Neuropathic Pain and Sickle Cell Disease: a Review of Pharmacologic Management

Activation of GPR55 alleviates neuropathic pain and chronic inflammation

Neuropathic pain (NP) significantly impacts the quality of life due to its prolonged duration and lack of effective treatment. Recent findings suggest that targeting neuroinflammation is a promising approach for treating NP. G protein-coupled receptor 55 (GPR55), a member of the GPCR family, plays an important role in neuroinflammatory regulation. CID16020046, a GPR55 agonist, possesses promising anti-neuroinflammatory effects. Herein, the therapeutic effect of CID16020046 on NP was investigated in an NP rat model. The NP model was established using the unilateral sciatic nerve chronic constriction injury (CCI) assay. Both sham and CCI rats were intraperitoneally administered with 20 mg/kg CID16020046. NP was assessed using paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). First, we showed that GPR55 was downregulated in the spinal dorsal horn of CCI rats. After CCI rats were treated with CID16020046, the values of PWT and PWL were increased, indicating their effect on pain relief. The treated rats had attenuated release of inflammatory cytokines in the spinal cord, decreased spinal malondialdehyde (MDA) levels, and increased spinal glutathione peroxidase (GSH-PX) activity. Additionally, the increased levels of phosphorylated nuclear factor (NF)-κB p65 in CCI rats were significantly alleviated by CID16020046 treatment. Mechanistically, we showed that CID16020046 significantly suppressed the activation of the Janus kinase (JAK2)/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway in the spinal cord of CCI-treated rats. However, Colivelin TFA (a STAT3 agonist) abolished the effect of CID16020046 on JAK2/STAT3 activation. In conclusion, our data demonstrate that the activation of GPR55 by CID16020046 alleviates NP and neuroinflammation in CCI rats by mediating the JAK2/STAT3 pathway.

Safety and efficacy of ketorolac continuous infusion for multimodal analgesia of vaso-occlusive crisis in patients with sickle cell disease

Pain is an hallmark of sickle-cell-related acute clinical manifestations as part of acute vaso-occlusive crisis (VOC). In SCD pain has different origins such as vascular or neuropathic pain, which requires multimodal analgesia. This is based on the administration of drugs with different pharmacological mechanisms of action, maximizing analgesia and minimizing their adverse events and the risk of drug-addition in patients experiencing acute-recurrent pain events as in SCD. Ketorolac is a potent non-narcotic analgesic, being relatively safe and effective during pain-management in children and adults. Up to now, there is a lack of safety information on continuous infusion ketorolac as used to control acute pain in patients with SCD, and the benefits/risks ratio needs to be investigated. Here, we report for the first time the safety profile of ketorolac in the special population of patients with SCD. We confirmed that ketorolac in combination with tramadol, an opioid like molecule, is effective in pain control of adult patients with SCD experiencing acute severe VOCs defined by pain visual analog scale. Our study shows that short term (72 h) continuous infusion of ketorolac plus tramadol is not associated with adverse events such as liver or kidney acute disfunction or abnormalities in coagulation parameters during patients' hospitalization and within 30 days after patients discharge. This is extremely important for patients with SCD, who should have access to multimodal therapy to control recurrent acute pain crisis in order to limit central sensitization a fearsome issue of undertreated recurrent acute pain and of chronic pain.

Mitochondrial dysfunction and disulfidptosis co-regulate neuronal cell in neuropathic pain based on bioinformatics analysis

Neuropathic pain (NP) affects approximately 6.9-10% of the world's population and necessitates the development of novel treatments. Mitochondria are essential in the regulation of cell death. Neuroimmune mechanisms are implicated in various forms of cell death associated with NP. However, the specific involvement of mitochondrial dysfunction and disulfidptosis in NP remains uncertain. Further research is required to gain a better understanding of their combined contribution. Our comprehensive study employs a variety of bioinformatic analysis methods, including differential gene analysis, weighted gene co-expression network analysis, machine learning, functional enrichment analysis, immune infiltration, sub-cluster analysis, single-cell dimensionality reduction and cell-cell communication to gain insight into the molecular mechanisms behind these processes. Our study rationally defines a list of key gene sets for mitochondrial dysfunction and disulfidptosis. 6 hub mitochondrial genes and 3 disulfidptosis-related genes (DRGs) were found to be associated with NP. The key genes were predominantly expressed in neurons and were lowly expressed in the NP group compared to SHAM. In addition, our macrophages used the APP (Amyloid precursor protein)-CD74 (MHC class II invariant chain) pathway to interact with neurons. These results suggest that NP is interconnected with the mechanistic processes of mitochondrial dysfunction and disulfidptosis, which may contribute to clinically targeted therapies.

