Phase 1/2 open-label dose-escalation study of plasmid DNA expressing two isoforms of hepatocyte growth factor in patients with painful diabetic peripheral neuropathy

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.

Novel rAAV vector mediated intrathecal HGF delivery has an impact on neuroimmune modulation in the ALS motor cortex with TDP-43 pathology

Recombinant adeno-associated virus (rAAV)-based gene therapies offer an immense opportunity for rare diseases, such as amyotrophic lateral sclerosis (ALS), which is defined by the loss of the upper and the lower motor neurons. Here, we describe generation, characterization, and utilization of a novel vector system, which enables expression of the active form of hepatocyte growth factor (HGF) under EF-1α promoter with bovine growth hormone (bGH) poly(A) sequence and is effective with intrathecal injections. HGF's role in promoting motor neuron survival had been vastly reported. Therefore, we investigated whether intrathecal delivery of HGF would have an impact on one of the most common pathologies of ALS: the TDP-43 pathology. Increased astrogliosis, microgliosis and progressive upper motor neuron loss are important consequences of ALS in the motor cortex with TDP-43 pathology. We find that cortex can be modulated via intrathecal injection, and that expression of HGF reduces astrogliosis, microgliosis in the motor cortex, and help restore ongoing UMN degeneration. Our findings not only introduce a novel viral vector for the treatment of ALS, but also demonstrate modulation of motor cortex by intrathecal viral delivery, and that HGF treatment is effective in reducing astrogliosis and microgliosis in the motor cortex of ALS with TDP-43 pathology.

Stem cell therapy combined with controlled release of growth factors for the treatment of sphincter dysfunction

Sphincter dysfunction often occurs at the end of tubule organs such as the urethra, anus, or gastroesophageal sphincters. It is the primary consequence of neuromuscular impairment caused by trauma, inflammation, and aging. Despite intensive efforts to recover sphincter function, pharmacological treatments have not achieved significant improvement. Cell- or growth factor-based therapy is a promising approach for neuromuscular regeneration and the recovery of sphincter function. However, a decrease in cell retention and viability, or the short half-life and rapid degradation of growth factors after implantation, remain obstacles to the translation of these therapies to the clinic. Natural biomaterials provide unique tools for controlled growth factor delivery, which leads to better outcomes for sphincter function recovery in vivo when stem cells and growth factors are co-administrated, in comparison to the delivery of single therapies. In this review, we discuss the role of stem cells combined with the controlled release of growth factors, the methods used for delivery, their potential therapeutic role in neuromuscular repair, and the outcomes of preclinical studies using combination therapy, with the hope of providing new therapeutic strategies to treat incontinence or sphincter dysfunction of the urethra, anus, or gastroesophageal tissues, respectively.

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.

Gabapentin inhibits the analgesic effects and nerve regeneration process induced by hepatocyte growth factor (HGF) in a peripheral nerve injury model: Implication for the use of VM202 and gabapentinoids for peripheral neuropathy

Hepatocyte growth factor (HGF) is a multifunctional protein that plays a critical role in the angiogenic, neurotrophic, antifibrotic, and antiapoptotic activities of various cell types. It has been previously reported that intramuscular injection of pCK-HGF-X7 (or VM202), a plasmid DNA designed to express both native isoforms of human HGF (Pyun et al., 2010), significantly reduced the level of neuropathic pain in clinical studies as well as in a variety of animal models. In clinical studies, it has been observed that pCK-HGF-X7 appeared to give much higher pain-relieving effects in subjects not taking pregabalin or gabapentin, α2δ1 calcium channel blockers frequently prescribed for reducing pain in patients with diabetic peripheral neuropathy. In this study, we tested the effects of gabapentin on HGF-mediated pain reduction and nerve regeneration in vivo. Consistent with the data from clinical studies, gabapentin administration inhibited the pain reduction and axon regeneration effects mediated by HGF expression from pCK-HGF-X7. In the context of nerve regenerative effects, treatment with gabapentin or EGTA, a Ca²⁺ chelator, inhibited HGF-mediated axon outgrowth of injured sciatic nerves in vivo. Taken together, i.m. injection of HGF-encoding plasmid DNA ameliorated pain symptoms and enhanced the regeneration of injured nerves, and these therapeutic effects of HGF were significantly hindered by gabapentin treatment, suggesting the possible involvement of Ca²⁺ in the pro-regenerative activities of native HGF derived from treatment with pCK-HGF-X7.

