Delta Opioid Peptide [d-Ala2, d-Leu5]-Enkephalin Improves Physical and Cognitive Function and Increases Lifespan in Aged Female Mice.

In this study, we explored the potential application of [d-Ala2, d-Leu5]-enkephalin (DADLE) in anti-ageing field in response to the trend of increasing global population ageing. We aimed to reveal experimentally whether DADLE can positively affect the lifespan and health of aged mammals through its unique anti-inflammatory or metabolic mechanisms. Forty-two female C57/BL6J mice aged 18 months were intraperitoneally injected with DADLE or normal saline for 2 months. Cognitive and motor functions were assessed using a water maze and treadmill stress test, respectively. The expressions of P16INK4A, Lamin B1 and sirtuin 1 were observed in the hippocampus and heart. The level of pro-inflammatory cytokines in the serum was measured by enzyme-linked immunosorbent assay. The telomere length of the mice was determined using the polymerase chain reaction method. Transcriptome analysis of 6-month-old female C57BL/6 J mice brains and hearts was assessed for body weight effects. Supplementation of exogenous DADLE to aged mice has demonstrated significant benefits, including improved motor function, enhanced cognitive performance and significantly extended lifespan. DADLE treatment resulted in a substantial increase in anti-ageing markers and a corresponding decrease in pro-ageing markers in the heart and brain of these mice. DADLE attenuated age-related inflammation, as evidenced by reductions in serum pro-inflammatory cytokines and inflammatory cell infiltration in tissues. Furthermore, DADLE supplementation significantly prolonged relative telomere length in aged female mice, suggesting a potential mechanism for its anti-ageing effects. Transcriptome analysis revealed that immune response and cellular signalling pathways are intricately involved in the protective effects of DADLE in aged mice, providing further insights into its mechanism of action. Inflammatory reaction may be improved by DADLE by regulating the infiltration of inflammatory cells in the liver and kidney and regulating the cognitive function of the brain and the ageing of the heart in mice.

Intranasal Delivery of Quillaja brasiliensis Saponin-Based Nanoadjuvants Improve Humoral Immune Response of Influenza Vaccine in Aged Mice.

Increasing the effectiveness of vaccines against respiratory viruses is particularly relevant for the elderly, since they are prone to develop serious infections due to comorbidities and the senescence of the immune system. The addition of saponin-based adjuvants is an interesting strategy to increase the effectiveness of vaccines. We have previously shown that ISCOM matrices from Q. brasiliensis (IMXQB) are a safe and potent adjuvant. In this study, we evaluated the use of IMXQB as an adjuvant for the seasonal trivalent influenza vaccine (TIV) in an aged mice model. Herein, we show that subcutaneous injection of the adjuvanted vaccine promoted higher titers of IgM, IgG (and isotypes), and serum hemagglutination inhibition titers (HAI). Notably, aged mice immunized by intranasal route also produced higher IgG (and isotypes) and IgA titers up to 120 days after priming, as well as demonstrating an improvement in the HAI antibodies against the TIV. Further, experimental infected aged mice treated once with sera from adult naïve mice previously immunized with TIV-IMXQB subcutaneously successfully controlled the infection. Overall, TIV-IMXQB improved the immunogenicity compared to TIV by enhancing systemic and mucosal immunity in old mice conferring a faster recovery after the H1N1pdm09-like virus challenge. Thus, IMXQB nanoparticles may be a promising platform for next-generation viral vaccines.

Effect of Wei Qi Booster on immune and anti-oxidative function in aged mice.

This research was conducted to examine the impact of Wei Qi Booster (WQB) on immune parameters and anti-oxidative function in aged mice. Fifty aged mice were randomly assigned to five different groups. Group A was designated as the control group. Mice in Group B were receiving Levamisole at 10 mg/kg body weight. Each mouse in groups C, D and E received 0.1, 1, and 2% WQB, respectively. Another ten young mice, designated as group F, were fed regularly. The mice were fed according to the above methods for 28 days. Results showed that relative to the control group, the body weight and immune organs indexes experienced a substantial rise in the group with 1% WQB. In addition, 1% WQB could improve the activity of SOD and reduce the MDA levels. Expressions of CD4 and sIgA increased while CD8 decreased in the jejunum of aged mice treated with WQB. IL2 and IFN-γ levels increased in the 1% WQB group, showing no notable difference compared to the young mice group. The results demonstrated that WQB can elevate immune levels and enhance anti-oxidative functions in aged mice.

