Exposure to Chinese famine and the risk of hyperuricemia in later life: a population-based cross-sectional study.

Background: Limited studies have investigated the relationship between famine exposure and the risk of hyperuricemia in later life. Consequently, the primary purpose of the current study was to examine the potential association between exposure to Chinese famine and hyperuricemia, as well as any gender disparities in this relationship. Method: The data were obtained from the China PEACE (China Patient-Centered Evaluative Assessment of Cardiac Events) Million Persons Project in Rongchang. The study participants were enrolled into different cohorts based on their birthdates: the fetal-exposed cohort (born between 1959 and 1962), the childhood-exposed cohort (born between 1949 and 1958), the adolescence-exposed cohort (born between 1941 and 1948), and the non-exposed cohorts (born between 1963 and 1974). The potential association between famine exposure and hyperuricemia was assessed using binary logistic regression models. Results: A total of 6,916 individuals were enrolled in the current study with an average age of 60.11 ± 9.22 years, out of which 3,544 were women. After adjusting for confounding factors, fetal (OR = 0.530, 95% CI: 0.411-0.0.683), childhood (OR = 0.642, 95% CI: 0.494-0.833) exposure to the Chinese famine for men was negatively associated with hyperuricemia. Conversely, exposure to the Chinese famine during fetal (OR = 2.144, 95% CI: 1.622-2.834), childhood (OR = 1.485, 95% CI: 1.105-1.997), and adolescence (OR = 1.967, 95% CI: 1.465-2.641) for women was positively associated with hyperuricemia. Furthermore, the impact of famine on hyperuricemia that has been observed in exposed women might be intensified by the presence of dyslipidemia, abdominal obesity, and overweight/obesity. Conclusion: Women exposed to the Chinese famine during fetal, childhood, and adolescence were positively associated with hyperuricemia, while men exhibited a negative association during fetal and childhood. Additionally, the effect of famine on hyperuricemia in exposed women appears to be intensified by the presence of dyslipidemia, abdominal obesity, and overweight/obesity.

PGC-1α activation ameliorates cancer-induced bone pain via inhibiting apoptosis of GABAergic interneurons.

Cancer-induced bone pain (CIBP) stands out as one of the most challenging issues in clinical practice due to its intricate and not fully elucidated pathophysiological mechanisms. Existing evidence has pointed toward the significance of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) down-regulation in contributing to pain behaviors in various rodent models of neuropathic pain. In our current study, we aimed to investigate the role of PGC-1α in CIBP. Our results unveiled a reduction in PGC-1α expression within the spinal cord of CIBP rats, particularly in GABAergic interneurons. Notably, intrathecal administration of the PGC-1α activator ZLN005 suppressed the loss of spinal GABAergic interneurons. This suppression was achieved by inhibiting caspase-3-mediated apoptosis, ultimately leading to the alleviation of mechanical allodynia in CIBP rats. Further exploration into the mechanism revealed that PGC-1α activation played a pivotal role in mitigating ATP depletion and reactive oxygen species accumulation linked to mitochondrial dysfunction. This was achieved through the restoration of mitochondrial biogenesis and the activation of the SIRT3-SOD2 pathway. Impressively, the observed effects were prominently reversed upon the application of SR18292, a specific PGC-1α inhibitor. In conclusion, our findings strongly suggest that PGC-1α activation acts as a potent inhibitor of apoptosis in spinal GABAergic interneurons. This inhibition is mediated by the improvement of mitochondrial function, facilitated in part through the enhancement of mitochondrial biogenesis and the activation of the SIRT3-SOD2 pathway. The results of our study shed light on potential therapeutic avenues for addressing CIBP.

Heat Shock Protein 22 Attenuates Nerve Injury-induced Neuropathic Pain Via Improving Mitochondrial Biogenesis and Reducing Oxidative Stress Mediated By Spinal AMPK/PGC-1α Pathway in Male Rats.