Pharmacogenetics of pain management in Zimbabwean patients with sickle cell disease

Background: Pain is a common cause of hospitalization in sickle cell disease (SCD) patients. Failure to effectively control pain remains a challenge in patient care. Materials & methods: The authors conducted a cross-sectional study to determine the effect of CYP2D6 and UGT2B7 polymorphisms on pain management in 106 Zimbabwean SCD patients. Participant information was collected on a questionnaire. Genotyping was conducted using the GenoPharm® pharmacogenomics open array panel containing CYP2D6 and UGT genetic variants implicated in opioid response. Results: The reduced function alleles CYP2D6*17 and *29 had high frequencies of 15.9% and 12.9%, respectively. UGT2B7 rs73823859 showed a statistically significant correlation with pain levels (p = 0.0454). Conclusion: This study demonstrated the role of UGT2B7 polymorphism in SCD patient pain management.

Identification of pyroptosis‑related genes in neuropathic pain based on bioinformatics analysis

Pyroptosis is defined as inflammation-induced programmed cell death. However, gene expression levels related to pyroptosis and their role in neuropathic pain (NP) remain unclear. The present study aimed to develop and validate an NP-predictive signature based on the genes associated with pyroptosis. Gene expression level profiles were downloaded from the Gene Expression Omnibus database. Weighted gene co-expression network analysis was used to identify the pyroptotic genes most highly associated with NP. NP-related pyroptosis gene signature was constructed using multivariate logistic regression. A rat model of neuropathic pain was established through chronic constriction injury to analyse the inflammatory infiltration and myelin damage around the sciatic nerve, and examine the expression levels of macrophage markers S100 calcium-binding protein β (S100β) and ionized calcium-binding adapter molecule 1 (Iba-1). Finally, flow cytometry analysis was used to examine the lipopolysaccharide (LPS)-induced cell death ratio of RSC96 cells (Schwann cells), while the expression levels of LPS-induced pyroptosis-related genes in RSC96 cells were measured via reverse transcription-quantitative PCR. The results demonstrated that pyroptosis-related genes (gasdermin D, NLR family pyrin domain containing 3, neuronal apoptosis inhibitory protein and NLR family CARD domain containing 4) were identified to increase the risk of NP. NP-related pyroptosis signatures were constructed based on these four genes. Moreover, the high-risk group had a higher level of macrophage infiltration compared with the low-risk group, as determined by the CIBERSORT algorithm. H&E staining results showed that the myelin structure of the sciatic nerve tissue of chronic constriction injury (CCI) rats was destroyed and inflammatory cells infiltrated around neurons. The results of immunohistochemistry showed that compared with in the sham group, the expression levels of Iba-1 and sS100β in the sciatic nerve of the CCI group were increased. Furthermore, the expression levels of cell death and pyroptosis-related genes in Schwann cells induced by LPS were increased compared with in the control group. In conclusion, an NP-related pyroptosis gene signature was constructed based on four pyroptosis-related genes and it was found that the expression of pyroptosis-related genes was upregulated in the early steps of the neuroinflammatory process in RSC96 cells.

Prevalence of neuropathic pain in adolescents with sickle cell disease: A single-center experience

BACKGROUND

Neuropathic pain (NP) has been previously explored in adolescents with sickle cell disease (SCD). This study aims to describe the prevalence of NP in adolescents with SCD at a single institution and to explore associated risk factors.

PROCEDURE

We used the painDETECT questionnaire, one of the few pain phenotyping questionnaires validated for adolescents. We also evaluated the relationships between painDETECT scores and frequency of acute care visits and admissions for pain in the previous 12 months, and age, respectively. Patients 12-18 years old were surveyed from June to July 2019. A retrospective approach was used to answer the remaining research questions.

RESULTS

Eighty-one and seven surveys were completed in the outpatient and inpatient settings, respectively. PainDETECT scores suggestive of NP were more prevalent in inpatient surveys than in outpatient surveys. The difference between the mean painDETECT scores of each group was significant when using a general linear mixed model. Most inpatients surveyed had ≥3 pain events in the previous 12 months. Further, older age and increased number of pain events in the previous 12 months were independently associated with higher painDETECT scores.

CONCLUSIONS

Overall, in our opinion, NP is not being evaluated for and treated sufficiently in pediatric SCD, especially in the setting of inpatient acute vaso-occlusive crisis. Age and number of acute pain events/admissions in the previous 12 months can be used to identify patients likely to be at risk for NP. It is important to continue to identify NP and develop NP-targeting treatment plans.

Glycosides for Peripheral Neuropathic Pain: A Potential Medicinal Components

Neuropathic pain is a refractory disease that occurs across the world and pharmacotherapy has limited efficacy and/or safety. This disease imposes a significant burden on both the somatic and mental health of patients; indeed, some patients have referred to neuropathic pain as being 'worse than death'. The pharmacological agents that are used to treat neuropathic pain at present can produce mild effects in certain patients, and induce many adverse reactions, such as sedation, dizziness, vomiting, and peripheral oedema. Therefore, there is an urgent need to discover novel drugs that are safer and more effective. Natural compounds from medical plants have become potential sources of analgesics, and evidence has shown that glycosides alleviated neuropathic pain via regulating oxidative stress, transcriptional regulation, ion channels, membrane receptors and so on. In this review, we summarize the epidemiology of neuropathic pain and the existing therapeutic drugs used for disease prevention and treatment. We also demonstrate how glycosides exhibit an antinociceptive effect on neuropathic pain in laboratory research and describe the antinociceptive mechanisms involved to facilitate the discovery of new drugs to improve the quality of life of patients experiencing neuropathic pain.

