Gene therapy for pancreatitis pain

Therapeutic potential of gene therapy for gastrointestinal diseases: Advancements and future perspectives

Advancements in understanding the pathogenesis mechanisms underlying gastrointestinal diseases, encompassing inflammatory bowel disease, gastrointestinal cancer, and gastroesophageal reflux disease, have led to the identification of numerous novel therapeutic targets. These discoveries have opened up exciting possibilities for developing gene therapy strategies to treat gastrointestinal diseases. These strategies include gene replacement, gene enhancement, gene overexpression, gene function blocking, and transgenic somatic cell transplantation. In this review, we introduce the important gene therapy targets and targeted delivery systems within the field of gastroenterology. Furthermore, we provide a comprehensive overview of recent progress in gene therapy related to gastrointestinal disorders and shed light on the application of innovative gene-editing technologies in treating these conditions. These developments are fueling a revolution in the management of gastrointestinal diseases. Ultimately, we discuss the current challenges (particularly regarding safety, oral efficacy, and cost) and explore potential future directions for implementing gene therapy in the clinical settings for gastrointestinal diseases.

Application of nanotechnology in the diagnosis and treatment of acute pancreatitis

Acute pancreatitis (AP) is a common digestive system disease. The severity of AP ranges from mild edema in the pancreas to severe systemic inflammatory responses leading to peripancreatic/pancreatic necrosis, multi-organ failure and death. Improving the sensitivity of AP diagnosis and developing alternatives to traditional methods to treat AP have gained the attention of researchers. With the continuous rise of nanotechnology, it is being widely used in daily life, biomedicine, chemical energy and many other fields. Studies have demonstrated the effectiveness of nanotechnology in the diagnosis and treatment of AP. Nanotechnology has the advantages of simplicity, rapidity and sensitivity in detecting biomarkers of AP, as well as enhancing imaging, which helps in the early diagnosis of AP. On the other hand, nanoparticles (NPs) have oxidative stress inhibiting and anti-inflammatory effects, and can also be loaded with drugs as well as being used in anti-infection therapy, providing a new approach for the treatment of AP. In this article, we elaborate and summarize on the potential of nanoparticles for diagnostic and therapeutic applications in AP from the current reported literature and experimental results to provide useful guidelines for further research on the application of nanotechnology.

Efficacy and Safety of Pancreas-Targeted Hydrodynamic Gene Delivery in Rats

Development of an effective, safe, and convenient method for gene delivery to the pancreas is a critical step toward gene therapy for pancreatic diseases. Therefore, we tested the possibility of applying the principle of hydrodynamic gene delivery for successful gene transfer to pancreas using rats as a model. The established procedure involves the insertion of a catheter into the superior mesenteric vein with temporary blood flow occlusion at the portal vein and hydrodynamic injection of DNA solution. We demonstrated that our procedure achieved efficient pancreas-specific gene expression that was 2,000-fold higher than that seen in the pancreas after the systemic hydrodynamic gene delivery. In addition, the level of gene expression achieved in the pancreas by the pancreas-specific gene delivery was comparable to the level in the liver achieved by a liver-specific hydrodynamic gene delivery. The optimal level of reporter gene expression in the pancreas requires an injection volume equivalent to 2.0% body weight with flow rate of 1 mL/s and plasmid DNA concentration at 5 μg/mL. With the exception of transient expansion of intercellular spaces and elevation of serum amylase levels, which recovered within 3 days, no permanent tissue damage was observed. These results suggest that pancreas-targeted hydrodynamic gene delivery is an effective and safe method for gene delivery to the pancreas and clinically applicable.

MnSOD mediated by HSV vectors in the periaqueductal gray suppresses morphine withdrawal in rats

