Pain Neurology

State-of-the-Art Personalized Therapy Approaches for Chronic Non-Specific Low Back Pain: Understanding the Mechanisms and Drivers

Chronic non-specific low back pain (CNSLBP) is a debilitating condition that affects millions of people worldwide, significantly impacting quality of life and imposing a substantial socioeconomic burden. Traditional treatment approaches often rely on a one-size-fits-all strategy, failing to account for individual variations in pathophysiological mechanisms, drivers, and the principles of personalized medicine. Furthermore, an overemphasis on biomechanical findings from imaging may lead to ineffective interventions and unnecessary surgical procedures, obscuring other important factors that contribute to pain perception. While highlighting the limitations of universal treatment approaches, in this review we present a practical clinical approach aimed at elucidating the main pathophysiological mechanisms and various factors underlying the development and maintenance of CNSLBP in order to create a personalized treatment program. In conclusion, this review underscores the need for personalized therapeutic strategies that take into account the unique characteristics of each patient, recognizing the complex interaction of biological, psychological, social, and other factors that contribute to the development of individual pain. By combining a comprehensive understanding of the complexities of this condition, we aim to improve clinical outcomes and provide information on the development of effective personalized treatment algorithms, particularly in the field of neurological practice.

Prevalence, patterns and determinants of peripheral neuropathy among leprosy patients in Northeast Ethiopia: A retrospective study

BACKGROUND

Leprosy, also known as Hansen's disease, is a bacterial disease caused by Mycobacterium leprae (M. leprae). Leprosy is believed to have originated initially in Eastern African regions and spread worldwide through the migration of people. Leprosy causes skin and nerve infections. It has been investigated that the Hansen's bacillus, M. leprae, predominantly targets peripheral nerves.

METHODOLOGY/PRINCIPAL FINDINGS

The present study reviewed charts of 380 patients with complete records fulfilling the inclusion criteria. An institution-based retrospective cross-sectional study design was employed. The study was conducted at Boru meda General Hospital, located in the South Wollo zone, Amhara region, Ethiopia from September 2019 to August 2021. In the current study, the prevalence of peripheral neuropathy among leprosy patients is found to be 60%. Male sex, advanced age, presence of leprosy reactions, presence of more than four skin lesions, longer duration of the disease, and MB leprosy were the risk factors associated with leprosy peripheral neuropathy. Sensory impairment was the most common presentation followed by motor impairment.

CONCLUSIONS/SIGNIFICANCE

In Ethiopia, data is scarce regarding the prevalence, pattern and determinants of leprosy peripheral neuropathy. Hence, this study was intended to assess the prevalence, pattern and determinants of leprosy peripheral neuropathy. The result of this study would be served as an important input to develop recommendations that inform some clues for future researchers in this area. This study showed high prevalence of leprosy peripheral neuropathy among registered leprosy patients reflecting how much significant the study is.

Global, regional, and national burden of low back pain for adults aged 55 and older 1990-2021: an analysis for the global burden of disease study 2021

BACKGROUND

Low back pain (LBP) is a widespread condition that increasingly affects the older adults, highlighting the need for a detailed examination of its global impact. Our research aimed to evaluate the LBP's burden and trends in individuals over 55 years of age across 204 countries and territories from 1990 to 2021.

METHODS

We analyzed the data from the Global Burden of Disease 2021, focusing on LBP prevalence, incidence, and years lived with disability (YLDs), along with associated risk factors.

RESULTS

In 2021, a total of 271,680,057 individuals aged 55 and older globally suffered from LBP. The age-standardized prevalence rate was 18,282.8 per 100,000 population, marking a 10.4% decrease since 1990. The age-standardized incidence and YLD rates had decreased by 9.4% and 11.0%, respectively. Central and Eastern Europe and Australasia had the highest burden, while Andean Latin America, Caribbean, and East Asia had the lowest. Notably, there were significant gender differences, with males experiencing lower rates than females. Occupational ergonomic factors, smoking, and high body mass index were identified as major contributors to the LBP burden.

