Transport of the Proinflammatory Chemokines C-C Motif Chemokine Ligand 2 (MCP-1) and C-C Motif Chemokine Ligand 5 (RANTES) across the Intact Mouse Blood-Brain Barrier Is Inhibited by Heparin and Eprodisate and Increased with Systemic Inflammation.

One important function of the vascular blood-brain barrier (BBB) is to facilitate neuroimmune communication. The BBB fulfills this function, in part, through its ability to transport cytokines and chemokines. C-C motif chemokine receptor 2 (CCL2) (MCP-1) and C-C motif chemokine receptor 5 (CCL5) (RANTES) are proinflammatory chemokines that mediate neuroimmune responses to acute insults and aspects of brain injury and neurodegenerative diseases; however, a blood-to-brain transport system has not been evaluated for either chemokine in vivo. Therefore, we determined whether CCL2 and CCL5 in blood can cross the intact BBB and enter the brain. Using CD-1 mice, we found that 125I-labeled CCL2 and CCL5 crossed the BBB and entered the brain parenchyma. We next aimed to identify the mechanisms of 125I-CCL2 and 125I-CCL5 transport in an in situ brain perfusion model. We found that both heparin and eprodisate inhibited brain uptake of 125I-CCL2 and 125I-CCL5 in situ, whereas antagonists of their receptors, CCR2 or CCR5, respectively, did not, suggesting that heparan sulfates at the endothelial surface mediate BBB transport. Finally, we showed that CCL2 and CCL5 transport across the BBB increased following a single injection of 0.3 mg/kg lipopolysaccharide. These data demonstrate that CCL2 and CCL5 in the brain can derive, in part, from the circulation, especially during systemic inflammation. Further, binding to the BBB-associated heparan sulfate is a mechanism by which both chemokines can cross the intact BBB, highlighting a novel therapeutic target for treating neuroinflammation. SIGNIFICANCE STATEMENT: Our work demonstrates that C-C motif chemokine ligand 2 (CCL2) and C-C motif chemokine ligand 5 (CCL5) can cross the intact blood-brain barrier and that transport is robustly increased during inflammation. These data suggest that circulating CCL2 and CCL5 can contribute to brain levels of each chemokine. We further show that the transport of both chemokines is inhibited by heparin and eprodisate, suggesting that CCL2/CCL5-heparan sulfate interactions could be therapeutically targeted to limit accumulation of these chemokines in the brain.

Viable human brain microvessels for the study of aging and neurodegenerative diseases.

The brain microvasculature is altered in normal aging and in the presence of disease processes, such as neurodegeneration or ischemia, but there are few methods for studying living tissues. We now report that viable microvessels (MV) are readily isolated from brain tissue of subjects enrolled in studies of neurodegenerative diseases who undergo rapid autopsy (performed with <12 h postmortem interval - PMI). We find that these MV retain their morphology and cellular components and are fairly uniform in size. Sufficient MV (~3-5000) are obtained from 3 to 4 g of tissue to allow for studies of cellular composition as well as extracellular matrix (ECM). Using live/dead assays, these MV are viable for up to 5 days in tissue culture media (2D) designed to support endothelial cells and up to 11 days post-isolation in a 3-dimensional (3D) matrix (Low Growth Factor Matrigel™). Assays that measure the reducing potential of live cells \demonstrated that the majority of the MV maintain high levels of metabolic activity for a similar number of days as the live/dead assays. Functional cellular components (such as tight junctions and transporter proteins) and ECM of MV in tissue culture media, and to a lesser extent in 3D matrices, were readily visualized using immunofluorescence techniques. MV in tissue culture media are lysed and protein content analyzed, but MV in 3D matrix first require removal of the supporting matrix, which can confound the analysis of MV ECM. Finally, MV can be preserved in cryoprotective media, whereby over 50% retain their baseline viability upon thawing. In summary, we find that MV isolated from human brains undergoing rapid autopsy are viable in standard tissue culture for up to 5 days and the timeframe for experiments can be extended up to 11 days by use of a supportive 3D matrix. Viable human MV allow for temporal and spatial analysis of relevant cellular and ECM components that have implications for microvascular function in neurodegenerative diseases, vascular brain injury, and neurotrauma.

