue muscle oxygenation after therapeutic angiogenesis for patients with critical limb ischemia: A multicenter, randomized, controlled trial

Critical limb ischemia (CLI) is a potentially life-threatening condition that involves severely reduced blood flow to the peripheral arteries due to arteriosclerosis obliterans (ASO) of the limbs or a similar condition. CLI patients must undergo revascularization to avoid amputation of the lower limbs and improve their survival prognosis. However, the outcomes of conventional surgical revascularization or endovascular therapy are inadequate; therefore, establishing further effective treatment methods is an urgent task. We perform therapeutic angiogenesis using autologous bone marrow-derived mononuclear cells in clinical practice and demonstrated its safety and efficacy for CLI patients for whom conventional treatments failed or are not indicated. Exercise therapies must be devised for CLI patients who have undergone therapeutic angiogenesis to save their limbs and improve survival. Because evidence regarding the efficacy and safety of exercise therapy for CLI patients is lacking, we plan to perform a prospective trial of the efficacy and safety of optimal exercise therapy following therapeutic angiogenesis for CLI patients.The trial will enroll 30 patients between 20 and 79 years with Rutherford category 4 or 5 CLI caused by ASO who will undergo therapeutic angiogenesis. Participants will be randomly allocated to receive either optimal exercise therapy or fixed exercise therapy. Those receiving optimal exercise therapy will undergo tissue muscle oxygen saturation monitoring using near-infrared spectroscopy while performing exercises and will be prescribed optimal exercise therapy. The optimal amount of exercise will be determined on day 8, 31, 61, 91 and 181 after therapeutic angiogenesis. Ethics and disseminationThis protocol was approved by the Institutional Review Boards of Kyoto Prefectural University of Medicine. In accordance with the Helsinki Declaration, written informed consent has been obtained from all participants prior to enrollment. The results of this trial will be disseminated by publication in a peer-reviewed journal. Trial registrationThis trial is registered at http://www.umin.ac.jp/ctr/index.htm (identifier: UMIN000035288).

Ways of limbs salvage in postoperative period of treatment of complications of diabetic foot syndrome

The article deals with the use of a genetically engineered drug for stimulation of angiogenesis as a component of combined treatment of complications of ischaemic form of diabetic foot syndrome, showing comparative results of using therapeutic angiogenesis in patients in whom it was impossible to perform operative revascularization of the affected extremity, also providing a detailed description of the methodology of combined treatment of pyonecrotic complications of diabetic foot syndrome. The study included a total of 62 patients with pyonecrotic complications of Wagner grade III-IV diabetic foot syndrome. The patients were divided into two groups. Group One patients after minor amputation on the foot were assigned to receive conventional basic therapy and topical treatment of the foot wound with antiseptics and modern dressings. Group Two patients, besides basic therapy, additionally received combined treatment which was carried out in two stages and included urokinase, sulodexide, and a venotonic agent. Local treatment of the foot wound was performed with the help of two-stage vacuum therapy. Both groups were further subdivided into subgroups A and B. The patients in subgroups B of both groups in order to prevent progression of limb ischaemia were additionally given Neovasculgen, a genetically engineered drug for stimulation of angiogenesis. The patients of subgroups A of both groups did not receive this drug. The immediate results were assessed on the 1st, 7th and 14th days of treatment by the dynamics of changes in subjective symptoms, cytograms of the wound surface, level of partial pressure of oxygen in capillary blood of foot tissues, and the necessity to perform repeated necrectomy. The remote results were evaluated by the dynamics of changes in the pain-free walking distance, maximum distance walked, ankle-brachial index, linear velocity of blood flow through tibial arteries and partial pressure of oxygen in capillary blood of the affected limb at the 6th, 12th and 36th months after the performed treatment, as well as by the limb salvage and patients' survival during 3 years.

Manipulating Intracellular Ca2+ Signals to Stimulate Therapeutic Angiogenesis in Cardiovascular Disorders.

