Age-associated Changes Research Articles

Early Generation Telomerase Deficient Mice to Investigate Clonal Hematopoiesis in Aging

Clonal hematopoiesis is an age-associated condition characterized by the expansion of hematopoietic stem cell (HSC) pools with somatic mutations, observed in 10-30% of individuals older than 70 years. This phenomenon is primarily driven by mutations in transcriptional regulators such as DNMT3A, TET2, and ASXL1. While the clonal expansion of mutated HSCs is ubiquitous with age, it appears largely benign in the absence of strong selective pressures. These benign clones might compensate for the loss of regenerative HSC capacity during aging, and skew differentiation towards the myeloid lineage. Telomere erosion plays a significant role in this process. Telomeres normally prevent the activation of the DNA damage response (DDR) machinery. However, with each cell division, telomeres shorten until they reach a critical length, eventually leading to apoptosis or senescence. Previous studies have suggested a potential involvement of telomere attrition in the development of clonal hematopoiesis (Hinds et al. Blood 2016; Zink et al. Blood 2017). Late generation telomerase deficient (Terc-/- G5) mice develop premature bone marrow failure and mortality, however earlier generation Terc-/- G3 (3 homozygous crosses) have shortened telomeres but appear relatively normal. Importantly, inhibitors of telomerase have recently entered clinical trials for haematological malignancies and therefore understanding the long-term effects of telomerase inhibition is important. By studying the interplay between telomere attrition, HSC aging, and the development of CHIP, we aim to gain insights into the mechanisms underlying age-associated hematopoietic changes and their potential clinical implications. We examined young (age 8-10 week) and aged (10-12 month) Terc-/- G3 mice. Telomere lengths were significantly reduced in bone marrow cells from young Terc G3 (15 kb) when compared to wild-type mice (30 kb) with mild reduction in BM cellularity. Absolute long-term HSC numbers were reduced, as were megakaryocyte erythroid progenitors, but there was preservation of granulocyte macrophage progenitors and common myeloid progenitors. Spleen progenitor numbers were not affected. In comparison, aged (10-12 months old) Terc G3 mice showed enhanced differentiation skewing in the peripheral blood with significantly increased myeloid (n = 8 wt; n = 12 Terc ko; p = 0.0004) and concomitantly reduced B cell (p = 0.0002) and T cell (p = 0.0320) populations. There was marked mobilization of bone marrow progenitors to the spleen, most notably GMP (p = 0.0004) but also MEP and CMP in aged Terc G3. Furthermore, aged Terc G3 ko now exhibited marked reduction in bone marrow CMP (p < 0.0001) and MEP (p < 0.0001), but skewing towards GMP (p<0.001) resulting in normal total GMP numbers, but markedly reduced CMP and MEP numbers (p < 0.0001). Compared to young Terc G3 mice, the aged Terc G3 mice had relative expansion of the BM LT-HSC population, and therefore normal numbers of BM LT-HSC compared to aged matched controls. Aged Terc G3 BM LTHSC have been isolated for gene expression and clonality analysis. Together, these findings are consistent with accelerated aging in G3 Terc-/- mice, providing a model for examining clonal hematopoiesis. In order to assess the cell intrinsic function of Terc G3 LTHSC, we next performed non-competitive bone marrow transplantation experiments from Terc ko or wild-type donors into lethally irradiated young wild-type recipients (n = 9 per group), and analysed these at 4 months post-transplant. There was reduced, but stable reconstitution by Terc G3 cells, consistent with previous competitive bone marrow transplants in Terc G3 (Bruedigam et al. Cell Stem Cell 2014). We observed a similar reduction in bone marrow cellularity in Terc ko transplanted recipients (p = 0.003). Lineage skewing was less pronounced but CMP percentages were significantly reduced in Terc ko compared to wild-type conditions (p = 0.03). In contrast to primary mice, mobilization of progenitors to the spleen was not observed, suggesting that this finding was ameliorated by normal bone marrow and splenic supporting cells. The aged G3 Terc ko model faithfully recapitulates the haematopoietic phenotype of aging in humans and we propose to utilise this model to further our understanding of the mechanisms and physiological consequences of clonal hematopoiesis, to eventually help identify strategies to mitigate its clinical consequences.

A Retrospective Study of Degenerative Cervical Myelopathy and the Surgical Management Within Northern Ireland.

