N-Butyrylated Hyaluronic Acid Achieves Anti-Inflammatory Effects In Vitro and in Adjuvant-Induced Immune Activation in Rats.

Previously synthesized N-butyrylated hyaluronic acid (BHA) provides anti-inflammatory effects in rat models of acute gouty arthritis and hyperuricemia. However, the mechanism of action remains to be elucidated. Herein, the anti-inflammatory and antioxidative activities of BHA and the targeted signaling pathways were explored with LPS-induced RAW264.7 and an adjuvant-induced inflammation in a rat model. Results indicated that BHA inhibited the generation of pro-inflammatory cytokines TNFα, IL-1ß and IL-6, reduced ROS production and down-regulated JAK1-STAT1/3 signaling pathways in LPS-induced RAW264.7. In vivo, BHA alleviated paw and joint swelling, decreased inflammatory cell infiltration in paw tissues, suppressed gene expressions of p38 and p65, down-regulated the NF-κB and MAPK signaling pathways and reduced protein levels of TNFα, IL-1ß and IL-6 in joint tissues of arthritis rats. This study demonstrated the pivotal role of BHA in anti-inflammation and anti-oxidation, suggesting the potential clinical value of BHA in the prevention of inflammatory arthritis and is worthy for development as a new pharmacological treatment.

Secreted Phosphoprotein 24 is a Biomarker of Mineral Metabolism.

The 24 kD form of secreted phosphoprotein (SPP-24), a cytokine-binding bone matrix protein with various truncated C-terminal products, is primarily synthesized by the liver. SPP-24 shares homology with fetuin-A, a potent vascular and soft tissue calcification inhibitor and SPP-24 is one component of calciprotein particles (CPPs), a circulating fetuin-mineral complex. The limited molecular evidence to date suggests that SPP-24 may also function as an inhibitor of bone formation and ectopic vascular calcification, potentially through bone morphogenic protein 2 (BMP-2) and Wnt-signaling mediated actions. The C-terminal products of SPP-24 bind to BMP-2 and attenuate BMP-2-induced bone formation. The aim of this study was to assess circulating SPP-24 in relation to kidney function and in concert with markers of mineral metabolism in humans. SPP-24 was measured in the serum of total of 192 subjects using ELISA-based measurements. Subjects were participants of one of two cohorts: (1) mGFR Cohort (n = 80) was participants of a study of measured GFR (mGFR) using inulin urinary clearance, recruited mostly from a chronic kidney disease clinic with low-range kidney function (eGFR 38.7 ± 25.0 mL/min/1.73 m2) and (2) CaMOS Cohort (n = 112) was a subset of randomly selected, community-dwelling participants of year 10 of the Canadian Multicentre Osteoporosis Study with eGFR in the normal range of 75.0 ± 15.9 mL/min/1.73 m2. In the combined cohort, the mean SPP-24 was 167.7 ± 101.1 ng/mL (range 33.4-633.6 ng/mL). The mean age was 66.5 ± 11.3, 57.1% female and mean eGFR (CKD-EPI) was 59.9 ± 27.0 mL/min/1.73 m2 (range 8-122 mL/min/1.73 m2). There was a strong inverse correlation between SPP-24 and eGFR (R = - 0.58, p < 0.001) that remained after adjustment for age. Following adjustment for age, eGFR, and sex, SPP-24 was significantly associated with phosphate (R = - 0.199), PTH (R = 0.298), and the Wnt-signaling inhibitor Dickkopf-related protein 1 (R = - 0.156). The results of this study indicate that SPP-24 is significantly altered by kidney function and is the first human data linking levels of SPP-24 to other biomarkers involved in mineral metabolism. Whether there is a role for circulating SPP-24 in bone formation and ectopic mineralization requires further study.

Statin Use is Associated With Insulin Resistance in Participants of the Canadian Multicentre Osteoporosis Study.