Endothelial progenitor cells (EPCs) are mobilized in peripheral blood to rescue blood perfusion in ischemic tissues. Several approaches were, therefore, designed to inject autologous EPCs and induce therapeutic angiogenesis in patients affected by cardiovascular disorders. Endothelial colony forming cells (ECFCs) represent the only truly endothelial precursors and are regarded as the most suitable substrate for cell based therapy of ischemic diseases. Intracellular Ca2+ signalling drives ECFC proliferation, migration, homing and neovessel formation. Vascular endothelial growth factor (VEGF) triggers repetitive oscillations in intracellular Ca2+ concentration ([Ca2+]i) in peripheral blood- and umbilical cord blood-derived ECFCs by initiating a dynamic interplay between inositol-1,4,5-trisphosphate (InsP3)-dependent Ca2+ release and store-operated Ca2+ entry (SOCE). SOCE, in turn, is mediated by Stim1, Orai1 and Transient Receptor Potential (TRP) Canonical 1 (TRPC1). Intriguingly, intracellular Ca2+ oscillations are triggered by TRPC3 in umbilical cord blood-derived ECFCs, which display higher proliferative potential. Additionally, stromal cell-derived factor-1α (SDF-1α) triggers a biphasic increase in [Ca2+]i in ECFCs which is mediated by InsP3 receptors (InsP3Rs) and SOCE. Finally, arachidonic acid (AA) and nicotinic acid adenine dinucleotide phosphate (NAADP) stimulate ECFC proliferation by stimulating two-pore channel 1 (TPC1), thereby promoting Ca2+ release from the endolysosomal Ca2+ compartment. AA-evoked Ca2+ signals are further supported by InsP3Rs and TRP Vanilloid 4 (TRPV4). In this article, we describe how genetic manipulation of the Ca2+ toolkit (i.e. TRPC3, SOCE, TPC1) endowed to circulating ECFCs could rejuvenate or restore their reparative phenotype for therapeutic angiogenesis purposes.

The Role of Angiogenesis in Coronary Artery Disease: A Double-Edged Sword: Intraplaque Angiogenesis in Physiopathology and Therapeutic Angiogenesis for Treatment.

Angiogenesis is described as a sprouting and growth process of new blood vessels from pre-existing vasculature. The relationship between angiogenesis and coronary artery disease (CAD) is double-sided. On one hand, angiogenesis within plaques is responsible for facilitating the growth and vulnerability of plaques by causing intraplaque hemorrhage and inflammatory cell influx, and overabundance of erythrocytes and inflammatory cells within a plaque probably causes plaque rupture, further leading to acute coronary syndrome. Therefore, inhibiting intraplaque angiogenesis has been considered as a potential therapeutic target for CAD. On the other hand, aiming at improving reperfusion to the ischemic myocardium in patients with CAD, angiogenesis promoting has been utilized as a therapeutic approach to expand myocardial microvascular network. Current strategies include direct administration of angiogenic growth factors (protein therapy), promoting angiogenic genes expression in vivo (gene therapy), and delivering stem cells (cell therapy) or exosomes (cell free therapy). This article will start by clarifying the basic concept of angiogenesis, interpret the mechanism of excessive intraplaque angiogenesis in atherosclerosis, and discuss its role in the growth and vulnerability of plaques. Then we will focus on the four distinct strategies of therapeutic angiogenesis. Despite promising animal studies and smallscale clinical trials of therapeutic angiogenesis in patients with ischemic heart disease, investigations have far not shown definite evidence of clinical efficacy. Hence, while acknowledging future work that remains to be done to validate the clinical results, we reviewed the critical challenges in this arena and highlighted the exciting progress that has occurred recently.

Терапевтический ангиогенез у больных с облитерирующими заболеваниями артерий и синдромом критической ишемии нижних конечностей: возможности терапии с позиций доказательной медицины

Терапевтический ангиогенез у больных с облитерирующими заболеваниями артерий и синдромом критической ишемии нижних конечностей: возможности терапии с позиций доказательной медицины

Ghrelin, MicroRNAs, and Critical Limb Ischemia: Hungering for a Novel Treatment Option.

Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease. It is characterized by chronic pain at rest, skin ulcerations, and gangrene tissue loss. CLI is a highly morbid condition, resulting in a severely diminished quality of life and a significant risk of mortality. The primary goal of therapy for CLI is to restore blood flow to the affected limb, which is only possible by surgery, but is inadvisable in up to 50% of patients. This subset of patients who are not candidates for revascularisation are referred to as “no-option” patients and are the focus of investigation for novel therapeutic strategies. Angiogenesis, arteriogenesis and vasculogenesis are the processes whereby new blood vessel networks form from the pre-existing vasculature and primordial cells, respectively. In therapeutic angiogenesis, exogenous stimulants are administered to promote angiogenesis and augment limb perfusion, offering a potential treatment option for “no option” patients. However, to date, very few clinical trials of therapeutic angiogenesis in patients with CLI have reported clinically significant results, and it remains a major challenge. Ghrelin, a 28-amino acid peptide, is emerging as a potential novel therapeutic for CLI. In pre-clinical models, exogenous ghrelin has been shown to induce therapeutic angiogenesis, promote muscle regeneration, and reduce oxidative stress via the modulation of microRNAs (miRs). miRs are endogenous, small, non-coding ribonucleic acids of ~20–22 nucleotides which regulate gene expression at the post-transcriptional level by either translational inhibition or by messenger ribonucleic acid cleavage. This review focuses on the mounting evidence for the use of ghrelin as a novel therapeutic for CLI, and highlights the miRs which orchestrate these physiological events.

Efficacy of medication for therapeutic angiogenesis in combined treatment of patients with diabetes mellitus and critical limb ischemia

The combination of peripheral atherosclerosis and diabetes mellitus is a severe pathology, characterized by a high rate, mortality and social significance. The results of limb salvage and distant survival in this pathology in a remote period are unsatisfactory in spite of all existing treatment methods. Clinical trials in previous years have shown efficacy and safety of the medication, which is a plasmid construct with the gene encoding vascular endothelial growth factor - kambiogenplasmid, in patients with disease stage IIa-III according to the A.V. Pokrovsky and Fontaine classification, who were not indicated for surgical treatment. The article presents the clinical cases of successful use of this drug for therapeutic angiogenesis in patients with critical limb ischemia and severe type 2 diabetes mellitus. The inclusion of therapeutic angiogenesis in the conservative treatment algorithms is promising for the treatment of this group of patients. There is a need for further research on the efficacy and safety of the medication in patients with peripheral atherosclerosis and diabetes mellitus in a remote period.

Relationship between thrombospondin-1, endostatin, angiopoietin-2, and coronary collateral development in patients with chronic total occlusion.

This study is aimed to investigate whether serum angiostatic factors (thrombospondin-1 [TSP-1] and endostatin) or angiogenic factors (angiopoietin-2 [Ang-2]) are related to coronary collateral vessel development in patients with chronic total occlusion (CTO).A total of 149 patients were enrolled in the study, and 39 patients with coronary artery disease but without significant stenosis were included in control group. In 110 patients with CTO lesion, 79 with Rentrop grades 2 to 3 collaterals were grouped as good collateral, while 31 with Rentrop grades 0 to 1 collaterals were grouped as poor collateral. Serum TSP-1, endostatin, and Ang-2 levels were studied.Serum endostatin level was significantly higher in poor collateral group compared with control group and good collateral group, respectively (96.2 ± 30.4 vs 77.8 ± 16.5 ng/mL, P = 0.007; 96.2 ± 30.4 vs 81.2 ± 30.4 ng/mL, P = 0.018). In multivariate analysis, decreased serum endostatin level was independently related to good coronary collateral development. Serum TSP-1 level was lower in patients with CTO compared with control group. However, no difference in TSP-1 level was detected between poor and good collateral group. The serum Ang-2 level did not show a significant difference among 3 groups.Circulatory endostatin may be a useful biomarker for coronary collateral development and potential target for therapeutic angiogenesis in patients with CTO.