Degenerative cervical myelopathy (DCM) is a condition of growing concern due to its increasing incidence among the ageing population. It involves age-associated pathological changes of the cervical spine that can result in spinal cord compression. This can lead to deficits in motor and sensory function of the upper and lower limbs, issues with balance and dexterity, as well as bladder and bowel disturbance. Patients can be categorised as having mild, moderate, or severe degenerative cervical myelopathy depending on their modified Japanese Orthopaedic Association (mJOA) score. This condition is generally managed surgically; however, patients with mild degenerative cervical myelopathy may be offered or opt for non-surgical treatment initially. The main aim of this study is to evaluate the surgical management of patients with DCM and to ascertain the degree of mJOA improvement from pre-surgery and one-year post-surgery follow-up. The second aim of the study is to explore the demographics within Northern Ireland who are diagnosed with DCM and who undergo surgery. This information could allow for better planning of services in the future for this patient cohort. This is a retrospective review of the surgical management of degenerative cervical myelopathy within the Regional Spinal Orthopaedic Unit in Northern Ireland over three years with one-year follow-up. The data was retrospectively collected from the Fracture Outcome Research Database. A total of 102 patients (10:7, male:female) with DCM were retrospectively evaluated. Exclusion criteria included all patients diagnosed with spinal tumour, fracture, central cord syndrome, and dislocation. Two patients were removed due to incorrect coding of DCM diagnosis and were not included. Key variables assessed were gender, age, symptoms, type of surgery, complications, and MRC score and mJOA score pre-surgery, 48 hours, six months, and one year post surgery. The choice of surgery was guided by the maximal angle of compression, the number of vertebral levels involved, patient comorbidities, and anesthetic risk. The sample consisted of 60 men (58.82%) and 42 women (41.17%) with an average age of 57.17 ± 12.13 years ranging from 27 to 83 years old. Statistical analysis was conducted to explore the effect of time before and after surgery up to one year on the mJOA score. There was a significant difference in mJOA score pre-surgery and at six months and one year post surgery (R = 0.579053, p <0.001). Of the patients,61.8% with a length of stay greater than three days and 71.4% of patients with a length of stay greater than seven days had a posterior approach surgery. A multiple linear regression analysis revealed that the mJOA score pre-surgery and the presence of complications significantly predicted the length of stay post-surgery (β -1.044, p = .011 and β -5.791, p = .028). The first key finding of this study is that the mJOA score tends to improve after surgery for the majority of patients, particularly at six months, which is consistent with the literature. The second key finding is that anterior approach surgery is associated with a lower rate of complications and shorter post-surgery length of stay in hospital compared to posterior approach surgery. The third key finding is that the pre-surgery mJOA score and the presence of complications post surgery significantly predict the post-surgery length of stay.

Inosine monophosphate dehydrogenase intranuclear inclusions are markers of aging and neuronal stress in the human substantia nigra

We explored mechanisms involved in the age-dependent degeneration of human substantia nigra (SN) dopamine (DA) neurons. Owing to its important metabolic functions in post-mitotic neurons, we investigated the developmental and age-associated changes in the purine biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH). Tissue microarrays prepared from post-mortem samples of SN from 85 neurologically intact participants humans spanning the age spectrum were immunostained for IMPDH combined with other proteins. SN DA neurons contained two types of IMPDH structures: cytoplasmic IMPDH filaments and intranuclear IMPDH inclusions. The former were not age-restricted and may represent functional units involved in sustaining purine nucleotide supply in these highly metabolically active cells. The latter showed age-associated changes, including crystallization, features reminiscent of pathological inclusion bodies, and spatial associations with Marinesco bodies; structures previously associated with SN neuron dysfunction and death. We postulate dichotomous roles for these two subcellularly distinct IMPDH structures and propose a nucleus-based model for a novel mechanism of SN senescence that is independent of previously known neurodegeneration-associated proteins.

Incremental residual polarization caused by aging in human skin.

The study of the effect of aging on the optical properties of biological tissues, in particular polarization, is important in the development of new diagnostic approaches. This work aims to provide a comprehensive analysis of the factors and mechanisms that contribute to the alteration of skin polarization properties caused by aging, using polarization-sensitive hyperspectral imaging measurements and Monte Carlo simulation. Our investigation involved both experimental studies of in vivo human skin of volunteers of different ages and computational modeling that accounted for changes in the absorption and scattering properties of the skin model. Specifically, we analyzed alterations in the degree of linear polarization (DOLP) to better understand the impact of aging on skin polarization properties. A statistically significant increase in the DOLP was found for the elderly group. At the same time, there was no correlation between changes in polarization and the calculated blood volume fraction parameter for different ages. According to the simulation results, it was also found that a change in the scattering properties of biological tissues has a more significant effect on the change in polarizing light compared to the change in absorption. The results of the work prove that the sensitivity of polarization imaging to age- or pathological-related skin changes may be primarily due to changes in scattering, which in turn is associated with changes in the collagen fibers of the dermis. The proposed technique shows promise for in vivo non-invasive real-time assessment of age-associated skin changes and can also be extended to monitor changes associated with the development of age-related pathologies.