CONCLUSION

This study analyzed the global burden of LBP in adults aged 55 and older, noting a decrease in age-standardized rates but an increase in total cases and regional disparities. It stressed the need to tackle modifiable risk factors like occupational ergonomics, smoking, and obesity to lessen LBP's impact. The study also called for region-specific, gender-sensitive healthcare policies to ensure fair health outcomes for all adults aged 55 and older.

The causal relationship between sleep characteristics and multi-site pain perception: a two-sample Mendelian randomization study

Objective

This Mendelian Randomization (MR) study aims to explore the potential causal relationships between four sleep traits and pain in 10 different body sites.

Materials and methods

The study utilizes exposure and outcome data from the GWAS database, employing the Inverse Variance Weighting Method (IVW) for primary causal estimates. Cochran Q and Rücker Q heterogeneity tests are conducted using IVW and MR-Egger methods, with the Egger-intercept method for pleiotropy testing, leave-one-out sensitivity analysis, and calculation of F-statistics to assess the presence of weak instrument bias.

Results

The study reveals that genetically predicted insomnia significantly increases the risk of unspecified pain, chest pain, gum pain, upper abdominal pain, and lower abdominal pain occurrence. Daytime napping is associated with a moderate reduction in the likelihood of joint pain but may concomitantly elevate the risk of chest pain, upper abdominal pain, and generalized abdominal pain. Neither sleep chronotype nor sleep duration demonstrated a definitive causal relationship with pain perception.

Conclusion

This study elucidates the causal relationships between four sleep characteristics and pain across 10 different body regions. Overall, the contribution of insomnia and sleep deficiency to pain in multiple body regions is more pronounced. Conversely, the association between adequate sleep and the likelihood of somatic pain is relatively lower and less significant.

The Burden of Pelvic Pain Associated With Endometriosis Among Women in Selected European Countries and the United States: A Restricted Systematic Review

OBJECTIVE

To evaluate the burden of endometriosis-associated pelvic pain (EAPP) on health-related quality of life (HRQoL) among women living in similar socio-economic conditions.

DATA SOURCES

Searches were performed in PubMed and Embase on September 26, 2022. The review was performed in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis protocol (PRISMA-P) and was registered on PROSPERO (ID: CRD42023370363).

METHODS OF STUDY SELECTION

Due to the high volume of eligible publications following initial review, inclusion criteria were restricted to studies undertaken in France, Germany, Italy, Spain, the United Kingdom, and the United States. This restriction was applied before screening as these countries have broad social and economic similarities, and previous studies in the literature suggest pain reporting and experience are influenced by numerous socio-cultural factors. Eligible studies were those published between 2013 and 2022 and include a sample size of ≥50 participants. The search strategy identified all relevant publications relating to the burden of illness due to EAPP. A variety of terms are used in the literature to describe pain associated with endometriosis, and this was considered in the design of the search strategy and screening procedure.

TABULATION, INTEGRATION, AND RESULTS

The database searches resulted in a total of 6139 records. After removal of duplicates, 3855 records were assessed further. A total of 27 publications were identified as eligible. Fourteen (52%) were from Italy, 5 (19%) were multinational studies, 4 (15%) were from the United States, 3 (11%) were from Spain, and 1 (4%) was from Germany. Most studies were cross-sectional (n = 15; 56%); 7 (26%) were case-control studies; 3 (11%) were cohort studies; and 2 (7%) were longitudinal studies. These publications collectively highlighted an association between EAPP and reduced HRQoL. Several studies showed that EAPP was associated with lower HRQoL when compared with endometriosis without pain and potentially with chronic pelvic pain caused by other conditions, although the evidence is limited in this case. Moreover, the studies reported detrimental effects on general HRQoL, mental health functioning, and sexual functioning, culminating in reduced work productivity and difficulties in performing everyday activities. The associations were generally similar across study populations, including adolescents, as well as younger and older women. Results were consistent across the range of different patient-reported outcome tools used to assess HRQoL.

