Hospital-Based Health Professionals' Perceptions of Frailty in Older People.

BACKGROUND AND OBJECTIVES: There is a high prevalence of frailty amongst older patients in hospital settings. Frailty guidelines exist but implementation to date has been challenging. Understanding health professional attitudes, knowledge, and beliefs about frailty is critical in understanding barriers and enablers to guideline implementation and the aim of this study was to understand these in rehabilitation multidisciplinary teams in hospital settings. RESEARCH DESIGN AND METHODS: Twenty-three semi-structured interviews were conducted with health professionals working in multi-disciplinary teams on geriatric and rehabilitation wards in Adelaide and Sydney, Australia. Interviews were audio recorded, transcribed, and coded by two researchers. A codebook was created and interviews re-coded and applied to the Framework Method of thematic analysis. RESULTS: Three domains were developed: diagnosing frailty, communicating about frailty, and managing frailty. Within these domains, eight themes were identified: (1) diagnosing frailty has questionable benefits, (2) clinicians don't use frailty screening tools, (3) frailty can be diagnosed on appearance and history, (4) frailty has a stigma, (5) clinicians don't use the word "frail" with patients, (6) frailty isn't always reversible, (7) there is a lack of continuity of care after acute admission, and (8) the community setting lacks resources. DISCUSSION AND IMPLICATIONS: Implementation of frailty guidelines will remain challenging while staff avoid using the term "frail", don't perceive benefit of using screening tools, and focus on the individual aspects of frailty rather than the syndrome holistically. Clinical champions and education about frailty identification, reversibility, management, and communication techniques may improve the implementation of frailty guidelines in hospitals.

Updated Analysis of Radon Exposure and Lung Cancer Mortality in the Cohort of Newfoundland Fluorspar Miners (1950-2016).

The commercial mining of fluorspar in St. Lawrence Newfoundland began in 1933. Miners who worked underground were exposed to high levels of radon progeny, especially before ventilation was introduced into the mines in 1960. The mean cumulative radon exposure for underground miners in this cohort was 380.9 working level months (WLM). A series of studies of this cohort have characterized the increased risks of lung cancer mortality due to radon. We have extended the follow-up of this cohort an additional 15 years to provide additional insights on the risks of low levels of radon exposure, and the modifying effects of time since exposure, age at first exposure, attained age, duration of exposure, and cigarette smoking. The cohort consisted of 1,735 underground and 315 male surface miners who, combined, accrued 81,650 person-years of follow-up. The mortality experience of the cohort was determined from 1950-2016 through record linkage to Canadian national death data. Individual-level estimates of exposure to radon progeny, in WLMs, were determined for each year of employment. We compared the mortality experience of the underground miners to Newfoundland men using the standardized mortality ratio (SMR). Poisson regression models were fit to estimate excess relative risks (ERR) per 100 WLM. There were 236 lung cancer deaths identified, and of these, 221 occurred among underground workers. The SMR for lung cancer among underground miners compared to Newfoundland men was 2.67 (95% CI: 2.33, 3.04). The ERR per 100 WLM for lung cancer mortality, assuming a 5-year exposure lag, was 0.41 (95% CI: 0.23, 0.59). Attained age and time since exposure were important modifiers to the radon-lung cancer relationship. The joint relationship between smoking and radon on lung cancer risk was sub-additive, however, the smoking data were limited and available for only half of the cohort.

Varying the RGD concentration on a hyaluronic acid hydrogel influences dormancy versus proliferation in brain metastatic breast cancer cells.

