Safety and efficacy of plasmid DNA expressing two isoforms of hepatocyte growth factor in patients with critical limb ischemia

Recombinant Human Hepatocyte Growth Factor Plasmids for Treating Patients with Chronic Limb Threatening Ischaemia: A Systematic Review and Meta-analysis

OBJECTIVE

Recombinant human hepatocyte growth factor (HGF) plasmids are novel alternatives to salvage limbs in patients with chronic limb threatening ischaemia (CLTI). A systematic review and meta-analysis of data was conducted to assess the therapeutic efficacy of HGF plasmids in patients with CLTI.

DATA SOURCES

Randomised controlled studies evaluating HGF plasmid efficacy in patients with CLTI were identified using MEDLINE, Embase, Cochrane Database of Systematic Reviews, and ClinicalTrials.gov databases.

REVIEW METHODS

Meta-analyses of the reported relative risk (RR) or mean difference (MD) were conducted. Subgroup analyses were performed to determine the efficacy of HGF plasmids in cohorts excluding Buerger's disease. Certainty of evidence for each outcome was assessed.

RESULTS

Seven studies (n = 655 participants) were included. Based on low certainty evidence, patients treated with HGF had a significantly higher complete ulcer healing rate (RR 1.99, 95% confidence interval [CI] 1.30 - 3.04; p = .002) than patients treated with placebo. HGF treatment was associated with reduced visual analogue scale (VAS) scores of pain severity (MD -1.56, 95% CI -2.12 - -1.00; p < .001) vs. placebo in patients with CLTI assessed at three month follow up (low certainty evidence); no significant differences were observed in major amputation (RR 0.91, 95% CI 0.48 - 1.73; p = .77) (low certainty evidence) or all cause mortality rate (RR 0.93, 95% CI 0.38 - 2.27; p = .87) (low certainty evidence) between patients treated with HGF and placebo. Low certainty evidence suggested no significant differences in change in ankle brachial index at six months (MD 0.00, 95% CI -0.09 - 0.09; p = 1.0) between patients treated with HGF and placebo. The complete ulcer healing rate and improved three month VAS scores of pain severity benefits persisted in subgroup analyses (low certainty evidence).

CONCLUSION

Low certainty evidence suggested that HGF treatment is associated with an increased complete ulcer healing rate and reduced ischaemic pain in patients with CLTI.

Gene therapy for diabetic foot ulcers: Interim analysis of a randomised, placebo-controlled phase 3 study of VM202 (ENGENSIS), a plasmid DNA expressing two isoforms of human hepatocyte growth factor

To evaluate the status of a 7-month phase 3 study conducted to test the effect of intramuscular injections of VM202 (ENGENSIS), a plasmid DNA encoding human hepatocyte growth factor, into the calf muscles of chronic nonhealing diabetic foot ulcers with concomitant peripheral artery disease. The phase 3 study, originally aimed to recruit 300 subjects, was discontinued because of slow patient recruitment. An unprespecified interim analysis was performed for the 44 subjects enrolled to assess the status and determine the future direction. Statistical analyses were carried out for the Intent-to-Treat (ITT) population and separately for subjects with neuroischemic ulcers, using a t-test and Fisher's exact test. A logistic regression analysis was also conducted. VM202 was safe and potentially should have benefits. In the ITT population (N = 44), there was a positive trend toward closure in the VM202 group from 3 to 6 months but with no statistical significance. Levels of ulcer volume or area were found to be highly skewed between the placebo and VM202 groups. Forty subjects, excluding four outliers in both arms, showed significant wound-closing effects at month 6 (P = .0457). In 23 patients with neuroischemic ulcers, the percentage of subjects reaching complete ulcer closure was significantly higher in the VM202 group at months 3, 4, and 5 (P = .0391, .0391, and .0361). When two outliers were excluded, a significant difference was evident in months 3, 4, 5, and 6 (P = .03 for all points). A potentially clinically meaningful 0.15 increase in Ankle-Brachial Index was observed in the VM202 group at day 210 in the ITT population (P = .0776). Intramuscular injections of VM202 plasmid DNA to calf muscle may have promise in the treatment of chronic neuroischemic diabetic foot ulcers (DFUs). Given the safety profile and potential healing effects, continuing a larger DFU study is warranted with modifications of the current protocol and expansion of enrolling sites.