CONTEXT: Statins have been linked to the development of diabetes and atherosclerotic plaque calcification in patients with cardiac disease. OBJECTIVE: To determine the association between statin use and statin characteristics and insulin resistance and abdominal aortic calcification (AAC) in participants of the Canadian Multicentre Osteoporosis Study (CaMos). DESIGN: Observational study. SETTING: General community. PARTICIPANTS: Nondiabetic participants of the Kingston CaMos site. INTERVENTION: Insulin resistance and AAC in statin users and nonstatin users were compared with and without the inclusion of a propensity score (PS) to be on a statin. The covariates of hypertension, sex, body mass index, smoking, kidney stones, and age that were included in the PS were selected based on clinical judgment confirmed by the statistical analysis of a difference between statin users and nonstatin users. MAIN OUTCOME MEASURES: Insulin resistance measured by the homeostasis model assessment (HOMA-IR) and AAC assessed on lateral spine radiographs using the Framingham methodology. RESULTS: Using a general linear model, statin use was associated with higher levels of HOMA-IR after stratified PS adjustment (ß = 1.52, [1.18-1.95], P < 0.01). Hydrophilic statin users (n = 9) and lipophilic statins users (n = 30) had higher HOMA-IR compared to nonstatin users (n = 125) ([ß = 2.29, (1.43-3.68), P < 0.001] and [ß = 1.36, (1.04-1.78), P < 0.05]), respectively, in general linear models after stratified PS adjustment. Statin use was associated with AAC without stratifying by PS in the Wilcoxon test, but was no longer significant when stratified by PS. CONCLUSIONS: Statins, widely prescribed drugs to lower cholesterol, may have unintended consequences related to glucose homeostasis that could be relevant in healthy aging.

Is Rheumatoid Arthritis a Risk Factor for Fractures: A Systematic Review of Observational Studies.

AIM: The primary objective was to assess the risk of fractures in adults with RA compared with controls from the general population. The review also assessed an increased risk of fractures in RA patients when accounting for steroid use, RA disease severity or functional impairment. METHODS: Citations were screened from MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and CINAHL. Included citations were written in English, including adult patients at least 18 years of age and compared fracture incidence or prevalence between RA patients and a control group. Case-control, cohort and cross-sectional studies were included. RESULTS: There were a total of 3451 citations; after application of the inclusion criteria, 17 studies were selected. In 14 of the 17 studies, there was an increase in the risk of fracture in RA patients compared to controls. In studies that evaluated for glucocorticoid use, four of 13 demonstrated an increased risk of fracture with glucocorticoid use, however, only two of these four studies specifically assessed glucocorticoid use amongst patients with RA. In studies that analyzed RA severity or functional impairment, two of seven demonstrated disease severity or impairment as a risk factor for fracture. There was marked study heterogeneity in terms of patient and fracture characteristics, which was a limitation of the analysis that impeded the ability to make direct comparisons. CONCLUSION: The risk of fracture in RA patients is elevated when compared to the general population, although the etiology of the increased risk remains to be elucidated.

Post-Streptococcal Reactive Arthritis.

INTRODUCTION: Post-Streptococcal Reactive Arthritis (PSRA) is defined as inflammatory arthritis of ≥1 joint associated with a recent group A streptococcal infection in a patient who does not fulfill the Jones criteria for the diagnosis of Acute Rheumatic Fever (ARF). METHODS: In this narrative review, we conducted a systematic search on MEDLINE, EMBASE, Cochrane Library and Google Scholar using the words poststreptococcal reactive arthritis. The search covered the time period between 1982 and 2016. The purpose of this review is to summarize the current state of knowledge of PSRA with respect to the definition, epidemiology, clinical presentation and treatment. We also summarize the key differences between PSRA, reactive arthritis (ReA) and ARF. RESULTS: PSRA has a bimodal age distribution at ages 8-14 and 21-37 years with an almost equal male to female ratio. Clinically, it causes acute asymmetrical non-migratory polyarthritis, however, tenosynovitis and small joint arthritis may occur. This disease entity can be associated with extraarticular manifestations, including erythema nodosum, uveitis and glomerulonephritis. The frequency of HLA-B27 in PSRA does not differ from that of the normal population, which suggests that it is a separate entity from ReA. Involvement of the axial skeleton, including sacroiliitis, is uncommon in PSRA. PSRA tends to occur within 10 days of a group A streptococcal infection, as opposed to the 2 to 3 weeks delay for ARF. PSRA can be associated with prolonged or recurrent arthritis, in contrast to ARF, in which arthritis usually lasts a few days to 3 weeks. Treatment usually involves NSAIDs or corticosteroids. CONCLUSION: We summarize clinical features that help differentiate PSRA from ARF and ReA. First-line treatment options include NSAIDs and corticosteroids. Most cases resolve spontaneously within a few weeks, but some cases are recurrent or prolonged. There are no published randomized controlled trials of PSRA.