Designing electrospun fiber platforms for efficient delivery of genetic material and genome editing tools

Electrospun fibers are versatile biomaterial platforms with great potential to support regeneration. Electrospun fiber characteristics such as fiber diameter, degree of alignment, rate of degradation, and surface chemistry enable the creation of unique, tunable scaffolds for various drug or gene delivery applications. The delivery of genetic material and genome editing tools via viral and non-viral vectors are approaches to control cellular protein production. However, immunogenicity, off-target effects, and low delivery efficiencies slow the progression of gene delivery strategies to clinical settings. The delivery of genetic material from electrospun fibers overcomes such limitations by allowing for localized, tunable delivery of genetic material. However, the process of electrospinning is harsh, and care must be taken to retain genetic material bioactivity. This review presents an up-to-date summary of strategies to incorporate genetic material onto or within electrospun fiber platforms to improve delivery efficiency and enhance the regenerative potential of electrospun fibers for various tissue engineering applications.

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.

Platelet-rich plasma and cytokines in neuropathic pain: A narrative review and a clinical perspective

BACKGROUND AND OBJECTIVE

Neuropathic pain arises as a direct consequence of a lesion or disease affecting the somatosensory system. A number of preclinical studies have provided evidence for the involvement of cytokines, predominantly secreted by a variety of immune cells and by glial cells from the nervous system, in neuropathic pain conditions. Clinical trials and the use of anti-cytokine drugs in different neuropathic aetiologies support the relevance of cytokines as treatment targets. However, the use of such drugs, in particularly biotherapies, can provoke notable adverse effects. Moreover, it is challenging to select one given cytokine as a target, among the various neuropathic pain conditions. It could thus be of interest to target other proteins, such as growth factors, in order to act more widely on the neuroinflammation network. Thus, platelet-rich plasma (PRP), an autologous blood concentrate, is known to contain a natural concentration of growth factors and immune system messengers and is widely used in the clinical setting for tissue regeneration and repair.

DATABASE AND DATA TREATMENT

In the present review, we critically assess the current knowledge on cytokines in neuropathic pain by taking into consideration both human studies and animal models.

RESULTS

This analysis of the literature highlights the pathophysiological importance of cytokines. We particularly highlight the concept of time- and tissue-dependent cytokine activation during neuropathic pain conditions.

RESULTS

Conclusion: Thus, direct or indirect cytokines modulation with biotherapies or growth factors appears relevant. In addition, we discuss the therapeutic potential of localized injection of PRP as neuropathic pain treatment by pointing out the possible link between cytokines and the action of PRP.

SIGNIFICANCE

Preclinical and clinical studies highlight the idea of a cytokine imbalance in the development and maintenance of neuropathic pain. Clinical trials with anticytokine drugs are encouraging but are limited by a 'cytokine candidate approach' and adverse effect of biotherapies. PRP, containing various growth factors, is a new therapeutic used in regenerative medicine. Growth factors can be also considered as modulators of cytokine balance. Here, we emphasize a potential therapeutic effect of PRP on cytokine imbalance in neuropathic pain. We also underline the clinical interest of the use of PRP, not only for its therapeutic effect but also for its safety of use.

Combined Analysis of Clinical Data on HGF Gene Therapy to Treat Critical Limb Ischemia in Japan

OBJECTIVE

The objective of this combined analysis of data from clinical trials in Japan, using naked plasmid DNA encoding hepatocyte growth factor (HGF), was to document the safety and efficacy of intramuscular HGF gene therapy in patients with critical limb ischemia (CLI).

METHODS

HGF gene transfer was performed in 22 patients with CLI in a single-center open trial at Osaka University; 39 patients in a randomized, placebo-controlled, multi-center phase III trial, 10 patients with Buerger's disease in a multi-center open trial; and 6 patients with CLI in a multi-center open trial using 2 or 3 intramuscular injections of naked HGF plasmid at 2 or 4 mg. Resting pain on a visual analogue scale (VAS) and wound healing as primary endpoints were evaluated at 12 weeks after the initial injection. Serious adverse events caused by gene transfer were detected in 7 out of 77 patients (9.09%). Only one patient experienced peripheral edema (1.30%), in contrast to those who had undergone treatment with VEGF. At 12 weeks after gene transfer, combined evaluation of VAS and ischemic ulcer size demonstrated a significant improvement in HGF gene therapy group as compared to the placebo group (P=0.020).

RESULTS

The long-term analysis revealed a sustained decrease in the size of ischemic ulcer in HGF gene therapy group. In addition, VAS score over 50 mm at baseline (total 27 patients) demonstrated a tendency (P=0.059), but not significant enough, to improve VAS score in HGF gene therapy as compared to the placebo group.

CONCLUSION

The findings indicated that intramuscular injection of naked HGF plasmid tended to improve the resting pain and significantly decreased the size of the ischemic ulcer in the patients with CLI who did not have any alternative therapy, such as endovascular treatment (EVT) or bypass graft surgery. An HGF gene therapy product, CollategeneTM, was recently launched with conditional and time-limited approval in Japan to treat ischemic ulcer in patients with CLI. Further clinical trials would provide new therapeutic options for patients with CLI.