Rationale and design for the study of recombinant human hepatocyte growth factor plasmid in the treatment of patients with chronic limb-threatening ischemia (HOPE CLTI): Randomized, placebo-controlled, double-blind, phase III clinical trials

BACKGROUND

Although patients with CLTI have benefited from the rapid development of endovascular techniques, many patients are considered unsuitable for revascularization procedures. A previous phase II clinical trial has suggested that recombinant human hepatocyte growth factor plasmid (NL003) can salvage limbs during the treatment of patients with CLTI. However, the safety and efficacy of this drug need to be evaluated in a larger cohort.

STUDY DESIGN

HOPE CLTI is a multicenter, randomized, double-blind, placebo-controlled phase III clinical study to evaluate the efficacy and safety of intramuscular injection of NL003 in CLTI patients. This study consisted of 22 trials: HOPE CLTI-1, which includes patients with rest pain (Rutherford stage 4), and HOPE CLTI-2, which includes patients with limb ulcers (Rutherford stage 5). In both trials, patients are randomized with a 2:1 ratio of intramuscular injection of NL003 to placebo. The primary endpoint of HOPE CLTI-1 is the complete pain relief rate. The primary endpoint of HOPE CLTI-2 is the complete ulcer healing rate. The safety endpoint was assessed based on adverse events after injection of NL003. Enrollment began in July 2019. The HOPE CLTI-1 trial aims to complete the randomization of at least 300 patients, while the HOPE CLTI-2 trial aims to enroll at least 240 patients. Both trials are organized such that patients will be followed for 6 months after the first intramuscular injection.

CONCLUSIONS

HITOP CLTI, which is comprised of 2 multicenter, double-blind, placebo-controlled phase III clinical trials, aims to evaluate the efficacy and safety of the intramuscular administration of NL003 in patients with CLTI.

Endothelium-targeted delivery of PPARδ by adeno-associated virus serotype 1 ameliorates vascular injury induced by hindlimb ischemia in obese mice

Diabetic vasculopathy is a major health problem worldwide. Peripheral arterial disease (PAD), and in its severe form, critical limb ischemia is a major form of diabetic vasculopathy with limited treatment options. Existing literature suggested an important role of PPARδ in vascular homeostasis. It remains elusive for using PPARδ as a potential therapeutic target due to mostly the side effects of PPARδ agonists. To explore the roles of PPARδ in endothelial homeostasis, endothelial cell (EC) selective Ppard knockout and controlled mice were subjected to hindlimb ischemia (HLI) injury. The muscle ECs were sorted for single-cell RNA sequencing (scRNA-seq) analysis. HLI was also performed in high fat diet (HFD)-induced obese mice to examine the function of PPARδ in obese mice with delayed vascular repair. Adeno-associated virus type 1 (AAV1) carrying ICAM2 promoter to target endothelium for overexpressing PPARδ was injected into the injured muscles of normal chow- and HFD-fed obese mice before HLI surgery was performed. scRNA-seq analysis of ECs in ischemic muscles revealed a pivotal role of PPARδ in endothelial homeostasis. PPARδ expression was diminished both after HLI injury, and also in obese mice, which showed further delayed vascular repair. Endothelium-targeted delivery of PPARδ by AAV1 improved perfusion recovery, increased capillary density, restored endothelial integrity, suppressed vascular inflammation, and promoted muscle regeneration in ischemic hindlimbs of both lean and obese mice. Our study indicated the effectiveness of endothelium-targeted PPARδ overexpression for restoring functional vasculature after ischemic injury, which might be a promising option of gene therapy to treat PAD and CLI.

Advanced Gene-Targeting Therapies for Motor Neuron Diseases and Muscular Dystrophies

Gene therapy is a revolutionary, cutting-edge approach to permanently ameliorate or amend many neuromuscular diseases by targeting their genetic origins. Motor neuron diseases and muscular dystrophies, whose genetic causes are well known, are the frontiers of this research revolution. Several genetic treatments, with diverse mechanisms of action and delivery methods, have been approved during the past decade and have demonstrated remarkable results. However, despite the high number of genetic treatments studied preclinically, those that have been advanced to clinical trials are significantly fewer. The most clinically advanced treatments include adeno-associated virus gene replacement therapy, antisense oligonucleotides, and RNA interference. This review provides a comprehensive overview of the advanced gene therapies for motor neuron diseases (i.e., amyotrophic lateral sclerosis and spinal muscular atrophy) and muscular dystrophies (i.e., Duchenne muscular dystrophy, limb-girdle muscular dystrophy, and myotonic dystrophy) tested in clinical trials. Emphasis has been placed on those methods that are a few steps away from their authoritative approval.