CONCLUSION

The existing literature suggests that, among women in selected European countries and the United States, EAPP is associated with reduced HRQoL, including impaired mental and sexual functioning, as well as reduced work performance and productivity; each of which may contribute to the societal burden of endometriosis.

Pain symptoms are associated with two-point discrimination threshold in patients with temporomandibular disorders

OBJECTIVE

This study aimed to explore the associations of orofacial two-point discrimination (2-PD) test result with pain symptoms and psychological factors in patients with Temporomandibular Disorders (TMDs).

METHODS

193 patients with TMDs were included in this study. Patients' demographics, pain intensity, and psychological status were recorded. The 2-PDs in the bilateral temporal, zygomatic, mandibular, and temporomandibular joint (TMJ) regions of the patients were measured. Statistical analyses were conducted to observe the associations between variables.

RESULTS

For Pain-related TMDs (PT) patients, Monthly Visual Analogue Scale (VAS-M) and Current Analogue Scale (VAS-C) were correlated with TMJ, zygomatic and temporal 2-PDs. Patients with PT tended to have higher TMJ 2-PDs[Right: β = 1.827 mm, 95%CI(0.107, 3.548), P = 0.038], zygomatic 2-PDs[Right: β = 1.696 mm, 95%CI(0.344, 3.048), P = 0.014], temporal 2-PDs[Left: β = 2.138 mm, 95%CI(0.127, 4.149), P = 0.037; Right: β = 1.893 mm, 95%CI(0.011, 3.775), P = 0.049]. Associations were also observed between VAS-C and TMJ 2-PDs[Left: β = 0.780, 95%CI(0.190, 1.370), P = 0.01; Right: β = 0.885, 95%CI(0.406, 1.364), P = 0.001], Zygomatic 2-PDs[Right: β = 0.555, 95%CI(0.172, 0.938), P = 0.005]; VAS-M and TMJ 2-PDs[Left: β = 0.812, 95%CI(0.313, 1.311), P = 0.002; Right: β = 0.567, 95%CI(0.152, 0.983), P = 0.008], zygomatic 2-PDs[Left: β = 0.405, 95%CI(0.075, 0.735), P = 0.016; Right: β = 0.545, 95%CI(0.221, 0.870), P = 0.001], and temporal 2-PDs [Left: β = 0.741, 95%CI(0.258, 1.224), P = 0.003; Right: β = 0.519, 95%CI(0.063, 0.975), P = 0.026].

CONCLUSION

TMJ, zygomatic, and temporal 2-PDs were significantly associated with PT and pain intensity. Age, gender and psychological factors were not associated with orofacial 2-PDs. PT patients exhibited weaker tactile acuity compared to Non-PT patients. Further discussion on the underlying mechanism is needed.

CLINICAL RELEVANCE

Orofacial tactile acuity of TMDs patients was associated with their pain symptoms, which researchers should take account into when performing 2-PD tests for TMDs patients. The 2-PD test can be considered as a potential tool along with the current procedures for the differentiations of PT and Non-PT.

Design and synthesis of novel dithiazole carboxylic acid Derivatives: In vivo and in silico investigation of their Anti-Inflammatory and analgesic effects