Mechanism research on microRNA-669f-5p/deoxycytidylate deaminase axis mediating sevoflurane-induced cognitive dysfunction in aged mice.

OBJECTIVE: To investigate the role of the microRNA (miRNA)-669f-5p/deoxycytidylate deaminase (Dctd) axis in sevoflurane inducing cognitive dysfunction in aged mice. METHODS: Sixty-six C57BL/6J mice were used in the experiment model and were randomly divided into the sevoflurane group and the control group. The mice in the sevoflurane group were anesthetised with 3.4% sevoflurane, whereas those in the control group were air-treated for the same period. The study was then performed using bioinformatics sequencing, as well as in vitro and in vivo validation. RESULTS: The mice in the sevoflurane group showed significant cognitive impairments in terms of a decrease in both spatial learning and memory abilities. Experimental doses of miR-669f-5p agonist exhibited no obvious effect on cognitive function following sevoflurane inhalation, but inhibiting the expression of miR-669f-5p could alleviate the impairments. Based on the results of the bioinformatics sequencing, miR-669f-5p/Dctd and the toll-like receptor (TLR) signalling pathway could be the key miRNA, gene and pathway leading to postoperative cognitive dysfunction following sevoflurane inhalation. The aged mice showed significantly increased expression of miR-669f-5p in the hippocampus following sevoflurane inhalation, and upregulating/inhibiting its expression could increase/decrease TLR expression in the hippocampus. Furthermore, miR-669f-5p could reduce the expression of the Dctd gene by binding to its 3'untranslated region. CONCLUSION: The miR-669f-5p/Dctd axis plays an important role in sevoflurane inducing cognitive dysfunction in aged mice, providing a new direction for further development of therapeutic strategies concerning the prevention and treatment of cognitive dysfunction associated with sevoflurane anaesthesia.

Radiofrequency Treatment Attenuates Age-Related Changes in Dermal-Epidermal Junctions of Animal Skin.

The dermal-epidermal junction (DEJ) is essential for maintaining skin structural integrity and regulating cell survival and proliferation. Thus, DEJ rejuvenation is key for skin revitalization, particularly in age-related DEJ deterioration. Radiofrequency (RF) treatment, known for its ability to enhance collagen fiber production through thermal mechanisms and increase heat shock protein (HSP) expression, has emerged as a promising method for skin rejuvenation. Additionally, RF activates Piezo1, an ion channel implicated in macrophage polarization toward an M2 phenotype and enhanced TGF-ß production. This study investigated the impact of RF treatment on HSP47 and HSP90 expression, known stimulators of DEJ protein expression. Furthermore, using in vitro and aged animal skin models, we assessed whether RF-induced Piezo1 activation and the subsequent M2 polarization could counter age-related DEJ changes. The RF treatment of H2O2-induced senescent keratinocytes upregulated the expression of HSP47, HSP90, TGF-ß, and DEJ proteins, including collagen XVII. Similarly, the RF treatment of senescent macrophages increased Piezo1 and CD206 (M2 marker) expression. Conditioned media from RF-treated senescent macrophages enhanced the expression of TGF-ß and DEJ proteins, such as nidogen and collagen IV, in senescent fibroblasts. In aged animal skin, RF treatment increased the expression of HSP47, HSP90, Piezo1, markers associated with M2 polarization, IL-10, and TGF-ß. Additionally, RF treatment enhanced DEJ protein expression. Moreover, RF reduced lamina densa replication, disrupted lesions, promoted hemidesmosome formation, and increased epidermal thickness. Overall, RF treatment effectively enhanced DEJ protein expression and mitigated age-related DEJ structural changes by increasing HSP levels and activating Piezo1.

Supplementation of seasonal vaccine with multi-subtype neuraminidase and M2 ectodomain virus-like particle improves protection against homologous and heterologous influenza viruses in aged mice.