Diabetic polyneuropathy: Bridging the translational gap

Clinical trials for diabetic polyneuropathy (DPN) have failed to identify therapeutic impacts that have arrested or reversed the disorder, despite a long history. This review considers DPN in the context of a unique neurodegenerative disorder that targets peripheral neurons and their companion glial cells. The approach is to examine what cells, cell substructures, and pathways are implicated in causing DPN and how they might be addressed therapeutically. These include axonopathy, neuronopathy, hyperglycemia, polyol flux, advanced glycation endproduct (AGE)-receptor AGE signaling, growth factor disruption, abnormal insulin signaling, and abnormalities of other intrinsic neuron pathways. Mitochondrial dysfunction and lipid toxicity are largely delegated to the companion review in this issue by Stino and Feldman. Finally, the linkage between axon plasticity of cutaneous nerves, peripheral neuroregenerative pathways, and diabetes are discussed.

pUDK-HGF Gene Therapy to Relieve CLI Rest Pain and Ulcer: A Phase II, Double-Blind, Randomized Placebo-Controlled Trial

This phase II clinical trial investigated the efficacy and safety of intramuscular injection of plasmid pUDK-HGF, which encodes the human hepatocyte growth factor gene in patients with critical limb ischemia. Resting pain patients (n = 119) and patients with leg ulcers (n = 121) were enrolled as two cohorts and randomized to receive pUDK-HGF treatment on days 0, 14, and 28. In the resting pain cohort, the proportion of patients with complete pain relief on day 180 after receiving pUDK-HGF injection, as the primary outcome, was significantly higher than that of the placebo group on the same day (p = 0.0148). More responders with >50% pain reduction were also observed in the pUDK-HGF groups than in the placebo groups (p = 0.0168). In the ulcer cohort of patients, pUDK-HGF treatment tended to be superior to the placebo in the percentage of patients with both complete ulcer healing and >50% ulcer healing. No significant differences in the incidence of adverse events (AEs) or serious AEs were observed among the groups. The mid-dose pUDK-HGF (6 mg) was the most efficacious, and is therefore an appropriate dose for use in a phase III clinical trial. This study was approved by the China Food and Drug Administration (2013L00637), China Clinical Trial Registry URL: www.chinadrugtrials.org.cn. Unique Identifier: 20130378.

Diabetic neuropathy and neuropathic pain: a (con)fusion of pathogenic mechanisms?

Neuropathy is a common complication of long-term diabetes that impairs quality of life by producing pain, sensory loss and limb amputation. The presence of neuropathy in both insulin-deficient (type 1) and insulin resistant (type 2) diabetes along with the slowing of progression of neuropathy by improved glycemic control in type 1 diabetes has caused the majority of preclinical and clinical investigations to focus on hyperglycemia as the initiating pathogenic lesion. Studies in animal models of diabetes have identified multiple plausible mechanisms of glucotoxicity to the nervous system including post-translational modification of proteins by glucose and increased glucose metabolism by aldose reductase, glycolysis and other catabolic pathways. However, it is becoming increasingly apparent that factors not necessarily downstream of hyperglycemia can also contribute to the incidence, progression and severity of neuropathy and neuropathic pain. For example, peripheral nerve contains insulin receptors that transduce the neurotrophic and neurosupportive properties of insulin, independent of systemic glucose regulation, while the detection of neuropathy and neuropathic pain in patients with metabolic syndrome and failure of improved glycemic control to protect against neuropathy in cohorts of type 2 diabetic patients has placed a focus on the pathogenic role of dyslipidemia. This review provides an overview of current understanding of potential initiating lesions for diabetic neuropathy and the multiple downstream mechanisms identified in cell and animal models of diabetes that may contribute to the pathogenesis of diabetic neuropathy and neuropathic pain.

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.

The Potential Role of Hepatocyte Growth Factor in Degenerative Disorders of the Synovial Joint and Spine

This paper aims to provide a comprehensive review of the changing role of hepatocyte growth factor (HGF) signaling in the healthy and diseased synovial joint and spine. HGF is a multifunctional growth factor that, like its specific receptor c-Met, is widely expressed in several bone and joint tissues. HGF has profound effects on cell survival and proliferation, matrix metabolism, inflammatory response, and neurotrophic action. HGF plays an important role in normal bone and cartilage turnover. Changes in HGF/c-Met have also been linked to pathophysiological changes in degenerative joint diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IDD). A therapeutic role of HGF has been proposed in the regeneration of osteoarticular tissues. HGF also influences bone remodeling and peripheral nerve activity. Studies aimed at elucidating the changing role of HGF/c-Met signaling in OA and IDD at different pathophysiological stages, and their specific molecular mechanisms are needed. Such studies will contribute to safe and effective HGF/c-Met signaling-based treatments for OA and IDD.