Liver Fibrosis Marker and Postoperative Mortality in Patients Without Overt Liver Disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) can progress to advanced fibrosis, which, in the nonsurgical population, is associated with poor hepatic and extrahepatic outcomes. Despite its high prevalence, NAFLD and related liver fibrosis may be overlooked during the preoperative evaluation, and the role of liver fibrosis as an independent risk factor for surgical-related mortality has yet to be tested. The aim of this study was to assess whether fibrosis-4 (FIB-4), which consists of age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelets, a validated marker of liver fibrosis, is associated with postoperative mortality in the general surgical population. METHODS: A historical cohort of patients undergoing general anesthesia at an academic medical center between 2014 and 2018 was analyzed. Exclusion criteria included known liver disease, acute liver disease or hepatic failure, and alcohol use disorder. FIB-4 score was categorized into 3 validated predefined categories: FIB-4 ≤1.3, ruling out advanced fibrosis; >1.3 and <2.67, inconclusive; and ≥2.67, suggesting advanced fibrosis. The primary analytic method was propensity score matching (FIB-4 was dichotomized to indicate advanced fibrosis), and a secondary analysis included a multivariable logistic regression. RESULTS: Of 19,861 included subjects, 1995 (10%) had advanced fibrosis per FIB-4 criteria. Mortality occurred intraoperatively in 15 patients (0.1%), during hospitalization in 272 patients (1.4%), and within 30 days of surgery in 417 patients (2.1%). FIB-4 ≥2.67 was associated with increased intraoperative mortality (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.25-10.58), mortality during hospitalization (OR, 3.14; 95% CI, 2.37-4.16), and within 30 days from surgery (OR, 2.46; 95% CI, 1.95-3.10), after adjusting for other risk factors. FIB-4 was related to increased mortality in a dose-dependent manner for the 3 FIB-4 categories ≤1.3 (reference), >1.3 and <2.67, and ≥2.67, respectively; during hospitalization (OR, 1.89; 95% CI, 1.34-2.65 and OR, 4.70; 95% CI, 3.27-6.76) and within 30 days from surgery (OR, 1.77; 95% CI, 1.36-2.31 and OR, 3.55; 95% CI, 2.65-4.77). In a 1:1 propensity-matched sample (N = 1994 per group), the differences in mortality remained. Comparing the FIB-4 ≥2.67 versus the FIB-4 <2.67 groups, respectively, mortality during hospitalization was 5.1% vs 2.2% (OR, 2.70; 95% CI, 1.81-4.02), and 30-day mortality was 6.6% vs 3.4% (OR, 2.26; 95% CI, 1.62-3.14). CONCLUSIONS: A simple liver fibrosis marker is strongly associated with perioperative mortality in a population without apparent liver disease, and may aid in future surgical risk stratification and preoperative optimization.

Frailty status as a potential factor in increased postoperative opioid use in older adults.

BACKGROUND: Prescription opioids are commonly used for postoperative pain relief in older adults, but have the potential for misuse. Both opioid side effects and uncontrolled pain have detrimental impacts. Frailty syndrome (reduced reserve in response to stressors), pain, and chronic opioid consumption are all complex phenomena that impair function, nutrition, psychologic well-being, and increase mortality, but links among these conditions in the acute postoperative setting have not been described. This study seeks to understand the relationship between frailty and patterns of postoperative opioid consumption in older adults. METHODS: Patients ≥ 65 years undergoing elective surgery with a planned hospital stay of at least one postoperative day were recruited for this cohort study at pre-anesthesia clinic visits. Preoperatively, frailty was assessed by Edmonton Frailty and Clinical Frailty Scales, pain was assessed by Visual Analog and Pain Catastrophizing Scales, and opioid consumption was recorded. On the day of surgery and subsequent hospitalization days, average pain ratings and total opioid consumption were recorded daily. Seven days after hospital discharge, patients were interviewed using uniform questionnaires to measure opioid prescription use and pain rating. RESULTS: One hundred seventeen patients (age 73.0 (IQR 67.0, 77.0), 64 % male), were evaluated preoperatively and 90 completed one-week post discharge follow-up. Preoperatively, patients with frailty were more likely than patients without frailty to use opioids (46.2 % vs. 20.9 %, p = 0.01). Doses of opioids prescribed at hospital discharge and the prescribed morphine milligram equivalents (MME) at discharge did not differ between groups. Seven days after discharge, the cumulative MME used were similar between cohorts. However, patients with frailty used a larger fraction of opioids prescribed to them (96.7 % (31.3, 100.0) vs. 25.0 % (0.0, 83.3), p = 0.007) and were more likely (OR 3.7, 95 % CI 1.13-12.13) to use 50 % and greater of opioids prescribed to them. Patients with frailty had higher pain scores before surgery and seven days after discharge compared to patients without frailty. CONCLUSIONS: Patterns of postoperative opioid use after discharge were different between patients with and without frailty. Patients with frailty tended to use almost all the opioids prescribed while patients without frailty tended to use almost none of the opioids prescribed.