Heat shock protein 22 (hsp22) plays a significant role in mitochondrial biogenesis and redox balance. Moreover, it's well accepted that the impairment of mitochondrial biogenesis and redox imbalance contributes to the progress of neuropathic pain. However, there is no available evidence indicating that hsp22 can ameliorate mechanical allodynia and thermal hyperalgesia, sustain mitochondrial biogenesis and redox balance in rats with neuropathic pain. In this study, pain behavioral test, western blotting, immunofluorescence staining, quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and Dihydroethidium staining are applied to confirm the role of hsp22 in a male rat model of spared nerve injury (SNI). Our results indicate that hsp22 was significantly decreased in spinal neurons post SNI. Moreover, it was found that intrathecal injection (i.t.) with recombinant heat shock protein 22 protein (rhsp22) ameliorated mechanical allodynia and thermal hyperalgesia, facilitated nuclear respiratory factor 1 (NRF1)/ mitochondrial transcription factor A (TFAM)-dependent mitochondrial biogenesis, decreased the level of reactive oxygen species (ROS), and suppressed oxidative stress via activation of spinal adenosine 5'monophosphate-activated protein kinase (AMPK)/ peroxisome proliferative activated receptor γ coactivator 1α (PGC-1α) pathway in male rats with SNI. Furthermore, it was also demonstrated that AMPK antagonist (compound C, CC) or PGC-1α siRNA reversed the improved mechanical allodynia and thermal hyperalgesia, mitochondrial biogenesis, oxidative stress, and the decreased ROS induced by rhsp22 in male rats with SNI. These results revealed that hsp22 alleviated mechanical allodynia and thermal hyperalgesia, improved the impairment of NRF1/TFAM-dependent mitochondrial biogenesis, down-regulated the level of ROS, and mitigated oxidative stress through stimulating the spinal AMPK/PGC-1α pathway in male rats with SNI.

Matrix metalloproteinases as attractive therapeutic targets for chronic pain: A narrative review.

Chronic pain constitutes an abnormal pain state that detrimentally affects the quality of life, daily activities, occupational performance, and stability of mood. Despite the prevalence of chronic pain, effective drugs with potent abirritation and minimal side effects remain elusive. Substantial studies have revealed aberrant activation of the matrix metalloproteinases (MMPs) in multiple chronic pain models. Additionally, emerging evidence has demonstrated that the downregulation of MMPs can alleviate chronic pain in diverse animal models, underscoring the unique and crucial role of MMPs in different stages and types of chronic pain. This review delves into the mechanistic insights and roles of MMPs in modulating chronic pain. The aberrant activation of MMPs has been linked to neuropathic pain through mechanisms involving myelin abnormalities in peripheral nerve and spinal dorsal horn (SDH), hyperexcitability of dorsal root ganglion (DRG) neurons, activation of N-methyl-d-aspartate receptors (NMDAR) and Ca2+-dependent signals, glial cell activation, and proinflammatory cytokines release. Different MMPs also contribute significantly to inflammatory pain and cancer pain. Furthermore, we summarized the substantial therapeutic potential of MMP pharmacological inhibitors across different types of chronic pain. Overall, our findings underscore the promising therapeutic prospects of MMPs targeting for managing chronic pain.

Interleukin-17: A Putative Novel Pharmacological Target for Pathological Pain.

Pathological pain imposes a huge burden on the economy and the lives of patients. At present, drugs used for the treatment of pathological pain have only modest efficacy and are also plagued by adverse effects and risk for misuse and abuse. Therefore, understanding the mechanisms of pathological pain is essential for the development of novel analgesics. Several lines of evidence indicate that interleukin-17 (IL-17) is upregulated in rodent models of pathological pain in the periphery and central nervous system. Besides, the administration of IL-17 antibody alleviated pathological pain. Moreover, IL-17 administration led to mechanical allodynia which was alleviated by the IL-17 antibody. In this review, we summarized and discussed the therapeutic potential of targeting IL-17 for pathological pain. The upregulation of IL-17 promoted the development of pathological pain by promoting neuroinflammation, enhancing the excitability of dorsal root ganglion neurons, and promoting the communication of glial cells and neurons in the spinal cord. In general, the existing research shows that IL-17 is an attractive therapeutic target for pathologic pain, but the underlying mechanisms still need to be investigated.

Targeting the JAK2/STAT3 signaling pathway for chronic pain.