Inflammation is a complex set of interactions that can occur in tissues as the body's defensive response to infections, trauma, allergens, or toxic compounds. Therefore, in almost all diseases, it can be observed because of primary or secondary reasons. Since it is important to control and even eliminate the symptoms of inflammation in the treatment of many diseases, anti-inflammatory and analgesic drugs are always needed in the clinic. Therefore, the discovery of new anti-inflammatory/analgesic drugs with increased effectiveness and safer side effect profiles is among the popular topics of medicinal chemistry. Therefore, in this study, in order to synthesize and diversify new molecules, we focused on the N,N-dithiazole carboxylic acid core and linked it with the chalcone functional group. The final eleven molecules were analyzed via HRMS, 1H NMR, and 13C NMR. The antinociceptive effects of the test compounds were examined by tail-clip, hot-plate, and formalin methods in mice, while their anti-inflammatory activities were investigated by carrageenan-induced inflammation tests in rats. The motor activities of the experimental animals were evaluated using an activity-meter device. Obtained findings revealed that none of the test compounds (10 mg/kg) were effective in the tail-clip and hot-plate tests. However, compounds 4b, 4c, 4f, 4 h, and 4 k in the serial shortened the paw-licking times of mice in the late phase of the formalin test indicating that these compounds had peripherally-mediated antinociceptive effects. The same compounds, moreover, showed potent anti-inflammatory effects by significantly reducing paw edema of rats in the inflammation tests. To provide an approach to pharmacological findings regarding possible mechanisms of action, the binding modes of the most active compounds were investigated by in silico approaches. The results of molecular docking studies indicated that the anti-inflammatory and analgesic activities of the compounds might be related to the inhibition of both COX-1 and COX-2 isoenzymes. Findings obtained from in silico studies showed that 4 k, which was chosen as a model for its analogs in the series, forms strong bindings to the basic residues (Arg120, Tyr355), side pocket loop area and deep hydrophobic regions of the enzyme. Moreover, results of the molecular dynamics simulation studies revealed that ligand-COX enzyme complexes are quite stable. Obtained results of in vivo and in silico studies are in harmony, and all together point out that compounds 4b, 4c, 4f, 4 h, and 4 k have significant anti-inflammatory and analgesic activities with good ADME profiles. The potential of the derivatives, whose pharmacological activities were revealed for the first time in this study, as anti-inflammatory and analgesic drug candidates, needs to be evaluated through comprehensive clinical studies.

Progress in the development of TRPV1 small-molecule antagonists: Novel Strategies for pain management

Transient receptor potential vanilloid 1 (TRPV1) channels are widely distributed in sensory nerve endings, the central nervous system, and other tissues, functioning as ion channel proteins responsive to thermal pain and chemical stimuli. In recent years, the TRPV1 receptor has garnered significant interest as a potential therapeutic approach for various pain-related disorders, particularly TRPV1 antagonists. The present review offers a comprehensive, systematic exploration of both first- and second-generation TRPV1 antagonists in the context of pain management. Antagonists are categorized and explicated according to their structural characteristics. Detailed examination of binding modes, structural features, and pharmacological activities, alongside a critical appraisal of the advantages and limitations inherent to typical compounds within each structural category, are undertaken. Detailed discussions of the binding modes, structural features, pharmacological activities, advantages, and limitations of typical compounds within each structural category offer valuable insights and guidance for the future research and development of safer, more effective, and more targeted TRPV1 antagonists.

Potential role of Schwann cells in neuropathic pain

Neuropathic pain (NPP) is a common syndrome associated with most forms of disease, which poses a serious threat to human health. NPP may persist even after the nociceptive stimulation is eliminated, and treatment is extremely challenging in such cases. Schwann cells (SCs) form the myelin sheaths around neuronal axons and play a crucial role in neural information transmission. SCs can secrete trophic factors to nourish and protect axons, and can further secrete pain-related factors to induce pain. SCs may be activated by peripheral nerve injury, triggering the transformation of myelinated and non-myelinated SCs into cell phenotypes that specifically promote repair. These differentiated SCs provide necessary signals and spatial clues for survival, axonal regeneration, and nerve regeneration of damaged neurons. They can further change the microenvironment around the regions of nerve injury, and relieve the pain by repairing the injured nerve. Herein, we provide a comprehensive overview of the biological characteristics of SCs, discuss the relationship between SCs and nerve injury, and explore the potential mechanism of SCs and the occurrence of NPP. Moreover, we summarize the feasible strategies of SCs in the treatment of NPP, and attempt to elucidate the deficiencies and defects of SCs in the treatment of NPP.

