Hearing loss, depression and social participation of older adults: Evidence from the China health and retirement longitudinal study.

AIM: Hearing loss and depression in older adults are associated with a lower social participation rate. However, few studies have thoroughly analyzed the relationship between them. METHODS: The data were obtained from the China Health and Retirement Longitudinal Study carried out in 2011, 2013 and 2015, and data from 24 306 participants ranging in age from 50 to 80 years were used in this study. Hearing loss, depression and social participation were assessed by self-reported hearing status, the 10-item Center for the Epidemiological Studies of Depression Short Form, and self-reported social participation activity types and frequency. The fixed effects logistic regression and random effects logistic regression were used to examine the relationship between hearing loss and social participation. The Sobel method was used to explore the relationship between hearing loss, depression and social participation. RESULTS: Compared with older adults without hearing loss, persons with hearing loss engaged in significantly fewer types of activities (ß = -0.070, 95% CI -0.109, -0.031, P < 0.001) and at a lower frequency (ß = -0.176, 95% CI -0.260, -0.093, P < 0.001). Depression significantly existed in the relationship between hearing loss and social participation as a mediating variable, and the percentage of indirect effects in this relationship were 16.5% and 20.8%. CONCLUSIONS: The findings of this study suggest that when facing an aging society, improving the hearing status of older adults should be considered by policymakers. More efforts should be made to help older adults cope with depression. Geriatr Gerontol Int 2022; 22: 529-535.

LncRNA IRAR regulates chemokines production in tubular epithelial cells thus promoting kidney ischemia-reperfusion injury.

Increasing evidence demonstrates that long noncoding RNAs (lncRNAs) play an important role in several pathogenic processes of the kidney. However, functions of lncRNAs in ischemic acute kidney injury (AKI) remain undefined. In this study, global lncRNA profiling indicated that many lncRNA transcripts were deregulated in kidney after ischemia reperfusion (IR). Among them, we identified IRAR (ischemia-reperfusion injury associated RNA) as a potential lncRNA candidate, which was mostly expressed by the tubular epithelial cells (TECs) after IR, involved in the development of AKI. GapmeR-mediated silencing and viral-based overexpression of IRAR were carried out to assess its function and contribution to IR-induced AKI. The results revealed that in vivo silencing of IRAR significantly reduced IR-induced proinflammatory cells infiltration and AKI. IRAR overexpression induced chemokine CCL2, CXCL1 and CXCL2 expression both in mRNA and protein levels in TECs, while, silencing of IRAR resulted in downregulation of these chemokines. RNA immunoprecipitation and RNA pulldown assay validated the association between IRAR and CCL2, CXCL1/2. Further examination revealed that specific ablation of CCL2 in TECs reduced macrophages infiltration and proinflammatory cytokine production, attenuated renal dysfunction in IR mice. Inhibition of CXC chemokine receptor 2 (receptor of CXCL1/2) reduced neutrofils infiltration, but had no overt effect on kidney function. To explore the mechanism of IRAR upregulation in kidney during IR, we analyzed promoter region of IRAR and predicted a potential binding site for transcription factor C/EBP ß on IRAR promoter. Silencing of C/EBP ß reduced IRAR expression in TECs. A dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP) confirmed that IRAR was a transcriptional target of the C/EBP ß. Altogether, our findings identify IRAR as a new player in the development of ischemic AKI through regulating chemokine production and immune cells infiltration, suggesting that IRAR is a potential target for prevention and/or attenuation of AKI.

Depletion of miR-21 in dendritic cells aggravates renal ischemia-reperfusion injury.

Dendritic cells (DCs) play an important role in the pathophysiology of renal ischemia-reperfusion injury (IRI). The mechanisms underlying DCs phenotypic modulation and their function are not fully understood. In this study, we examined the effect of miR-21 on the phenotypic modulation of DCs in vitro and in vivo, and further investigated the impact of miR-21-overexpression DC or miR-21-deficient DC on renal IRI. We found that treatment with hypoxia/reoxygenation (H/R) suppressed miR-21 expression in bone marrow-derived dendritic cells (BMDCs), and significantly increased the percentage of mature DCs (CD11c+ /MHC-II+ /CD80+ ). Using a selection of microRNA mimics, we successfully induced the upregulation of miR-21 in BMDCs, which induced immature DC phenotype and an anti-inflammatory DC response. However, deletion of miR-21 in BMDCs promoted maturation of DCs under H/R. Adoptive transfer of miR-21-overexpression BMDCs could alleviate renal IR-induced pro-inflammatory cytokines production and acute kidney injury (AKI). Mice with miR-21 deficiency in DCs subjected to renal IR showed more severe renal dysfunction and inflammatory response compared with wild-type mice. In addition, chemokine C receptor 7 (CCR7), a surface marker of mature DC, was a target gene of miR-21, and silencing of CCR7 in BMDCs led to reduced mature DCs under H/R. In conclusion, our findings highlight miR-21 as a key regulator of DCs subset phenotype and a potential therapeutic target in renal IRI.