A majority of breast cancer deaths occur due to metastasis of cancer cells to distant organs. In particular, brain metastasis is very aggressive with an extremely low survival rate. Breast cancer cells that metastasize to the brain can enter a state of dormancy, which allows them to evade death. The brain microenvironment provides biophysical, biochemical, and cellular cues, and plays an important role in determining the fate of dormant cancer cells. However, how these cues influence dormancy remains poorly understood. Herein, we employed hyaluronic acid (HA) hydrogels with a stiffness of ~0.4 kPa as an in vitro biomimetic platform to investigate the impact of biochemical cues, specifically alterations in RGD concentration, on dormancy versus proliferation in MDA-MB-231Br brain metastatic breast cancer cells. We applied varying concentrations of RGD peptide (0, 1, 2, or 4 mg/mL) to HA hydrogel surfaces and confirmed varying degrees of surface functionalization using a fluorescently labeled RGD peptide. Post functionalization, ~10,000 MDA-MB-231Br cells were seeded on top of the hydrogels and cultured for 5 days. We found that an increase in RGD concentration led to changes in cell morphology, with cells transitioning from a rounded to spindle-like morphology as well as an increase in cell spreading area. Also, an increase in RGD concentration resulted in an increase in cell proliferation. Cellular dormancy was assessed using the ratio of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK) to phosphorylated p38 (p-p38) positivity, which was significantly lower in hydrogels without RGD and in hydrogels with lowest RGD concentration compared to hydrogels functionalized with higher RGD concentration. We also demonstrated that the HA hydrogel-induced cellular dormancy was reversible. Finally, we demonstrated the involvement of ß1 integrin in mediating cell phenotype in our hydrogel platform. Overall, our results provide insight into the role of biochemical cues in regulating dormancy versus proliferation in brain metastatic breast cancer cells.

Middle aged and older adult's perspectives of their own home environment: a review of qualitative studies and meta-synthesis.

BACKGROUND: Most people prefer to remain in their homes and communities as long as possible. Staying at home is widely beneficial as ageing within the home promotes independence and costs less than residential aged care. Understanding meanings and drivers of remaining at home is an area of importance. OBJECTIVE: The objective of this systematic review of qualitative studies was to synthesise middle and older aged adult's perspective of their home environment and determine the factors that are important when making decisions about future housing. METHODS: This review and meta-synthesis was conducted in accordance with JBI (formally known as the Joanna Briggs Institute) methodology for systematic reviews of qualitative evidence. Meta-aggregation was used as the method of synthesis. Included qualitative studies involved middle and older aged adults and their views about ageing and housing. Published studies were identified in four electronic databases and grey literature. Critical appraisal and extraction were conducted using JBI tools and findings were categorised and synthesised into findings. RESULTS: A total of 46 papers with 5183 participants on the concept of home were included. Most of the participants were older (> 65 years old) and the perspectives of middle-aged people were largely absent. Factors impacting on future housing decisions among individuals were identified. Seven synthesized findings emerged-independence, finances, stigma, attitudes towards ageing, attachments with home, aesthetics, and family connection. CONCLUSION: Older people have a greater sense of independence and autonomy if they remain in their own home. Multiple external factors impacted on their perspectives including a sense of stigma about ageing, fear of being a burden to others and their own financial position which in some cases restricted their options. This review provides a comprehensive description of the different factors that need to be considered when planning future housing needs; both for individuals and for communities.

Mobile Health Intervention in Patients With Type 2 Diabetes: A Randomized Clinical Trial.