Plasma Catestatin: A Useful Biomarker for Coronary Collateral Development with Chronic Myocardial Ischemia.

BackgroundsCatestatin is an endogenous multifunctional neuroendocrinepeptide. Recently, catestatin was discovered as a novel angiogenic cytokine. The study was to investigate the associations between endogenous catestatin and coronary collateral development among the patients with chronic myocardial ischemia.MethodsThirty-eight patients with coronary artery chronic total occlusions (CTO) (CTO group) and 38 patients with normal coronary arteries (normal group) were enrolled in the series. Among the patients with CTO, coronary collateral development was graded according to the Rentrop score method. Rentrop score 0–1 collateral development was regarded as poor collateral group and 2–3 collateral development was regarded as good collateral group. Plasma catestatin level and vascular endothelial growth factor (VEGF) were measured by ELISA kits.ResultsThe plasma catestatin levels in CTO group were significantly higher than that in normal group (1.97±1.01 vs 1.36±0.97ng/ml, p = 0.009). In the CTO group, the patients with good collateral development had significantly higher catestatin and VEGF levels than those with poor collateral development (2.36±0.73 vs 1.61±1.12 ng/ml, p = 0.018; 425.23±140.10 vs 238.48±101.00pg/mL, p<0.001). There is a positive correlation between plasma catestatin levels and Rentrop scores (r = 0.40, p = 0.013) among the patients with CTO. However, there is no correlations between plasma catestatin levels and VEGF (r = -0.06, p = 0.744). In the multiple linear regression models, plasma catestatin level was one of the independent factors of coronary collateral development after adjustment for confounders.ConclusionsPlasma catestatin was associated with coronary collateral developments. It may be a useful biomarker for coronary collateral development and potential target for therapeutic angiogenesis in patients with CTO.

Abstract 16109: A Selective Cargo of Non-coding RNAs Mediate Therapeutic Potential of Human CD34+ Stem Cell-derived Exosomes

Introduction: Clinical application of human CD34+ stem cells is associated with improved exercise tolerance and therapeutic angiogenesis in patients with myocardial ischemia. We reported the first description of independent therapeutic potential of CD34+ stem cell-derived exosomes (CD34Exo) to that of parent cell by mechanisms that still remain poorly understood. Hypothesis: Herein, we tested the hypothesis that CD34Exo may selectively carry non-coding RNA (ncRNA) cargo targeted for pro-angiogenic signaling and ischemic tissue repair. Methods and Results: Murine models of myocardial ischemia employed throughout the study. Cell-free CD34Exo replicated the therapeutic activity of their parent cells by significantly improving myocardial ischemia (ejection fraction, 42±4 v 22±6%; capillary density, 113±7 v 66±6/HPF; fibrosis, 27±2 v 48±7%; p&lt;0.05, n=7-12) compared with a PBS control. Confocal imaging and flow cytometry analyses revealed that CD34Exo was selectively internalized into endothelial cells and cardiomyocytes in the CD34Exo-injected ischemic hearts. MicroRNA (miR) profiling identified several pro-angiogenic miRs including miR-126 that are selectively enriched in CD34Exo. Mice injected with CD34Exo show elevated miR-126 and several pro-angiogenic mRNAs in ischemic myocardium, however did not affect endogenous miR-126 synthesis suggestive of direct CD34Exo-mediated miR-126 transfer. Depletion of miR-126 reduced the therapeutic efficacy of CD34Exo both in vitro and in vivo indicating a critical role for miR-126. Using fluorescent-tagged miR-126, we monitored in real-time the uptake and transfer of miR-126 by endothelial cells both in vitro and in vivo. We finally provide novel insights underlying CD34Exo function in regulating endothelial proliferation through identification of novel pathways regulated by miR-126 in endothelial cells. Conclusion: Our results reveal specific CD34Exo-shuttled microRNAs and pathways regulated in the ischemic myocardium. Our work presents a molecular framework for CD34Exo mechanism and function in therapeutic angiogenesis. Precise understanding of CD34Exo mechanisms could significantly amplify the therapeutic benefits of CD34Exo in ischemic tissue regeneration and repair.