Using Multilayered Hydrogel Bioink in Three-Dimensional Bioprinting for Homogeneous Cell Distribution.

During the extrusion-based three-dimensional bioprinting process, liquid-like bioinks with low viscosity can protect cells from membrane damage induced by shear stress and improve the survival of the encapsulated cells. However, rapid gravity-driven cell sedimentation in the reservoir could lead to an inhomogeneous cell distribution in bioprinted structures and therefore hinder the application of liquid-like bioinks. Here, we developed a novel multilayered modified strategy for liquid-like bioinks (e.g., gelatin methacryloyl with low viscosity) to prevent the sedimentation of encapsulated cells. Multiple liquid interfaces were manipulated in the multilayered bioink to provide interfacial retention. Consequently, the cell sedimentation action going across adjacent layers in the multilayered system was retarded in the bioink reservoir. It was found that the interfacial retention was much higher than the sedimental pull of cells, demonstrating a critical role of the interfacial retention in preventing cell sedimentation and promoting a more homogeneous dispersion of cells in the multilayered bioink.

Uncoupling protein 1 inhibits mitochondrial reactive oxygen species generation and alleviates acute kidney injury.

BACKGROUND: Uncoupling protein 1 (UCP1) is predominantly found in brown adipose tissue mitochondria, and mediates energy dissipation to generate heat rather than ATP via functional mitochondrial uncoupling. However, little is known about its expression and function in kidney. METHODS: We carried out a mRNA microarray analysis in mice kidneys with ischemia reperfusion (IR) injury. The most dramatically downregulated gene UCP1 after IR was identified, and its role in generation of mitochondrial reactive oxygen species (ROS) and oxidative stress injury was assessed both in vitro and in vivo. Genetic deletion of UCP1 was used to investigate the effects of UCP1 on ischemia or cisplatin-indued acute kidney injury (AKI) in mice. FINDINGS: UCP1 was located in renal tubular epithelial cells in kidney and downregulated in a time-dependent manner during renal IR. Deletion of UCP1 increased oxidative stress in kidneys and aggravated ischemia or cisplatin induced AKI in mice.Viral-based overexpression of UCP1 reduced mitochondrial ROS generation and apoptosis in hypoxia-treated tubular epithelial cells. Furthermore, UCP1 expression was regulated by peroxisome proliferator-activator receptor (PPAR) γ in kidneys during renal IR. Overexpression of PPAR-γ resembled UCP1-overexpression phenotype in vitro. Treatment with PPAR-γ agonist could induce UCP1 upregulation and provide protective effect against renal IR injury in UCP1+/+mice, but not in UCP1-/-mice. INTERPRETATION: UCP1 protects against AKI likely by suppressing oxidative stress, and activation of UCP1 represents a potential therapeutic strategy for AKI. FUND: National Natural Science Foundation of China grants, Science and Technology Commission of Shanghai.

Hydrogel Bioink with Multilayered Interfaces Improves Dispersibility of Encapsulated Cells in Extrusion Bioprinting.

