Inflammatory pain resolution by mouse serum-derived small extracellular vesicles.

Chronic pain is a significant public health issue. Current treatments have limited efficacy and significant side effects, warranting research on alternative strategies for pain management. One approach involves using small extracellular vesicles (sEVs) to transport beneficial biomolecular cargo to aid pain resolution. Exosomes are 30-150 nm sEVs that can carry RNAs, proteins, and lipid mediators to recipient cells via circulation. Exosomes can be beneficial or harmful depending on their source and contents. To investigate the short and long-term effects of mouse serum-derived sEVs in pain modulation, sEVs from naïve control or spared nerve injury (SNI) model donor mice were injected intrathecally into naïve recipient mice. Basal mechanical thresholds transiently increased in recipient mice. This effect was mediated by opioid signaling as this outcome was blocked by naltrexone. Mass Spectrometry of sEVs detected endogenous opioid peptide leu-enkephalin. A single prophylactic intrathecal injection of sEVs two weeks prior to induction of the pain model in recipient mice delayed mechanical allodynia in SNI model mice and accelerated recovery from inflammatory pain after complete Freund's adjuvant (CFA) injection. ChipCytometry of spinal cord and dorsal root ganglion (DRG) from sEV treated mice showed that prophylactic sEV treatment reduced the number of natural killer (NK) and NKT cells in spinal cord and increased CD206+ anti-inflammatory macrophages in (DRG) after CFA injection. Further characterization of sEVs showed the presence of immune markers suggesting that sEVs can exert immunomodulatory effects in recipient mice to promote the resolution of inflammatory pain. Collectively, these studies demonstrate multiple mechanisms by which sEVs can attenuate pain.

Impact of a financial incentive scheme on purchase of fruits and vegetables from unorganised retailers in rural India: a cluster-randomised controlled trial.

Background: Inadequate intake of fruits and vegetables is prevalent in rural areas of India, where around 65% of the population reside. Financial incentives have been shown to increase the purchase of fruits and vegetables in urban supermarkets, but their feasibility and effectiveness with unorganised retailers in rural India is unclear. Methods: A cluster-randomised controlled trial of a financial incentive scheme involving ∼20% cashback on purchase of fruits and vegetables from local retailers was conducted in six villages (3535 households). All households in three intervention villages were invited to participate in the scheme which ran for three months (February-April 2021), while no intervention was offered in control villages. Self-reported (pre-intervention and post-intervention) data on purchase of fruits and vegetables were collected from a random sub-sample of households in control and intervention villages. Findings: A total of 1109 households (88% of those invited) provided data. After the intervention, the weekly quantity of self-reported fruits and vegetables purchased were (i) 18.6 kg (intervention) and 14.2 kg (control), baseline-adjusted mean difference 4 kg (95% CI: -6.4 to 14.4) from any retailer (primary outcome); and (ii) 13.1 kg (intervention) and 7.1 kg (control), baseline-adjusted mean difference 7.4 kg (95% CI: 3.8-10.9) from local retailers participating in the scheme (secondary outcome). There was no evidence of differential effects of the intervention by household food security or by socioeconomic position, and no unintended adverse consequences were noted. Interpretation: Financial incentive schemes are feasible in unorganised food retail environments. Effectiveness in improving diet quality of the household likely hinges on the percentage of retailers willing to participate in such a scheme. Funding: This research has been funded by the Drivers of Food Choice (DFC) Competitive Grants Program, which is funded by the UK Government's Department for International Development and the Bill & Melinda Gates Foundation, and managed by the University of South Carolina, Arnold School of Public Health, USA; however, the views expressed do not necessarily reflect the UK Government's official policies.

Hsa-miR-605 regulates the proinflammatory chemokine CXCL5 in complex regional pain syndrome.