Imaging Angiogenesis Using 99mTc-Macroaggregated Albumin Scintigraphy in Patients with Peripheral Artery Disease.

One problem of vascular angiogenesis therapy is the lack of reliable methods for evaluating blood flow in the microcirculation. We aimed to assess whether (99m)Tc-macroaggregated albumin perfusion scintigraphy ((99m)Tc-MAA) predicts quantitated blood flow after therapeutic angiogenesis in patients with peripheral artery disease. Forty-six patients with peripheral artery disease were treated with bone marrow mononuclear cell implantation (BMCI). Before and 4 wk after BMCI, blood flow was evaluated via transcutaneous oxygen tension (TcPO2), ankle-brachial index, intravenous (99m)Tc-tetrofosmin perfusion scintigraphy ((99m)Tc-TF), and intraaortic (99m)Tc-MAA. Four weeks after BMCI, TcPO2 improved significantly (20.4 ± 14.4 to 36.0 ± 20.0 mm Hg, P < 0.01), but ankle-brachial index did not (0.65 ± 0.30 to 0.76 ± 0.24, P = 0.07). Improvement in (99m)Tc-TF count (0.60 ± 0.23 to 0.77 ± 0.29 count ratio/pixel, P < 0.01) and (99m)Tc-MAA count (5.21 ± 3.56 to 10.33 ± 7.18 count ratio/pixel, P = 0.02) was observed in the foot region but not the lower limb region, using both methods. When these data were normalized by subtracting the pixel count of the untreated side, the improvements in (99m)Tc-TF count (-0.04 ± 0.26 to 0.08 ± 0.32 count ratio/pixel, P = 0.04) and (99m)Tc-MAA count (1.49 ± 3.64 to 5.59 ± 4.84 count ratio/pixel, P = 0.03) in the foot remained significant. (99m)Tc-MAA indicated that the newly developed arteries were approximately 25 μm in diameter. BMCI induced angiogenesis in the foot, which was detected using (99m)Tc-TF and (99m)Tc-MAA. (99m)Tc-MAA is a useful method to quantitate blood flow, estimate vascular size, and evaluate flow distribution after therapeutic angiogenesis.

Therapeutic angiogenesis for critical limb ischaemia

Peripheral arterial disease (PAD) is caused by occlusive atherosclerosis in a vascular bed other than the heart. The lower extremity is the most-common location for PAD. Critical limb ischaemia (CLI) is the most-severe clinical manifestation of PAD. Despite improvements in medical care and revascularization, patients with CLI continue to have a high risk of major amputation (below the knee or higher) and cardiovascular death. The primary goal of therapy in CLI is to achieve blood flow to the distal limb vessels with angioplasty or bypass surgery. However, many patients with CLI are unsuitable for revascularization, or the procedure is unsuccessful. Angiogenesis is the growth and proliferation of blood vessels from an existing vascular structure. In therapeutic angiogenesis, attempts are made to utilize blood vessel growth to augment perfusion. In this Review, data from phase II and III clinical trials of therapeutic angiogenesis in patients with PAD will be presented and discussed. Potential explanations for the limited success of therapeutic angiogenesis in humans will be viewed in the context of advances in our understanding of the complex mechanisms underlying angiogenesis and vascular remodelling. This Review will also cover how advances in systems biology, genetics, and gene therapy might still allow the development of new approaches to therapeutic angiogenesis and achieve the goal of restoring perfusion.

Serum erythropoietin: a useful biomarker for coronary collateral development and potential target for therapeutic angiogenesis among the patients with coronary chronic total occlusion

The study was to investigate the association of endogenous erythropoietin (EPO) and coronary collateral development. Forty-nine patients (31 with chronic total occlusion (CTO), 18 with normal coronary artery) were consecutively enrolled. The serum EPO was positively related with Rentrop class. Increased serum EPO was one of the independent predictors of good collateral development (odds ratio 1.31; p = 0.025). A significantly positive correlation was seen between serum EPO and vascular endothelial growth factor (VEGF) levels (r = 0.96, p < 0.001). Circulatory EPO may be a useful biomarker for coronary collateral development and potential target for therapeutic angiogenesis in patients with CTO.