One of the challenges for extrusion bioprinting using low-viscosity bioinks is the fast gravity-driven sedimentation of cells. Cells in a hydrogel bioink that features low viscosity tend to settle to the bottom of the bioink reservoir, and as such, their bioprintability is hindered by association with the inhomogeneous cellularized structures that are deposited. This is particularly true in cases where longer periods are required to print complex or larger tissue constructs. Increasing the bioink's viscosity efficiently retards sedimentation but gives rise to cell membranolysis or functional disruption due to increased shear stress on the cells during the extrusion process. Inspired by the rainbow cocktail, we report the development of a multilayered modification strategy for gelatin methacryloyl (GelMA) bioink to manipulate multiple liquid interfaces, providing interfacial retention to retard cell sedimentation in the bioink reservoir. Indeed, the interfacial tension in our layer-by-layer bioink system, characterized by the pendant drop method, was found to be exponentially higher than the sedimental pull (ΔGravity-Buoyancy = ∼10-9 N) of cells, indicating that the interfacial retention is crucial for preventing cell sedimentation across the adjacent layers. It was demonstrated that the encapsulated cells displayed better dispersibility in constructs bioprinted using the multilayered GelMA bioink system than that of pristine GelMA where the index of homogeneity of the cell distribution in the multilayered bioink was 4 times that of the latter.

The comparison of healthcare utilization inequity between URRBMI and NCMS in rural China.

BACKGROUND: The inequity of healthcare utilization in rural China is serious, and the urban-rural segmentation of the medical insurance system intensifies this problem. To guarantee that the rural population enjoys the same medical insurance benefits, China began to establish Urban and Rural Resident Basic Medical Insurance (URRBMI) nationwide in 2016. Against this backdrop, this paper aims to compare the healthcare utilization inequity between URRBMI and New Cooperative Medical Schemes (NCMS) and to analyze whether the inequity is reduced under URRBMI in rural China. METHODS: Using the data from a national representative survey, the China Health and Retirement Longitudinal Study (CHARLS), which was conducted in 2015, a binary logistic regression model was applied to analyze the influence of income on healthcare utilization, and the decomposition of the concentration index was adopted to compare the Horizontal inequity index (HI index) of healthcare utilization among the individuals insured by URRBMI and NCMS. RESULTS: There is no statistically significant difference in healthcare utilization between URRBMI and NCMS, but in outpatient utilization, there are significant differences among different income groups in NCMS; high-income groups utilize more outpatient care. The Horizontal inequity indexes (HI indexes) in outpatient utilization for individuals insured by URRBMI and NCMS are 0.024 and 0.012, respectively, indicating a pro-rich inequity. Meanwhile, the HI indexes in inpatient utilization under the two groups are - 0.043 and - 0.028, respectively, meaning a pro-poor inequity. For both the outpatient and inpatient care, the inequity degree of URRBMI is larger than that of NCMS. CONCLUSIONS: This paper shows that inequity still exists in rural areas after the integration of urban-rural medical insurance schemes, and there is still a certain gap between the actual and the expected goal of URRBMI. Specifically, compared to NCMS, the pro-rich inequity in outpatient care and the pro-poor inequity in inpatient care are more serious in URRBMI. More chronic diseases should be covered and moral hazard should be avoided in URRBMI. For the vulnerable groups, special policies such as reducing the deductible and covering these groups with catastrophic medical insurance could be considered.

Delayed Remote Ischemic Preconditioning ConfersRenoprotection against Septic Acute Kidney Injury via Exosomal miR-21.

Sepsis is a common and life-threatening systemic disorder, often leading to acute injury of multiple organs. Here, we show that remote ischemic preconditioning (rIPC), elicited by brief episodes of ischemia and reperfusion in femoral arteries, provides protective effects against sepsis-induced acute kidney injury (AKI). Methods: Limb rIPC was conducted on mice in vivo 24 h before the onset of cecal ligation and puncture (CLP), and serum exosomes derived from rIPC mice were infused into CLP-challenged recipients. In vitro, we extracted and identified exosomes from differentiated C2C12 cells (myotubes) subjected to hypoxia and reoxygenation (H/R) preconditioning, and the exosomes were administered to lipopolysaccharide (LPS)-treated mouse tubular epithelial cells (mTECs) or intravenously injected into CLP-challenged miR-21 knockout mice for rescue experiments. Results: Limb rIPC protected polymicrobial septic mice from multiple organ dysfunction, systemic accumulation of inflammatory cytokines and accelerated parenchymal cell apoptosis through upregulation of miR-21 in a hypoxia-inducible factor 1α (HIF-1α)-dependent manner in the ischemic limbs of mice. However, in miR-21 knockout mice or mice that received HIF-1α siRNA injection into hind limb muscles, the organ protection conferred by limb rIPC was abolished. Mechanistically, we discovered that miR-21 was transported from preischemic limbs to remote organs via serum exosomes. In kidneys, the enhanced exosomal miR-21 derived from cultured myotubes with H/R or the serum of mice treated with rIPC integrated into renal tubular epithelial cells and then targeted the downstream PDCD4/NF-κB and PTEN/AKT pathways, exerting anti-inflammatory and anti-apoptotic effects and consequently attenuating sepsis-induced renal injury both in vivo and in vitro. Conclusion: This study demonstrates a critical role for exosomal miR-21 in renoprotection conferred by limb rIPC against sepsis and suggests that rIPC and exosomes might serve as the possible therapeutic strategies for sepsis-induced kidney injury.