Chronic pain is a notable health concern because of its prevalence, persistence, and associated mental stress. Drugs targeting chronic pain with potent abirritation, and minimal side effects remain unidentified. Substantial evidence indicates that the Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway plays a distinct and critical role in different stages of chronic pain. Aberrant activation of the JAK2/STAT3 signaling pathway is evident in multiple chronic pain models. Moreover, an increasing number of studies have demonstrated that the downregulation of JAK2/STAT3 can attenuate chronic pain in different animal models. In this review, we investigated the mechanism and role of the JAK2/STAT3 signaling pathway in modulating chronic pain. The aberrant activation of JAK2/STAT3 can trigger chronic pain by interacting with microglia and astrocytes, releasing proinflammatory cytokines, inhibiting anti-inflammatory cytokines, and regulating synaptic plasticity. We also retrospectively reviewed current reports on JAK2/STAT3 pharmacological inhibitors that demonstrated their significant therapeutic potential in different types of chronic pain. In summary, our results provide strong evidence that the JAK2/STAT3 signaling pathway is a promising therapeutic target for chronic pain.

Inhibition of Brd4 alleviates osteoarthritis pain via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling.

BACKGROUND AND PURPOSE: Osteoarthritis (OA) pain remains a major clinical problem. It is urgent to identify novel therapeutic approaches for OA pain states. Bromodomain and extra-terminal (BET) protein inhibitors have robust anti-inflammatory effects in several pain models. However, the underlying mechanisms of these inhibitors in OA pain have not been determined. We, therefore, investigated the effects and the underlying mechanism(s) of BET inhibition on pain-related behaviours in a rat model of OA. EXPERIMENTAL APPROACH: The OA model was established by intra-articular injection of monosodium iodoacetate (MIA) in rat knees. Pain behaviours were assessed in rats by hindlimb weight-bearing asymmetry, mechanical allodynia and thermal hyperalgesia. Possible mechanisms underlying BET inhibition were explored in the MIA-induced OA pain model in the spinal cord and dorsal root ganglia (DRG). KEY RESULTS: Inhibiting bromodomain-containing protein 4 (Brd4) with either JQ1 or MS417, or using AAV2/9-shRNA-Brd4-EGFP-mediated knockdown of Brd4 genes, significantly attenuated MIA-induced pain behaviours. Brd4 inhibition suppressed NF-κB and NF-κB-mediated inflammatory cytokines in both the spinal cord and DRG in rats with MIA-induced OA pain. Brd4 inhibition also attenuated the oxidative stress and promoted nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent antioxidant genes in both the spinal cord and DRG in our odel of MIA-induced OA pain. CONCLUSIONS AND IMPLICATIONS: In conclusion, Brd4 inhibition alleviated MIA-induced OA pain in rats, via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling. Although our model does not perfectly represent how OA develops in humans, inhibition of Brd4 may provide novel insights into possible treatments for OA pain.

Female exposed to the Chinese famine increases the risk of dyslipidemia in later life.

The Developmental Origins of Health and Disease theory suggests that early-life malnutrition is associated with an increased risk of chronic disease in adulthood. In this study, we aimed to analyze the association between exposure to the Chinese famine during fetal, childhood, and adolescence, while also exploring potential gender disparities in this association. From August 2018 to 2022 December, a 3-stage stratified random sampling method was employed to recruit 6916 eligible participants in Chongqing for this study. The participants were enrolled into 4 cohorts based on their birthdates: non-exposed, fetal-exposed, childhood-exposed, and adolescence-exposed. Participants were defined as having dyslipidemia according to the 2016 Chinese guideline for the management of dyslipidemia in adults, as well as self-reported dyslipidemia. In total, 6916 eligible participants were interviewed, including 1686 participants exposed when fetal, 1626 participants exposed during childhood, 1648 participants exposed during adolescence, and 1956 participants who had no exposure. The prevalence of dyslipidemia in the non-exposed, fetal-exposed, childhood-exposed, and adolescence-exposed cohorts was 21.43%, 25.00%, 24.38%, 22.52% in males and 20.00%, 36.57%, 34.60%, 32.59% in females, respectively. There was an increased risk of dyslipidemia among females exposed to the Chinese famine during the fetal (odds ratio [OR] = 1.613, 95% confidence interval [CI]: 1.179-2.205), childhood (OR = 1.857, 95% CI: 1.384-2.491), adolescence (OR = 1.531, 95% CI: 1.137-2.060) stage, However, no significant association was observed in male adults. Exposure to the Chinese famine during fetal, childhood, and adolescence stages increases the risk of dyslipidemia in adulthood in females, but not in males. The observed gender differences may be attributed to mortality advantage and son preference in China.

Targeting the nitric oxide/cGMP signaling pathway to treat chronic pain.