Importance: Clinical pharmacists and health coaches using mobile health (mHealth) tools, such as telehealth and text messaging, may improve blood glucose levels in African American and Latinx populations with type 2 diabetes. Objective: To determine whether clinical pharmacists and health coaches using mHealth tools can improve hemoglobin A1c (HbA1c) levels. Design, Setting, and Participants: This randomized clinical trial included 221 African American or Latinx patients with type 2 diabetes and elevated HbA1c (≥8%) from an academic medical center in Chicago. Adult patients aged 21 to 75 years were enrolled and randomized from March 23, 2017, through January 8, 2020. Patients randomized to the intervention group received mHealth diabetes support for 1 year followed by monitored usual diabetes care during a second year (follow-up duration, 24 months). Those randomized to the waiting list control group received usual diabetes care for 1 year followed by the mHealth diabetes intervention during a second year. Interventions: The mHealth diabetes intervention included remote support (eg, review of glucose levels and medication intensification) from clinical pharmacists via a video telehealth platform. Health coach activities (eg, addressing barriers to medication use and assisting pharmacists in medication reconciliation and telehealth) occurred in person at participant homes and via phone calls and text messaging. Usual diabetes care comprised routine health care from patients' primary care physicians, including medication reconciliation and adjustment. Main Outcomes and Measures: Outcomes included HbA1c (primary outcome), blood pressure, cholesterol, body mass index, health-related quality of life, diabetes distress, diabetes self-efficacy, depressive symptoms, social support, medication-taking behavior, and diabetes self-care measured every 6 months. Results: Among the 221 participants (mean [SD] age, 55.2 [9.5] years; 154 women [69.7%], 148 African American adults [67.0%], and 73 Latinx adults [33.0%]), the baseline mean (SD) HbA1c level was 9.23% (1.53%). Over the initial 12 months, HbA1c improved by a mean of -0.79 percentage points in the intervention group compared with -0.24 percentage points in the waiting list control group (treatment effect, -0.62; 95% CI, -1.04 to -0.19; P = .005). Over the subsequent 12 months, a significant change in HbA1c was observed in the waiting list control group after they received the same intervention (mean change, -0.57 percentage points; P = .002), while the intervention group maintained benefit (mean change, 0.17 percentage points; P = .35). No between-group differences were found in adjusted models for secondary outcomes. Conclusions and Relevance: In this randomized clinical trial, HbA1c levels improved among African American and Latinx adults with type 2 diabetes. These findings suggest that a clinical pharmacist and health coach-delivered mobile health intervention can improve blood glucose levels in African American and Latinx populations and may help reduce racial and ethnic disparities. Trial Registration: ClinicalTrials.gov Identifier: NCT02990299.

Evaluating a new emergency department avoidance service for older people: patient and relative experiences.

BACKGROUND: High emergency department (ED) usage by older individuals for non-emergencies is a global concern. ED avoidance initiatives have proven effective in addressing this issue. To specifically cater to individuals aged 65 and above, the Southern Adelaide Local Health Network introduced an innovative ED avoidance service. This study assessed the acceptability of the service among its users. METHOD: The Complex And RestorativE (CARE) Centre is a six-bed unit staffed by a multidisciplinary geriatric team. Patients are transported directly to CARE after calling for an ambulance and being triaged by a paramedic. The evaluation took place between September 2021 and September 2022. Semi-structured interviews were conducted with patients and relatives who had accessed the service. Data analysis was performed using a six-step thematic analysis. RESULTS: Seventeen patients and 15 relatives were interviewed, who described the experience of 32 attendances to the urgent CARE centre between them. Patients accessed the service for several reasons but over half were associated with falls. There was a hesitation to call emergency services for several reasons, the primary being long wait times in ED and/or the prospect of an overnight stay in hospital. Some individuals attempted to contact their General Practitioner (GP) for the presenting problem but were unable to get a timely appointment. Most participants had previously attended a local ED and had a negative experience. All individuals reported favouring the CARE centre over the traditional ED for numerous reasons including a quieter and safer environment and specially trained geriatric staff who were less rushed than ED staff. Several participants would have appreciated a standardised follow-up process after discharge. CONCLUSION: Our findings suggest that ED admission avoidance programmes may be an acceptable alternative treatment for older people requiring urgent care, potentially benefiting both public health systems and user experience.

A Systematic Review of Outcomes Measured Following New Wheelchair and Seating-Prescription Interventions in Adults.

Objectives: To determine the outcomes and outcome-measurement tools currently used during the prescription of new wheelchairs and/or seating systems. A systematic review of studies was performed to identify outcome-measurement tools. Data Sources: MEDLINE, CINAHL, EMBASE, and PsycINFO were searched from earliest available to March 2022. Study Selection: Studies were included if they focused on a new wheelchair or seating-system prescription with adults. Data Extraction: Data extraction and quality assessments were conducted by 2 reviewers; disagreements were resolved by consensus. Risk of bias was assessed using the PEDro scale (for randomized controlled trials) and the Newcastle-Ottawa Quality Assessment Scale (for non-randomized studies). Data Synthesis: 48 articles were included which identified 37 standardized outcome-measurement tools. Use of study-specific outcome-measurement tools was common. Wheelchair use, user satisfaction, activity, and participation were the most studied outcome domains. Commonly used standardized assessments included the QUEST 2.0, functional independence measure, WHODAS II, IPPA, and PIADS. Conclusion: Outcome measures to evaluate wheelchair and seating-system prescription vary, and the use of study-specific outcome-measurement tools is high. There is a need to choose consistent outcome measures that are reliable and valid, and deal with this complex area through ensuring carefully constructed study designs.