Efficacy of nonviral gene transfer of human hepatocyte growth factor (HGF) against ischemic-reperfusion nerve injury in rats

Ischemic neuropathy is common in subjects with critical limb ischemia, frequently causing chronic neuropathic pain. However, neuropathic pain caused by ischemia is hard to control despite the restoration of an adequate blood flow. Here, we used a rat model of ischemic-reperfusion nerve injury (IRI) to investigate possible effects of hepatocyte growth factor (HGF) against ischemic neuropathy. Hemagglutinating virus of Japan (HVJ) liposomes containing plasmids encoded with HGF was delivered into the peripheral nervous system by retrograde axonal transport following its repeated injections into the tibialis anterior muscle in the right hindlimb. First HGF gene transfer was done immediately after IRI, and repeated at 1, 2 and 3 weeks later. Rats with IRI exhibited pronounced mechanical allodynia and thermal hyperalgesia, decreased blood flow and skin temperature, and lowered thresholds of plantar stimuli in the hind paw. These were all significantly improved by HGF gene transfer, as also were sciatic nerve conduction velocity and muscle action potential amplitudes. Histologically, HGF gene transfer resulted in a significant increase of endoneurial microvessels in sciatic and tibial nerves and promoted nerve regeneration which were confirmed by morphometric analysis. Neovascularization was observed in the contralateral side of peripheral nerves as well. In addition, IRI elevated mRNA levels of P2X3 and P2Y1 receptors, and transient receptor potential vanilloid receptor subtype 1 (TRPV1) in sciatic nerves, dorsal root ganglia and spinal cord, and these elevated levels were inhibited by HGF gene transfer. In conclusion, HGF gene transfer is a potent candidate for treatment of acute ischemic neuropathy caused by reperfusion injury, because of robust angiogenesis and enhanced nerve regeneration.

Multipotent Neurotrophic Effects of Hepatocyte Growth Factor in Spinal Cord Injury

Spinal cord injury (SCI) results in neural tissue loss and so far untreatable functional impairment. In addition, at the initial injury site, inflammation induces secondary damage, and glial scar formation occurs to limit inflammation-mediated tissue damage. Consequently, it obstructs neural regeneration. Many studies have been conducted in the field of SCI; however, no satisfactory treatment has been established to date. Hepatocyte growth factor (HGF) is one of the neurotrophic growth factors and has been listed as a candidate medicine for SCI treatment. The highlighted effects of HGF on neural regeneration are associated with its anti-inflammatory and anti-fibrotic activities. Moreover, HGF exerts positive effects on transplanted stem cell differentiation into neurons. This paper reviews the mechanisms underlying the therapeutic effects of HGF in SCI recovery, and introduces recent advances in the clinical applications of HGF therapy.

Intrathecal delivery of recombinant AAV1 encoding hepatocyte growth factor improves motor functions and protects neuromuscular system in the nerve crush and SOD1-G93A transgenic mouse models

Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disease resulting from motor neuron degeneration that causes muscle weakness, paralysis, and eventually respiratory failure. We investigated whether recombinant adeno-associated virus encoding human hepatocyte growth factor (rAAV-HGF) could generate beneficial effects in two mouse models with neuromuscular problems when intrathecally delivered to the subarachnoid space. We chose AAV serotype 1 (rAAV1) based on the expression levels and distribution of HGF protein in the lumbar spinal cord (LSC). After a single intrathecal (IT) injection of rAAV1-HGF, the protein level of HGF in the LSC peaked on day 14 and thereafter gradually decreased over the next 14 weeks. rAAV1-HGF was initially tested in the mouse nerve crush model. IT injection of rAAV1-HGF improved mouse hindlimb strength and rotarod performance, while histological analyses showed that the length of regenerated axons was increased and the structure of the neuromuscular junction (NMJ) was restored. rAAV1-HGF was also evaluated in the SOD1-G93A transgenic (TG) mouse model. Again, rAAV1-HGF not only improved motor performance but also increased the survival rate. Moreover, the number and diameter of spinal motor neurons (SMNs) were increased, and the shape of the NMJs restored. Data from in vitro motor cortical culture experiments indicated that treatment with recombinant HGF protein (rHGF) increased the axon length of corticospinal motor neurons (CSMNs). When cultures were treated with an ERK inhibitor, the effects of HGF on axon elongation, protein aggregation, and oxidative stress were suppressed, indicating that ERK phosphorylation played an important role(s). Taken together, our results suggested that HGF might play an important role(s) in delaying disease progression in the SOD1-G93A TG mouse model by reducing oxidative stress through the control of ERK phosphorylation.