Nitric oxide (NO)/cyclic guanosine 3',5'-monophosphate (cGMP) signaling has been shown to act as a mediator involved in pain transmission and processing. In this review, we summarize and discuss the mechanisms of the NO/cGMP signaling pathway involved in chronic pain, including neuropathic pain, bone cancer pain, inflammatory pain, and morphine tolerance. The main process in the NO/cGMP signaling pathway in cells involves NO activating soluble guanylate cyclase, which leads to subsequent production of cGMP. cGMP then activates cGMP-dependent protein kinase (PKG), resulting in the activation of multiple targets such as the opening of ATP-sensitive K+ channels. The activation of NO/cGMP signaling in the spinal cord evidently induces upregulation of downstream molecules, as well as reactive astrogliosis and microglial polarization which participate in the process of chronic pain. In dorsal root ganglion neurons, natriuretic peptide binds to particulate guanylyl cyclase, generating and further activating the cGMP/PKG pathway, and it also contributes to the development of chronic pain. Upregulation of multiple receptors is involved in activation of the NO/cGMP signaling pathway in various pain models. Notably the NO/cGMP signaling pathway induces expression of downstream effectors, exerting both algesic and analgesic effects in neuropathic pain and inflammatory pain. These findings suggest that activation of NO/cGMP signaling plays a constituent role in the development of chronic pain, and this signaling pathway with dual effects is an interesting and promising target for chronic pain therapy.

A high-performance porous flexible composite film sensor for tension monitoring.

Flexible, lightweight sensors with a wide strain-sensing range are showing increasing significance in structural health monitoring compared with conventional hard sensors, which typically have a small strain range, are heavyweight, and have a large volume. In this work, salt particle precipitation and mechanical coating methods are used to fabricate porous graphene nanoplatelet (GNP)/polydimethylsiloxane (PDMS) flexible sensors for tension monitoring in structural health applications. The signal transformation through the Back Propagation (BP) algorithm is integrated to provide monitoring data that are comparable with other sensors. The results reveal that the flexible sensors with a low content of GNPs (0.1-0.25 wt%) possess better flexibility, allowing tensile strains over 200% to be measured. In addition, due to the enhanced deformation capacity of the pore structures, they can achieve high sensitivity (1-1000) under 65% strain, and a fast response time (70 ms) under 10% strain at 60 mm min-1. They also show high performance in the fatigue test (20 000 cycles) under 5% strain, and can effectively respond to bending and torsion. In addition, the sensors show an obvious response to temperature. Overall, the prepared flexible composite sensors in this work have the advantages of a wide strain-sensing range, a full-coverage conductive network, and being lightweight, and show potential for structural health monitoring in the near future.

Targeting α7 nicotinic acetylcholine receptors for chronic pain.

Despite rapid advances in the field of chronic pain, it remains extremely challenging in the clinic. Pain treatment strategies have not improved for decades as opioids remain the main prescribed drugs for chronic pain management. However, long-term use of opioids often leads to detrimental side effects. Therefore, uncovering the mechanisms underlying the development and maintenance of chronic pain may aid the discovery of novel therapeutics to benefit patients with chronic pain. Substantial evidence indicates downregulation of α7 nicotinic acetylcholine receptors (α7 nAChR) in the sciatic nerve, dorsal root ganglia, and spinal cord dorsal horn in rodent models of chronic pain. Moreover, our recent study and results from other laboratories demonstrate that potentiation of α7 nAChR attenuates pain behaviors in various murine models of chronic pain. This review summarized and discussed the preclinical evidence demonstrating the therapeutic potential of α7 nAChR agonists and allosteric modulators in chronic pain. This evidence indicates that potentiation of α7 nAChR is beneficial in chronic pain, mostly by alleviating neuroinflammation. Overall, α7 nAChR-based therapy for chronic pain is an area with great promise, but more research regarding its detailed mechanisms is warranted.

Dimethyl Fumarate Attenuates Pain Behaviors in Osteoarthritis Rats via Induction of Nrf2-Mediated Mitochondrial Biogenesis.