'Put in a room and left': a qualitative study exploring the lived experiences of COVID-19 isolation and quarantine among rehabilitation inpatients.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic has resulted in significant changes to health care delivery and the patient's experience in hospital. Changes for those who contracted COVID-19 or were close contacts included isolation and quarantine, visitor restrictions and changes to usual models of care to reduce viral transmission. Traditional models of inpatient rehabilitation utilise communal spaces (e.g. shared gyms and dining rooms) and involve a multidisciplinary team interacting with the patient daily. OBJECTIVES: To report the experience of COVID-19 related isolation and quarantine among rehabilitation inpatients and their family members who experienced a nosocomial outbreak and to make recommendations for rehabilitation units. METHODS: A qualitative phenomenological methodology using semi-structured telephone interviews. RESULTS: 19 semi-structured interviews were conducted comprising of 13 general rehabilitation inpatients and 6 family members. Five themes were established: (1) the impact of social and physical isolation; (2) boredom and limited access to therapy; (3) the impact of technology; (4) inadequate information sharing and (5) positive experiences and things done well. Several novel insights were identified including: the desire for increased social interaction from staff to compensate for a lack of visitors; the impact of physical and cognitive deficits on a patient's ability to reach basic items around their room or call for help, and the unique impact of isolation and quarantine on individuals who have a history of trauma, discrimination or mental illness. CONCLUSIONS: This study establishes key areas that should be considered by rehabilitation units globally to adjust traditional models which are not suitable in this pandemic. Strategies to mitigate the impact of isolation include providing training to increase use of technologies such as tablet devices, increased staff social engagement to reduce isolation and tailoring the environment to suit specific patient groups.KEY MESSAGESCOVID-19 related isolation and quarantine has a significant and unique impact on patients with cognitive and physical impairments such as those in inpatient rehabilitation. Patients who are required to isolate in inpatient settings expressed a desire for compensatory increased social interaction from staff and required specific assistance with basic daily tasks while isolated. The study makes key recommendations for other rehabilitation units to integrate into their approach for managing patients required to isolate or quarantine.

Circulatory system disease mortality and occupational exposure to radon progeny in the cohort of Newfoundland Fluorspar Miners between 1950 and 2016.

OBJECTIVES: Exposure to ionizing radiation may increase the risk of circulatory diseases, including heart disease. A limited number of cohort studies of underground miners have investigated these associations. We previously reported a positive but non-statistically significant association between radon progeny and heart disease in a cohort of Newfoundland fluorspar miners. In this study, we report updated findings that incorporate 15 additional years of follow-up. METHODS: The cohort included 2050 miners who worked in the fluorspar mines from 1933 to 1978. Statistics Canada linked the personal identifying data of the miners to Canadian mortality data to identify deaths from 1950 to 2016. We used previously derived individual-level estimates of annual radon progeny exposure in working-level months. Cumulative exposure was categorized into quantiles. We estimated relative risks and their 95% confidence intervals using Poisson regression for deaths from circulatory, ischemic heart disease and acute myocardial infarction. Relative risks were adjusted for attained age, calendar year, and the average number of cigarettes smoked daily. RESULTS: Relative to the Newfoundland male population, the standardized mortality ratio for circulatory disease in this cohort was 0.82 (95% CI 0.74-0.91). Those in the highest quantile of cumulative radon progeny exposure had a relative risk of circulatory disease mortality of 1.03 (95% CI 0.76-1.40) compared to those in the lowest quantile. The corresponding estimates for ischemic disease and acute myocardial infarction were 0.99 (95% CI 0.66-1.48), and 1.39 (95% CI 0.84-2.30), respectively. CONCLUSIONS: Our findings do not support the hypothesis that occupational exposure to radon progeny increases the risk of circulatory disease.