A Rapid Method to Preoperatively Assess Frailty for Older Patients with Pelvic Floor Conditions.

PURPOSE: Assessment of frailty can help surgeons predict perioperative risk and guide preoperative counseling. However, current methods are often cumbersome in the clinical setting. We prospectively compared the effectiveness of a rapid picture based Clinical Frailty Scale (CFS-9) assessed by patient and surgeon against reference standard Fried Frailty Index in older patients with pelvic floor conditions. MATERIALS AND METHODS: We enrolled 71 patients between March 2018 and June 2019. Frailty assessment using CFS-9 (scale ranging from very fit to terminally ill) was performed followed by the Fried Frailty Index, a validated tool of 5 measures (shrinking, physical energy, activity, grip strength, walking speed). Correlations and agreement between Fried Frailty Index and CFS-9 scores from the treating surgeon, a second surgeon (surgeon 2) and patient were analyzed using sensitivity, specificity, area under the curve and Cohen's Kappa. RESULTS: The patient cohort was mostly female (97.2%), with a mean age (±SD) of 73.0 (±5.9) years and 23.9% were frail using the Fried Frailty Index. Compared to the Fried Frailty Index, CFS-9 scores of the treating surgeon, surgeon 2 and patient had AUC values (95% CI) of 0.86 (0.77-0.86), 0.91 (0.84-0.91) and 0.88 (0.79-0.88), respectively. As assessed by Cohen's Kappa the CFS-9 scores all had substantial (surgeon 2, Kappa 0.66, 95% CI 0.46-0.85 or moderate (all other CFS-9 measures, Kappa 0.44 to 0.58) agreement with the Fried Frailty Index scores. CONCLUSIONS: Rapid and effective validated tools to screen for frailty are needed in the clinical setting. CFS-9 is an excellent predictor of frailty compared to the Fried Frailty Index for patients with pelvic floor conditions.

Frailty assessment: from clinical to radiological tools.

Frailty is a syndrome of cumulative decline across multiple physiological systems, which predisposes vulnerable adults to adverse events. Assessing vulnerable patients can potentially lead to interventions that improve surgical outcomes. Anaesthesiologists who care for older patients can identify frailty to improve preoperative risk stratification and subsequent perioperative planning. Numerous clinical tools to diagnose frailty exist, but none has emerged as the standard tool to be used in clinical practice. Radiological modalities, such as computed tomography and ultrasonography, are widely performed before surgery, and are therefore available to be used opportunistically to objectively evaluate surrogate markers of frailty. This review presents the importance of frailty assessment by anaesthesiologists; lists common clinical tools that have been applied; and proposes that utilising radiological imaging as an objective surrogate measure of frailty is a novel, expanding approach for which anaesthesiologists can significantly contribute to broad implementation.

Comparison of bedside screening methods for frailty assessment in older adult trauma patients in the emergency department.