Effects of acupuncture in the treatment of occipital neuralgia: A systematic review and meta-analysis

BACKGROUND

Acupuncture is used to treat subjects with occipital neuralgia, which is 1 of the main causes of occipital pain; however, its effect is conflicting. Hence, the current study aims to evaluate the effects of acupuncture in the treatment of occipital neuralgia.

METHODS

In a systematic search of PubMed, Embase, OVID, China National Knowledge Infrastructure, Cochrane Library, Chinese Biomedical Literature Database, Wanfang databases, and Google Scholar until July 2021, 15 studies aimed to evaluate the effects of acupuncture in the treatment of occipital neuralgia were included. Human-related trials were considered in different languages. The size of the study was not considered a limit for its inclusion and the study intervention should focus on comparing the impact of acupuncture in the intervention group compared with the control group.The odds ratio (OR) and the mean difference (MD) with 95% confidence intervals (CIs) were calculated with a random or fixed-effect model for different subgroup analyses. Publication bias was assessed using the Egger test, while the risk of bias was assessed using the Review manager software.

RESULTS

Acupuncture had a significantly higher effective rate of treatment (OR, 5.40; 95% CI, 2.48 to 11.77, P < .001) compared to control in the treatment of occipital neuralgia and lower visual analogue scale (MD, -2.45; 95% CI, -2.69 to -2.21, P < .001). Acupuncture plus medication had a significantly higher effective rate of treatment (OR, 3.96; 95% CI, 2.10 to 7.47, P < .001) compared to medication in the treatment of occipital neuralgia. Acupuncture analysis for safety issues showed a significant reduction of adverse events compared with the medication group.

CONCLUSION

Acupuncture alone or acupuncture plus medication had a significantly beneficial effect on the effective rate of treatment, safety and visual analog scale compared to medication in the treatment of occipital neuralgia. Further studies are required to validate these findings.

Manual Therapy Effect in Placebo-Controlled Trials: A Systematic Review and Meta-Analysis

PURPOSE

Background: Evaluate whether the design of placebo control groups could produce different interpretations of the efficacy of manual therapy techniques.

METHODS

Nine databases were searched (EMBASE, CINAHL, PsycINFO, MEDLINE, PubMed, SCOPUS, WEB of SCIENCE, COCHRANE, and PEDro). Randomized placebo-controlled clinical trials that used manual therapy as a sham treatment on subjects suffering from pain were included. Data were summarized qualitatively, and meta-analyses were conducted with R.

RESULTS

53 articles were included in the qualitative analysis and 48 were included in the quantitative analyses. Manipulation techniques did not show higher effectiveness when compared with all types of sham groups that were analyzed (SMD 0.28; 95%CI [-0.24; 0.80]) (SMD 0.28; 95%CI [-0.08; 0.64]) (SMD 0.42; 95%CI [0.16; 0.67]) (SMD 0.82; 95%CI [-0.57; 2.21]), raising doubts on their therapeutic effect. Factors such as expectations of treatment were not consistently evaluated, and analysis could help clarify the effect of different sham groups. As for soft tissue techniques, the results are stronger in favor of these techniques when compared to sham control groups (SMD 0.40; 95%CI [0.19, 0.61]). Regarding mobilization techniques and neural gliding techniques, not enough studies were found for conclusions to be made.

CONCLUSIONS

The literature presents a lack of a unified placebo control group design for each technique and an absence of assessment of expectations. These two issues might account for the unclear results obtained in the analysis.