Abstract 13461: Early Vascular Aging is Associated With Early Cardiac Aging, Upregulation of Left Ventricle Pro-Fibrotic and Inflammatory Genes and Memory Decline in Aged Dahl Salt-Sensitive Rats

Introduction: Blood pressure (BP) begins to increase early in life in Dahl salt-sensitive rats (DSS) that consume a normal salt (NS) diet. Epidemiologic studies have shown that early vascular aging (EVA) is associated with central arterial stiffening (CAS) and hypertension, which develop earlier in life than expected in general population and contribute to cognitive impairment later in life. Hypotheses: (i) DSS rats will develop EVA earlier in life on NS diet, and with advancing age will exhibit early CV aging; (ii) In DSS, CV remodeling and CAS are implicated in memory decline. We tested these hypotheses using a longitudinal repeated measure design in DSS and their parental breed Sprague-Dawley rats (SD) at 3- &amp; 12-mo of age. Methods: Male SD and DSS were kept on NS diet (0.5% NaCl; n=8/group) for entire experiment. Repeated measures of systolic BP (SBP), pulse wave velocity (PWV; an index of CAS), echocardiography, and non-repeated measures of Morris water maze (MWM) to test spatial memory, aortic collagen, elastin (histochemistry), and left ventricle (LV) mRNA expression (qPCR) were assessed at 3- &amp; 12-mo. Data analyses: linear mixed-effect 2-way ANOVA, t-test &amp; linear regression (LR) modeling. A 2-sided p&lt;0.05 was considered significant. Results: SBP, PWV, aortic weight, wall thickness and collagen/elastin ratio were higher in DSS-3 vs. SD-3, and in DSS-12 vs. DSS-3. RWT and LV expression of pro-fibrotic, inflammatory and senescence genes were higher in DSS-12 vs. DSS-3 and vs. SD-12 (Table). DSS-12 spent more time to find a hidden platform in MWM vs. SD-12; their impaired spatial hippocampal memory was positively associated with PWV and LV mass by LR analysis. Conclusions: EVA, indexed as higher BP, PWV and aortic remodeling was associated with early CV aging, manifested by activation of LV senescence, inflammatory and pro-fibrotic genes and by higher rates of age-associated changes in BP, RWT and LV mass in DSS vs. SD. In DSS, early CV aging was associated with memory decline.

Abstract 12226: Aging Impairs the Neuro-Vascular Interface in the Heart

Aging is a major risk factor for impaired cardiovascular function. The aging heart is characterized by vascular dysfunction, increased hypertrophy, fibrosis and electrophysiological alterations. However, the interaction between the different age-associated changes in cardiac remodelling is poorly define. Since vessels are aligned with nerves, and this interplay is critical for tissue homeostasis, we investigated whether an impairment of the neuro-vascular interface may contribute to age-associated pathologies in the heart. We show that aging reduces sympathetic and sensory nerve fibers, which both align to arteries and arterioles. Aging induced a dysregulation of vascular-derived neuro-regulatory genes, especially the axon repellent factor Sema3A, which was augmented by 2.4±0.1-fold in old heart endothelial cells. Consistently, endothelial Sema3a overexpression reduced axon density in vivo, thus mimicking the observed aged heart phenotype. Since cellular senescence was induced at the same time point when nerve density declined (16 months of age) and senescence endothelial cells showed a higher expression of Sema3a, we hypothesized that endothelial senescence may contribute to cardiac denervation. Indeed, supernatants of senescent endothelial cells reduced neurite outgrowth in vitro in a Sema3A-dependent manner. In vivo studies further confirmed that endothelial-specific induction of senescence by overexpression of Progerin induced left ventricular denervation and induced Sema3a expression. By contrast, the pharmacological removal of senescent cells by the senolytic drugs dasatinib and quercetin rescued age-induced denervation and prevented the age-induced induction of endothelial Sema3a expression. Functional studies additionally demonstrated that endothelial senescence reduced heart rate variability, while senolytics preserved heart rate variability, restored age-associated declines in sympathetic and parasympathetic activity and reduced age-associated increase in arrhythmias. These data suggest that senescence-associated regulation of neuro-regulatory genes in endothelial cells is associated with reduced nerve density and, thereby, contributes to age-associated cardiac dysfunction.

Vasospasm risk following aneurysmal subarachnoid hemorrhage in older adults.