Treatment of Critical Limb Ischemia by pIRES/VEGF165/HGF Administration

BACKGROUND

Prognosis of peripheral artery disease (PAD), especially critical limb ischemia (CLI), is very poor despite the development of endovascular therapy and bypass surgery. Many patients result in having leg amputation. We decided to investigate the safety and efficacy of plasmid of internal ribosome entry site/vascular endothelial growth factor (VEGF) 165/hepatocyte growth factor (HGF) gene therapy (GT) in patients suffered from CLI.

METHODS

Administration of plasmid of internal ribosome entry site/VEGF165/HGF was performed in 12 limbs of 12 patients with rest pain and ischemic ulcers due to CLI. Plasmid was injected into the muscles of the ischemic limbs. The levels of VEGF in serum and the ankle-brachial index (ABI) were measured before and after treatment.

RESULTS

Mean (±SD) plasma levels of VEGF increased nonsignificantly from 258 ± 81 pg/L to 489 ± 96 pg/L (P > 0.05) 2 weeks after therapy, and the ABI improved significantly from 0.27 ± 0.20 to 0.50 ± 0.22 (P < 0.001) 3 months after therapy. Ischemic ulcers healed in 9 limbs. Amputation was performed in 3 patients because of advanced necrosis and wound infection. However, the level of amputations was lowered below knee in these cases. Complications were limited to transient leg edema in 3 patients and fever in 2 patients.

CONCLUSIONS

Intramuscular administration of plasmid of internal ribosome entry site/VEGF165/HGF is safe, feasible, and effective for patients with critical leg ischemia.

Disproportionately high levels of HGF induce the degradation of the c-met receptor through the proteasomal degradation pathway

Hepatocyte growth factor (HGF) receptor is a member of the receptor tyrosine kinases (RTKs) and has been reported to perform diverse functions in various cell types during both the developmental and adult stages. Among different roles, HGF is best known for its angiogenic effects of inducing the migration of endothelial cells. Because angiogenesis is one of the prerequisite steps for tumor metastasis, HGF-dependent cell migration has to be tightly controlled. However, the underlying mechanisms regulating the optimum level of HGF/c-met signaling have been poorly understood. In this study, we tested whether the migration of endothelial cells is regulated by a negative feedback mechanism under disproportionately large amounts of HGF. Data from endothelial cell migration assays showed that HGF activity increased as its concentration increased, but declined beyond a certain point. Under limiting conditions, amounts of phosphorylated Erk and Akt surged, reaching a plateau in which the enhanced level was more or less maintained. The c-met receptor was degraded when unnecessarily large amounts of HGF were present. Under these conditions, HGF could no longer activate downstream signaling pathways even if cells were re-treated with optimal amounts of HGF. Excessive doses of HGF increased the phosphorylation of tyrosine residue 1003 involved in the ubiquitination of c-met, and phosphorylated c-met was diverted toward the proteasomal degradation pathway. Taken together, HGF/c-met signaling is tightly regulated by a negative feedback loop through an ubiquitin-proteasomal degradation pathway.

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.

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.

Wherefore Art Thou, O Treatment for Diabetic Neuropathy?

As of March 2016, we continue to advocate the diagnosis of diabetic neuropathy using a simple foot examination or monofilament, which identifies only those with severe neuropathy and hence risk of foot ulceration. Given the fact that the 5-year mortality rate of diabetic patients with foot ulceration is worse than that of most common cancers, surely we should be identifying patients at an earlier stage of neuropathy to prevent its progression to a stage with such a high mortality? Of course, we lament that there is no licensed treatment for diabetic neuropathy. Who is to blame? As researchers and carers, we have a duty of care to our patients with diabetic neuropathy. So, we have to look forward not backwards, and move away from our firmly entrenched views on the design and conduct of clinical trials for diabetic neuropathy. Relevant organizations such as Neurodiab, the American Diabetes Association and the Peripheral Nerve Society have to acknowledge that they cannot continue to endorse a bankrupt strategy. The FDA needs an open and self-critical dialogue with these organizations, to give pharmaceutical companies at least a fighting chance to deliver effective new therapies for diabetic neuropathy.