Stem cell implantation in the treatment of peripheral vascular disease

Treatment options of ischemic vascular disease of the lower limbs are a challenged field that necessitates new therapeutic modalities. Stem cell transplantation offers a promising achievement of therapeutic angiogenesis in patients with ischemic limbs. Our study investigated the efficacy and safety of the implantation of autologous peripheral blood mononuclear cells (PBMNCs) mobilized by granulocyte colony-stimulating factor (G-CSF) in patients with chronic limb ischemia. Twenty-four patients with chronic lower limb ischemia were enrolled and divided randomly into two groups: the implanted group (n = 12) and the control group (n = 12). In the implanted group, the patients received subcutaneous injections of recombinant human G-CSF (300 μg/day) for 5 days to mobilize stem/progenitor cells, and their PBMNCs were harvested using a blood cell separator and were implanted by multiple intramuscular injections into the ischemic limbs, while the control group was injected with sterile saline and received conventional medical treatment. All patients were followed up after 12 weeks. At the end of the follow-up period, the main manifestations significantly improved in patients of the implanted group compared with the control group. The mean of rest pain decreased from the baseline level of 6.42 ± 2.15 to 1.67 ± 0.389 (P < 0.001). The mean of pain-free walking distance increased from 25.00 ± 8.90 to 409.00 ± 104.00 (P < 0.001). The mean ankle–brachial pressure index increased from 0.45 ± 0.12 to 0.79 ± 0.38 (P = 0.005). Seven out of nine limb ulcers and wounds (77.8 %) of implanted patients healed after cell implantation. Two lower limb amputations (16.67 %) occurred in the implanted patients. In contrast, eight control patients (66.67 %) had to receive lower limb amputation. Implantation of stem/progenitor cells is a feasible and readily available effective strategy for therapeutic angiogenesis in patients with chronic limb ischemia.

Enhancement of Cell-Based Therapeutic Angiogenesis Using a Novel Type of Injectable Scaffolds of Hydroxyapatite-Polymer Nanocomposite Microspheres

BackgroundClinical trials demonstrate the effectiveness of cell-based therapeutic angiogenesis in patients with severe ischemic diseases; however, their success remains limited. Maintaining transplanted cells in place are expected to augment the cell-based therapeutic angiogenesis. We have reported that nano-hydroxyapatite (HAp) coating on medical devices shows marked cell adhesiveness. Using this nanotechnology, HAp-coated poly(l-lactic acid) (PLLA) microspheres, named nano-scaffold (NS), were generated as a non-biological, biodegradable and injectable cell scaffold. We investigate the effectiveness of NS on cell-based therapeutic angiogenesis.Methods and ResultsBone marrow mononuclear cells (BMNC) and NS or control PLLA microspheres (LA) were intramuscularly co-implanted into mice ischemic hindlimbs. When BMNC derived from enhanced green fluorescent protein (EGFP)-transgenic mice were injected into ischemic muscle, the muscle GFP level in NS+BMNC group was approximate fivefold higher than that in BMNC or LA+BMNC groups seven days after operation. Kaplan-Meier analysis demonstrated that NS+BMNC markedly prevented hindlimb necrosis (P<0.05 vs. BMNC or LA+BMNC). NS+BMNC revealed much higher induction of angiogenesis in ischemic tissues and collateral blood flow confirmed by three-dimensional computed tomography angiography than those of BMNC or LA+BMNC groups. NS-enhanced therapeutic angiogenesis and arteriogenesis showed good correlations with increased intramuscular levels of vascular endothelial growth factor and fibroblast growth factor-2. NS co-implantation also prevented apoptotic cell death of transplanted cells, resulting in prolonged cell retention.ConclusionA novel and feasible injectable cell scaffold potentiates cell-based therapeutic angiogenesis, which could be extremely useful for the treatment of severe ischemic disorders.