Approaches to Modulate the Chronic Wound Environment Using Localized Nucleic Acid Delivery

Significance: Nonhealing wounds have been the subject of decades of basic and clinical research. Despite new knowledge about the biology of impaired wound healing, little progress has been made in treating chronic wounds, leaving patients with few therapeutic options. Diabetic ulcers are a particularly common form of nonhealing wound. Recent Advances: Recently, investigation of therapeutic nucleic acids (TNAs), including plasmid DNA, small interfering RNA, microRNA mimics, anti-microRNA oligonucleotides, messenger RNA, and antisense oligonucleotides, has created a new treatment strategy for chronic wounds. TNAs can modulate the wound toward a prohealing environment by targeting gene pathways associated with inflammation, proteases, cell motility, angiogenesis, epithelialization, and oxidative stress. A variety of delivery systems have been investigated for TNAs, including dendrimers, lipid nanoparticles (NPs), polymeric micelles, polyplexes, metal NPs, and hydrogels. This review summarizes recent developments in TNA delivery for therapeutic targets associated with chronic wounds, with an emphasis on diabetic ulcers. Critical Issues: Translational potential of TNAs remains a key challenge; we highlight some drug delivery approaches for TNAs that may hold promise. We also describe current commercial efforts to locally deliver nucleic acids to modulate the wound environment. Future Directions: Localized nucleic acid delivery holds promise for the treatment of nonhealing chronic wounds. Future efforts to improve targeting of these nucleic acid therapies in the wound with both spatial and temporal control through drug delivery systems will be crucial to successful clinical translation.

Outcomes of Conservative Treatment in Patients with Chronic Limb Threatening Ischaemia: A Systematic Review and Meta-Analysis

OBJECTIVE

Chronic limb threatening ischaemia (CLTI) is the most severe form of peripheral arterial disease. International guidelines recommend arterial revascularisation in patients with CLTI. However, these patients are often fragile elderly people with significant comorbidities, whose vascular anatomy is not always suitable for open or endovascular revascularisation. Recent studies have suggested acceptable outcomes of conservative treatment. A systematic review of the available literature was conducted to obtain best estimates of outcomes of conservative treatment in patients with CLTI.

DATA SOURCES

MEDLINE, Embase, and Cochrane Central.

REVIEW METHODS

A systematic review and meta-analysis was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. MEDLINE, Embase, and Cochrane Central were searched from inception until September 2019. All studies reporting on outcomes of conservative treatment for CLTI were considered. Study selection, data extraction, and risk of bias assessment were done by two investigators independently. Risk of bias was evaluated with a modified version of the Cochrane tool for observational studies. Outcomes of interest were all cause mortality, major amputation, and amputation free survival (AFS) after at least 12 months of follow up. A random effects model was used for meta-analyses.

RESULTS

Twenty-seven publications were included, consisting of 12 observational studies and 15 placebo arms from randomised clinical trials, totalling 1 642 patients. Most studies included patients with non-reconstructable CLTI. Overall study quality was moderate. The pooled 12 month all cause mortality rate in 14 studies comprising 1 003 patients was 18% (95% confidence interval [CI] 13 - 25, I² = 73%). The pooled major amputation rate from 14 studies comprising 755 patients was 27% (95% CI 20 - 36, I² = 65%) after one year, and pooled AFS rate after 12 months in 11 studies with 970 patients was 60% (95% CI 52 - 67, I² = 75%).

CONCLUSION

Conservative treatment for patients with CLTI may be considered and does not always result in loss of limb or patient demise. The results of this review can be used to inform patients with CLTI about conservative treatment as part of a shared decision making process.

Bioengineering strategies for the treatment of peripheral arterial disease

Peripheral arterial disease (PAD) is a progressive atherosclerotic disorder characterized by narrowing and occlusion of arteries supplying the lower extremities. Approximately 200 million people worldwide are affected by PAD. The current standard of operative care is open or endovascular revascularization in which blood flow restoration is the goal. However, many patients are not appropriate candidates for these treatments and are subject to continuous ischemia of their lower limbs. Current research in the therapy of PAD involves developing modalities that induce angiogenesis, but the results of simple cell transplantation or growth factor delivery have been found to be relatively poor mainly due to difficulties in stem cell retention and survival and rapid diffusion and enzymolysis of growth factors following injection of these agents in the affected tissues. Biomaterials, including hydrogels, have the capability to protect stem cells during injection and to support cell survival. Hydrogels can also provide a sustained release of growth factors at the injection site. This review will focus on biomaterial systems currently being investigated as carriers for cell and growth factor delivery, and will also discuss biomaterials as a potential stand-alone method for the treatment of PAD. Finally, the challenges of development and use of biomaterials systems for PAD treatment will be reviewed.