Exploratory study for identifying systemic biomarkers that correlate with pain response in patients with intervertebral disc disorders

Molecular events that drive disc damage and low back pain (LBP) may precede clinical manifestation of disease onset and can cause detrimental long-term effects such as disability. Biomarkers serve as objective molecular indicators of pathological processes. The goal of this study is to identify systemic biochemical factors as predictors of response to treatment of LBP with epidural steroid injection (ESI). Since inflammation plays a pivotal role in LBP, this pilot study investigates the effect of ESI on systemic levels of 48 inflammatory biochemical factors (cytokines, chemokines, and growth factors) and examines the relationship between biochemical factor levels and pain or disability in patients with disc herniation (DH), or other diagnoses (Other Dx) leading to low back pain, which included spinal stenosis (SS) and degenerative disc disease (DDD). Study participants (n = 16) were recruited from a back pain management practice. Pain numerical rating score (NRS), Oswestry Disability Index (ODI), and blood samples were collected pre- and at 7 to 10 days post-treatment. Blood samples were assayed for inflammatory mediators using commercial multiplex assays. Mediator levels were compared pre- and post-treatment to investigate the potential correlations between clinical and biochemical outcomes. Our results indicate that a single ESI significantly decreased systemic levels of SCGF-β and IL-2. Improvement in pain in all subjects was correlated with changes in chemokines (MCP-1, MIG), hematopoietic progenitor factors (SCGF-β), and factors that participate in angiogenesis/fibrosis (HGF), nociception (SCF, IFN-α2), and inflammation (IL-6, IL-10, IL-18, TRAIL). Levels of biochemical mediators varied based on diagnosis of LBP, and changes in pain responses and systemic mediators from pre- to post-treatment were dependent on the diagnosis cohort. In the DH cohort, levels of IL-17 and VEGF significantly decreased post-treatment. In the Other Dx cohort, levels of IL-2Rα, IL-3, and SCGF-β significantly decreased post-treatment. In order to determine whether mediator changes were related to pain, correlations between change in pain scores and change in mediator levels were performed. Subjects with DH demonstrated a profile signature that implicated hematopoiesis factors (SCGF-β, GM-CSF) in pain response, while subjects with Other Dx demonstrated a biomarker profile that implicated chemokines (MCP-1, MIG) and angiogenic factors (HGF, VEGF) in pain response. Our findings provide evidence that systemic biochemical factors in patients with LBP vary by diagnosis, and pain response to treatment is associated with a unique profile of biochemical responses in each diagnosis group. Future hypothesis-based studies with larger subject cohorts are warranted to confirm the findings of this pilot exploratory study.

Nanoparticle-enhanced generation of gene-transfected mesenchymal stem cells for in vivo cardiac repair

Transplantation of gene-transfected bone marrow-derived mesenchymal stem cells (BMMSCs) is a promising strategy for ischemic myocardium repair, but current therapeutic strategy suffers from high toxicity and inefficient gene transfection in primary BMMSCs. Here we designed and synthesized molecularly organic-inorganic hybrid hollow mesoporous organosilica nanoparticles (HMONs) based on nano-synthetic chemistry, which are featured with concurrent large pore size over 20 nm, small particulate size, hollow cavity and high dispersity for gene transfection in BMMSCs and subsequent in vivo cardiac repair. To efficiently create the therapeutic gene-transfected stem-cell lines, hepatocyte growth factor (HGF) gene was applied to transfect BMMSCs via biocompatible surface-engineered HMONs as a high-performance gene-delivery nanosystem. On the rat model of myocardial infarction, transplantation of HGF gene-transfected BMMSCs enables the largely decreased apoptotic cardiomyocytes, reduced infarct scar size, relieved interstitial fibrosis, and increased angiogenesis in myocardium. The resultant cardiac repair further promotes the significant improvement of heart function. Therefore, the fabricated organic-inorganic hybrid HMONs with large pore size represent a generalizable strategy and platform for gene transfection in BMMSCs and further regenerative medicine.

Measuring Therapy-Induced Peripheral Neuropathy: Preliminary Development and Validation of the Treatment-Induced Neuropathy Assessment Scale

Various sensory and motor effects are associated with cancer treatment-induced peripheral neuropathy. The current method for capturing the multifaceted nature of neuropathy includes a combination of objective tests, clinician evaluation, and subjective patient report, an approach that is often not logistically feasible, especially for multisite trials. We report the performance of a brief yet comprehensive, easily administered measure, the Treatment-Induced Neuropathy Assessment Scale (TNAS), for assessing the severity and course of neuropathy across various cancer treatments. Data were derived from 4 longitudinal or cross-sectional patient cohorts (N = 573). Patients with multiple myeloma treated primarily with bortezomib and patients with colorectal cancer receiving oxaliplatin evaluated candidate items. Cognitive debriefing showed that all items were easy to understand, and this preliminary TNAS demonstrated reliability, validity, and sensitivity. Numbness/tingling was the most severe item, regardless of therapeutic agent. Although numbness and general pain were moderately correlated, patients perceived them as distinct. Most TNAS items were more severe at follow-up, demonstrating the sensitivity of the instrument to accumulating dose. The TNAS will be refined with further patient input, with final psychometric evaluation conducted in a new patient sample receiving treatments known to be associated with peripheral neuropathy. The nonpainful component of neuropathy may be more disabling than the pain component.

