Hip fractures in the older adult: orthopaedic and geriatric shared care model in Southland, New Zealand-a 5-year follow-up study.

BACKGROUND: Neck of femur fractures are common with associated high morbidity and mortality rates. National standards include provision of orthogeriatric care to any patient with a hip fracture. This study assessed the outcomes at 5 years following implementation of a collaborative orthogeriatric service at Southland Hospital in 2012. METHODS: Retrospective data were collected for patients aged 65 years and older admitted with a fragility hip fracture. Data were collated for 2011 (preimplementation) and 2017 (postimplementation). Demographic data and American Society of Anesthesiologists (ASA) scores were recorded to ensure comparability of the patient groups. Length of stay, postoperative complications and 30-day and 1-year mortality were assessed. RESULTS: 74 admissions with mean age at surgery of 84.2 years in 2011 and 107 admissions with mean age of 82.6 years in 2017. There was a higher proportion of ASA 2 and ASA 3 patients in 2017 compared with 2011 (p=0.036). The median length of stay in the orthopaedic ward was unchanged in the two cohorts but there was a shorter median length of stay by 6.5 days and mean length of stay by 11 days in 2017 in the rehabilitation ward (p<0.001 for both median and mean). Through logistic regression controlling for age, sex and ASA score, there was a reduction in the odds of having a complication by 12% (p<0.001). The study was too small to undertake statistical testing to calculate significant difference in overall 30-day and 1-year mortality between the groups. CONCLUSION: The orthogeriatric service has reduced the frequency of complications and length of stay on the rehabilitation ward 5 years following implementation.

Maternal Fructose Intake Causes Developmental Reprogramming of Hepatic Mitochondrial Catalytic Activity and Lipid Metabolism in Weanling and Young Adult Offspring.

Excess dietary fructose is a major public health concern, yet little is known about its influence on offspring development and later-life disease when consumed in excess during pregnancy. To determine whether increased maternal fructose intake could have long-term consequences on offspring health, we investigated the effects of 10% w/v fructose water intake during preconception and pregnancy in guinea pigs. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD; providing 16% of total daily caloric intake) ad libitum 60 days prior to mating and throughout gestation. Dietary interventions ceased at day of delivery. Offspring were culled at day 21 (D21) (weaning) and at 4 months (4 M) (young adult). Fetal exposure to excess maternal fructose intake significantly increased male and female triglycerides at D21 and 4 M and circulating palmitoleic acid and total omega-7 through day 0 (D0) to 4 M. Proteomic and functional analysis of significantly differentially expressed proteins revealed that FD offspring (D21 and 4 M) had significantly increased mitochondrial metabolic activities of ß-oxidation, electron transport chain (ETC) and oxidative phosphorylation and reactive oxygen species production compared to the CD offspring. Western blotting analysis of both FD offspring validated the increased protein abundances of mitochondrial ETC complex II and IV, SREBP-1c and FAS, whereas VDAC1 expression was higher at D21 but lower at 4 M. We provide evidence demonstrating offspring programmed hepatic mitochondrial metabolism and de novo lipogenesis following excess maternal fructose exposure. These underlying asymptomatic programmed pathways may lead to a predisposition to metabolic dysfunction later in life.

Sex-specific alterations in hepatic cholesterol metabolism in low birth weight adult guinea pigs.