The conventional inactivated split seasonal influenza vaccine offers low efficacy, particularly in the elderly and against antigenic variants. Here, to improve the efficacy of seasonal vaccination for the elderly population, we tested whether supplementing seasonal bivalent (H1N1 + H3N2) split (S) vaccine with M2 ectodomain repeat and multi-subtype consensus neuraminidase (NA) proteins (N1 NA + N2 NA + flu B NA) on a virus-like particle (NA-M2e) would induce enhanced cross-protection against different influenza viruses in aged mice. Immunization with split vaccine plus NA-M2e (S + NA-M2e) increased vaccine-specific IgG antibodies towards T-helper type 1 responses and hemagglutination inhibition titers. Aged mice with NA-M2e supplemented vaccination were protected against homologous and heterologous viruses at higher efficacies, as evidenced by preventing weight loss, lowering lung viral loads, inducing broadly cross-protective humoral immunity, and IFN-γ+ CD4 and CD8 T cell responses than those with seasonal vaccine. Overall, this study supports a new strategy of NA-M2e supplemented vaccination to enhance protection against homologous and antigenically different viruses in the elderly.

Antioxidant and Anti-Fatigue Effects of a Standardized Botanical Extract Fraction (HemoHIM) in Forced-Exercised Aged Mice.

HemoHIM is a standardized medicinal herbal preparation consisting of extracts of Angelica gigas Nakai, Cnidium officinale Makino, and Paeonia lactiflora Pallas that possesses immune regulatory activities. This study aimed to research the potential antioxidant effects of HemoHIM and its capacity for reducing fatigue in aged mice subjected to forced exercise. After administering HemoHIM 125 (500 mg/kg orally) for 4 weeks in 8-month-old female C57BL/6 mice (4 groups of 10 mice), various parameters were evaluated. The analyses revealed that HemoHIM enhanced swimming time and grip strength. In addition, it significantly reduced serum lactate levels and increased liver glutathione peroxidase (GPx) levels after exercise challenge. The expression levels of antioxidant enzymes and factors, including nuclear factor erythroid 2-related factor-2 (Nrf-2), heme oxygenase 1, superoxide dismutase, GPx, and glutathione reductase, were significantly higher in liver and muscle tissues of mice treated with HemoHIM. These results indicate that HemoHIM might function as an anti-fatigue and antioxidant agent by modulating the Nrf-2 signaling pathway.

Effect of age on orthodontic tooth movement in mice.

Background/purpose: The number of middle-aged and elderly orthodontic patients is increasing due to changes in age composition. It is important to investigate the detailed mechanisms of bone remodeling in orthodontic tooth movement (OTM) in the elderly. However, there are few reports on the mechanism of tooth movement in the elderly. The purpose of the present study was to analyze OTM and osteoclastogenesis in aged mice and to elucidate the mechanism. Materials and methods: It has been reported that tumor necrosis factor (TNF)-α plays an important role in osteoclast formation and OTM. First, 8-week-old and 78-week-old male C57BL/6J mice were subcutaneously injected with TNF-α into the calvaiae, and micro-CT, tartrate-resistant acid phosphatase (TRAP) staining, and real-time PCR were performed to evaluate osteoclast formation and bone resorption. Furthermore, osteoclastogenesis by TNF-α and receptor activator of nuclear factor-kappa B ligand (RANKL) using bone marrow cells was evaluated in vitro. Finally, a nickel-titanium closed-coil spring was attached, mesial movement of the maxillary left first molar was performed, and tooth movement distance and osteoclast formation were evaluated. Results: Compared to 8-week-old mice, 78-week-old mice had decreased TNF-α-induced bone resorption, osteoclastogenesis, and TRAP and cathepsin K expression in the calvariae. In vitro osteoclast formation also decreased in 78-week-old mice. Furthermore, tooth movement distance and osteoclastogenesis were reduced. Conclusion: OTM decreased in aged mice, which was shown to be caused by a decrease in osteoclastogenesis. Therefore, it was suggested that it is necessary to keep in mind that tooth movement may be suppressed when treating elderly patients.

Long-term exposure to dietary emulsifier Tween 80 promotes liver lipid accumulation and induces different-grade inflammation in young and aged mice.