Cerebral arterial vasospasm is a dreaded sequela of aneurysm rupture and can result in significant narrowing of the surrounding vasculature and subsequent cerebral ischemia. Treatment interventions are associated with distinct side effect profiles, including the risk of thrombosis and worsened ischemia, which may be associated with increased mortality-especially in older adults. An improved understanding of the likelihood of vasospasm in elderly patients would enable clinicians and patients to better consider the risks and benefits of vasospasm prophylaxis in this vulnerable population. This retrospective chart review aimed to assess the relationship between age at onset and the incidence of cerebral vasospasm among patients treated at the University of North Carolina Medical Center with spontaneous aneurysmal subarachnoid hemorrhage (aSAH). Electronic health record data from the Epic Systems Corp. database, compiled by the Carolina Data Warehouse for Health, were analyzed for patients older than 18 years who were previously treated for an SAH secondary to aneurysm at the University of North Carolina Medical Center within the past 10 years, ranging from June 2011 through June 2021. Logistic regression was used to calculate odds ratios and to determine the association of age with the occurrence of vasospasm following aSAH. Of the 386 cases analyzed, 149 patients (38.6%) were older than 65 years at the time of aSAH. A total of 192 of the 386 patients (49.7%) developed vasospasm within the first 3-21 days following aSAH. Among the patients who developed vasospasm, only 31 of 192 patients (16.1%) were older than 65 years at the time of aneurysm rupture. Odds ratio calculations revealed that older adults (> 65 years) were 8 times less likely to develop vasospasm compared to their younger counterparts (p < 0.0001; 95% CI 5.0-13.0). This study found that older patients are less likely to develop cerebral vasospasm following aSAH than are younger individuals. Age-associated changes in arteriosclerosis, inflammatory responses, and CSF dynamics may mitigate vascular narrowing in response to aSAH. This finding suggests that the aSAH treatment and vasospasm prevention paradigms should be revised to minimize potentially unnecessary interventions and avoid adverse outcomes for older adults.

From aging to long COVID: exploring the convergence of immunosenescence, inflammaging, and autoimmunity.

The process of aging is accompanied by a dynamic restructuring of the immune response, a phenomenon known as immunosenescence. This mini-review navigates through the complex landscape of age-associated immune changes, chronic inflammation, age-related autoimmune tendencies, and their potential links with immunopathology of Long COVID. Immunosenescence serves as an introductory departure point, elucidating alterations in immune cell profiles and their functional dynamics, changes in T-cell receptor signaling, cytokine network dysregulation, and compromised regulatory T-cell function. Subsequent scrutiny of chronic inflammation, or "inflammaging," highlights its roles in age-related autoimmune susceptibilities and its potential as a mediator of the immune perturbations observed in Long COVID patients. The introduction of epigenetic facets further amplifies the potential interconnections. In this compact review, we consider the dynamic interactions between immunosenescence, inflammation, and autoimmunity. We aim to explore the multifaceted relationships that link these processes and shed light on the underlying mechanisms that drive their interconnectedness. With a focus on understanding the immunological changes in the context of aging, we seek to provide insights into how immunosenescence and inflammation contribute to the emergence and progression of autoimmune disorders in the elderly and may serve as potential mediator for Long COVID disturbances.

Aging and Environmental Associated Changes of Facial Soft Tissues are Detectable on Clinical High Resolution MRI Scans

Aging and Environmental Associated Changes of Facial Soft Tissues are Detectable on Clinical High Resolution MRI Scans

Trimodal single-cell profiling reveals a novel pediatric CD8αα+ T cell subset and broad age-related molecular reprogramming across the T cell compartment

Age-associated changes in the T cell compartment are well described. However, limitations of current single-modal or bimodal single-cell assays, including flow cytometry, RNA-seq (RNA sequencing) and CITE-seq (cellular indexing of transcriptomes and epitopes by sequencing), have restricted our ability to deconvolve more complex cellular and molecular changes. Here, we profile >300,000 single T cells from healthy children (aged 11–13 years) and older adults (aged 55–65 years) by using the trimodal assay TEA-seq (single-cell analysis of mRNA transcripts, surface protein epitopes and chromatin accessibility), which revealed that molecular programming of T cell subsets shifts toward a more activated basal state with age. Naive CD4+ T cells, considered relatively resistant to aging, exhibited pronounced transcriptional and epigenetic reprogramming. Moreover, we discovered a novel CD8αα+ T cell subset lost with age that is epigenetically poised for rapid effector responses and has distinct inhibitory, costimulatory and tissue-homing properties. Together, these data reveal new insights into age-associated changes in the T cell compartment that may contribute to differential immune responses.