Morphine appears to be the most active metabolite of heroin; therefore, the effects of morphine are important in understanding the ramifications of heroin abuse. Opioid physical dependence (withdrawal response) may have very long-lasting effects on the motivation for reward, including the incubation of cue-induced drug-seeking behavior. However, the exact mechanisms of morphine withdrawal (MW) are not clear yet, and its treatment remains elusive. Periaqueductal gray (PAG) is one of the important sites in the pathogenesis of MW. Here, we used recombinant herpes simplex virus (HSV) vectors that encode the sod2 gene expressing manganese superoxide dismutase (MnSOD) to evaluate its therapeutic potential in MW. Microinjection of HSV vectors expressing MnSOD into the PAG reduced the MW syndrome. MnSOD vectors suppressed the upregulated mitochondrial superoxide, and endoplasmic reticulum stress markers (glucose-related protein 78 (GRP78) and activating transcription factor 6 alpha (ATF6α)) in the PAG induced by MW. Immunostaining showed that mitochondrial superoxide, GRP78 and ATF6α were colocalized with neuronal nuclei (a neuronal-specific marker), suggesting that they are located in the neurons in the PAG. These results suggest that overexpression of MnSOD by HSV vectors may relieve opioid dependence. This study may provide a novel therapeutic approach to morphine physical withdrawal response.

Neurobiological studies of chronic pain and analgesia: Rationale and refinements

Chronic pain is a complex condition for which the need for specialized research and therapies has been recognized internationally. This review summarizes the context for the international call for expansion of pain research to improve our understanding of the mechanisms underlying pain in order to achieve improvements in pain management. The methods for conducting sensory assessment in animal models are discussed and the development of animal models of chronic pain is specifically reviewed, with an emphasis on ongoing refinements to more closely mimic a variety of human pain conditions. Pharmacological correspondences between pre-clinical pain models and the human clinical experience are noted. A discussion of the 3Rs Framework (Replacement, Reduction, Refinement) and how each may be considered in pain research is featured. Finally, suggestions are provided for engaging principal investigators, IACUC reviewers, and institutions in the development of strong partnerships to simultaneously expand our knowledge of the mechanisms underlying pain and analgesia while ensuring the humane use of animals in research.

Pharmacological management of pain in chronic pancreatitis

Introduction:

Chronic pancreatitis is a condition that is rising in incidence in the Western World. It is predominated by severe intractable abdominal pain that presents a significant impact on patients’ quality of life and physical functioning. The pain is persistent in many patients, requiring admission to hospital for the majority at some stage in their illness. There is no current NICE or SIGN guideline with associated grading for the pharmacological management of this symptom. This paper aims to investigate and summarise the current pharmacological therapies for pain control in an attempt to formulate the levels of evidence supporting their use.

Methods:

The online digital archives PubMed, Science Direct, Medscape and the Cochrane Library were searched for the keywords pain and chronic pancreatitis. Hand searches of relevant journals and citations were used to complete the investigation of current literature on the topic. Relevant articles and studies were critically analysed in a standard format with relation to study type, population, number, end point and outcomes. Publications not relevant to the management of pain in chronic pancreatitis were excluded.

Results:

Medical therapies, including oral analgesics and enzyme preparations, were included in the analysis of current modalities for treating pain in chronic pancreatitis.

Conclusions:

A summary of the evidence base for different pharmacological treatments in the context of chronic pancreatitis has shown that large number trials evaluating their efficacy in managing pain are lacking and offer scope for future research on this topic. The use of ‘alternative’ treatments such as antioxidant preparations and enzyme antagonists has shown promise. With regard to opioids, tramadol is as effective as morphine with less neuropsychiatric and gastrointestinal side effects. Oxycodone may derive more benefit than morphine due to an additional Κ-agonist effect.

Chronic pancreatitis: an update for home care and hospice clinicians

Chronic pancreatitis is a relentlessly painful condition associated most commonly with alcoholism. Patients suffer wasting and depression as a result of chronic pain. It is important for home care clinicians to recognize the signs of pancreatitis and understand the current evidence-based treatment strategies to control the symptoms. Although alcoholism and depression are frequent comorbidities of pancreatitis, a full discussion of alcoholism and depression is outside the scope of this article.

Pain management in pancreatic cancer

A majority of pancreatic cancer patients present with pain at the time of diagnosis. Pain management can be challenging in light of the aggressive nature of this cancer. Apart from conventional pharmacotherapy, timely treatment with neurolytic celiac plexus block (NCPB) has been shown to be of benefit. NCPB has demonstrated efficacious pain control in high quality studies with analgesic effects lasting one to two months. NCPB has also shown to decrease the requirements of narcotics, and thus decrease opioid related side effects. Another option for the control of moderate to severe pain is intrathecal therapy (IT). Delivery of analgesic medications intrathecally allows for lower dosages of medications and thus reduced toxicity. Both of the above mentioned interventional procedures have been shown to have low complication rates, and be safe and effective. Ultimately, comprehensive pancreatic cancer pain management necessitates understanding of pain mechanisms and delivery of sequential validated therapeutic interventions within a multidisciplinary patient care model.