With the advent of industrialization, there has been a substantial increase in the production and consumption of ultra-processed foods (UPFs). These processed foods often contain artificially synthesized additives, such as emulsifiers. Emulsifiers constitute approximately half of the total amount of food additives, with Tween 80 being a commonly used emulsifier in the food industry. Concurrently, China is undergoing significant demographic changes, transitioning into an aging society. Despite this demographic shift, there is insufficient research on the health implications of food emulsifiers, particularly on the elderly population. In this study, we present novel findings indicating that even at low concentrations, Tween 80 suppressed the viability of multiple cell types. Prolonged in vivo exposure to 1 % Tween 80 in drinking water induced liver lipid accumulation and insulin resistance in young adult mice under a regular chow diet. Intriguingly, in mice with high-fat diet (HFD) induced metabolic dysfunction-associated steatotic liver disease (MASLD), this inductive effect was masked. In aged mice, liver lipid accumulation was replicated under prolonged Tween 80 exposure. We further revealed that Tween 80 induced inflammation in both adult and aged mice, with a more pronounced inflammation in aged mice. In conclusion, our study provides compelling evidence that Tween 80 could contribute to a low-grade inflammation and liver lipid accumulation. These findings underscore the need for increasing attention regarding the consumption of UPFs with Tween 80 as the emulsifier, particularly in the elderly consumers.

A mixed antioxidant supplement improves cognitive function, and coordination in aged mice.

Accumulation of oxidative damage increases the risk of several disorders. To prevent these diseases, people consume supplements. However, there is little evidence of the impact of supplement intake on cognitive function. Recently, frailty and sarcopenia have become serious issues, and these phenomena include a risk of mild cognitive impairment. In this study, aged mice were fed the combination supplement and cognitive and motor functions were measured. Following 1 month of treatment with the supplement, significant improvements in cognitive function and neuromuscular coordination were observed. Following 2 weeks of treadmill training, treatment with the supplement dramatically increased running distance compared to that in untreated normal aged mice. Serum indices such as triglyceride and total cholesterol were significantly decreased in the supplement-treated aged mice compared to untreated aged mice. These results indicate that the combination supplement may play a role in maintaining cognitive function, coordination ability and improving lipid metabolism.

A Blended Vitamin Supplement Improves Spatial Cognitive and Short-Term Memory in Aged Mice.

Although many types of antioxidant supplements are available, the effect is greater if multiple types are taken simultaneously rather than one type. However, it is difficult to know which type and how much to take, as it is possible to take too many of some vitamins. As it is difficult for general consumers to make this choice, it is important to provide information based on scientific evidence. This study investigated the various effects of continuous administration of a blended supplement to aging mice. In 18-month-old C57BL/6 mice given a blended supplement ad libitum for 1 month, spatial cognition and short-term memory in the Morris water maze and Y-maze improved compared with the normal aged mice (spontaneous alternative ratio, normal aged mice, 49.5%, supplement-treated mice, 68.67%, p < 0.01). No significant differences in brain levels of secreted neurotrophic factors, such as nerve growth factor and brain-derived neurotrophic factor, were observed between these two groups. In treadmill durability tests before and after administration, the rate of increase in running distance after administration was significantly higher than that of the untreated group (increase rate, normal aged mice, 91.17%, supplement-treated aged mice, 111.4%, p < 0.04). However, training had no reinforcing effect, and post-mortem serum tests showed a significant decrease in aspartate aminotransferase, alanine aminotransferase, and total cholesterol values. These results suggest continuous intake of a blended supplement may improve cognitive function and suppress age-related muscle decline.

Aged AßPPswe/PS1ΔE9 mice as a useful animal model for studying the link between immunological senescence and diseases.

The APPswe/PS1ΔE9 mouse is a double transgenic murine model that harbors two transgenes for Alzheimer's Disease (AD)-related mutant proteins. We previously discovered that this double transgenic animal had a premature immunosenescence phenotype. However, it is unclear how this phenotype progresses to a later stage. This study aimed to elucidate the changes in systemic characteristics aside from those associated with AD between elderly APPswe/PS1ΔE9 mice and littermate control wild-type mice. Tumors in all organs were considerably more frequent in AD mice aged 24 months than in the control wild-type mice. In addition, the survival rate of aged AD mice was considerably lower than that of wild-type control mice. Further, we discovered that the phenotypic difference was mainly caused by severe immunological aging, as evidenced by a high proportion of exhausted T lymphocytes in AD mice compared to wild-type mice of the same age. Based on our findings, the harm produced by normal aging is not as severe as immunological senescence. Addressing immunological aging, as opposed to anti-aging alone, may be a more crucial target for a long life free of cancer.

Iron accumulation induced by hepcidin1 knockout accelerates the progression of aging osteoporosis.