Gene therapy for diabetic peripheral neuropathy: A randomized, placebo-controlled phase III study of VM202, a plasmid DNA encoding human hepatocyte growth factor

VM202 is a plasmid DNA encoding two isoforms of hepatocyte growth factor (HGF). A previous phase II study in subjects with painful diabetic peripheral neuropathy (DPN) showed significant reductions in pain. A phase III study was conducted to evaluate the safety and efficacy of VM202 in DPN. The trial was conducted in two parts, one for 9 months (DPN 3-1) with 500 subjects (VM202: 336 subjects; and placebo: 164) and a preplanned subset of 101 subjects (VM202: 65 subjects; and placebo: 36) with a noninterventional extension to 12 months (DPN 3-1b). VM202 or placebo was administered to calf muscles on days 0 and 14, and on days 90 and 104. The primary end point in DPN 3-1 was change from baseline in the mean 24-h Numerical Rating Scale (NRS) pain score. In DPN 3-1b, the primary end point was safety, whereas the secondary efficacy end point was change in the mean pain score. VM202 was well-tolerated in both studies without significant adverse events. VM202 failed to meet its efficacy end points in DPN 3-1. In DPN 3-1b, however, VM202 showed significant and clinically meaningful pain reduction versus placebo. Pain reduction in DPN 3-1b was even greater in subjects not receiving gabapentin or pregabalin, confirming an observation noted in the phase II study. In DPN 3-1b, symptomatic relief was maintained for 8 months after the last injection suggesting that VM202 treatment might change disease progression. Despite the perplexing discrepancy between the two studies, the safety and long-lasting pain-relieving effects of VM202 observed in DPN 3-1b warrant another rigorous phase III study. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? Current therapies for painful diabetic peripheral neuropathy (DPN) are palliative and do not target the underlying mechanisms. Moreover, symptomatic relief is often limited with existing neuropathic pain drugs. Thus, there is a great medical need for safer and effective treatments for DPN. WHAT QUESTION DID THIS STUDY ADDRESS? Can nonviral gene delivery of hepatocyte growth factor reduce pain in patients with DPN and potentially modify progression of the disorder? WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? Nonviral gene therapy can be used safely and practically to treat DPN. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? As the first gene medicine to enter advanced clinical trials for the treatment of DPN, this study provides the proof of concept of an entirely new potential approach to the disorder.

Therapeutic Angiogenesis by a "Dynamic Duo": Simultaneous Expression of HGF and VEGF165 by Novel Bicistronic Plasmid Restores Blood Flow in Ischemic Skeletal Muscle

Therapeutic angiogenesis is a promising strategy for relief of ischemic conditions, and gene delivery was used to stimulate blood vessels' formation and growth. We have previously shown that intramuscular injection of a mixture containing plasmids encoding vascular endothelial growth factor (VEGF)165 and hepatocyte growth factor (HGF) leads to restoration of blood flow in mouse ischemic limb, and efficacy of combined delivery was superior to each plasmid administered alone. In this work, we evaluated different approaches for co-expression of HGF and VEGF165 genes in a panel of candidate plasmid DNAs (pDNAs) with internal ribosome entry sites (IRESs), a bidirectional promoter or two independent promoters for each gene of interest. Studies in HEK293T culture showed that all plasmids provided synthesis of HGF and VEGF165 proteins and stimulated capillary formation by human umbilical vein endothelial cells (HUVEC), indicating the biological potency of expressed factors. Tests in skeletal muscle explants showed a dramatic difference and most plasmids failed to express HGF and VEGF165 in a significant quantity. However, a bicistronic plasmid with two independent promoters (cytomegalovirus (CMV) for HGF and chicken b-actin (CAG) for VEGF165) provided expression of both grow factors in skeletal muscle at an equimolar ratio. Efficacy tests of bicistronic plasmid were performed in a mouse model of hind limb ischemia. Intramuscular administration of plasmid induced significant restoration of perfusion compared to an empty vector and saline. These findings were supported by increased CD31+ capillary density in animals that received pHGF/VEGF. Overall, our study reports a first-in-class candidate gene therapy drug to deliver two pivotal angiogenic growth factors (HGF and VEGF165) with properties that provide basis for future development of treatment for an unmet medical need-peripheral artery disease and associated limb ischemia.