Age-associated changes in lower limb weight-bearing strategy during walking

BackgroundAs people age there is a proximal shift of joint moment generation from ankle plantarflexion and knee extension toward hip extension and flexion moments. This age-related redistribution has been documented in the context of propulsive force generation during the push-off phase with less evidence in the context of weight bearing. Additionally, these sagittal plane joint moments have been a primary focus of studies though the hip frontal plane moment also contributes to vertical support but has received less attention. Furthermore, how aging affects the relationships between changes in sagittal and frontal joint moments and changes in vertical support force as a function of walking speed remains unclear Research questionHow does aging affect the contributions of sagittal and frontal plane joint moments to weight-bearing across different walking speeds? MethodsGait analysis was performed on 24 young and 17 healthy older subjects walked on the treadmill at their preferred and 30 % faster speeds. Stepwise linear regression analysis was performed to determine the joint moments that predict the peak amplitudes of the vertical ground reaction force (VGRF) across different walking speeds. ResultsHip abduction and knee extension moments were the primary contributors to leading limb weight-bearing in young, whereas hip extension moment was the primary contributor in older adults. Ankle plantarflexion moment was the main contributor to trailing limb weight-bearing in young and hip flexion moment was the main contributor in older adults. From preferred to faster walking speed changes in knee extension moment were the primary contributor to changes in the trailing limb weight-bearing in young whereas changes in hip extension moment were the primary contributor in olderadults. SignificanceThese findings suggested that older and younger adults used different joint moment contributions to produce leading limb and trailing limb vertical support forces across different walking speeds.

Deconvolution reveals cell-type-specific transcriptomic changes in the aging mouse brain

Mounting evidence highlights the crucial role of aging in the pathogenesis of Alzheimer's disease (AD). We have previously explored human apoE-targeted replacement mice across different ages and identified distinct molecular pathways driven by aging. However, the specific contribution of different brain cell types to the gene modules underlying these pathways remained elusive. To bridge this knowledge gap, we employed a computational deconvolution approach to examine cell-type-specific gene expression profiles in major brain cell types, including astrocytes (AS), microglia (MG), oligodendroglia (OG), neurons (NEU), and vascular cells (VC). Our findings revealed that immune module genes were predominantly expressed in MG, OG, and VC. The lipid metabolism module genes were primarily expressed in AS, MG, and OG. The mitochondria module genes showed prominent expression in VC, and the synapse module genes were primarily expressed in NEU and VC. Furthermore, we identified intra- and inter-cell-type interactions among these module genes and validated their aging-associated expression changes using published single cell studies. Our study dissected bulk brain transcriptomics data at the cellular level, providing a closer examination of the cell-type contributions to the molecular pathways driven by aging.

THU045 WIP1 Phosphatase Is A Novel Specific Target For Epithelial GH Action

Abstract Disclosure: T. Apaydin: None. S. Zonis: None. C. Zhou: None. R. Barrett: None. V. Chesnokova: None. S. Melmed: None. Deficient DNA repair and accumulated DNA damage underlie age-associated pathological changes, tissue fragility, and neoplastic development. ATM kinase, an activator of DNA damage responses (DDR), phosphorylates DDR effectors including CHK2, p53, and γH2AX to ensure DNA repair. We have shown that GH suppresses epithelial DDR activity by suppressing ATM phosphorylation, resulting in DNA damage accumulation due to repressed DNA repair. Wip1 dephosphorylates ATM thereby attenuating DNA damage repair. We found that GH significantly induced Wip1 expression (1.6-fold) in both human normal colon cells (hNCC) and in human 3-dimensional intestinal organoids, resulting in dephosphorylated ATM, CHK2, γH2AX, and p53. Mice bearing GH-secreting tumors with high circulating GH also exhibited induced colon Wip1 expression with lower phospho-ATM, γH2AX, and p53 as well as increased DNA damage. Twofold higher Wip1 expression was observed in blood buffy coats derived from patients with GH-secreting adenoma vs patients with non-functioning pituitary adenoma. Specificity of these observations was validated by showing that in GH-treated cells, blocking GH receptor (GHR) with pegvisomant or blocking STAT5 phosphorylation with the inhibitor CAS 285986-31-4 constrained Wip1 induction and restored ATM phosphorylation, indicating that GH effects on Wip1 are GHR/STAT5-mediated concordant with the observed decreased colon Wip1 expression in GHR-/- mice devoid of GH signaling. Furthermore, Wip1 inhibition with the small molecule inhibitor (GSK2830371) reversed GH-induced DNA damage by restoring phosphorylation of ATM and other key DDR proteins. To determine a mechanism for Wip1 induction, we tested homeodomain-interacting protein kinase 2 (HIPK2) which is regulated by AMPK and potentiates Wip1 proteasomal degradation and its activity. We observed that GH increased phospho-AMPK expression, while blocking AMPK kinase activity with Compound C abrogated GH induction of Wip1. Src upregulates AMPK and triggers HIPK2 cytoplasmic relocation thereby inactivating HIPK2. We found that GH, by activating Src/AMPK phosphorylation, elicits HIPK2 cytoplasmic relocation, thus suppressing Wip1 ubiquitination and increasing its stability. Consistent with these findings, blocking Src phosphorylation with the tyrosine kinase inhibitor dasatinib abolished Wip1 upregulation and induced phosphorylation of its downstream targets. These results indicate that GH suppresses DDR by inducing Wip1 expression, and suppression of Wip1 may prevent epithelial accumulation of unrepaired DNA damage. These findings identify Wip1 as a specific novel target for GH action mediating GH-attenuation of DNA repair. Presentation: Thursday, June 15, 2023