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by inflammation and debilitating pain. CRPS patients with pain refractory to more conventional analgesics can be treated with subanesthetic doses of ketamine. Our previous studies found that poor responders to ketamine had a 22-fold downregulation of the miRNA hsa-miR-605 in blood prior to ketamine treatment. Hence, we sought to investigate the functional significance of miR-605 downregulation and its impact on target gene expression, as investigating target mRNAs of differentially expressed miRNAs can provide important insights on aberrant gene expression that may contribute to disease etiology. Using a bioinformatics prediction, we identified that miR-605 can target the proinflammatory chemokine CXCL5, which plays a role in leukocyte recruitment and activation. We hypothesized that downregulation of miR-605 in poor responders to ketamine could increase CXCL5 expression and thereby contribute to inflammation in these patients. We confirmed that miR-605 regulates CXCL5 by using a miRNA mimic and inhibitor in human primary endothelial cells. Inhibition of miR-605 increased CXCL5 secretion and migration of human monocytic cells, thereby demonstrating a functional impact of miR-605 on chemotaxis. Additionally, CXCL5 mRNA was upregulated in whole blood from poor responders to ketamine, and CXCL5 protein was increased in plasma from CRPS patients. Thus, our studies suggest that miR-605 regulation of CXCL5 can regulate inflammation.

Therapeutic and prophylactic effects of macrophage-derived small extracellular vesicles in the attenuation of inflammatory pain.

Small extracellular vesicles (sEVs) derived from antigen-presenting cells such as macrophages can induce therapeutically relevant immune responses. Anti-inflammatory miRNAs are elevated in sEVs secreted by RAW 264.7 mouse macrophages after lipopolysaccharide (LPS) stimulation. We observed uptake of these sEVs by primary mouse cortical neurons, microglia and astrocytes followed by downregulation of proinflammatory miRNA target genes in recipient cells. Pre-treating primary microglia with these sEVs decreased pro-inflammatory gene expression. A single intrathecal injection of sEVs derived from LPS stimulated RAW 264.7 cells attenuated mechanical hyperalgesia in the complete Freund's adjuvant (CFA) mouse model of inflammatory pain and formalin induced acute pain. Importantly, sEVs did not alter the normal pain threshold in control mice. RNA sequencing of dorsal horn of the spinal cord showed sEVs-induced modulation of immune regulatory pathways. Further, a single prophylactic intrathecal injection of sEVs two weeks prior, attenuated CFA-induced pain hypersensitivity and was ineffective in formalin model. This indicates that prophylactic sEVs administration can be beneficial in attenuating chronic pain without impacting responses to the protective physiological and acute inflammatory pain. Prophylactic administration of sEVs could form the basis for a safe and novel vaccine-like therapy for chronic pain or as an adjuvant, potentially reducing the dose of drugs needed for pain relief.

Can we better prioritize resources for cost-utility research?

PURPOSE: We examined 512 published cost-utility analyses (CUAs) in the U.S. and other developed countries from 1976 through 2001 to determine: 1) the types of interventions studied; 2) whether they cover diseases and conditions with the highest burden; and, 3) to what extent they have covered leading health concerns defined by the Healthy People 2010 report. DATA AND METHODS: We compared rankings of the most common diseases covered by the CUAs to rankings of U.S. disease burden. We also examined the extent to which CUAs covered key Healthy People 2010 priorities. RESULTS: CUAs have focused mostly on pharmaceuticals (40%) and surgical procedures (16%). When compared to leading causes of DALYs, the data show overrepresentation of CUAs in cerebrovascular disease, diabetes, breast cancer, and HIV/AIDS, and underrepresentation in depression and bipolar disorder, injuries, and substance abuse disorders. Few CUAs have targeted Healthy People 2010 areas, such as physical activity. CONCLUSIONS: Published CUAs are associated with burden measures, but have not covered certain important health problems. These discrepancies do not alone indicate that society has been targeting resources for research inefficiently, but they do suggest the need to formalize the question of where each CUA research dollar might do the most good.