BACKGROUND: Frailty is linked to poor outcomes in older patients. We prospectively compared the utility of the picture-based Clinical Frailty Scale (CFS9), clinical assessments, and ultrasound muscle measurements against the reference FRAIL scale in older adult trauma patients in the emergency department (ED). METHODS: We recruited a convenience sample of adults 65 yrs. or older with blunt trauma and injury severity scores <9. We queried subjects (or surrogates) on the FRAIL scale, and compared this to: physician-based and subject/surrogate-based CFS9; mid-upper arm circumference (MUAC) and grip strength; and ultrasound (US) measures of muscle thickness (limbs and abdominal wall). We derived optimal diagnostic thresholds and calculated performance metrics for each comparison using sensitivity, specificity, predictive values, and area under receiver operating characteristic curves (AUROC). RESULTS: Fifteen of 65 patients were frail by FRAIL scale (23%). CFS9 performed well when assessed by subject/surrogate (AUROC 0.91 [95% CI 0.84-0.98] or physician (AUROC 0.77 [95% CI 0.63-0.91]. Optimal thresholds for both physician and subject/surrogate were CFS9 of 4 or greater. If both physician and subject/surrogate provided scores <4, sensitivity and negative predictive value were 90.0% (54.1-99.5%) and 95.0% (73.1-99.7%). Grip strength and MUAC were not predictors. US measures that combined biceps and quadriceps thickness showed an AUROC of 0.75 compared to the reference standard. CONCLUSION: The ED needs rapid, validated tools to screen for frailty. The CFS9 has excellent negative predictive value in ruling out frailty. Ultrasound of combined biceps and quadriceps has modest concordance as an alternative in trauma patients who cannot provide a history.

Trauma Providers' Perceptions of Frailty Assessment: A Mixed-Methods Analysis of Knowledge, Attitudes, and Beliefs.

OBJECTIVES: Quality improvement in geriatric trauma depends on timely identification of frailty, yet little is known about providers' knowledge and beliefs about frailty assessment. This study sought to understand trauma providers' understanding, beliefs, and practices for frailty assessment. METHODS: We developed a 20-question survey using the Health Belief Model of health behavior and surveyed physicians, advanced practice providers, and trainees on the trauma services at a single institution that does not use formal frailty screening of all injured seniors. Results were analyzed via mixed methods. RESULTS: One hundred fifty-one providers completed the survey (response rate 92%). Respondents commonly included calendar age as an integral factor in their determinations of frailty but also included a variety of other factors, highlighting limited definitional consensus. Respondents perceived frailty as important to older adult patient outcomes, but assessment techniques were varied because only 24/151 respondents (16%) were familiar with current formal frailty assessment tools. Perceived barriers to performing a formal frailty screening on all injured older adults included the burdensome nature of assessment tools, insufficient training, and lack of time. When prompted for solutions, 20% of respondents recommended automation of the screening process by trained, dedicated team members. CONCLUSIONS: Providers seem to recognize the impact that a diagnosis of frailty has on outcomes, but most lack a working knowledge of how to assess for frailty syndrome. Some providers recommended screening by designated, formally trained personnel who could notify decision makers of a positive screen result.

Lidocaine Impairs Proliferative and Biosynthetic Functions of Aged Human Dermal Fibroblasts.