AIMS: Osteoarthritis (OA), a chronic degenerative disease, leads to pain and loss of function. Existing treatments for OA pain have limited efficacy and show significant side effects. Dimethyl fumarate, a robust nuclear factor erythroid 2-related factor 2 (Nrf2) activator, could alleviate pain behaviors in chronic pain. This study aims to investigate the role of dimethyl fumarate in a rat model of OA and its underlying mechanisms. METHODS: We used von Frey filaments to assess the mechanical allodynia. Weight-bearing apparatus was employed to assess the hindlimb weight distribution. Western blot was employed to investigate the protein expressions of mitochondrial biogenesis markers. RT-qPCR was employed to examine the copy number of mitochondrial DNA (mtDNA). RESULTS: Dimethyl fumarate upregulated mechanical paw withdrawal threshold (MIA + Vehicle, 1.6 ± 0.13g [mean ± SEM]; MIA + DMF, 10.5 ± 0.96g; P ＜ 0.0001). Hindlimb weight distribution was alao upregulated by dimethyl fumarate (MIA + Vehicle, 38.17 ± 0.72g; MIA + DMF, 43.59 ± 1.01g; P ＜ 0.01). Besides, activation of Nrf2 remarkably upregulated the protein levels of PGC-1α (MIA + Vehicle, 0.69 ± 0.07; MIA + DMF, 1.08 ± 0.09; P = 0.0037), NRF1 (MIA + Vehicle, 0.69 ± 0.04; MIA + DMF, 1.00 ± 0.11; P = 0.0114), TFAM (MIA + Vehicle, 0.62 ± 0.11; MIA + DMF, 1.02 ± 0.12; P = 0.0147), and the copy number of mtDNA(MIA + Vehicle, 0.52 ± 0.05; MIA + DMF, 3.81 ± 0.21; P ＜ 0.0001) Conclusions: Taken together, these results show that dimethyl fumarate alleviated pain-related behaviors in a rat model of OA through activation of Nrf2-induced mitochondrial biogenesis.

The Emerging Role of Quercetin in the Treatment of Chronic Pain.

Despite much research efforts being devoted to designing alternative pharmacological interventions, chronic pain remains to be an unresolved clinical problem. Quercetin, a compound that belongs to the flavonoids family, is abundantly found in fruits and vegetables. Emerging evidence indicates that quercetin possesses anti-nociceptive effects in different rodent models of chronic pain, including inflammatory pain, neuropathic pain and cancer pain. In this review, we summarize the mechanisms underlying the analgesic effect of quercetin in preclinical studies. These studies showed that quercetin exerts potent analgesic effects against chronic pain via suppressing neuroinflammation and oxidative stress as well as modulation of synaptic plasticity, GABAergic system, and opioidergic system. Considering that the safety of quercetin is well established, it has great potential for clinical use in pain treatment.

Naringenin promoted spinal microglia M2 polarization in rat model of cancer-induced bone pain via regulating AMPK/PGC-1α signaling axis.

Cancer-induced bone pain (CIBP) treatment remains a clinical challenge because the pathophysiological mechanisms are not fully understood. Recently, it was verified that shifting microglial polarization toward the M2 phenotype reveals a potential strategy for CIBP treatment. Naringenin, a natural flavone flavonoid, has been reported to have antioxidant, anti-inflammatory and neuroprotective properties. However, the role of naringenin on regulating microglial polarization in CIBP rats and the molecular mechanisms participating in this process have not been fully clarified. Herein, we investigated the potential effect of naringenin on M1/M2 microglial polarization and further explored the potential mechanisms of this action. Our study demonstrated that intraperitoneal administration of naringenin could upregulate the antioxidative molecule glutathione peroxidase 4 (GPx4) level in the spinal cord, as well as bone cancer-induced mechanical allodynia in rats. Moreover, naringenin treatment also suppressed microglia-mediated neuroinflammation by downregulating the phosphorylation of nuclear factor κB (NF-κB) p65 expression and promoting microglial polarization toward the M2 phenotype in CIBP rats. The promoting effects mediated by naringenin on M1/M2 microglial polarization are dependent on the serine/threonine protein kinase adenosine monophosphate-activated protein kinase (AMPK)/proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling pathway. Inhibition of AMPK activation with the classical AMPK inhibitor Compound C attenuated this effect of naringenin. These results improved the understanding of the anti-inflammatory property of naringenin on microglial polarization, which might provide new alternative avenues for CIBP treatment.

Notch signaling activation contributes to paclitaxel-induced neuropathic pain via activation of A1 astrocytes.