Changes in vascular calcification and bone mineral density in calcium supplement users from the Canadian Multi-center Osteoporosis Study (CaMOS).

BACKGROUND AND AIMS: Calcium supplements have been associated with increased cardiovascular events. This study investigates the relationship between calcium supplement use and the 5 year progression of abdominal aorta calcification (AAC) in participants from one center of the Canadian Multi-Centre Osteoporosis Study (CaMOS). METHODS: Participants (n = 296; 217 women and 79 men) had lateral spine X-rays and DEXA bone mineral density (BMD) scans (femoral neck, lumbar spine and total hip) taken at two time points within a 5 year interval. AAC was assessed using the Framingham Method. Calcium supplement use was assessed by a facilitated health history questionnaire and medication inventory. RESULTS: AAC significantly increased over 5 years, AAC progression was significantly greater in calcium supplement users, as compared to non-users, overall and in females. The amount of calcium was positively correlated to AAC progression. A multi-variable linear regression model was generated for women only, as there were not enough men for multivariable modelling. Calcium supplement use and amount remained significantly associated with AAC progression after adjustment for age, hypertension, diabetes and smoking history. Change in AAC score was not associated with change in BMD T-Score. In univariate analyses of males, calcium supplement use was associated with a significantly greater BMD loss at the lumbar spine, hip, and femoral neck. CONCLUSIONS: Older female calcium supplement users had significantly higher AAC progression over 5 years, but did not have any significant BMD preservation. These results suggest that vascular calcification may contribute to the cardiovascular events observed in calcium supplement users.

Vertebral Fractures in Individuals With Type 2 Diabetes: More Than Skeletal Complications Alone.

OBJECTIVE: We aimed to assess whether individuals with type 2 diabetes (T2D) have increased risk of vertebral fractures (VFs) and to estimate nonvertebral fracture and mortality risk among individuals with both prevalent T2D and VFs. RESEARCH DESIGN AND METHODS: A systematic PubMed search was performed to identify studies that investigated the relationship between T2D and VFs. Cohorts providing individual participant data (IPD) were also included. Estimates from published summary data and IPD cohorts were pooled in a random-effects meta-analysis. Multivariate Cox regression models were used to estimate nonvertebral fracture and mortality risk among individuals with T2D and VFs. RESULTS: Across 15 studies comprising 852,705 men and women, individuals with T2D had lower risk of prevalent (odds ratio [OR] 0.84 [95% CI 0.74-0.95]; I 2 = 0.0%; P het = 0.54) but increased risk of incident VFs (OR 1.35 [95% CI 1.27-1.44]; I 2 = 0.6%; P het = 0.43). In the IPD cohorts (N = 19,820), risk of nonvertebral fractures was higher in those with both T2D and VFs compared with those without T2D or VFs (hazard ratio [HR] 2.42 [95% CI 1.86-3.15]) or with VFs (HR 1.73 [95% CI 1.32-2.27]) or T2D (HR 1.94 [95% CI 1.46-2.59]) alone. Individuals with both T2D and VFs had increased mortality compared with individuals without T2D and VFs (HR 2.11 [95% CI 1.72-2.59]) or with VFs alone (HR 1.84 [95% CI 1.49-2.28]) and borderline increased compared with individuals with T2D alone (HR 1.23 [95% CI 0.99-1.52]). CONCLUSIONS: Based on our findings, individuals with T2D should be systematically assessed for presence of VFs, and, as in individuals without T2D, their presence constitutes an indication to start osteoporosis treatment for the prevention of future fractures.