Progress of Gene Therapy in Cardiovascular Disease

Gene therapy has been extensively studied in peripheral and cardiac ischemia, heart and vein graft failure, and dyslipidemia, but most clinical trials failed to show their efficacies despite good outcomes in preclinical studies. So far, 2 gene therapies for dyslipidemia and one for critical limb ischemia in peripheral artery disease have been approved. In critical limb ischemia, gene therapy using proangiogenic factors has emerged as a novel therapeutic modality for promoting angiogenesis. Initial researches mainly focused on vascular endothelial growth factor, fibroblast growth factor, or hepatocyte growth factor. After the favorable results of basic research, several phase I and II clinical trials of these proangiogenic factors have shown promising results. However, only a phase III clinical trial of the intramuscular injection of hepatocyte growth factor plasmid DNA has shown successful outcomes, and it was recently approved in Japan for treating patients with critical limb ischemia who have ulcers and for whom no alternative therapeutic options are available. DNA vaccine is another promising modality of gene therapy. An antitumor vaccine suppressing angiogenesis through the inhibition of proangiogenic factors and an antihypertensive vaccine inhibiting the renin–angiotensin system are representative DNA vaccines. The advantage of DNA vaccine is its long-term effectiveness with a few vaccinations; however, the benefits and risks, such as adverse T-cell reaction against self-antigen or long-term side effects, of DNA vaccines should be carefully evaluated. In this review, we discuss the recent advances in proangiogenic gene therapy for critical limb ischemia and DNA vaccine for hypertension.

A Randomized, Double-Blind, Placebo-Controlled Phase II Study of Hepatocyte Growth Factor in the Treatment of Critical Limb Ischemia

NL003 is a plasmid engineered to simultaneously express two isoforms of hepatocyte growth factor. This phase II study was performed to assess the clinical safety and efficacy of intramuscular injection of NL003 in critical limb ischemia (CLI) patients for 6 months. Two hundred patients (Rutherford scale 4-5) were randomly assigned: placebo (n = 50), low-dose NL003 (n = 50), middle-dose NL003 (n = 50), or high-dose NL003 (n = 50). The drug was administered in the affected limb of 197 patients on days 0, 14, and 28. No significant differences in the incidence of adverse events (AEs) or serious AEs were found among the groups. At 6 months, pain severity was significantly reduced in all NL003 groups, but not in the placebo group (p < 0.05). The proportion of patients with complete ulcer healing in the high-dose group was significantly higher than that of the placebo group (p = 0.0095). There were no statistically significant differences in transcutaneous oxygen pressure (TcPO2), ankle-brachial index (ABI), or toe-brachial index (TBI) value among the four groups throughout the study period. These results provide the first effective evidence of significant improvements in total healing of ulcers in treated legs, complete pain relief without analgesics, and safety for NL003 in patients with Rutherford stage 4-5.

Hepatocyte Growth Factor Regulates Macrophage Transition to the M2 Phenotype and Promotes Murine Skeletal Muscle Regeneration

Hepatocyte growth factor (HGF) is well known for its role in the migration of embryonic muscle progenitors and the activation of adult muscle stem cells, yet its functions during the adult muscle regeneration process remain to be elucidated. In this study, we showed that HGF/c-met signaling was activated during muscle regeneration, and that among various infiltrated cells, the macrophage is the major cell type affected by HGF. Pharmacological inhibition of the c-met receptor by PHA-665752 increased the expression levels of pro-inflammatory (M1) macrophage markers such as IL-1β and iNOS while lowering those of pro-regenerative (M2) macrophage markers like IL-10 and TGF-β, resulting in compromised muscle repair. In Raw 264.7 cells, HGF decreased the RNA level of LPS-induced TNF-α, IL-1β, and iNOS while enhancing that of IL-10. HGF was also shown to increase the phosphorylation of AMPKα through CaMKKβ, thereby overcoming the effects of the LPS-induced deactivation of AMPKα. Transfection with specific siRNA to AMPKα diminished the effects of HGF on the LPS-induced gene expressions of M1 and M2 markers. Exogenous delivery of HGF through intramuscular injection of the HGF-expressing plasmid vector promoted the transition to M2 macrophage and facilitated muscle regeneration. Taken together, our findings suggested that HGF/c-met might play an important role in the transition of the macrophage during muscle repair, indicating the potential use of HGF as a basis for developing therapeutics for muscle degenerative diseases.

Challenges in Translating from Bench to Bed-Side: Pro-Angiogenic Peptides for Ischemia Treatment

We describe progress and obstacles in the development of novel peptide-hydrogel therapeutics for unmet medical needs in ischemia treatment, focusing on the development and translation of therapies specifically in peripheral artery disease (PAD). Ischemia is a potentially life-threatening complication in PAD, which affects a significant percentage of the elderly population. While studies on inducing angiogenesis to treat PAD were started two decades ago, early results from animal models as well as clinical trials have not yet been translated into clinical practice. We examine some of the challenges encountered during such translation. We further note the need for sustained angiogenic effect involving whole growth factor, gene therapy and synthetic growth factor strategies. Finally, we discuss the need for tissue depots for de novo formation of microvasculature. These scaffolds can act as templates for neovasculature development to improve circulation and healing at the preferred anatomical location.