ADAR3 alleviated inflammation and pyroptosis of neuropathic pain by targeting NLRP3 in chronic constriction injury mice

BACKGROUND

Adenosine deaminase acting on RNA 3 (ADAR3) was known as a prognosis factor in gliomas, while its function on neuropathic pain (NP) is barely investigated. Therefore, our present study concentrated on the potential role of ADAR3 in NP.

METHODS

The chronic constriction injury (CCI) mouse model was established to induce NP in vivo. Behavioral experiments were carried out to analyze mechanical allodynia and thermal hyperalgesia. RT-qPCR and western blotting assays were used to detect the mRNA and protein expressions. The ADAR3-overexpressed adenovirus was injected into the CCI mice through an intrathecal catheter. ELISA was used to detect the contents of IL (interleukin)-6, IL-10, TNF (tumor necrosis factor)-α, IL-1β and IL-18. NLR Family Pyrin Domain Containing 3 (NLRP3) was predicted to be the target gene of ADAR3 using Starbase. The interaction between ADAR3 and NLRP3 was verified via RNA pull-down, RNA immunoprecipitation and Pearson's correlation coefficient assays. Immunohistochemical staining assay visualized the expressions of NLRP3 and caspase1.

RESULTS

Allodynia and hyperalgesia were exacerbated in the CCI mice, which implied a successful establishment of the NP model, while ADAR3 expression level was suppressed. After injecting ADAR3-overexpressed adenovirus into the CCI mice, allodynia, hyperalgesia and inflammation were all restrained. Moreover, NLRP3 was verified to negatively correlated with ADAR3. Additionally, the pyroptosis-related protein NLRP3, ASC, caspase1, IL-1β, IL-18 and GSDMD expressions were all decreased by ADAR3.

CONCLUSION

In conclusion, ADAR3 alleviated inflammation and pyroptosis of NP through targeting NLRP3, which suggested a therapeutical target for NP.

Considerations for Cannabis Use to Treat Pain in Sickle Cell Disease

Pain in Sickle Cell Disease (SCD) is a major comorbidity and unique with acute pain due to recurrent and episodic vaso-occlusive crises as well as chronic pain, which can span an individual's entire life. Opioids are the mainstay treatment for pain in SCD. Due to recent health crises raised by adverse effects including deaths from opioid use, pain management in SCD is adversely affected. Cannabis and its products are most widely used for pain in multiple conditions and also by patients with SCD on their own. With the availability of "Medical Cannabis" and approval to use cannabis as medicine across majority of States in the United States as well as over-the-counter preparations, cannabis products are being used increasingly for SCD. The reliability of many of these products remains questionable, which poses a major health risk to the vulnerable individuals seeking pain relief. Therefore, this review provides up to date insights into available categories of cannabis-based treatment strategies, their mechanism of action and pre-clinical and clinical outcomes in SCD. It provides evidence for the benefits and risks of cannabis use in SCD and cautions about the unreliable and unvalidated products that may be adulterated with life-threatening non-cannabis compounds.

Data Quality Issues With Physician-Rating Websites: Systematic Review

BACKGROUND

In recent years, online physician-rating websites have become prominent and exert considerable influence on patients' decisions. However, the quality of these decisions depends on the quality of data that these systems collect. Thus, there is a need to examine the various data quality issues with physician-rating websites.

OBJECTIVE

This study's objective was to identify and categorize the data quality issues afflicting physician-rating websites by reviewing the literature on online patient-reported physician ratings and reviews.

METHODS

We performed a systematic literature search in ACM Digital Library, EBSCO, Springer, PubMed, and Google Scholar. The search was limited to quantitative, qualitative, and mixed-method papers published in the English language from 2001 to 2020.

RESULTS

A total of 423 articles were screened. From these, 49 papers describing 18 unique data quality issues afflicting physician-rating websites were included. Using a data quality framework, we classified these issues into the following four categories: intrinsic, contextual, representational, and accessible. Among the papers, 53% (26/49) reported intrinsic data quality errors, 61% (30/49) highlighted contextual data quality issues, 8% (4/49) discussed representational data quality issues, and 27% (13/49) emphasized accessibility data quality. More than half the papers discussed multiple categories of data quality issues.

CONCLUSIONS

The results from this review demonstrate the presence of a range of data quality issues. While intrinsic and contextual factors have been well-researched, accessibility and representational issues warrant more attention from researchers, as well as practitioners. In particular, representational factors, such as the impact of inline advertisements and the positioning of positive reviews on the first few pages, are usually deliberate and result from the business model of physician-rating websites. The impact of these factors on data quality has not been addressed adequately and requires further investigation.