N-Butyrylated hyaluronic acid ameliorates gout and hyperuricemia in animal models.

Context: Hyaluronic acid (HA) plays critical roles in the structural skeleton, joint lubrication, renal function and cell signaling. We previously showed that partially N-butyrylated, low molecular weight, hyaluronic acid (BHA) exhibited an anti-inflammatory effect in cultured human macrophage, where inflammation was induced either by a TL-4 agonist or the low molecular weight HA itself, in dose-dependent fashion. Objectives: To investigate the anti-inflammatory, antioxidative, and antihyperuricemic effects of BHA using animal models of acute gouty arthritis and hyperuricemia. Materials and methods: The anti-inflammatory effect of articular BHA (10 and 50 µg) injections was evaluated by measuring joint swelling and the serum levels of inflammatory cytokines in a model of acute gouty arthritis induced by intra-articular injection of monosodium urate crystals in Wistar rats (n = 10/group), in comparison to the control group with saline injection. Antioxidative and antihyperuricemic activities were investigated using intraperitoneal injections of oteracil potassium and yeast extract hyperuricemic Balb/C mice, which were treated with intraperitoneal injection of BHA at day 6-8 in the model. Results: In the gouty arthritis rat model, BHA at a higher dosage (50 µg) demonstrated a strong anti-inflammatory effect by reducing the degree of articular swelling and the serum levels of IL-1ß, IL-8, IFN-γ, and MCP-1 by 5.56%, 6.55%, 15.58% and 33.18%. In the hyperuricemic mouse model, lower dosage BHA (10 µg) was sufficient to provide antioxidative activities by significantly decreasing the ROS levels in both serum and liver by 14.87% and 8.04%, while improving liver SOD by 12.77%. Intraperitoneal injection of BHA suppressed uric acid production through reducing liver XO activity by 19.78% and decreased the serum uric acid level in hyperuricemic mice by 30.41%. Conclusions: This study demonstrated for the first time that BHA exhibits anti-inflammatory, antioxidative and antihyperuricemic effects in vivo, suggesting a potential therapeutic application of BHA in gouty arthritis and hyperuricemia.

A Low Molecular Weight Hyaluronic Acid Derivative Accelerates Excisional Wound Healing by Modulating Pro-Inflammation, Promoting Epithelialization and Neovascularization, and Remodeling Collagen.

Recent knowledge of the cellular and molecular mechanisms underlying cutaneous wound healing has advanced the development of medical products. However, patients still suffer from the failure of current treatments, due to the complexity of healing process and thus novel therapeutic approaches are urgently needed. Previously, our laboratories produced a range of low molecular weight hyaluronic acid (LMW-HA) fragments, where a proportion of the glucosamine moieties were chemically N-acyl substituted. Specifically, N-butyrylation results in anti-inflammatory properties in a macrophage system, and we demonstrate the importance of N-acyl substituents in modulating the inflammatory response of LMW-HA. We have set up an inter-institutional collaborative program to examine the biomedical applications of the N-butyrylated LMW-HA (BHA). In this study, the potentials of BHA for dermal healing are assessed in vitro and in vivo. Consequently, BHA significantly promotes dermal healing relative to a commercial wound care product. By contrast, the "parent" partially de-acetylated LMW-HA (DHA) and the re-acetylated DHA (AHA) significantly delays wound closure, demonstrating the specificity of this N-acylation of LMW-HA in wound healing. Mechanistic studies reveal that the BHA-mediated therapeutic effect is achieved by targeting three phases of wound healing (i.e., inflammation, proliferation and maturation), demonstrating the significant potential of BHA for clinical translation in cutaneous wound healing.

Predictors of imminent non-vertebral fracture in elderly women with osteoporosis, low bone mass, or a history of fracture, based on data from the population-based Canadian Multicentre Osteoporosis Study (CaMos).