PERSPECTIVE

Our data suggest that the nonpainful components of neuropathy may be more disabling than the pain component during cancer treatment. Here we report data on sensory and motor symptoms reported by patients receiving neurotoxic cancer therapy, and we detail the development of a neuropathy assessment scale that follows regulatory guidance for patient-reported outcomes.

Clinical Safety and Preliminary Efficacy of Plasmid pUDK-HGF Expressing Human Hepatocyte Growth Factor (HGF) in Patients with Critical Limb Ischemia

OBJECTIVE

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease and a major unmet public health care need. This phase I clinical study was performed to assess the safety and preliminary efficacy of naked plasmid DNA (pUDK-HGF) expressing human hepatocyte growth factor (HGF) in patients with critical limb ischemia (CLI).

DESIGN

Twenty-one patients with CLI were enrolled and randomly divided into four dose groups (4-16 mg) to receive local injection of pUDK-HGF into ischemic calf and/or thigh muscles twice on days 1 and 15. Safety, including adverse events and physiological parameters, and preliminary efficacy, including pain severity score (VAS), ulcer size, transcutaneous oxygen pressure (TcPO2), and ankle brachial index (ABI), were evaluated throughout a 3 month follow up period.

RESULTS

All doses of pUDK-HGF were well tolerated by the patients. None of the adverse effects was considered to be related to pUDK-HGF injection. Two significant clinical results were observed after pUDK-HGF administration. The mean VAS value of all patients decreased from 4.52 at baseline to 0.30 (p < .01), and pain had disappeared in 14 out of 17 evaluable patients by day 91. Two of four ulcers had completely healed, with the other two patients having more than 25% ulcer size reduction in the long axis diameter. Of five patients with gangrene, one gangrenous wound had healed completely and two patients showed marked size reduction by day 91. The mean hemodynamic parameters (ABI, TcPO2) were also improved.

CONCLUSION

Intramuscular injection of pUDK-HGF is safe, and may provide symptomatic relief for CLI patients. A larger, randomized, double blinded phase II trial will provide more information on safety and efficacy.

Bone Marrow-Derived Mesenchymal Stem Cells Improve Diabetic Neuropathy by Direct Modulation of Both Angiogenesis and Myelination in Peripheral Nerves

Recent evidence has suggested that diabetic neuropathy (DN) is pathophysiologically related to both impaired angiogenesis and a deficiency of neurotrophic factors in the nerves. It is widely known that vascular and neural growths are intimately associated. Mesenchymal stem cells (MSCs) promote angiogenesis in ischemic diseases and have neuroprotective effects, particularly on Schwann cells. Accordingly, we investigated whether DN could be improved by local transplantation of MSCs by augmenting angiogenesis and neural regeneration such as remyelination. In sciatic nerves of streptozotocin (STZ)-induced diabetic rats, motor and sensory nerve conduction velocities (NCVs) and capillary density were reduced, and axonal atrophy and demyelination were observed. After injection of bone marrow-derived MSCs (BM-MSCs) into hindlimb muscles, NCVs were restored to near-normal levels. Histological examination demonstrated that injected MSCs were preferentially and durably engrafted in the sciatic nerves, and a portion of the engrafted MSCs were distinctively localized close to vasa nervora of sciatic nerves. Furthermore, vasa nervora increased in density, and the ultrastructure of myelinated fibers in nerves was observed to be restored. Real-time RT-PCR experiments showed that gene expression of multiple factors involved in angiogenesis, neural function, and myelination were increased in the MSC-injected nerves. These findings suggest that MSC transplantation improved DN through direct peripheral nerve angiogenesis, neurotrophic effects, and restoration of myelination.

Double-blind, placebo-controlled study of HGF gene therapy in diabetic neuropathy

OBJECTIVE

To evaluate the safety and efficacy of a plasmid (VM202) containing two human hepatocyte growth factor isoforms given by intramuscular injections in patients with painful diabetic neuropathy.

METHODS

In a double-blind, placebo-controlled study, patients were randomized to receive injections of 8 or 16 mg VM202 per leg or placebo. Divided doses were administered on Day 0 and Day 14. The prospective primary outcome was change in the mean pain score measured by a 7 day pain diary. Secondary outcomes included a responder analysis, quality of life and pain measures, and intraepidermal nerve fiber density.