OBJECTIVE: Iron accumulation is associated with osteoporosis. This study aims to explore the effect of chronic iron accumulation induced by hepcidin1 deficiency on aging osteoporosis. METHODS: Iron accumulation in hepcidin1 knockout aging mice was assessed by atomic absorption spectroscopy and Perl's staining. Bone microarchitecture was observed using Micro-CT. Hepcidin, ferritin, oxidative stress, and markers of bone turnover in serum were detected by enzyme-linked immunosorbent assay. Bone formation and resorption markers were measured by real-time quantitative PCR. Cell aging was induced by D-galactose treatment. CCK-8, flow cytometry, EdU assays, and Alizarin red staining were performed to reveal the role of hepcidin1 knockout in cell model. Iron Colorimetric Assay Kit and western blot were applied to detect iron and ferritin levels in cells, respectively. RESULTS: In hepcidin1-knockout mice, the ferritin and iron contents in liver and tibia were significantly increased. Iron accumulation induced by hepcidin1 knockout caused a phenotype of low bone mass and deteriorated bone microarchitecture. Osteogenic marker was decreased and osteoclast marker was increased in mice, accompanied by increased oxidative stress level. The mRNA expression levels of osteoclast differentiation markers (RANKL, Mmp9, OPG, Trap, and CTSK) were up-regulated, while bone formation markers (OCN, ALP, Runx2, SP7, and Col-1) were down-regulated in model group, compared to wild type mice. In vitro, hepcidin1 knockdown inhibited proliferation and osteogenic differentiation, while promoted apoptosis, with increased levels of iron and ferritin. CONCLUSION: Iron accumulation induced by hepcidin1 deficiency aggravates the progression of aging osteoporosis via inhibiting osteogenesis and promoting osteoclast genesis.

Aged AG129 mice support the generation of highly virulent novel mouse-adapted DENV (1-4) viruses exhibiting neuropathogenesis and high lethality.

Dengue virus infection in humans ranges from asymptomatic infection to severe infection, with ∼2.5 % overall disease fatality rate. Evidence of neurological manifestations is seen in the severe form of the disease, which might be due to the direct invasion of the viruses into the CNS system but is poorly understood. In this study, we demonstrated that the aged AG129 mice are highly susceptible to dengue serotypes 1-4, and following the adaptation, this resulted in the generation of neurovirulent strains that showed enhanced replication, aggravated disease severity, increased neuropathogenesis, and high lethality in both adult and aged AG129 mice. The infected mice had endothelial dysfunction, elicited pro-inflammatory cytokine responses, and exhibited 100 % mortality. Further analysis revealed that aged-adapted DENV strains induced measurable alterations in TLR expression in the aged mice as compared to the adult mice. In addition, metabolomics analysis of the serum samples from the infected adult mice revealed dysregulation of 18 metabolites and upregulation of 6-keto-prostaglandin F1 alpha, phosphocreatine, and taurocholic acid. These metabolites may serve as key biomarkers to decipher and comprehend the severity of dengue-associated severe neuro-pathogenesis.

Environmental Enrichment Improves Motor Function and Muscle Transcriptome of Aged Mice.

Aging results in the progressive decline of muscle strength. Interventions to maintain muscle strength may mitigate the age-related loss of physical function, thus maximizing health span. The work on environmental enrichment (EE), an experimental paradigm recapitulating aspects of an active lifestyle, has revealed EE-induced metabolic benefits mediated by a brain-fat axis across the lifespan of mice. EE initiated at 18-month of age shows a trend toward an increased mean lifespan. While previous work described EE's influences on the aging dynamics of several central-peripheral processes, its influence on muscle remained understudied. Here, the impact of EE is investigated on motor function, neuromuscular physiology, and the skeletal muscle transcriptome. EE is initiated in 20-month-old mice for a five-month period. EE mice exhibit greater relative lean mass that is associated with improved mobility and hindlimb grip strength. Transcriptomic profiling of muscle tissue reveals an EE-associated enrichment of gene expression within several metabolic pathways related to oxidative phosphorylation and the TCA cycle. Many mitochondrial-related genes-several of which participate in the electron transport chain-are upregulated. Stress-responsive signaling pathways are downregulated because of EE. The results suggest that EE improves motor function-possibly through preservation of mitochondrial function-even late in life.

Let-7b-TLR7 Signaling Axis Contributes to the Anesthesia/Surgery-Induced Cognitive Impairment.