Association between exposures to radon and γ-ray radiation and histologic type of lung cancer in Eldorado uranium mining and milling workers from Canada.

BACKGROUND: The authors assessed the association between radon decay products (RDP) exposure and histologic types of incident lung cancer in a cohort of 16,752 (91.6% male) Eldorado uranium workers who were first employed from 1932 to 1980 and were followed through 1969-1999. METHODS: Substantially revised identifying information and RDP exposures were obtained on workers from the Port Radium and Beaverlodge uranium mines and from the Port Hope radium and uranium refinery and processing facility in Canada. Poisson regression was conducted using the National Research Council's Biological Effects of Ionizing Radiation (BEIR) VI-type models to estimate the risks of lung cancer by histologic type from RDP exposures and γ-ray doses. RESULTS: Lung cancer incidence was significantly higher in workers compared with the general Canadian male population. Radiation risks of lung cancer for all histologic types (n = 594; 34% squamous cell, 16% small cell, 17% adenocarcinoma) increased with increasing RDP exposure, with no indication of curvature in the dose response (excess relative risk per 100 working level months = 0.61; 95% confidence interval, 0.39-0.91). Radiation risks did not differ by histologic type (p = .144). The best-fitting BEIR VI-type model included adjustments for the significant modifying effects of time since exposure, exposure rate, and attained age. The addition of γ-ray doses to the model with RDP exposures improved the model fit, but the risk estimates remained unchanged. CONCLUSIONS: The first analysis of radiation risks of lung cancer histologic types in the Eldorado cohort supported the use of BEIR VI-type models to predict the future risk of histologic types of lung cancer from past and current RDP exposures. LAY SUMMARY: Lung cancer survival depends strongly on the cell type of lung cancer. The best survival rates are for patients who have the adenocarcinoma type. This study included 16,752 Eldorado uranium workers who were exposed to radon and γ-ray radiation during 1932-1980, were alive in 1969, and were followed for the development of new lung cancer during 1969-1999. One third of all lung cancers were of the squamous cell type, whereas the adenocarcinoma and small cell types accounted for less than 20% each. Radiation risks of lung cancer among men increased significantly with increasing radon exposure for all cell types, with the highest risks estimated for small cell and squamous cell lung cancers.

Self-assessment of the home environment to plan for successful ageing: Report from a digital health co-design workshop.

Many middle aged and older people will need to adapt or modify their home in order to age in place. Arming older people and their families with the knowledge and tools to assess their home and plan simple modifications ahead of time will decrease reliance on professional assessment. The objective of this project was to co-design a tool which enables people to assess their own home environment and make future plans for ageing in the home. We recruited members of the public who were aged 60 or older to attend a series of two co-design workshops. Thirteen participants worked through a series of discussions and activities including appraising different types of tools available and mapping what a digital health tool might look like. Participants had a good understanding of the main types of home hazards in their own homes and the types of modifications which may be useful. Participants believed the concept of the tool would be worthwhile and identified a number of features which were important including a checklist, examples of good design which was both accessible and aesthetically pleasing and links to other resources such as websites which provide advice about to make basic home improvements. Some also wanted to share the results of their assessment with family or friends. Participants highlighted that features of the neighbourhood, such as safety and proximity to shops and cafes, were also important when considering the suitability of their home for ageing in place. Findings will be used to develop a prototype for usability testing.

COHERE - strengthening cooperation within the Canadian government on radiation research.

PURPOSE: Canadian Organization on Health Effects from Radiation Exposure (COHERE) is a government initiative to better understand biological and human health risks from ionizing radiation exposures relevant to occupational and environmental settings (<100 mGy, <6 mGy/h). It is currently a partnership between two federal agencies, Health Canada (HC) and the Canadian Nuclear Safety Commission (CNSC). COHERE's vision is to contribute knowledge to reduce scientific uncertainties from low dose and dose-rate exposures. COHERE will advance our understanding by bridging the knowledge gap between human health risks and linkages to molecular- and cellular-level responses to radiation. Research focuses on identifying sensitive, early, and key molecular events of relevance to risk assessment. CONCLUSIONS: The initiative will address questions of relevance to better apprize Canadians, including radiation workers and members of the public and Indigenous peoples, on health risks from low dose radiation exposure and inform radiation protection frameworks at a national and international level. Furthermore, it will support global efforts to conduct collaborative undertakings and better coordinate research. Here, we describe a historical overview of the research conducted, the strategic research agenda that outlines the scientific framework, stakeholders, opportunities to harmonize internationally, and how research outcomes will better inform communication of risk to Canadians.