Paclitaxel-induced neuropathic pain (PINP) is a progressive and refractory side effect of chemotherapy with few effective treatments at present. It is well-established that astrocytes activation contributes to the development of PINP. Recent reports showed astrocytes can be divided into A1 and A2 phenotypes. However, whether the transformation of astrocytes participates in PINP and the underlying mechanisms remain unknown. As Notch signaling pathway have shown to be involved in neuropathic pain, we aimed to investigate the relationship between Notch signaling pathway and A1 astrocytes in PINP. Herein we found that both A1 astrocytes and Notch signaling were markedly activated in the spinal cord of PINP rats and the downstream molecules of Notch signaling were colocalized with A1 astrocytes. DAPT (an inhibitor of Notch signaling) not only suppressed the mechanical allodynia of PINP rats, but also inhibited the activation of Notch signaling pathway and A1 astrocytes. Furthermore, Jagged1 (a ligand of Notch1 receptors) dose-dependently induced mechanical hyperalgesia in naïve rats and simultaneously led to Notch signaling activation and A1 astrocytes transformation, all of which were inhibited by DAPT. Taken together, these results demonstrate Notch signaling activation contributes to PINP via A1 astrocytes activation, which provides a promising therapeutic target for PINP.

DKK3 ameliorates neuropathic pain via inhibiting ASK-1/JNK/p-38-mediated microglia polarization and neuroinflammation.

BACKGROUND: Neuropathic pain is a common and severely disabling state that affects millions of people worldwide. Microglial activation in the spinal cord plays a critical role in the pathogenesis of neuropathic pain. However, the mechanisms underlying spinal microglial activation during neuropathic pain remain incompletely understood. Here, we investigated the role of Dickkopf (DKK) 3 and its interplay with microglial activation in the spinal cord in neuropathic pain. METHODS: In this study, we investigated the effects of intrathecal injection of recombinant DKK3 (rDKK3) on mechanical allodynia and microglial activation in the spinal cord after spared nerve injury (SNI) in rats by western blot (WB), immunofluorescence (IF), quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay (ELISA). RESULTS: We found that SNI induced a significant decrease in the levels of DKK3, Kremen-1 and Dishevelled-1 (DVL-1) and up-regulated the expression of phosphorylated apoptosis signal-regulating kinase 1 (p-ASK1), phosphorylated c-JUN N-terminal kinase (p-JNK), phosphorylated p38 (p-p38) in the spinal cord. Moreover, our results showed that exogenous intrathecal administration of rDKK3 inhibited expression of p-ASK1, p-JNK, p-p38, promoted the transformation of microglia from M1 type to M2 type, and decreased the production of pro-inflammatory cytokines compared to the rats of SNI + Vehicle. However, these effects were reversed by intrathecal administration of Kremen-1 siRNA or Dishevelled-1 (DVL-1) siRNA. CONCLUSIONS: These results suggest that DKK3 ameliorates neuropathic pain via inhibiting ASK-1/JNK/p-38-mediated microglia polarization and neuroinflammation, at least partly, by the Kremen-1 and DVL-1 pathways.

SIRT1: A promising therapeutic target for chronic pain.

Chronic pain remains an unresolved problem. Current treatments have limited efficacy. Thus, novel therapeutic targets are urgently required for the development of more effective analgesics. An increasing number of studies have proved that sirtuin 1 (SIRT1) agonists can relieve chronic pain. In this review, we summarize recent progress in understanding the roles and mechanisms of SIRT1 in mediating chronic pain associated with peripheral nerve injury, chemotherapy-induced peripheral neuropathy, spinal cord injury, bone cancer, and complete Freund's adjuvant injection. Emerging studies have indicated that SIRT1 activation may exert positive effects on chronic pain relief by regulating inflammation, oxidative stress, and mitochondrial dysfunction. Therefore, SIRT1 agonists may serve as potential therapeutic drugs for chronic pain.

A Response Surface Analysis of the Combination of Dexmedetomidine and Sufentanil for Attenuating the Haemodynamic Response to Endotracheal Intubation.