Using data from the Canadian Multicentre Osteoporosis Study, several risk factors predictive of imminent (2-year) risk of low-trauma non-vertebral fracture among high-risk women were identified, including history of falls, history of low-trauma fracture, poorer physical function, and lower T score. Careful consideration should be given to targeting this population for therapy. PURPOSE: Fracture risk assessment has focused on a long-term horizon and populations with a broad risk range. For elderly women with osteoporosis or low bone mass, or a history of fragility fractures ("high-risk women"), risk prediction over a shorter horizon may have greater clinical relevance. METHODS: A repeated-observations design and data from the Canadian Multicentre Osteoporosis Study were employed. Study population comprised women aged ≥ 65 years with T score (total hip, femoral neck, spine) ≤ - 1.0 or prior fracture. Hazard ratios (HR) for predictors of low-trauma non-vertebral fracture during 2-year follow-up were estimated using multivariable shared frailty model. RESULTS: The study population included 3228 women who contributed 5004 observations; 4.8% experienced low-trauma non-vertebral fracture during the 2-year follow-up. In bivariate analyses, important risk factors included age, back pain, history of falls, history of low-trauma fracture, physical function, health status, and total hip T score. In multivariable analyses, only four independent predictors were identified: falls in past 12 months (≥ 2 falls: HR = 1.9; 1 fall: HR = 1.5), low-trauma fracture in past 12 months (≥ 1 fracture: HR = 1.7), SF-36 physical component summary score (≤ 42.0: HR = 1.6), and total hip T score (≤ - 3.5: HR = 3.7; > - 3.5 to ≤ - 2.5: HR = 2.5; > - 2.5 to ≤ - 1: HR = 1.3). CONCLUSIONS: Imminent risk of low-trauma non-vertebral fracture is elevated among high-risk women with a history of falls or low-trauma fracture, poorer physical function, and lower T score. Careful consideration should be given to identifying and targeting this population for therapy.

Chemical Modification of the N-Acetyl Moieties of Hyaluronic Acid from Streptococcus equi for Studies in Cytokine Production.

Partial N-deacetylation and certain N-reacylations of low-molecular-weight hyaluronic acid (hyaluronan) abate its proinflammatory properties in mammalian systems. Here, we describe the treatment of bacterial hyaluronic acid by hydrazine or NaOH to yield smaller partially deacetylated polymers. These N-deacetylated polymers can be reacylated with acyl anhydrides to yield substituted hyaluronic acid derivatives of equivalent size and equimolar N-acyl substitutions.

Frailty and Risk of Fractures in Patients With Type 2 Diabetes.

OBJECTIVE: We aimed to explore whether frailty was associated with fracture risk and whether frailty could modify the propensity of type 2 diabetes toward increased risk of fractures. RESEARCH DESIGN AND METHODS: Data were from a prospective cohort study. Our primary outcome was time to the first incident clinical fragility fracture; secondary outcomes included time to hip fracture and to clinical spine fracture. Frailty status was measured by a Frailty Index (FI) of deficit accumulation. The Cox model incorporating an interaction term (frailty × diabetes) was used for analyses. RESULTS: The analysis included 3,149 (70% women) participants; 138 (60% women) had diabetes. Higher bone mineral density and FI were observed in participants with diabetes compared with control subjects. A significant relationship between the FI and the risk of incident fragility fractures was found, with a hazard ratio (HR) of 1.02 (95% CI 1.01-1.03) and 1.19 (95% CI 1.10-1.33) for per-0.01 and per-0.10 FI increase, respectively. The interaction was also statistically significant (P = 0.018). The HR for per-0.1 increase in the FI was 1.33 for participants with diabetes and 1.19 for those without diabetes if combining the estimate for the FI itself with the estimate from the interaction term. No evidence of interaction between frailty and diabetes was found for risk of hip and clinical spine fractures. CONCLUSIONS: Participants with type 2 diabetes were significantly frailer than individuals without diabetes. Frailty increases the risk of fragility fracture and enhances the effect of diabetes on fragility fractures. Particular attention should be paid to diabetes as a risk factor for fragility fractures in those who are frail.

A novel quantitative approach to the measurement of abdominal aortic calcification as applied to the Canadian Multicenter Osteoporosis Study (CaMOS).