Low radon exposures and lung cancer risk: joint analysis of the Czech, French, and Beaverlodge cohorts of uranium miners.

It is well established that high radon exposures increase the risk of lung cancer mortality. The effects of low occupational exposures and the factors that confound and modify this risk are not clear and are needed to inform current radiation protection of miners. The risk of lung cancer mortality at low radon exposures (< 100 working-level months) was assessed in the joint cohort analysis of Czech, French, and Canadian uranium miners, employed in 1953 or later. Statistical analysis was based on linear Poisson regression modeling with grouped cohort survival data. Two sensitivity analyses were used to assess potential confounding from tobacco smoking. A statistically significant linear relationship between radon exposure and lung cancer mortality was found. The excess relative risk per working-level month was 0.022 (95% confidence intervals: 0.013-0.034), based on 408 lung cancer deaths and 394,236 person-years of risk. Time since exposure was a statistically significant modifier; risk decreased with increasing time since exposure. A tendency for a decrease in risk with increasing attained age was observed, but this was not statistically significant. Exposure rate was not found to be a modifier of the excess relative risk. The potential confounding effect of tobacco smoking was estimated to be small and did not substantially change the radon-lung cancer mortality risk estimates. This joint cohort analysis provides strong evidence for an increased risk of lung cancer mortality from low occupational radon exposures. The results suggest that radiation protection measures continue to be important among current uranium miners.

Melatonin and tannic acid supplementation in vitro improve fertilization and embryonic development in pigs.

The objective of this study was to determine the effects of melatonin supplementation during maturation and tannic acid supplementation during IVF on fertilization kinetics and early embryonic development. Experiment 1 determined the optimum concentration of melatonin supplemented to the oocytes for subsequent embryonic development. Oocytes (n = 400) were supplemented at 22 h of maturation with 0, 75, 100, or 150 nm melatonin and then subjected to IVF and embryo culture. After IVF, a portion of the embryos were evaluated for penetration, polyspermy, and male pronuclear (MPN) formation rates. Embryos were evaluated 48 h after IVF for cleavage and 144 h for blastocyst formation. There were no significant differences between treatment groups with respect to penetration and polyspermy. Supplementation of 150 nm melatonin produced a significantly greater (P < 0.05) percent of embryos with MPN compared to those supplemented with 75 nm or 100 nm. Supplementation of 150 nm melatonin produced significantly less (P < 0.05) embryos cleaved by 48 h after IVF while 75 nm melatonin supplementation had a significantly higher (P < 0.05) percentage of blastocyst formation by 144 h after IVF. Based on the optimal concentration of melatonin observed in experiment 1, experiment 2 determined the effects of supplementing 75 nm melatonin to the maturation media and 5.0 µg/ml tannic acid supplementation during IVF on oxidative stress, fertilization kinetics, and embryonic development. Oocytes (n = 720) were supplemented at 22 h of maturation with or without 75 nm melatonin and then fertilized with frozen-thawed sperm supplemented with or without 5 µg/ml tannic acid. Reactive oxygen species levels were measured in matured oocytes using 2',7'-dichlorodihydrofluorescein diacetate. Oocytes supplemented with 75 nm melatonin had significantly less (P < 0.05) reactive oxygen species generation and oocytes fertilized with sperm incubated with tannic acid had a significantly less (P < 0.05) incidence of polyspermic penetration compared to no supplementation. All treatment groups had significantly greater (P < 0.05) incidence of male pronuclear formation compared to oocytes not supplemented with melatonin and fertilized without tannic acid. Oocytes that were supplemented with melatonin and fertilized with sperm incubated with tannic acid had a significantly higher (P < 0.05) percentage of blastocyst formation by 144 h post-IVF compared all other treatment groups. Results indicate that supplementation of 75 nm melatonin during oocyte maturation and 5 µg/ml tannic acid during IVF leads to a decrease in oxidative stress, increase in IVF success and subsequent embryo development in pigs.