Long-term neuropathic pain behaviors correlate with synaptic plasticity and limbic circuit alteration: a comparative observational study in mice

ABSTRACT

Neuropathic pain has long-term consequences in affective and cognitive disturbances, suggesting the involvement of supraspinal mechanisms. In this study, we used the spared nerve injury (SNI) model to characterize the development of sensory and aversive components of neuropathic pain and to determine their electrophysiological impact across prefrontal cortex and limbic regions. Moreover, we evaluated the regulation of several genes involved in immune response and inflammation triggered by SNI. We showed that SNI led to sensorial hypersensitivity (cold and mechanical stimuli) and depressive-like behavior lasting 12 months after nerve injury. Of interest, changes in nonemotional cognitive tasks (novel object recognition and Y maze) showed in 1-month SNI mice were not evident normal in the 12-month SNI animals. In vivo electrophysiology revealed an impaired long-term potentiation at prefrontal cortex-nucleus accumbens core pathway in both the 1-month and 12-month SNI mice. On the other hand, a reduced neural activity was recorded in the lateral entorhinal cortex-dentate gyrus pathway in the 1-month SNI mice, but not in the 12-month SNI mice. Finally, we observed the upregulation of specific genes involved in immune response in the hippocampus of 1-month SNI mice, but not in the 12-month SNI mice, suggesting a neuroinflammatory response that may contribute to the SNI phenotype. These data suggest that distinct brain circuits may drive the psychiatric components of neuropathic pain and pave the way for better investigation of the long-term consequences of peripheral nerve injury for which most of the available drugs are to date unsatisfactory.

Pharmacogenetics and Pain Treatment with a Focus on Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and Antidepressants: A Systematic Review

Background: This systematic review summarizes the impact of pharmacogenetics on the effect and safety of non-steroidal anti-inflammatory drugs (NSAIDs) and antidepressants when used for pain treatment. Methods: A systematic literature search was performed according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines regarding the human in vivo efficacy and safety of NSAIDs and antidepressants in pain treatment that take pharmacogenetic parameters into consideration. Studies were collected from PubMed, Scopus, and Web of Science up to the cutoff date 18 October 2021. Results: Twenty-five articles out of the 6547 initially detected publications were identified. Relevant medication–gene interactions were noted for drug safety. Interactions important for pain management were detected for (1) ibuprofen/CYP2C9; (2) celecoxib/CYP2C9; (3) piroxicam/CYP2C8, CYP2C9; (4) diclofenac/CYP2C9, UGT2B7, CYP2C8, ABCC2; (5) meloxicam/CYP2C9; (6) aspirin/CYP2C9, SLCO1B1, and CHST2; (7) amitriptyline/CYP2D6 and CYP2C19; (8) imipramine/CYP2C19; (9) nortriptyline/CYP2C19, CYP2D6, ABCB1; and (10) escitalopram/HTR2C, CYP2C19, and CYP1A2. Conclusions: Overall, a lack of well powered human in vivo studies assessing the pharmacogenetics in pain patients treated with NSAIDs or antidepressants is noted. Studies indicate a higher risk for partly severe side effects for the CYP2C9 poor metabolizers and NSAIDs. Further in vivo studies are needed to consolidate the relevant polymorphisms in NSAID safety as well as in the efficacy of NSAIDs and antidepressants in pain management.

Aberrant functional connectivity in insular subregions in somatic depression: a resting-state fMRI study

BACKGROUND

Somatic depression (SD) is different from non-somatic depression (NSD), and insular subregions have been associated with somatic symptoms. However, the pattern of damage in the insular subregions in SD remains unclear. The aim of this study was to use functional connectivity (FC) analyses to explore the bilateral ventral anterior insula (vAI), bilateral dorsal anterior insula (dAI), and bilateral posterior insula (PI) brain circuits in SD patients.

METHODS

The study included 28 SD patients, 30 NSD patients, and 30 matched healthy control (HC) subjects. All participants underwent 3.0 T resting state functional magnetic resonance imaging. FC analyses were used to explore synchronization between insular subregions and the whole brain in the context of depression with somatic symptoms. Pearson correlation analyses were performed to assess relationships between FC values in brain regions showing significant differences and the total and factor scores on the 17-item Hamilton Rating Scale for Depression (HAMD17).