BACKGROUND AND AIMS: Lateral spine radiographs provide an inexpensive resource for characterizing abdominal aortic calcification (AAC). A widely accepted measurement of AAC is the semi-quantitative technique generated by the Framingham Heart Study (F-AAC-24). We sought to develop an analytical method to quantify ACC (QAAC) on lateral spine radiographs and compare the finding to conventional subjective measurements. METHODS: Severity of AAC was quantified by measuring pixel intensities in the user-defined region of the aorta with internal standardization to the vertebral endplates and background calibration to the density of the vertebral body. The association between bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DXA) and AAC measured by QAAC, F-AAC-24 and a modified Framingham score (F-AAC-12) was determined in 110 participants of the Canadian Multicenter Osteoporosis Study (CaMOS). RESULTS: The inter-observer reliability for the QAAC was slightly higher than with the visual and semi-quantitative Framingham method and the pseudo-colored images illustrate the potential to meaningfully resolve severity of calcification. There was a significant negative association between QAAC and BMD measures of the hip and spine. This association remained significant after adjustment for age, sex, estimated glomerular filtration rate, phosphate and hypertension. Significant predictors of F-ACC-12 and 24 included age and hypertension. CONCLUSIONS: The QAAC is a reproducible approach to measuring AAC. Whether it is capable of monitoring subtle calcific changes over time requires further study. This technique could be applied to large studies that seek to determine the impact of interventions that modify bone density as a treatment for vascular calcification and cardiovascular disease in the general population.

Rheological study of hyaluronic acid derivatives.

The viscoelastic properties of four novel, low molecular weight hyaluronic acid derivatives were investigated and compared to the parent hyaluronic acid compound. Briefly, all derivatives were synthesized by first deacetylating the parent hyaluronic acid. One sample was left as such, while two others were reacytelated. The final compound, of particular interest for its anti-inflammatory properties, was butyrylated. The compounds were dissolved in phosphate buffer solution (PBS) and studied at a concentration of 5 mg/mL. Shear thinning behaviour was observed for all compounds, however, derivative samples had a lower viscosity than the parent compound at high shear rates. Viscoelastic properties were also observed to decrease as a result of the derivative preparation method. It is believed that these changes are primarily caused by a decrease in hyaluronic acid molecular weight. By increasing the concentration of the anti-inflammatory compound, it may be possible to modulate the viscoelastic properties to more closely resemble those of commercial viscosupplements. As a result, an anti-inflammatory derivative of hyaluronic acid may potentially improve upon existing viscosupplements used to treat patients who are susceptible to flare up.

Human acetyl-CoA:glucosamine-6-phosphate N-acetyltransferase 1 has a relaxed donor specificity and transfers acyl groups up to four carbons in length.

Glucosamine-6-phosphate N-acetyltransferase1 (GNA1) catalyses the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to glucosamine-6-phosphate (GlcN6P) to form N-acetylglucosamine-6-phosphate (GlcNAc6P), which is an essential intermediate in UDP-GlcNAc biosynthesis. An analog of GlcNAc, N-butyrylglucosamine (GlcNBu) has shown healing properties for bone and articular cartilage in animal models of arthritis. The goal of this work was to examine whether GNA1 has the ability to transfer a butyryl group from butyryl-CoA to GlcN6P to form GlcNBu6P, which can then be converted to GlcNBu. We developed fluorescent and radioactive assays and examined the donor specificity of human GNA1. Acetyl, propionyl, n-butyryl, and isobutyryl groups were all transferred to GlcN6P, but isovaleryl-CoA and decanoyl-CoA did not serve as donor substrates. Site-specific mutants were produced to examine the role of amino acids potentially affecting the size and properties of the AcCoA binding pocket. All of the wild type and mutant enzymes showed activities of both acetyl and butyryl transfer and can therefore be used for the enzymatic synthesis of GlcNBu for biomedical applications.

Ten-year incident osteoporosis-related fractures in the population-based Canadian Multicentre Osteoporosis Study - comparing site and age-specific risks in women and men.