Heparosan-coated liposomes for drug delivery.

Liposomal encapsulation is a useful drug delivery strategy for small molecules, especially chemotherapeutic agents such as doxorubicin. Doxil® is a doxorubicin-containing liposome ("dox-liposome") that passively targets drug to tumors while reducing side effects caused by free drug permeating and poisoning healthy tissues. Polyethylene glycol (PEG) is the hydrophilic coating of Doxil® that protects the formulation from triggering the mononuclear phagocyte system (MPS). Evading the MPS prolongs dox-liposome circulation time thus increasing drug deposition at the tumor site. However, multiple doses of Doxil® sometimes activate an anti-PEG immune response that enhances liposome clearance from circulation and causes hypersensitivity, further limiting its effectiveness against disease. These side effects constrain the utility of PEG-coated liposomes in certain populations, justifying the need for investigation into alternative coatings that could improve drug delivery for better patient quality of life and outcome. We hypothesized that heparosan (HEP; [-4-GlcA-ß1-4-GlcNAc-α1-]n) may serve as a PEG alternative for coating liposomes. HEP is a natural precursor to heparin biosynthesis in mammals. Also, bacteria expressing an HEP extracellular capsule during infection escape detection and are recognized as "self," not a foreign threat. By analogy, coating drug-carrying liposomes with HEP should camouflage the delivery vehicle from the MPS, extending circulation time and potentially avoiding immune-mediated clearance. In this study, we characterize the postmodification insertion of HEP-lipids into liposomes by dynamic light scattering and coarse-grain computer modeling, test HEP-lipid immunogenicity in rats, and compare the efficacy of drug delivered by HEP-coated liposomes to PEG-coated liposomes in a human breast cancer xenograft mouse model.

Expanding glycosaminoglycan chemical space: towards the creation of sulfated analogs, novel polymers and chimeric constructs.

Glycosaminoglycans (GAGs) have therapeutic potential in areas ranging from angiogenesis, inflammation, hemostasis and cancer. GAG bioactivity is conferred by intrinsic structural features, such as disaccharide composition, glycosidic linkages and sulfation pattern. Unfortunately, the in vitro enzymatic synthesis of defined GAGs is quite restricted by a limited understanding of current GAG synthases and modifying enzymes. Our work provides insights into GAG-active enzymes through the creation of sulfated oligosaccharides, a new polysaccharide and chimeric polymers. We show that a C6-sulfonated uridine diphospho (UDP)-glucose (Glc) derivative, sulfoquinovose, can be used as an uronic acid donor, but not as a hexosamine donor, to cap hyaluronan (HA) chains by the HA synthase from the microbe Pasteurella multocida. However, the two heparosan (HEP) synthases from the same species, PmHS1 and PmHS2, could not employ the UDP-sulfoquinovose under similar conditions. Serendipitously, we found that PmHS2 co-polymerized Glc with glucuronic acid (GlcA), creating a novel HEP-like polymer we named hepbiuronic acid [-4-GlcAß1-4-Glcα1-]n. In addition, we created chimeric block polymers composed of both HA and HEP segments; in these reactions GlcA-, but not N-acetylglucosamine-(GlcNAc), terminated GAG acceptors were recognized by their noncognate synthase for further extension, likely due to the common ß-linkage connecting GlcA to GlcNAc in both of these GAGs. Overall, these GAG constructs provide new tools for studying biology and offer potential for future sugar-based therapeutics.

Aging Promotes Sirtuin 3-Dependent Cartilage Superoxide Dismutase 2 Acetylation and Osteoarthritis.