RESULTS

Compared with the NSD group, the SD group showed significantly decreased FC between the left vAI and the right rectus gyrus, right fusiform gyrus, and right angular gyrus; between the right vAI and the right middle cingulate cortex, right precuneus, and right superior frontal gyrus; between the left dAI and the left fusiform gyrus; and between the right dAI and the left postcentral gyrus. Relative to the NSD group, the SD group exhibited increased FC between the left dAI and the left fusiform gyrus. There were no differences in FC between bilateral PI and any brain regions among the SD, NSD, and HC groups. Within the SD group, FC values between the left vAI and right rectus gyrus were positively correlated with cognitive impairment scores on the HAMD17; FC values between the right vAI and right superior frontal gyrus were positively related to the total scores and cognitive impairment scores on the HAMD17 (p < 0.05, uncorrected).

CONCLUSIONS

Aberrant FC between the anterior insula and the frontal and limbic cortices may be one possible mechanism underlying SD.

Antioxidative and Analgesic Effects of Naringin through Selective Inhibition of Transient Receptor Potential Vanilloid Member 1

Transient receptor potential vanilloid member 1 (TRPV1) is activated in response to capsaicin, protons, temperature, and free reactive oxygen species (ROS) released from inflammatory molecules after exposure to harmful stimuli. The expression level of TRPV1 is elevated in the dorsal root ganglion, and its activation through capsaicin and ROS mediates neuropathic pain in mice. Its expression is high in peripheral and central nervous systems. Although pain is a response evolved for survival, many studies have been conducted to develop analgesics, but no clear results have been reported. Here, we found that naringin selectively inhibited capsaicin-stimulated inward currents in Xenopus oocytes using a two-electrode voltage clamp. The results of this study showed that naringin has an IC50 value of 33.3 μM on TRPV1. The amino acid residues D471 and N628 of TRPV1 were involved in its binding to naringin. Our study bridged the gap between the pain suppression effect of TRPV1 and the preventive effect of naringin on neuropathic pain and oxidation. Naringin had the same characteristics as a model selective antagonist, which is claimed to be ideal for the development of analgesics targeting TRPV1. Thus, this study suggests the applicability of naringin as a novel analgesic candidate through antioxidative and analgesic effects of naringin.

Pain management consultation for acute pancreatitis: impact on length of stay and opioid utilization

Aim: The purpose of the study was to understand the impact of a pain management consult for acute pancreatitis patients on their inpatient length of stay, morphine milligram equivalences (MMEs) and pancreatitis severity. Materials & methods: Adult patient data were extracted from the electronic health records from 1 October 2016 to 31 December 2018. Results & conclusion: Of 277 patients with a single acute pancreatitis hospitalization, 23 had a pain consultation (treatment group), whereas 254 did not (control group). There were statistically significant differences in median length of stay, median MME total and median MME per day between the treatment and control groups with comparable severity and pain scores (6.8 vs 3.1 days, 196.5 vs 33.8 MMEs, 30.9 vs 12.1 MMEs, respectively, p < 0.0001). This study emphasizes the complexity of pain management and the importance of further research in the field.

Efficacy and central mechanism of acupuncture treatment in patients with neck pain: study protocol for a randomized controlled trial

Background

Acupuncture is effective for reducing the symptoms of neck pain (NP). However, the underlying mechanisms are not fully elucidated. Based on evaluating the efficacy of two acupuncture prescriptions for treating NP, this study aims to investigate the potential central mechanism of acupuncture treatment for NP by functional magnetic resonance imaging (fMRI).

Methods

This is a randomized controlled trial; 86 patients will be randomly assigned into two acupuncture treatment groups at a ratio of 1:1. The whole study period includes 2 weeks baseline, 2 weeks treatments, and 12 weeks follow-up (4 and 12 weeks after treatment). The pain severity, the neck disability index, the cervical range of motion, and the pressure pain threshold, etc., will be used to evaluate the clinical efficacy of two acupuncture prescriptions for NP treatment. The MRI scans will be performed to detect cerebral activity changes of 20 patients in each group. The clinical data and MRI data will be analyzed, respectively. Pearson correlation coefficient will be used to evaluate the association between changes of cerebral activity features and improvement of clinical symptoms.