EP4 knockdown alleviates glomerulosclerosis through Smad and MAPK pathways in mesangial cells.

Prostaglandin E2 has exhibited pleiotropic effects in the regulation of glomerulosclerosis progression through its four receptors. The current study aimed to evaluate the effect of prostaglandin receptor EP4 on mesangial cell proliferation. In vivo, 5/6 nephrectomy was introduced into EP4+/­ and wild­type (WT) mice. Clinical parameters were monitored post­surgery. At 8 weeks post­surgery, glomerular fibrosis­associated indicators were measured by immunohistochemical staining and trichrome staining. In vitro, mesangial cells in different groups (transfected with green fluorescent protein, AD­EF4 or AD­CRE) were exposed to transforming growth factor (TGF)­ß1 for 24 h to detect the level of downstream signaling. Corresponding signaling inhibitors were also used to validate the signaling effects. Following surgery, EP4+/­ mice presented a higher survival rate and normal urine volume compared with the WT group, and serum creatinine level and 24 h urine protein were lower in the EP4+/­ mice. Furthermore, associated profibrotic indicators were identified to have decreased at 8 weeks post­surgery along with less tubule­interstitial fibrosis. In vivo, the inhibition of extracellular signal­regulated kinase and P38 phosphorylation alleviated the accumulation of mesangial matrix, and these signals were enhanced when EP4 was overexpressed. EP4 enhancement aggravated imbalanced mesangial cell proliferation stimulated by TGF­ß1 and GS of mice treated with 5/6 nephrectomy through the Smad and mitogen­activated protein kinase pathways.

Role of the ER stress in prostaglandin E2/E-prostanoid 2 receptor involved TGF-ß1-induced mice mesangial cell injury.

This study aims to investigate the relationship between prostaglandin E2 E-prostanoid 2 receptor (EP2) and Endoplasmic reticulum (ER) stress in transforming growth factor-ß1 (TGF-ß1)-induced mouse glomerular mesangial cells (MCs) injury. We cultured primary WT, EP2(-/-) MCs (EP2 deleted), and adenovirus-EP2-infected WT MCs (EP2 overexpressed). PCR, Western blot, flow cytometry, and immunohistochemical technique were used in in vitro and in vivo experiments. We found that TGF-ß1-induced PGE2 synthesis decreased in EP2-deleted MCs and increased in EP2-overexpressed MCs. EP2 deficiency in these MCs augmented the coupling of TGF-ß1 to ER stress-associated proteins [chaperone glucose-regulated protein 78 (GRP78), transient receptor potential channel 1 (TRPC1), and transient receptor potential channel 4 (TRPC4)], and upregulation of EP2 showed no significant change of GRP78, but augmented the expression of TRPC1, while TRPC4 expression was downregulated in comparison to normal MCs. In addition, EP2 deficiency in MCs augmented TGF-ß1-induced fibronectin (FN), cyclooxygenase-2 (COX2), and CyclinD1 expression. Silencing of EP2 also strengthened TGF-ß1-induced extracellular-signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Flow Cytometry showed that silencing of EP2 significantly promoted the apoptosis of MCs. In contrast, EP2 overexpression reversed the effects of EP2 deficiency. 8 weeks after 5/6 nephrectomy (Nx), blood urea nitrogen and creatinine concentrations were significantly increased in EP2(-/-) 5/6Nx mice as compared to those of WT 5/6Nx mice. The pathological changes in kidney of EP2(-/-) mice were markedly aggravated compared with WT mice. Immunohistochemical analysis showed significant augment of TRPC4 and ORP150 in the kidney of EP2(-/-) mice compared with WT mice. Considering all the findings, it is suggested that increased expression of EP2 may prevent TGF-ß1-induced MCs damage through ER stress regulatory pathway.