BACKGROUND: The aged are at increased risk of postoperative wound healing complications. Because local anesthetics are infiltrated commonly into the dermis of surgical wounds, we sought to determine whether local anesthetics adversely affect proliferative and biosynthetic functions of dermal fibroblasts. We also evaluated the effect of local anesthetics on insulin-like growth factor-1 (IGF-1) and transforming growth factor-ß1 (TGF-ß1), growth factors that are important regulators of wound healing. METHODS: Human dermal fibroblasts (HFB) from aged and young donors were exposed to local anesthetic agents at clinically relevant concentrations. We screened the effects of lidocaine, bupivacaine, mepivacaine, and ropivacaine on proliferation of HFB. Lidocaine was most detrimental to proliferation in HFB. We then evaluated the effect of lidocaine on expression and function of the growth factors, IGF-1 and TGF-ß1. Lastly, concurrent exposure to lidocaine and IGF-1 or TGF-ß1 was evaluated for their effects on proliferation and expression of dermal collagens, respectively. RESULTS: Lidocaine and mepivacaine inhibited proliferation in aged HFB (for lidocaine 88% of control, 95% confidence interval [CI], 80%-98%, P = .009 and for mepivacaine 90% of control, 95% CI, 81%-99%, P = .032) but not in young HFB. Ropivacaine and bupivacaine did not inhibit proliferation. Because of the clinical utility of lidocaine relative to mepivacaine, we focused on lidocaine. Lidocaine decreased proliferation in aged HFB, which was abrogated by IGF-1. Lidocaine inhibited transcripts for IGF-1 and insulin-like growth factor-1 receptor (IGF1R) in fibroblasts from aged donors (IGF-1, log2 fold-change -1.25 [42% of control, 95% CI, 19%-92%, P = .035] and IGF1R, log2 fold-change -1.00 [50% of control, 95% CI, 31%-81%, P = .014]). In contrast, lidocaine did not affect the expression of IGF-1 or IGF1R transcripts in the young HFB. Transcripts for collagen III were decreased after lidocaine exposure in aged and young HFB (log2 fold-change -1.28 [41% of control, 95% CI, 20%-83%, P = .022] in aged HFB and log2 fold-change -1.60 [33% of control, 95% CI, 15%-73%, P = .019] in young HFB). Transcripts for collagen I were decreased in aged HFB (log2 fold-change -1.82 [28% of control, 95% CI, 14%-58%, P = .006]) but not in the young HFB. Similar to the transcripts, lidocaine also inhibited the protein expression of collagen III in young and aged HFB (log2 fold-change -1.79 [29% of control, 95% CI, 18%-47%, P = .003] in young HFB and log2 fold-change -1.76 [30% of control, 95% CI, 9%-93%, P = .043] in aged HFB). The effect of lidocaine on the expression of collagen III protein was obviated by TGF-ß1 in both young and aged HFB. CONCLUSIONS: Our results show that lidocaine inhibits processes relevant to dermal repair in aged HFB. The detrimental responses to lidocaine are due, in part, to interactions with IGF-1 and TGF-ß1.

Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

BACKGROUND: Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain. METHODS: We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin. RESULTS: In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes. CONCLUSIONS: The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

The effect of aging on the cutaneous microvasculature.

Aging is associated with a progressive loss of function in all organs. Under normal conditions the physiologic compensation for age-related deficits is sufficient, but during times of stress the limitations of this reserve become evident. Explanations for this reduction in reserve include the changes in the microcirculation that occur during the normal aging process. The microcirculation is defined as the blood flow through arterioles, capillaries and venules, which are the smallest vessels in the vasculature and are embedded within organs and tissues. Optimal strategies to maintain the microvasculature following surgery and other stressors must use multifactorial approaches. Using skin as the model organ, we will review the anatomical and functional changes in the microcirculation with aging, and some of the available clinical strategies to potentially mitigate the effect of these changes on important clinical outcomes.

Chronic wound repair and healing in older adults: current status and future research.

The incidence of chronic wounds is increased among older adults, and the impact of chronic wounds on quality of life is particularly profound in this population. It is well established that wound healing slows with age. However, the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The impact of age and accompanying multi-morbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables, lack of standardization in data collection, and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this paper, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify key research questions to guide future study of age-associated changes in chronic wound healing.

Anesthesia, microcirculation, and wound repair in aging.

Age-related changes in skin contribute to impaired wound healing after surgical procedures. Changes in skin with age include decline in thickness and composition, a decrease in the number of most cell types, and diminished microcirculation. The microcirculation provides tissue perfusion, fluid homeostasis, and delivery of oxygen and other nutrients. It also controls temperature and the inflammatory response. Surgical incisions cause further disruption of the microvasculature of aged skin. Perioperative management can be modified to minimize insults to aged tissues. Judicious use of fluids, maintenance of normal body temperature, pain control, and increased tissue oxygen tension are examples of adjustable variables that support the microcirculation. Anesthetic agents influence the microcirculation of a combination of effects on cardiac output, arterial pressure, and local microvascular changes. The authors examined the role of anesthetic management in optimizing the microcirculation and potentially improving postoperative wound repair in older persons.

Decreased proliferative capacity of aged dermal fibroblasts in a three dimensional matrix is associated with reduced IGF1R expression and activation.