RESULTS

There were no significant adverse events attributable to VM202. Eighty-four patients completed the study. Patients receiving 8 mg VM202 per leg improved the most in all efficacy measures including a significant (P = 0.03) reduction at 3 months in the mean pain score and continued but not statistically significant reductions in pain at 6 and 9 months. Of these patients, 48.4% experienced a ≥50% reduction in pain compared to 17.6% of placebo patients. There were also significant improvements in the brief pain inventory for patients with diabetic peripheral neuropathy and the questionnaire portion of the Michigan Neuropathy Screening Instrument. Patients not on pregabalin or gabapentin had the largest reductions in pain.

INTERPRETATION

VM202 was safe, well tolerated and effective indicating the feasibility of a nonviral gene therapy approach to painful diabetic neuropathy. Two days of treatment were sufficient to provide symptomatic relief with improvement in quality of life for 3 months. VM202 may be particularly beneficial for patients not taking gabapentin or pregabalin.

Hepatocyte Growth Factor Isoforms in Tissue Repair, Cancer, and Fibrotic Remodeling

Hepatocyte growth factor (HGF), also known as scatter factor (SF), is a pleotropic factor required for normal organ development during embryogenesis. In the adult, basal expression of HGF maintains tissue homeostasis and is up-regulated in response to tissue injury. HGF expression is necessary for the proliferation, migration, and survival of epithelial and endothelial cells involved in tissue repair in a variety of organs, including heart, lung, kidney, liver, brain, and skin. The administration of full length HGF, either as a protein or using exogenous expression methodologies, increases tissue repair in animal models of tissue injury and increases angiogenesis. Full length HGF is comprised of an N-terminal hairpin turn, four kringle domains, and a serine protease-like domain. Several naturally occurring alternatively spliced isoforms of HGF were also identified. The NK1 variant contains the N-terminal hairpin and the first kringle domain, and the NK2 variant extends through the second kringle domain. These alternatively spliced forms of HGF activate the same receptor, MET, but they differ from the full length protein in their cellular activities and their biological functions. Here, we review the species-specific expression of the HGF isoforms, their regulation, the signal transduction pathways they activate, and their biological activities.

Gene therapy for peripheral arterial disease

INTRODUCTION

Gene therapy has emerged as a novel therapy to promote angiogenesis in patients with critical limb ischemia (CLI) caused by peripheral artery disease. Researchers working in this area have focused on pro-angiogenic factors, such as VEGF, fibroblast growth factor (FGF) and hepatocyte growth factor (HGF). Based on the elaborate studies and favorable results of basic research using naked plasmid DNA (pDNA) encoding these growth factors, some clinical Phase I and Phase II trials have been performed. The results of these studies demonstrate the safety of these approaches and their potential for symptomatic improvement in CLI patients. However, the Phase III clinical trials have so far been limited to HGF gene therapy. Because one pitfall of the Phase III trials has been the limited transgene expression achieved using naked pDNA alone, the development of more efficient gene transfer systems, such as ultrasound microbubbles and the needleless injector, as well as the addition of other genes will make these novel therapies more effective and ease the symptoms of CLI.

AREAS COVERED

This study reviews the previously published basic research and clinical trials that have studied VEGF, FGF and HGF gene therapies for the treatment of CLI. Adjunctive therapies, such as the addition of prostacyclin synthase genes and the development of more efficient gene transfer techniques for pDNA, are also reviewed.

EXPERT OPINION

To date, clinical studies have demonstrated the safety of gene therapy in limb ischemia but the effectiveness of this treatment has not been determined. Larger clinical studies, as well as the development of more effective gene therapy, are needed to achieve and confirm beneficial effects.

Diabetic neuropathy

Diabetic neuropathy (DN) is the most common and troublesome complication of diabetes mellitus, leading to the greatest morbidity and mortality and resulting in a huge economic burden for diabetes care. The clinical assessment of diabetic peripheral neuropathy and its treatment options are multifactorial. Patients with DN should be screened for autonomic neuropathy, as there is a high degree of coexistence of the two complications. A review of the clinical assessment and treatment algorithms for diabetic neuropathy, painful neuropathy, and autonomic dysfunction is provided.

Patent Highlights

Snapshot of key developments in the patent literature accompanied by explanatory synopses

New and developing drugs for the treatment of neuropathic pain in diabetes

A number of agents from diverse pharmacological classes are used to treat neuropathic pain associated with diabetic peripheral neuropathy. Only three of these have regulatory approval for this indication in the U.S. In this focused article, I will discuss selected drugs, newly approved or in development, to treat neuropathic pain in patients with diabetic neuropathy. These will include agonists and antagonists of the transient receptor potential channels, a family of receptor proteins that play a role in the transduction of physical stress; sodium channel isoform specific antagonists; a recently approved dual-action opioid receptor agonist-norepinephrine reuptake inhibitor; gene therapy for neuropathic pain; and anti-nerve growth factor molecules. Mechanisms of action, preclinical supporting data, clinical trial evidence, and adverse effects will be reviewed.