Lack of adrenomedullin in the central nervous system results in apparently paradoxical alterations on pain sensitivity

Adrenomedullin (AM) is a regulatory peptide, coded by the adm gene, which is involved in numerous physiological processes, including pain sensitivity. Previous studies have shown that intrathecal injection of AM induced hyperalgesia in the rat. Here, we explore pain sensitivity in a mouse conditional knockout for adm in neurons of the central nervous system, including the spinal cord and dorsal root ganglia. Double immunofluorescence in wild-type (WT) animals shows that AM immunoreactivity is found in calcitonin gene-related peptide-positive neurons of the dorsal root ganglia but not in neurons that bind isolectin B4. Mice lacking adm had modified expression of canonical sensorial neuropeptides, having significantly more calcitonin gene-related peptide and less substance P and enkephalin than their WT littermates. Furthermore, the spinal cord of adm knockout mice expressed higher levels of the AM receptor components, suggesting a compensation attempt to deal with the lack of afferent AM signaling. Behavioral nociceptive tests also found differences between genotypes. In the tail-flick test, which measures mostly spinal reflexes, the adm-null animals had a longer latency than their WT counterparts. On the other hand, in the hotplate test, which requires encephalic processing, mice lacking adm had shorter latencies than normal littermates. These results suggest that AM acts as a nociceptive modulator in spinal reflexes, whereas it may have an analgesic function at higher cognitive levels. This study confirms the important role of AM in pain sensitivity processing but unveils a more complex scenario than previously surmised.

HSV Recombinant Vectors for Gene Therapy

The very deep knowledge acquired on the genetics and molecular biology of herpes simplex virus (HSV), has allowed the development of potential replication-competent and replication-defective vectors for several applications in human healthcare. These include delivery and expression of human genes to cells of the nervous systems, selective destruction of cancer cells, prophylaxis against infection with HSV or other infectious diseases, and targeted infection to specific tissues or organs. Replication-defective recombinant vectors are non-toxic gene transfer tools that preserve most of the neurotropic features of wild type HSV-1, particularly the ability to express genes after having established latent infections, and are thus proficient candidates for therapeutic gene transfer settings in neurons. A replication-defective HSV vector for the treatment of pain has recently entered in phase 1 clinical trial. Replication-competent (oncolytic) vectors are becoming a suitable and powerful tool to eradicate brain tumours due to their ability to replicate and spread only within the tumour mass, and have reached phase II/III clinical trials in some cases. The progress in understanding the host immune response induced by the vector is also improving the use of HSV as a vaccine vector against both HSV infection and other pathogens. This review briefly summarizes the obstacle encountered in the delivery of HSV vectors and examines the various strategies developed or proposed to overcome such challenges.

HSV Recombinant Vectors for Gene Therapy

The very deep knowledge acquired on the genetics and molecular biology of herpes simplex virus (HSV), has allowed the development of potential replication-competent and replication-defective vectors for several applications in human healthcare. These include delivery and expression of human genes to cells of the nervous systems, selective destruction of cancer cells, prophylaxis against infection with HSV or other infectious diseases, and targeted infection to specific tissues or organs. Replication-defective recombinant vectors are non-toxic gene transfer tools that preserve most of the neurotropic features of wild type HSV-1, particularly the ability to express genes after having established latent infections, and are thus proficient candidates for therapeutic gene transfer settings in neurons. A replication-defective HSV vector for the treatment of pain has recently entered in phase 1 clinical trial. Replication-competent (oncolytic) vectors are becoming a suitable and powerful tool to eradicate brain tumours due to their ability to replicate and spread only within the tumour mass, and have reached phase II/III clinical trials in some cases. The progress in understanding the host immune response induced by the vector is also improving the use of HSV as a vaccine vector against both HSV infection and other pathogens. This review briefly summarizes the obstacle encountered in the delivery of HSV vectors and examines the various strategies developed or proposed to overcome such challenges.