Skin aging results in increased susceptibility to injury and impaired wound healing. Proliferation of fibroblasts is reduced in aged dermis, which contributes to delays in wound closure. Age-associated differences are regulated, in part, by local or systemic factors such as the IGF-1/IGF1R system. The aim of this study was to determine if expression and activation of IGF1R in aged human dermal fibroblasts, when compared to young fibroblasts, is associated with altered proliferative capacity in a 3D collagen matrix that better simulates the dermal extracellular matrix in vivo. The proliferation of young and aged human dermal fibroblasts in 3D collagen and its association with baseline levels of IGF1R expression were measured. The effect of stimulation and inhibition of Erk phosphorylation on the proliferative capacity of fibroblasts in a 3D collagen matrix was defined. Our results show that proliferation and Erk phosphorylation is reduced in aged dermal fibroblasts relative to young fibroblasts. Activation of Erk phosphorylation in aged fibroblasts is associated with a significant increase in fibroblast proliferation in 3D collagen.

Hyaluronan enhances wound repair and increases collagen III in aged dermal wounds.

Age-related changes in the extracellular matrix contribute to delayed wound repair in aging. Hyaluronan, a linear nonsulfated glycosaminoglycan, promotes synthesis and assembly of key extracellular matrix components, such as the interstitial collagens, during wound healing. The biological effects of hyaluronan are mediated, in part, by hyaluronan size. We have previously determined that dermal wounds in aged mice, relative to young mice, have deficits in the generation of lower molecular weight hyaluronan (defined as <300 kDa). Here, we tested the effect of exogenous hyaluronan of 2, 250, or 1,000 kDa sizes on full-thickness excisional wounds in aged mice. Only wounds treated with 250 kDa hyaluronan (HA250) were significantly improved over wounds that received carrier (water) alone. Treatment with HA250 was associated with increased expression of transcripts for the hyaluronan receptors CD44 and RHAMM, as well as collagens III and I. Analyses of dermal protein content by mass spectrometry and Western blotting confirmed significantly increased expression of collagen III in wounds treated with HA250 relative to control wounds. In summary, we find that HA250 improves wound repair and increases the synthesis of collagen III in aged dermal wounds.

Contrast-enhanced ultrasound imaging detects anatomical and functional changes in rat cervical spine microvasculature with normal aging.

Normal aging is associated with significant deleterious cerebrovascular changes; these have been implicated in disease pathogenesis and increased susceptibility to ischemic injury. While these changes are well documented in the brain, few studies have been conducted in the spinal cord. Here, we utilize specialized contrast-enhanced ultrasound (CEUS) imaging to investigate age-related changes in cervical spinal vascular anatomy and hemodynamics in male Fisher 344 rats, a common strain in aging research. Aged rats (24-26 mo., N=6) exhibited significant tortuosity in the anterior spinal artery and elevated vascular resistance compared to adults (4-6 mo., N=6; tortuosity index 2.20±0.15 vs 4.74±0.45, p<0.05). Baseline blood volume was lower in both larger vessels and the microcirculation in the aged cohort, specifically in white matter (4.44e14±1.37e13 vs 3.66e14±2.64e13 CEUS bolus AUC, p<0.05). To elucidate functional differences, animals were exposed to a hypoxia challenge; whereas adult rats exhibited significant functional hyperemia in both gray and white matter (GM: 1.13±0.10-fold change from normoxia, p<0.05; WM: 1.16±0.13, p<0.05), aged rats showed no response. Immunohistochemistry revealed reduced pericyte coverage and activated microglia behavior in aged rats, which may partially explain the lack of vascular response. This study provides the first in vivo description of age-related hemodynamic differences in the cervical spinal cord.

Mechanical Ventilation in Older Adults With Dementia: Opportunities to Promote Goal-Concordant Care.