BACKGROUND: Population-based incident fracture data aid fracture prevention and therapy decisions. Our purpose was to describe 10-year site-specific cumulative fracture incidence by sex, age at baseline, and degree of trauma with/without consideration of competing mortality in the Canadian Multicentre Osteoporosis Study adult cohort. METHODS: Incident fractures and mortality were identified by annual postal questionnaires to the participant or proxy respondent. Date, site and circumstance of fracture were gathered from structured interviews and medical records. Fracture analyses were stratified by sex and age at baseline and used both Kaplan-Meier and competing mortality methods. RESULTS: The baseline (1995-97) cohort included 6314 women and 2789 men (aged 25-84 years; mean±SD 62±12 and 59±14, respectively), with 4322 (68%) women and 1732 (62%) men followed to year-10. At least one incident fracture occurred for 930 women (14%) and 247 men (9%). Competing mortality exceeded fracture risk for men aged 65+years at baseline. Age was a strong predictor of incident fractures especially fragility fractures, with higher age gradients for women vs. men. Major osteoporotic fracture (MOF) (hip, clinical spine, forearm, humerus) accounted for 41-74% of fracture risk by sex/age strata; in women all MOF sites showed age-related increases but in men only hip was clearly age-related. The most common fractures were the forearm for women and the ribs for men. Hip fracture incidence was the highest for the 75-84 year baseline age-group with no significant difference between women 7.0% (95% CI 5.3, 8.9) and men 7.0% (95% CI 4.4, 10.3). INTERPRETATION: There are sex differences in the predominant sites and age-gradients of fracture. In older men, competing mortality exceeds cumulative fracture risk.

Chemically modified N-acylated hyaluronan fragments modulate proinflammatory cytokine production by stimulated human macrophages.

Low molecular mass hyaluronans are known to induce inflammation. To determine the role of the acetyl groups of low molecular mass hyaluronan in stimulating the production of proinflammatory cytokines, partial N-deacetylation was carried out by hydrazinolysis. This resulted in 19.7 ± 3.5% free NH2 functional groups, which were then acylated by reacting with an acyl anhydride, including acetic anhydride. Hydrazinolysis resulted in bond cleavage of the hyaluronan chain causing a reduction of the molecular mass to 30-214 kDa. The total NH2 and N-acetyl moieties in the reacetylated hyaluronan were 0% and 98.7 ± 1.5% respectively, whereas for butyrylated hyaluronan, the total NH2, N-acetyl, and N-butyryl moieties were 0, 82.2 ± 4.6, and 22.7 ± 3.8%, respectively, based on (1)H NMR. We studied the effect of these polymers on cytokine production by cultured human macrophages (THP-1 cells). The reacetylated hyaluronan stimulated proinflammatory cytokine production to levels similar to LPS, whereas partially deacetylated hyaluronan had no stimulatory effect, indicating the critical role of the N-acetyl groups in the stimulation of proinflammatory cytokine production. Butyrylated hyaluronan significantly reduced the stimulatory effect on cytokine production by the reacetylated hyaluronan or LPS but had no stimulatory effect of its own. The other partially N-acylated hyaluronan derivatives tested showed smaller stimulatory effects than reacetylated hyaluronan. Antibody and antagonist experiments suggest that the acetylated and partially butyrylated lower molecular mass hyaluronans exert their effects through the TLR-4 receptor system. Selectively N-butyrylated lower molecular mass hyaluronan shows promise as an example of a novel semisynthetic anti-inflammatory molecule.

Prospectively measured 10-year changes in health-related quality of life and comparison with cross-sectional estimates in a population-based cohort of adult women and men.