THU157 Epigenetic Regulation Of Genes Involved In The Signaling Cascade Of The GH Axis - IGF1 And Insulin. Implication In Children Postnatal Growth

Abstract Disclosure: L. Zoff: None. F. Garcia: None. G. Aschettino: None. G. Veneruzzo: None. M.C. Mattone: None. N. Perez Garrido: None. M. Juanes: None. N.I. Saraco: None. C. Alonso: None. G. Guercio: None. A. Belgorosky: None. M.S. Baquedano: None. Growth is influenced by genetic, nutritional, environmental, and hormonal factors, but it proceeds in a predictable pattern characterized by a constant growth deceleration between childhood and adolescence. This growth deceleration is coordinated in tissues and organs in order to maintain body proportions. Growth hormone (GH)/ insulin-like growth factor type 1 (IGF1) axis and insulin are crucial stimulators of growth, cell proliferation and metabolism. However, their levels do not change with age in a pattern that would explain the prepubertal decline in growth rate. DNA methylation represents a fundamental epigenetic mark that is associated with transcriptional repression during development. We hypothesize that the postnatal growth pattern could be orchestrated by epigenetic mechanisms. In order to analyze age related physiological changes, we evaluated promoter methylation in the GHR, IGF1R and INSR genes in peripheral blood from 40 healthy children of both sexes (females (F) n=21 and males (M) n=19), between 3 and 15 years old by using targeted deep-amplicon bisulfite sequencing on a MiSeq system. Sequencing libraries of 4 promoter CpG rich regions for GHR, 3 for IGF1R and 5 for INSR (104, 103 and 141 CpG sites, respectively) were analyzed for mean methylation values of all CpG sites using amplikyzer2 software. The results would suggest a sexual dimorphism in the epigenetic regulation of GH, IGF1 and insulin receptors gene expression. A significant negative correlation between GHR methylation and age was observed in both sexes (Multiple Spearman correlation, p&amp;lt;0.05), but in different GHR promoter regions. Specifically, a decrease in themethylation levels with age were detected in CpG-8, CpG+183 and CpG+243 in F; and in CpG+343, CpG+346, CpG+385, CpG+391, CpG+407 and CpG+487 in M. In contrast, in the IGF1R promoter region, a positive correlation was observed exclusively in F, between mean methylation levels and age in CpG-51, CpG-43, CpG-41, CpG-23, CpG-17, CpG-15, CpG-13, CpG-11, and CpG-9, p&amp;lt;0.05. Male-specific positive correlation between INSR promotermethylation values and age were found in CpG-768, CpG+10, CpG+31, CpG+87, CpG+95, CpG+163, CpG+199, CpG+206, CpG+238, CpG+700, CpG+815 and CpG+900, p&amp;lt;0.05.Taking together, our findings are in agreement with the hypothesis that age-associated DNA promoter methylation changes could be involved in the physiological growth pattern. Finally, the observed sexual dimorphism suggests age- and sex-dependent regulatory mechanisms for normal growth. Presentation: Thursday, June 15, 2023

Spatial mapping of human hematopoiesis at single-cell resolution reveals aging-associated topographic remodeling

AbstractThe spatial anatomy of hematopoiesis in the bone marrow (BM) has been extensively studied in mice and other preclinical models, but technical challenges have precluded a commensurate exploration in humans. Institutional pathology archives contain thousands of paraffinized BM core biopsy tissue specimens, providing a rich resource for studying the intact human BM topography in a variety of physiologic states. Thus, we developed an end-to-end pipeline involving multiparameter whole tissue staining, in situ imaging at single-cell resolution, and artificial intelligence–based digital whole slide image analysis and then applied it to a cohort of disease-free samples to survey alterations in the hematopoietic topography associated with aging. Our data indicate heterogeneity in marrow adipose tissue (MAT) content within each age group and an inverse correlation between MAT content and proportions of early myeloid and erythroid precursors, irrespective of age. We identify consistent endosteal and perivascular positioning of hematopoietic stem and progenitor cells (HSPCs) with medullary localization of more differentiated elements and, importantly, uncover new evidence of aging-associated changes in cellular and vascular morphologies, microarchitectural alterations suggestive of foci with increased lymphocytes, and diminution of a potentially active megakaryocytic niche. Overall, our findings suggest that there is topographic remodeling of human hematopoiesis associated with aging. More generally, we demonstrate the potential to deeply unravel the spatial biology of normal and pathologic human BM states using intact archival tissue specimens.