Gene therapy for peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD), caused by narrowing of the arteries in the limbs, is increasing in incidence and prevalence as our population is ageing and as diabetes is becoming more prevalent. PAD can cause pain in the limbs while walking, known as intermittent claudication, or can be more severe and cause pain while at rest, ulceration, and ultimately gangrene and limb loss. This more severe stage of PAD is known as 'critical limb ischaemia'. Treatments for PAD include medications that help to reduce the increased risk of cardiovascular events and help improve blood flow, as well as endovascular or surgical repair or bypass of the blocked arteries. However, many people are unresponsive to medications and are not suited to surgical or endovascular treatment, leaving amputation as the last option. Gene therapy is a novel approach in which genetic material encoding for proteins that may help increase revascularisation is injected into the affected limbs of patients. This type of treatment has been shown to be safe, but its efficacy, especially regarding ulcer healing, effects on quality of life, and other symptomatic outcomes remain unknown.

OBJECTIVES

To assess the effects of gene therapy for symptomatic peripheral arterial disease.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched Cochrane CENTRAL, the Cochrane Vascular Specialised Register, MEDLINE Ovid, Embase Ovid, CINAHL, and AMED, along with trials registries (all searched 27 November 2017). We also checked reference lists of included studies and systematic reviews for further studies.

SELECTION CRITERIA

We included randomised and quasi-randomised studies that evaluated gene therapy versus no gene therapy in people with PAD. We excluded studies that evaluated direct growth hormone treatment or cell-based treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, performed quality assessment, and extracted data from the included studies. We collected pertinent information on each study, as well as data for the outcomes of amputation-free survival, ulcer healing, quality of life, amputation, all-cause mortality, ankle brachial index, symptom scores, and claudication distance.

MAIN RESULTS

We included in this review a total of 17 studies with 1988 participants (evidence current until November 2017). Three studies limited their inclusion to people with intermittent claudication, 12 limited inclusion to people with varying levels of critical limb ischaemia, and two included people with either condition. Study investigators evaluated many different types of gene therapies, using different protocols. Most studies evaluated growth factor-encoding gene therapy, with six studies using vascular endothelial growth factor (VEGF)-encoding genes, four using hepatocyte growth factor (HGF)-encoding genes, and three using fibroblast growth factor (FGF)-encoded genes. Two studies evaluated hypoxia-inducible factor 1-alpha (HIF-1α) gene therapy, one study used a developmental endothelial locus-1 gene therapy, and the final study evaluated a stromal cell-derived factor-1 (SDF-1) gene therapy. Most studies reported outcomes after 12 months of follow-up, but follow-up ranged from three months to two years.Overall risk of bias varied between studies, with many studies not providing sufficient detail for adequate determination of low risk of bias for many domains. Two studies did not utilise a placebo control, leading to risk of performance bias. Several studies reported in previous protocols or in their Methods sections that they would report on certain outcomes for which no data were then reported, increasing risk of reporting bias. All included studies reported sponsorships from corporate entities that led to unclear risk of other bias. The overall quality of evidence ranged from moderate to very low, generally as the result of heterogeneity and imprecision, with few or no studies reporting on outcomes.Evidence suggests no clear differences for the outcomes of amputation-free survival, major amputation, and all-cause mortality between those treated with gene therapy and those not receiving this treatment (all moderate-quality evidence). Low-quality evidence suggests improvement in complete ulcer healing with gene therapy (odds ratio (OR) 2.16, 95% confidence interval (CI) 1.02 to 4.59; P = 0.04). We could not combine data on quality of life and can draw no conclusions at this time regarding this outcome (very low-quality evidence). We included one study in the meta-analysis for ankle brachial index, which showed no clear differences between treatments, but we can draw no overall association (low-quality evidence). We combined in a meta-analysis pain symptom scores as assessed by visual analogue scales from two studies and found no clear differences between treatment groups (very low-quality evidence). We carried out extensive subgroup analyses by PAD classification, dosage schedule, vector type, and gene used but identified no substantial differences.