PURPOSE: To prospectively assess changes in health-related quality of life (HRQOL) over 10 years, by age and sex, and to compare measured within-person change to estimates of change based on cross-sectional data. METHODS: Participants in the Canadian Multicentre Osteoporosis Study completed the 36-item short form (SF-36) in 1995/1997 and 2005/2007. Mean within-person changes for domain and summary components were calculated for men and women separately, stratified by 10-year age groups. Projected changes based on published age- and sex-stratified cross-sectional data were also calculated. Mean differences between the two methods were then estimated, along with the 95 % credible intervals of the differences. RESULTS: Data were available for 5,569/9,423 (59.1 %) of the original cohort. Prospectively collected 10-year changes suggested that the four physically oriented domains declined in all but the youngest group of men and women, with declines in the elderly men exceeding 25 points. The four mentally oriented domains tended to improve over time, only showing substantial declines in vitality and role emotional in older women, and all four domains in older men. Cross-sectional estimates identified a similar pattern of change but with a smaller magnitude, particularly in men. Correspondence between the two methods was generally high. CONCLUSIONS: Changes in HRQOL may be minimal over much of the life span, but physically oriented HRQOL can decline substantially after middle age. Although clinically relevant declines were more evident in prospectively collected data, differences in 10-year age increments of cross-sectional data may be a reasonable proxy for longitudinal changes, at least in those under 65 years of age. Results provide additional insight into the natural progression of HRQOL in the general population.

Effect of Anticholinergic Medications on Falls, Fracture Risk, and Bone Mineral Density Over a 10-Year Period.

BACKGROUND: Many medications used in older adults have strong anticholinergic (ACH) properties, which may increase the risk of falls and fractures. Use of these medications was identified in a population-based Canadian cohort. OBJECTIVE: To identify the fall and fracture risk associated with ACH medication use. METHODS: Data collection and analysis were conducted at baseline, year 5, and year 10. Cross-sectional analyses were performed to examine associations between ACH medication use and falls. Time-dependent Cox regression was used to examine time to first nontraumatic fracture. Finally, change in bone mineral density (BMD) over 10 years was compared in ACH medication users versus nonusers. RESULTS: Strongly ACH medications were used by 618 of 7753 participants (8.0%) at study baseline, 592 (9.5%) at year 5, and 334 (7.7%) at year 10. Unadjusted ACH medication use was associated with falls at baseline (odds ratio = 1.50; 95% CI = 1.14-1.98; P = 0.004), but the association was no longer significant after covariate adjustment. Similar results occurred at years 5 and 10. ACH medication use was associated with increased incident fracture risk before (hazard ratio = 1.22; CI = 1.13-1.32; P < 0.001) but not after covariate adjustment. Mean (SD) change in femoral neck BMD T-score over 10 years, in those using ACH medications at both years 0 and 5, was -0.60 (0.63) in ACH users versus -0.49 (0.45) in nonusers (P = 0.041), but this was not significant after covariate adjustment. CONCLUSIONS: ACH medications were not found to be independently associated with an increased risk of falling, fractures, or BMD loss. Rather, factors associated with ACH medication use explained the apparent associations.

Choice of lumbar spine bone density reference database for fracture prediction in men and women: a population-based analysis.

The diagnosis of osteoporosis in men is controversial, although most studies demonstrate similar fracture rates for men and women with the same level of hip bone mineral density (BMD). Whether this applies to the lumbar spine is currently uncertain and has important implications with respect to choice of reference population for T-score calculation and osteoporosis diagnosis. This question was specifically addressed in the population-based Canadian Multicentre Osteoporosis Study cohort of 4745 women and 1887 men ages 50+ yr at the time of baseline lumbar spine dual energy x-ray absorptiometry. In up to 10 yr of observation, incident clinical major osteoporotic fractures occurred in 110 men (5.8%) vs 543 women (11.4%) (p < 0.001). Mean lumbar spine BMD in men was greater than in women, both among those with and those without incident major osteoporotic fracture (p < 0.001). Men were at slightly lower risk for incident major osteoporotic fracture than women for an equivalent lumbar spine BMD (age- and BMD-adjusted rate ratio 0.75, 95% confidence interval 0.60-0.93, p = 0.008) with similar findings after adjustment for the World Health Organization fracture risk assessment clinical risk factors or competing mortality. No significant sex difference in the BMD relationship was seen for vertebral fractures (clinical or radiographic) or for all fractures. In summary, this large population-based longitudinal cohort study found similar or lower fracture risk for men vs women after adjustment for absolute lumbar spine BMD and additional covariates. The least complicated model for describing fracture risk is therefore to use the same reference lumbar spine data for generating T-scores in men and women.