BACKGROUND: Intrauterine growth restriction and low birth weight (LBW) have been widely reported as an independent risk factor for adult hypercholesterolaemia and increased hepatic cholesterol in a sex-specific manner. However, the specific impact of uteroplacental insufficiency (UPI), a leading cause of LBW in developed world, on hepatic cholesterol metabolism in later life, is ill defined and is clinically relevant in understanding later life liver metabolic health trajectories. METHODS: Hepatic cholesterol, transcriptome, cholesterol homoeostasis regulatory proteins, and antioxidant markers were studied in UPI-induced LBW and normal birth weight (NBW) male and female guinea pigs at 150 days. RESULTS: Hepatic free and total cholesterol were increased in LBW versus NBW males. Transcriptome analysis of LBW versus NBW livers revealed that "cholesterol metabolism" was an enriched pathway in LBW males but not in females. Microsomal triglyceride transfer protein and cytochrome P450 7A1 protein, involved in hepatic cholesterol efflux and catabolism, respectively, and catalase activity were decreased in LBW male livers. Superoxide dismutase activity was reduced in LBW males but increased in LBW females. CONCLUSIONS: UPI environment is associated with a later life programed hepatic cholesterol accumulation via impaired cholesterol elimination in a sex-specific manner. These programmed alterations could underlie later life cholesterol-induced hepatic lipotoxicity in LBW male offspring. IMPACT: Low birth weight (LBW) is a risk factor for increased hepatic cholesterol. Uteroplacental insufficiency (UPI) resulting in LBW increased hepatic cholesterol content, altered hepatic expression of cholesterol metabolism-related genes in young adult guinea pigs. UPI-induced LBW was also associated with markers of a compromised hepatic cholesterol elimination process and failing antioxidant system in young adult guinea pigs. These changes, at the current age studied, were sex-specific, only being observed in LBW males and not in LBW females. These programmed alterations could lead to further hepatic damage and greater predisposition to liver diseases in UPI-induced LBW male offspring as they age.

Species-specific metabolic responses of songbird, shorebird, and murine cultured myotubes to n-3 polyunsaturated fatty acids.

Migratory birds may benefit from diets rich in polyunsaturated fatty acids (PUFAs) that could improve exercise performance. Previous investigations suggest that different types of birds may respond differently to PUFA. We established muscle myocyte cell culture models from muscle satellite cells of a migratory passerine songbird (yellow-rumped warbler, Setophaga coronata coronata) and a nonpasserine shorebird (sanderling, Calidris alba). We differentiated and treated avian myotubes and immortalized murine C2C12 myotubes with n-3 PUFA docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and with monounsaturated oleic acid (OA) to compare effects on aerobic performance, metabolic enzyme activities, key fatty acid (FA) transporters, and expression of peroxisome proliferator-activated receptors (PPARs). Sanderling and C2C12 myotubes increased expression of PPARs with n-3 PUFA treatments, whereas expression was unchanged in yellow-rumped warblers. Both sanderlings and yellow-rumped warblers increased expression of fatty acid transporters, whereas C2C12 cells decreased expression following n-3 PUFA treatments. Only yellow-rumped warbler myotubes increased expression of some metabolic enzymes, whereas the sanderling and C2C12 cells were unchanged. PUFA supplementation in C2C12 myotubes increased mitochondrial respiratory chain efficiency, whereas sanderlings increased proton leak-associated respiration and maximal respiration (measurements were not made in warblers). This research indicates that songbirds and shorebirds respond differently to n-3 PUFA and provides support for the hypothesis that n-3 PUFA increase the aerobic capacity of migrant shorebird muscle, which may improve overall endurance flight performance.

Syncytialization and prolonged exposure to palmitate impacts BeWo respiration.

Placental villous trophoblast mitochondrial respiratory function is critical for a successful pregnancy and environmental influences such as maternal obesity have been associated with respiratory impairment at term. More recently, a gestational high fat diet independent of maternal body composition, has been highlighted as a potential independent regulator of placental mitochondrial metabolism. The current study aimed to characterize the direct impact of a prolonged and isolated exposure to the dietary fatty acids Palmitate (PA) and Oleate (OA) upon placental cell mitochondrial respiratory function. BeWo cytotrophoblast (CT) and syncytiotrophoblast (SCT) cells were treated for 72 h with 100 µM PA, OA or PA+OA (P/O). Live-cell metabolic function was analyzed via the Seahorse XF Mito and Glycolysis Stress tests. Immunoblots and spectrophotometric activity assays were utilized to examine the protein expression and function of electron transport chain (ETC) complexes and key mitochondrial regulatory enzymes. Syncytialization of BeWo cells resulted reduced respiratory activity in conjunction with altered complex I and II activity and decreased pyruvate dehydrogenase (PDH) protein expression and activity. PA and P/O treatments were associated with increased basal and maximal respiratory activities in BeWo CT cells without alterations in protein expression or activity of individual ETC complexes and mitochondrial substrate regulators. The metabolic suppression in BeWo SCTs was consistent with that previously observed in primary human trophoblast cell cultures, while the observed increases in respiratory activity in PA-treated BeWo CTs may be indicative of an early timepoint of specific dietary saturated fat-mediated placental cell mitochondrial dysfunction.