AUTHORS' CONCLUSIONS

Moderate-quality evidence shows no clear differences in amputation-free survival, major amputation, and all-cause mortality between those treated with gene therapy and those not receiving gene therapy. Some evidence suggests that gene therapy may lead to improved complete ulcer healing, but this outcome needs to be explored with improved reporting of the measure, such as decreased ulcer area in cm², and better description of ulcer types and healing. Further standardised data that are amenable to meta-analysis are needed to evaluate other outcomes such as quality of life, ankle brachial index, symptom scores, and claudication distance.

Hepatocyte Growth Factor Regulates the miR-206-HDAC4 Cascade to Control Neurogenic Muscle Atrophy following Surgical Denervation in Mice

Hepatocyte growth factor (HGF) has been well characterized for its roles in the migration of muscle progenitors during embryogenesis and the differentiation of muscle stem cells, but its function in adult neurogenic muscle atrophic conditions is poorly understood. Here we investigated whether HGF/c-met signaling has any effects on muscle-atrophic conditions. It was found that HGF expression was upregulated in skeletal muscle tissue following surgical denervation and in hSOD1-G93A transgenic mice showing severe muscle loss. Pharmacological inhibition of the c-met receptor decreased the expression level of pri-miR-206, enhanced that of HDAC4 and atrogenes, and resulted in increased muscle atrophy. In C2C12 cells, HGF inhibited phosphorylation of Smad3 and relieved TGF-β-mediated suppression of miR-206 expression via JNK. When extra HGF was exogenously provided through intramuscular injection of plasmid DNA expressing HGF, the extent of muscle atrophy was reduced, and the levels of all affected biochemical markers were changed accordingly, including those of primary and mature miR-206, HDAC4, and various atrogenes. Taken together, our finding suggested that HGF might play an important role in regard to neurogenic muscle atrophy and that HGF might be used as a platform to develop therapeutic agents for neuromuscular disorders.

Effective control of neuropathic pain by transient expression of hepatocyte growth factor in a mouse chronic constriction injury model

Hepatocyte growth factor (HGF) is a multifunctional protein that contains angiogenic and neurotrophic properties. In the current study, we investigated the analgesic effects of HGF by using a plasmid DNA that was designed to express 2 isoforms of human HGF—pCK-HGF-X7 (or VM202)—in a chronic constriction injury (CCI) –induced mouse neuropathic pain model. Intramuscular injection of pCK-HGF-X7 into proximal thigh muscle induced the expression of HGF in the muscle, sciatic nerve, and dorsal root ganglia (DRG). This gene transfer procedure significantly attenuated mechanical allodynia and thermal hyperalgesia after CCI. Injury-induced expression of activating transcription factor 3, calcium channel subunit α2δ1, and CSF1 in the ipsilateral DRG neurons was markedly down-regulated in the pCK-HGF-X7–treated group, which suggested that HGF might exert its analgesic effects by inhibiting pain-mediating genes in the sensory neurons. In addition, suppressed CSF1 expression in DRG neurons by pCK-HGF-X7 treatment was accompanied by a noticeable suppression of the nerve injury–induced glial cell activation in the spinal cord dorsal horn. Taken together, our data show that pCK-HGF-X7 attenuates nerve injury–induced neuropathic pain by inhibiting pain-related factors in DRG neurons and subsequent spinal cord glial activation, which suggests its therapeutic efficacy in the treatment of neuropathic pain.—Nho, B., Lee, J., Lee, J., Ko, K. R., Lee, S. J., Kim, S. Effective control of neuropathic pain by transient expression of hepatocyte growth factor in a mouse chronic constriction injury model.

Nanomedicines and gene therapy for the delivery of growth factors to improve perfusion and oxygenation in wound healing

Oxygen plays a key role in wound healing, and hypoxia is a major cause of wound healing impairment; therefore, treatments to improve hemodynamics and increase wound oxygenation are of particular interest for the treatment of chronic wounds. This article describes the roles of oxygen and angiogenesis in wound healing as well as the tools used to evaluate tissue oxygenation and perfusion and then presents a review of nanomedicines and gene therapies designed to improve perfusion and oxygenation and accelerate wound healing.

Growth factors for angiogenesis in peripheral arterial disease

BACKGROUND

Peripheral artery disease (PAD) is associated with a high clinical and socioeconomic burden. Treatments to alleviate the symptoms of PAD and decrease the risks of amputation and death are a high societal priority. A number of growth factors have shown a potential to stimulate angiogenesis. Growth factors delivered directly (as recombinant proteins), or indirectly (e.g. by viral vectors or DNA plasmids encoding these factors), have emerged as a promising strategy to treat patients with PAD.