Perioperative neurocognitive disorders (PNDs) are severe and common neurological complications among elderly patients following anesthesia and surgery. As the first line of defense of the innate immune system, Toll-like receptors (TLRs) have been found to be involved in the occurrence of neurodegenerative diseases in recent years. However, the role of TLR7 in the pathology and development of PNDs remains largely unclear. In our current study, we hypothesized that increased microRNA let-7b (let-7b) during anesthesia and surgical operation would activate TLR7 signaling pathways and mediate PNDs. Using a mouse model of PNDs, 18-20 months wild-type (WT) mice were undergoing unilateral nephrectomy, and increased TLR7 and let-7b expression levels were found in the surgery group compared with the Sham group. Of note, increased TLR7 was found to be co-localized with let-7b in the hippocampal area CA1 in the PNDs model. In addition, TLR7 and let-7b inhibition could improve hippocampus-dependent memory and attenuate the production of inflammatory cytokines. Together, our results indicated that TLR7 activation and up-regulation might be triggered by increased let-7b under stressful conditions and initiated the downstream inflammatory signaling, playing a substantial role in the development of PNDs.

Effects of Lactobacillus Rhamnosus GG on Activated Microglia and Tau Phosphorylation in the Hippocampus of Aged Mice Induced by Anesthesia and Surgery / 中山大学学报(医学科学版)

ObjectiveTo investigate the effects of Lactobacillus rhamnosus GG （LGG）on microglia and Tau phosphorylation in the hippocampus of aged mice induced by anesthesia and surgery. MethodsA total of thirty 18-month-old C57BL/6J mice were randomly divided into three groups： control group， anesthesia surgery group， and anesthesia surgery + LGG group （10 mice/group）. The aged mice were oral administered by NS or LGG 109 CFU 150 μL once a day for 20 days. Then anesthesia surgery group and anesthesia surgery +LGG group received anesthesia with isoflurane and exploratory laparotomy. The activation status of microglia in the hippocampus was detected by immunofluorescence staining 12 hours after surgery. IL-6 concentration changes was detected by ELISA. The expression changes of Tau protein phosphorylation site （Tau-pS202/pT205） and total Tau protein was detected by western blot. ResultsThe microglia in the hippocampus of the control group were in a resting state， and the concentration of inflammatory factor IL-6 was （82.08 ± 12.07） pg/mL in control group. Compared to the control group， the anesthesia surgery group showed microglial cell Microglia were activated， the concentration of inflammatory factors IL-6 increased significantly to （123.7±5.72） pg/mL （P=0.000）， and the expression of phosphorylated Tau-pS202/pT205 increased the hippocampus （P=0.002）. Compared to the anesthesia surgery group， the activated microglia were inhibited， the concentration of IL-6 decreased to （96.68±9.59） pg/mL （P=0.008）， and the expression of phosphorylated Tau-pS202/pT205 reduced significantly in the AS+LGG group （P=0.002）. While there were no significant changes in total Tau protein among 3 groups. ConclusionPreoperative administration of probiotic LGG can alleviate the activation of microglia， increased secretion of inflammatory factors， and increased Tau protein phosphorylation levels in the hippocampus of elderly mice caused by anesthesia surgery.

Divergent trajectory of replication and intrinsic pathogenicity of SARS-CoV-2 Omicron post-BA.2/5 subvariants in the upper and lower respiratory tract.

BACKGROUND: Earlier Omicron subvariants including BA.1, BA.2, and BA.5 emerged in waves, with a subvariant replacing the previous one every few months. More recently, the post-BA.2/5 subvariants have acquired convergent substitutions in spike that facilitated their escape from humoral immunity and gained ACE2 binding capacity. However, the intrinsic pathogenicity and replication fitness of the evaluated post-BA.2/5 subvariants are not fully understood. METHODS: We systemically investigated the replication fitness and intrinsic pathogenicity of representative post-BA.2/5 subvariants (BL.1, BQ.1, BQ.1.1, XBB.1, CH.1.1, and XBB.1.5) in weanling (3-4 weeks), adult (8-10 weeks), and aged (10-12 months) mice. In addition, to better model Omicron replication in the human nasal epithelium, we further investigated the replication capacity of the post-BA.2/5 subvariants in human primary nasal epithelial cells. FINDINGS: We found that the evaluated post-BA.2/5 subvariants are consistently attenuated in mouse lungs but not in nasal turbinates when compared with their ancestral subvariants BA.2/5. Further investigations in primary human nasal epithelial cells revealed a gained replication fitness of XBB.1 and XBB.1.5 when compared to BA.2 and BA.5.2. INTERPRETATION: Our study revealed that the post-BA.2/5 subvariants are attenuated in lungs while increased in replication fitness in the nasal epithelium, indicating rapid adaptation of the circulating Omicron subvariants in the human populations. FUNDING: The full list of funding can be found at the Acknowledgements section.