OBJECTIVE: To quantify functional age-related changes in the cartilage antioxidant network in order to discover novel mediators of cartilage oxidative stress and osteoarthritis (OA) pathophysiology. METHODS: We evaluated histopathologic changes of knee OA in 10-, 20-, and 30-month-old male F344BN rats and analyzed cartilage oxidation according to the ratio of reduced to oxidized glutathione. Antioxidant gene expression and protein abundance were analyzed by quantitative reverse transcription-polymerase chain reaction and selected reaction-monitoring mass spectrometry, respectively. Superoxide dismutase 2 (SOD2) activity and acetylation were analyzed by colorimetric enzyme assays and Western blotting, respectively. We examined human OA cartilage to evaluate the clinical relevance of SOD2 acetylation, and we tested age-related changes in the mitochondrial deacetylase sirtuin 3 (SIRT-3) in rats and mice. RESULTS: Cartilage oxidation and OA severity in F344BN rats increased with age and were associated with an increase in SOD2 expression and protein abundance. However, SOD2-specific activity decreased with age due to elevated posttranslational lysine acetylation. Consistent with these findings, SIRT-3 levels decreased substantially with age, and treatment with SIRT-3 increased SOD2 activity in an age-dependent manner. SOD2 was also acetylated in human OA cartilage, and activity was increased with SIRT-3 treatment. Moreover, in C57BL/6J mice, cartilage SIRT-3 expression decreased with age, and whole-body deletion of SIRT-3 accelerated the development of knee OA. CONCLUSION: Our results show that SIRT-3 mediates age-related changes in cartilage redox regulation and protects against early-stage OA. These findings suggest that mitochondrial acetylation promotes OA and that restoration of SIRT-3 in aging cartilage may improve cartilage resistance to oxidative stress by rescuing acetylation-dependent inhibition of SOD2 activity.

Mitochondrial respiration and redox coupling in articular chondrocytes.

INTRODUCTION: Chondrocytes rely primarily on glycolysis to meet cellular energy needs, but recent studies implicate impaired mitochondrial function in osteoarthritis (OA) pathogenesis. Our objectives were to investigate the ability of chondrocytes to upregulate mitochondrial respiration when challenged with a nutrient stress and determine the effect on mediators of chondrocyte oxidative homeostasis. METHODS: Primary bovine chondrocytes were isolated and cultured in alginate beads. Mitochondrial respiration was stimulated by culturing cells with galactose-supplemented media for a period of 1 or 5 days. Metabolic flexibility was assessed by measuring metabolite and enzymatic biomarkers of glycolytic and mitochondrial metabolism. Oxidative homeostasis was assessed by measuring (1) cellular glutathione content and redox homeostasis, (2) rates of nitric oxide and superoxide production, and (3) the abundance and activity of cellular anti-oxidant proteins, especially the mitochondrial isoform of superoxide dismutase (SOD2). The regulatory role of hypoxia-inducible factor 2α (HIF-2α) in mediating the metabolic and redox responses was evaluated by chemical stabilization with cobalt chloride (CoCl2). RESULTS: After 5 days of galactose culture, lactate production and lactate dehydrogenase activity were reduced by 92% (P<0.0001) and 28% (P=0.051), respectively. Conversely, basal oxygen consumption increased 35% (P=0.042) without increasing mitochondrial content. Glutathione redox homeostasis was unaffected by galactose culture. However, the production of nitric oxide and superoxide and the expression and activity of SOD2 were significantly reduced after 5 days in galactose culture. Nuclear protein expression and gene expression of HIF-2α, a transcription factor for SOD2, were significantly downregulated (more than twofold; P<0.05) with galactose culture. CoCl2-mediated stabilization of HIF-2α during the initial galactose response phase attenuated the reduction in SOD2 (P=0.028) and increased cell death (P=0.003). CONCLUSIONS: Chondrocyte metabolic flexibility promotes cell survival during a nutrient stress by upregulating mitochondrial respiration and reducing the rate of reactive nitrogen and oxygen species production. These changes are coupled to a substantial reduction in the expression and activity of the mitochondrial anti-oxidant SOD2 and its pro-catabolic transcription factor HIF-2α, suggesting that an improved understanding of physiologic triggers of chondrocyte metabolic flexibility may provide new insight into the etiology of OA.