Evaluation of Anti-aging Effects of Gemfibrozil on D-galactose induced Aging Mouse Model

Background: Aging is the sequential or progressive changes in the organisms that is associated with increasing susceptibility to disease and death. Advanced age is associated with increased incidence of a variety of chronic disease states that share oxidative stress and inflammation as causative role players. Accumulating evidence in published literature showed that the use of antioxidant and anti-inflammatory agents is an effective approach to alleviate or reverse aging-related changes with consequent reduction of the aging rate and related disease. Gemfibrozil, as a peroxisome proliferator-activated alpha receptor ligand (PPARα), is reported to have antioxidant and inflammatory activity. Aim of the study: Evaluate the anti-aging effect of gemfibrozil on many parameters associated with the aging process on the D-galactose induced aging mice model. Method: The current work was an experimental randomized controlled study in which 60 albino male mice weighing between 25 to 40 gm were randomly divided into 6 groups (10 mice each group). group1 apparently healthy group, receive normal saline orally. Group 2 (age induction group receive D-galactose 500 mg/kg) orally only for 6 weeks, group 3 (+D-galactose 500 mg/kg + vitc 100 mg/kg orally for 6 weeks) group 4 (D-galactose 500 mg/kg for 6 weeks then vitc 100 mg/kg for another 6 consecutive weeks group 5 (D-galactose 500 mg/kg + gemfibrozil 7.5 mg/kg concomitantly for 6 weeks) group 6 (D-galactose 500 mg/kg for 6 weeks then gemfibrozil 7.5 mg/kg for another 6 consecutive weeks. Then animals were sacrificed, liver and kidney were weighed for organ index measurement and tissue sections and heart homogenate were prepared for ELISA assay (measurement of TN alpha, IL1beta, SOD, GPX) and histopathological analysis of myocardial tissue. Results: results showed a significant rise in liver and kidney indices in animals that received gemfibrozil orally administered (during and after induction) compared to aged group, with a dramatic decrease in inflammatory and oxidative stress mediator level and a marked reversal effect on myocardial hypertrophy induced by D-galactose. Conclusion: Gemfibrozil oral administration alleviates aging-associated atrophic changes in liver and kidney, oxidative stress and inflammatory state in myocardial tissue and reverses aging-related myocardial hypertrophic changes.

Distinct SARS-CoV-2 specific NLRP3 and IL-1β responses in T cells of aging patients during acute COVID-19 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes Coronavirus Disease 2019 (COVID-19) that presents with varied clinical manifestations ranging from asymptomatic or mild infections and pneumonia to severe cases associated with cytokine storm, acute respiratory distress syndrome (ARDS), and even death. The underlying mechanisms contributing to these differences are unclear, although exacerbated inflammatory sequelae resulting from infection have been implicated. While advanced aging is a known risk factor, the precise immune parameters that determine the outcome of SARS-CoV-2 infection in elderly individuals are not understood. Here, we found aging-associated (age ≥61) intrinsic changes in T cell responses when compared to those from individuals aged ≤ 60, even among COVID-positive patients with mild symptoms. Specifically, when stimulated with SARS-CoV-2 peptides in vitro, peripheral blood mononuclear cell (PBMC) CD4+ and CD8+ T cells from individuals aged ≥61 showed a diminished capacity to produce IFN-γ and IL-1β. Although they did not have severe disease, aged individuals also showed a higher frequency of PD-1+ cells and significantly diminished IFN-γ/PD-1 ratios among T lymphocytes upon SARS-CoV-2 peptide stimulation. Impaired T cell IL-1β expression coincided with reduced NLRP3 levels in T lymphocytes. However, the expression of these molecules was not affected in the monocytes of individuals aged ≥61. Together, these data reveal SARS-CoV-2-specific CD4+ and CD8+ T-cell intrinsic cytokine alterations in the individuals older than 61 and may provide new insights into dysregulated COVID-directed immune responses in the elderly.