OBJECTIVES

To assess the effects of growth factors that promote angiogenesis for treating people with PAD of the lower extremities.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Specialised Register (June 2016) and CENTRAL (2016, Issue 5). We searched trial registries for details of ongoing or unpublished studies. We also checked the reference lists of relevant publications and, if necessary, tried to contact the trialists for details of the studies.

SELECTION CRITERIA

We included randomised controlled trials comparing growth factors (delivered directly or indirectly) with no intervention, placebo or any other intervention not based on the growth factor's action in patients with PAD of the lower extremities. The primary outcomes were limb amputation, death and adverse events. The secondary outcomes comprised walking ability, haemodynamic measures, ulceration and rest pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and assessed the risk of bias. We used outcomes of the studies at low risk of bias for the main analysis and of all studies in the sensitivity analyses. We calculated odds ratios (OR) for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals (CI). We evaluated statistical heterogeneity using the I2 statistic and Cochrane's Q test. We conducted meta-analysis for the overall effect and for each growth factor as a subgroup analysis using OR in a fixed-effect model. We evaluated the robustness of the results in a sensitivity analysis using risk ratio (RR) and/or a random-effects model. We also assessed the quality of the evidence for each outcome.

MAIN RESULTS

We included 20 trials in the review and used 14 studies (on approximately 1400 participants) with published results in the analyses. Six published studies compared fibroblast growth factors (FGF), four studies hepatocyte growth factors (HGF) and another four studies vascular endothelial growth factors (VEGF), versus placebo or no therapy. Six of these studies exclusively or mainly investigated participants with intermittent claudication and eight studies exclusively participants with critical limb ischaemia. Follow-up generally ranged from three months to one year. Two small studies provided some data at 2 years and one of them also at 10 years.The direction and size of effects for growth factors on major limb amputations (OR 0.99, 95% CI 0.71 to 1.38; 10 studies, N = 1075) and death (OR 0.99, 95% CI 0.69 to 1.41; 12 studies, N = 1371) at up to two years are uncertain. The quality of the evidence is low due to risk of bias and imprecision (at one year, moderate-quality evidence due to imprecision). However, growth factors may decrease the rate of any limb amputations (OR 0.56, 95% CI 0.31 to 0.99; 6 studies, N = 415). The quality of the evidence is low due to risk of bias and selective reporting.The direction and size of effects for growth factors on serious adverse events (OR 1.09, 95% CI 0.79 to 1.50; 13 studies, N = 1411) and on any adverse events (OR 1.10, 95% CI 0.73 to 1.64; 4 studies, N = 709) at up to two years are also uncertain. The quality of the evidence is low due to risk of bias and imprecision (for serious adverse events at one year, moderate-quality evidence due to imprecision).Growth factors may improve haemodynamic measures (low-quality evidence), ulceration (very low-quality evidence) and rest pain (very low-quality evidence) up to one year, but they have little or no effect on walking ability (low-quality evidence). We did not identify any relevant differences in effects between growth factors (FGF, HGF and VEGF).

AUTHORS' CONCLUSIONS

The results of this review do not support the use of therapy with the growth factors FGF, HGF or VEGF in people with PAD of the lower extremities to prevent death or major limb amputation or to improve walking ability. However, the use of these growth factors may improve haemodynamic measures and decrease the rate of any limb amputations (probably due to preventing minor amputations) with an uncertain effect on adverse events; an improvement of ulceration and rest pain is very uncertain. New trials at low risk of bias are needed to generate evidence with more certainty.

Open label study to assess the safety of VM202 in subjects with amyotrophic lateral sclerosis

OBJECTIVE

To assess safety and define efficacy measures of hepatocyte growth factor (HGF) DNA plasmid, VM202, administered by intramuscular injections in patients with amyotrophic lateral sclerosis (ALS).

METHODS

Eighteen participants were treated with VM202 administered in divided doses by injections alternating between the upper and lower limbs on d 0, 7, 14, and 21. Subjects were followed for nine months to evaluate possible adverse events. Functional outcome was assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R) as well as by serially measuring muscle strength, muscle circumference, and forced vital capacity.

RESULTS

Seventeen of 18 participants completed the study. All participants tolerated 64 mg of VM202 well with no serious adverse events (SAE) related to the drug. Twelve participants reported 26 mild or moderate injection site reactions. Three participants experienced five SAEs unrelated to VM202. One subject died from respiratory insufficiency secondary to ALS progression.

CONCLUSIONS

Multiple intramuscular injection of VM202 into the limbs appears safe in ALS subjects. Future trials with retreatment after three months will determine whether VM202 treatment alters the long-term course of ALS.