Purpose: Dexmedetomidine combined with opioids has been extensively used to blunt cardiovascular responses to endotracheal intubation. To determine their interaction, we aimed to develop a response surface model between dexmedetomidine and sufentanil. Methods: One hundred and twenty patients undergoing scheduled gynaecological surgery were recruited. According to a simulation of slice design, patients received different dose pairs of dexmedetomidine (0 to 1.1 µg/kg) and sufentanil (.1 to .5 µg/kg). The mean arterial blood pressure and heart rate of patients were recorded just before endotracheal intubation, immediately after intubation, and during the first 3 min after intubation. The primary outcomes were haemodynamic changes. The full dose-response relationship between dexmedetomidine and sufentanil was analysed using a logit model. Results: This response surface model revealed that the interaction between dexmedetomidine and sufentanil was additive. The dose pairs that could effectively attenuate the haemodynamic response to endotracheal intubation primarily ranged from .3 to .4 µg/kg and .5 to 1.1 µg/kg for sufentanil and dexmedetomidine, respectively. Conclusion: When used propofol as the main hypnotic drug during anaesthesia induction, dexmedetomidine could effectively reduce the requirement of sufentanil in an additive manner. However, it is not an effective drug for ablating the cardiovascular response to endotracheal intubation when used alone. The clinical trial registry. The trial registry name: Chinese Clinical Trial Registry. Registration number: ChiCTR1800015273. URL:http://www.chictr.org.cn.

A Neural Circuit from the Paraventricular Thalamus to the Bed Nucleus of the Stria Terminalis for the Regulation of States of Consciousness during Sevoflurane Anesthesia in Mice.

BACKGROUND: The neural circuitry underlying sevoflurane-induced modulation of consciousness is poorly understood. This study hypothesized that the paraventricular thalamus bed nucleus of the stria terminalis pathway plays an important role in regulating states of consciousness during sevoflurane anesthesia. METHODS: Rabies virus-based transsynaptic tracing techniques were employed to reveal the neural pathway from the paraventricular thalamus to the bed nucleus of the stria terminalis. This study investigated the role of this pathway in sevoflurane anesthesia induction, maintenance, and emergence using chemogenetic and optogenetic methods combined with cortical electroencephalogram recordings. Both male and female mice were used in this study. RESULTS: Both γ-aminobutyric acid-mediated and glutamatergic neurons in the bed nucleus of the stria terminalis receive paraventricular thalamus glutamatergic projections. Chemogenetic inhibition of paraventricular thalamus glutamatergic neurons prolonged the sevoflurane anesthesia emergence time (mean ± SD, hM4D-clozapine N-oxide vs. mCherry-clozapine N-oxide, 281 ± 88 vs. 172 ± 48 s, P < 0.001, n = 24) and decreased the induction time (101 ± 32 vs. 136 ± 34 s, P = 0.002, n = 24), as well as the EC5 0 for the loss or recovery of the righting reflex under sevoflurane anesthesia (mean [95% CI] for the concentration at which 50% of the mice lost their righting reflex, 1.16 [1.12 to 1.20] vs. 1.49 [1.46 to 1.53] vol%, P < 0.001, n = 20; and for the concentration at which 50% of the mice recovered their righting reflex, 0.95 [0.86 to 1.03] vs. 1.34 [1.29 to 1.40] vol%, P < 0.001, n = 20). Similar results were observed during suppression of the paraventricular thalamus bed nucleus-stria terminalis pathway. Optogenetic activation of this pathway produced the opposite effects. Additionally, transient stimulation of this pathway efficiently induced behavioral arousal during continuous steady-state general anesthesia with sevoflurane and reduced the depth of anesthesia during sevoflurane-induced burst suppression. CONCLUSIONS: In mice, axonal projections from the paraventricular thalamic neurons to the bed nucleus of the stria terminalis contribute to regulating states of consciousness during sevoflurane anesthesia.

Adipocytokines: Emerging therapeutic targets for pain management.

Although pain has lower mortality rates than cancer, diabetes and stroke, pain is a predominate source of distress and disability. However, the management of pain remains an enormous problem. Many drugs used to pain treatment have more or less side effects. Therefore, the development of novel therapeutic target is critical for the treatment of pain. Notably, studies have shown that adipocytokines have a dual role in pain. Growing shreds of evidence shows that the levels of adipocytokines are upregulated or downregulated in the development of pain. In addition, substantial evidence indicates that regulation of adipocytokines levels in models of pain attenuates or promotes pain behaviors. In this review, we summarized and discussed the effect of adipocytokines in pain. These evidence indicates that adipocytokines attenuate or promote pain behaviors through interacting with their receptors, activating serotonin pathway, interacting with µ-opioid receptor, activating microglia, infiltrating macrophage and so on. Overall, adipocytokines have some potential in treating pain, but the underlying mechanisms remain unclear and need to be further studied.