Spatial Transcriptomics of Aging Rat Ovaries Reveals Unexplored Cell Subpopulations with Reduced Antioxidative Defense

Introduction: Ovarian aging is characterized by a gradual decline in quantity and quality of oocytes and lower chance of fertility. Better understanding the genetic modulation during ovarian aging can further address available treatment options for aging-related ovarian diseases and fertility preservation. Methods: A novel technique spatial transcriptomics (ST) was used to investigate the spatial transcriptome features of rat ovaries. Transcriptomes from ST spots in the young and aged ovaries were clustered using differentially expressed genes. These data were analyzed to determine the spatial organization of age-induced heterogeneity and potential mechanisms underlying ovarian aging. Results: In this study, ST technology was applied to profile the comprehensive spatial imaging in young and aged rat ovary. Fifteen ovarian cell clusters with distinct gene-expression signatures were identified. The gene expression dynamics of granulosa cell clusters revealed three sub-types with sequential developmental stages. Aged ovary showed a significant decrease in the number of granulosa cells from the antral follicle. Besides, a remarkable rearrangement of interstitial gland cells was detected in aging ovary. Further analysis of aging-associated transcriptional changes revealed that the disturbance of oxidative pathway was a crucial factor in ovarian aging. Conclusions: This study firstly described an aging-related spatial transcriptome changes in ovary and identified the potential targets for prevention of ovarian aging. These data may provide the basis for further investigations of the diagnosis and treatment of aging-related ovarian disorders.

Age-associated increases in middle cerebral artery pulsatility differ between men and women.

Mechanisms underlying sex differences in brain aging remain unclear but may relate to changes in cerebral pulsatile blood flow. Sex differences in the stiffening of the large arteries and expansion of pulse pressure with age may accelerate changes in pulsatile (i.e., discontinuous) blood flow in the brain that contribute to brain health. The purpose of this cross-sectional, secondary analysis was to examine sex differences in age-associated changes in large artery (aorta and carotid) stiffness, carotid pulse pressure, and cerebral pulsatility in 206 men and 217 women between 18 and 72 yr of age. Outcomes included aortic stiffness [carotid-femoral pulse wave velocity (cfPWV)] and carotid pulse pressure via tonometry, carotid β-stiffness via ultrasound, and middle cerebral artery (MCA) pulsatility index via transcranial Doppler. Regression analyses revealed a significant age-by-sex interaction, with women exhibiting a slower rate of change compared with men for cfPWV (β = -0.21, P = 0.04), and greater rate of change for carotid stiffness (β = 0.27, P = 0.02), carotid pulse pressure (β = 0.98, P < 0.001), and MCA pulsatility index (β = 0.49, P = 0.002) after adjustment for covariates. The significant age-by-sex interaction for MCA pulsatility was abolished after further adjustment for carotid pulse pressure. Women exhibit accelerated increases in cerebral pulsatility during midlife, likely driven by exaggerated increases in carotid stiffness and pulse pressure compared with men. These data suggest that there are disproportionate increases in cerebral pulsatility in women during midlife that could contribute to accelerated brain aging compared with men.NEW & NOTEWORTHY We identify sex-specific associations between increasing age and cerebral pulsatility and its vascular mechanisms. When compared with men, women in our cross-sectional analysis exhibited greater age-associated increases in carotid stiffness, carotid pulse pressure, and cerebral pulsatility particularly during midlife. These data suggest that the rapid expansion of pulse pressure during midlife contributes to an exaggerated increase in cerebral pulsatility among women and suggest a potential mechanism contributing to sex differences in brain aging.

A single-cell transcriptomic atlas characterizes age-related changes of murine cranial stem cell niches.

The craniofacial bones provide structural support for the skull and accommodate the vulnerable brain tissue with a protective cavity. The bone tissue undergoes constant turnover, which relies on skeletal stem cells (SSCs) and/or mesenchymal stem cells (MSCs) and their niches. SSCs/MSCs and their perivascular niche within the bone marrow are well characterized in long bones. As for cranial bones, besides bone marrow, the suture mesenchyme has been identified as a unique niche for SSCs/MSCs of craniofacial bones. However, a comprehensive study of the two different cranial stem cell niches at single-cell resolution is still lacking. In addition, during the progression of aging, age-associated changes in cranial stem cell niches and resident cells remain uncovered. In this study, we investigated age-related changes in cranial stem cell niches via single-cell RNA sequencing (scRNA-seq). The transcriptomic profiles and cellular compositions have been delineated, indicating alterations of the cranial bone marrow microenvironment influenced by inflammaging. Moreover, we identified a senescent mesenchymal cell subcluster and several age-related immune cell subclusters by reclustering and pseudotime trajectory analysis, which might be closely linked to inflammaging. Finally, differentially expressed genes (DEGs) and cell-cell communications were analyzed during aging, revealing potential regulatory factors. Overall, this work highlights the age-related changes in cranial stem cell niches, which deepens the current understanding of cranial bone and suture biology and may provide therapeutic targets for antiaging and regenerative medicine.