Discussion

The results will provide further evidence for the clinical application of acupuncture in the treatment of NP.

Trial registration

Chinese Clinical Trial Registry ChiCTR2000040930. Registered on 16 December 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05507-y.

Pain control and related factors in hospitalized patients

Pain is a common health problem for hospitalized patients. It is necessary to understand the factors that affect patients' pain to provide individual and complete pain management. This study explored the severity and incidence of pain in hospitalized patients on the admission day, during the hospitalization, and the discharge day, and explored the predictive factors that affect the patient's pain on the discharge day.This was a retrospective study that reviewed the medical records of 73,814 hospitalized patients from January 2016 to April 2018. The number of pain assessments was 471,339.The incidence of pain on the discharge day of patients was significantly higher than that on the admission day. The factors that affect and predict the pain of patients on discharge day include the degree of pain on the day of admission, emotional distress on the day of discharge, disease category, gender, age, and length of stay in hospital. It shows that the higher the degree of pain on the day of admission, the higher the degree of emotional distress on the day of discharge, female patients, younger patients, longer hospitalization days, and surgical and gynecological patients have significantly higher pain levels on the day of discharge (P < .05).This study found that the incidence of pain on the discharge day of patients was 46.5%. Previous pain level, disease category, emotional distress, gender, age, and length of hospital stay were important factors affecting patient pain on the discharge day. The influencing factors of patient pain should be fully assessed to provide individual and complete pain management, and improve patient quality of life after discharge.

Targeting P2 receptors in purinergic signaling: a new strategy of active ingredients in traditional Chinese herbals for diseases treatment

Adenosine triphosphate (ATP) and its metabolites adenosine diphosphate, adenosine monophosphate, and adenosine in purinergic signaling pathway play important roles in many diseases. Activation of P2 receptors (P2R) channels and subsequent membrane depolarization can induce accumulation of extracellular ATP, and furtherly cause kinds of diseases, such as pain- and immune-related diseases, cardiac dysfunction, and tumorigenesis. Active ingredients of traditional Chinese herbals which exhibit superior pharmacological activities on diversified P2R channels have been considered as an alternative strategy of disease treatment. Experimental evidence of potential ingredients in Chinese herbs targeting P2R and their pharmacological activities were outlined in the study.

Cannabinoid receptor agonists from Conus venoms alleviate pain-related behavior in rats

Cannabinoid (CB) receptor agonists show robust antinociceptive effects in various pain models. However, most of the clinically potent CB1 receptor-active drugs derived from cannabis are considered concerning due to psychotomimetic side effects. Selective CB receptor ligands that do not induce CNS side effects are of clinical interest. The venoms of marine snail Conus are a natural source of various potent analgesic peptides, some of which are already FDA approved. In this study we evaluated the ability of several Conus venom extracts to interact with CB1 receptor. HEK293 cells expressing CB1 receptors were treated with venom extracts and CB1 receptor internalization was analyzed by immunofluorescence. Results showed C. textile (C. Tex) and C. miles (C. Mil) samples as the most potent. These were serially subfractionated by HPLC for subsequent analysis by internalization assays and for analgesic potency evaluated in the formalin test and after peripheral nerve injury. Intrathecal injection of C. Tex and C. Mil subfractions reduced flinching/licking behavior during the second phase of formalin test and attenuated thermal and mechanical allodynia in nerve injury model. Treatment with proteolytic enzymes reduced CB1 internalization of subfractions, indicating the peptidergic nature of CB1 active component. Further HPLC purification revealed two potent antinociceptive subfractions within C. Tex with CB1 and possible CB2 activity, with mild to no side effects in the CB tetrad assessment. CB conopeptides can be isolated from these active Conus venom-derived samples and further developed as novel analgesic agents for the treatment of chronic pain using cell based or gene therapy approaches.