Anesthesia/surgery-induced learning and memory dysfunction by inhibiting mitophagy-mediated NLRP3 inflammasome inactivation in aged mice.

Postoperative cognitive dysfunction (POCD) is a common postoperative complication, not only affects the quality of life of the elderly and increases the mortality rate, but also brings a greater burden to the family and society. Previous studies demonstrated that Nod-like receptor protein 3 (NLRP3) inflammasome participates in various inflammatory and neurodegenerative diseases. However, possible mitophagy mechanism in anesthesia/surgery-elicited NLRP3 inflammasome activation remains to be elucidated. Hence, this study clarified whether mitophagy dysfunction is related to anesthesia/surgery-elicited NLRP3 inflammasome activation. POCD model was established in aged C57BL/6 J mice by tibial fracture fixation under isoflurane anesthesia. Morris Water Maze (MWM) was used to evaluate learning and memory abilities. We found that in vitro experiments, lipopolysaccharide (LPS) significantly facilitated NLRP3 inflammasome activation and mitophagy inhibition in BV2 cells. Rapamycin restored mitophagy and improved mitochondrial function, and inhibited NLRP3 inflammasome activation induced by LPS. In vivo experiments, anesthesia and surgery caused upregulation of hippocampal NLRP3, caspase recruitment domain (ASC) and interleukin-1ß (IL-1 ß), and downregulation of microtubule-associated protein light chain 3II (LC3II) and Beclin1 in aged mice. Olaparib inhibited anesthesia/surgery-induced NLRP3, ASC, and IL-1ß over-expression in the hippocampus, while upregulated the expression of LC3II and Beclin1. Furthermore, Olaparib improved cognitive impairment in older mice. These results revealed that mitophagy was involved in NLRP3 inflammasome-mediated anesthesia/surgery-induced cognitive deficits in aged mice. Overall, our results suggested that mitophagy was related in NLRP3 inflammasome-induced cognitive deficits after anesthesia and surgery in aged mice. Activating mitophagy may have clinical benefits in the prevention of cognitive impairment induced by anesthesia and surgery in elderly patients.

Inhibition of MMP-2 and MMP-9 attenuates surgery-induced cognitive impairment in aged mice.

BACKGROUND: The inhibition of matrix metalloproteinases (MMPs) has shown potential in the treatment of various neurodegenerative diseases, and perioperative neurocognitive disorders (PND) is accompanied by the increased expression of MMP-2 and MMP-9 in the hippocampus. However, the effect of inhibiting MMP-2 and MMP-9 on PND is not clear. In this study we aimed to evaluate the effects of inhibiting MMP-2 and MMP-9 on cognitive function in the aged mice after surgery, in order to find a possible target for the prevention and treatment of PND METHODS: In this study, 14-month-old C57BL/6 mice were used to establish a PND model by tibial fracture surgery and sevoflurane anesthesia. Three days later, part of the mice were subjected to cognitive assessment and the other was sacrificed for biochemical analysis. We used the Novel object recognition test and Fear conditioning test to evaluate the postoperative cognitive function of mice. The expression of mmp-2 and MMP-9 was detected by western blotting. We also examined the expression of claudin-5 and occludin using Western blotting, and the activation of microglia and astrocytes using immunofluorescence. RESULTS: The results showed that surgery increased the expression of MMP-2 and MMP-9 in the hippocampus of mice, accompanied by cognitive impairment, decreased expression of claudin-5 and occludin, and increased activation of microglia and astrocytes. However, inhibition of MMP-2 and MMP-9 expression by SB-3CT reversed these changes. CONCLUSIONS: Our study shows that inhibition of MMP-2 and MMP-9 alleviates anesthesia/surgery-induced cognitive decline by increasing BBB integrity and inhibiting glial cell activation.