CONTEXT: Recent studies show increasing use of mechanical ventilation among people living with dementia. There are concerns that this trend may not be driven by patient preferences. OBJECTIVES: To better understand decision-making regarding mechanical ventilation in people living with dementia. METHODS: This was an electronic health record-based retrospective cohort study of older adults with dementia (n = 295) hospitalized at one of two teaching hospitals between 2015 and 2019 who were supported with mechanical ventilation (n = 191) or died without mechanical ventilation (n = 104). Multivariable logistic regression was used to examine associations between patient characteristics and mechanical ventilation use. RESULTS: The median age was 78 years (IQR 71-86), 41% were female, 28% resided in a nursing home, and 58% had clinical markers of advanced dementia (dehydration, weight loss, mobility limitations, or pressure ulcers). Among patients supported with mechanical ventilation, 70% were intubated within 24 hours of presentation, including 31% intubated before hospital arrival. Younger age, higher illness acuity, and absence of a treatment-limiting Physician Orders for Life-Sustaining Treatment document were associated with mechanical ventilation use; nursing home residence and clinical markers of advanced dementia were not. Most patients (89%) had a documented goals of care discussion (GOCD) during hospitalization. CONCLUSION: Future efforts to promote goal-concordant care surrounding mechanical ventilation use for people living with dementia should involve identifying barriers to goal-concordant care in pre-hospital settings, assessing the timeliness of in-hospital GOCD, and developing strategies for in-the-moment crisis communication across settings.

Implementation of a geriatric care bundle for older adults with acute burns.

BACKGROUND: Frailty and comorbidities are important outcome determinants in older patients (age ≥65) with burns. A Geriatric Burn Bundle (Geri-B) was implemented in 2019 at a regional burn center to standardize care for older adults. Components included frailty screening and protocolized geriatric co-management, malnutrition screening with nutritional support, and geriatric-centered pain regimens. METHODS: This study aimed to qualitatively evaluate the implementation of Geri-B using the Proctor Framework. From June-August 2022, older burn-injured patients, burn nurses, and medical staff providers (attending physicians and advanced practice providers) were surveyed and interviewed. Transcribed interviews were coded and thematically analyzed. From May 2022 to August 2023, the number of inpatient visits aged 65 + with a documented frailty screening was monitored. RESULTS: The study included 23 participants (10 providers, 13 patients). Participants highly rated Geri-B in all implementation domains. Most providers rated geriatric care effectiveness as 'good' or 'excellent' after Geri-B implementation. Providers viewed it as a reminder to tailor geriatric care and a safeguard against substandard geriatric care. Staffing shortages, insufficient protocol training, and learning resources were reported as implementation barriers. Many providers advocated for better bundle integration into the hospital electronic health record (EHR) (e.g., frailty screening tool, automatic admission order sets). Most patients felt comfortable being asked about their functional status with strong patient support for therapy services. The average frailty screening completion rate from May 2022 to August 2023 was 86%. CONCLUSIONS: Geri-B was perceived as valuable for the care of older burn patients and may serve as a framework for other burn centers.

The Brain and Spinal Microvasculature in Normal Aging.

Changes in the brain and spinal cord microvasculature during normal aging contribute to the "sensitive" nature of aged central nervous system tissue to ischemic insults. In this review, we will examine alterations in the central nervous system microvasculature during normal aging, which we define as aging without a dominant pathology such as neurodegenerative processes, vascular injury or disease, or trauma. We will also discuss newer technologies to improve the study of central nervous system microvascular structure and function. Microvasculature within the brain and spinal cord will be discussed separately as anatomy and physiology differ between these compartments. Lastly, we will identify critical areas for future studies as well as key unanswered questions.

Cellular senescence and the blood-brain barrier: Implications for aging and age-related diseases.

The blood-brain barrier (BBB) is a critical physiochemical interface that regulates communication between the brain and blood. It is comprised of brain endothelial cells which regulate the BBB's barrier and interface properties and is surrounded by supportive brain cell types including pericytes and astrocytes. Recent reports have suggested that the BBB undergoes dysfunction during normative aging and in disease. In this review, we consider the effect of cellular senescence, one of the nine hallmarks of aging, on the BBB. We first characterize known normative age-related changes at the BBB, and then evaluate changes in neurodegenerative diseases, with an emphasis on if/how cellular senescence is influencing these changes. We then discuss what insight has been gained from in vitro and in vivo studies of cellular senescence at the BBB. Finally, we evaluate mechanisms by which cellular senescence in peripheral pathologies can indirectly or directly affect BBB function.