Proteinase-Activated Receptor 4 Activation Triggers Cell Membrane Blebbing through RhoA and ß-Arrestin.

Proteinase-activated receptors (PARs) are a four-member family of G-protein-coupled receptors that are activated via proteolysis. PAR4 is a member of this family that is cleaved and activated by serine proteinases such as thrombin, trypsin, and cathepsin-G. PAR4 is expressed in a variety of tissues and cell types, including platelets, vascular smooth muscle cells, and neuronal cells. In studying PAR4 signaling and trafficking, we observed dynamic changes in the cell membrane, with spherical membrane protrusions that resemble plasma membrane blebbing. Since nonapoptotic membrane blebbing is now recognized as an important regulator of cell migration, cancer cell invasion, and vesicular content release, we sought to elucidate the signaling pathway downstream of PAR4 activation that leads to such events. Using a combination of pharmacological inhibition and CRISPR/CRISPR-associated protein 9 (Cas9)-mediated gene editing approaches, we establish that PAR4-dependent membrane blebbing occurs independently of the Gα q/11- and Gα i-signaling pathways and is dependent on signaling via the ß-arrestin-1/2 and Ras homolog family member A (RhoA) signaling pathways. Together these studies provide further mechanistic insight into PAR4 regulation of cellular function. SIGNIFICANCE STATEMENT: We find that the thrombin receptor PAR4 triggers cell membrane blebbing in a RhoA-and ß-arrestin-dependent manner. In addition to identifying novel cellular responses mediated by PAR4, these data provide further evidence for biased signaling in PAR4 since membrane blebbing was dependent on some, but not all, signaling pathways activated by PAR4.

The effects of tracheal occlusion on Wnt signaling in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Tracheal occlusion (TO) reverses pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. Wnt signaling plays a critical role in lung development, but few studies exist. The purpose of our study was to a) confirm that our CDH rabbit model produced PH which was reversed by TO and b) determine the effects of CDH +/- TO on Wnt signaling. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days, and lung collection at 31 days. Lung body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. mRNA and miRNA expression was determined in the left lower lobe using RT-qPCR. RESULTS: Fifteen CDH, 15 CDH + TO, 6 sham CDH, and 15 controls survived and were included in the study. LBWR was low in CDH, while CDH + TO was similar to controls (p = 0.003). MTBD was higher in CDH fetuses and restored to control levels in CDH + TO (p < 0.001). Reference genes TOP1, SDHA, and ACTB were consistently expressed within and between treatment groups. miR-33 and MKI67 were increased, and Lgl1 was decreased in CDH + TO. CONCLUSION: TO reversed pulmonary hypoplasia and stimulated early Wnt signaling in CDH fetal rabbits. TYPE OF STUDY: Basic science, prospective. LEVEL OF EVIDENCE: II.

Targeting a Proteinase-Activated Receptor 4 (PAR4) Carboxyl Terminal Motif to Regulate Platelet Function.

Thrombin initiates human platelet aggregation by coordinately activating proteinase-activated receptors (PARs) 1 and 4. However, targeting PAR1 with an orthosteric-tethered ligand binding-site antagonist results in bleeding, possibly owing to the important role of PAR1 activation on cells other than platelets. Because of its more restricted tissue expression profile, we have therefore turned to PAR4 as an antiplatelet target. We have identified an intracellular PAR4 C-terminal motif that regulates calcium signaling and ß-arrestin interactions. By disrupting this PAR4 calcium/ß-arrestin signaling process with a novel cell-penetrating peptide, we were able to inhibit both thrombin-triggered platelet aggregation in vitro and clot consolidation in vivo. We suggest that targeting PAR4 represents an attractive alternative to blocking PAR1 for antiplatelet therapy in humans.

Thrombin-Mediated Direct Activation of Proteinase-Activated Receptor-2: Another Target for Thrombin Signaling.

Thrombin is known to signal to cells by cleaving/activating a G-protein-coupled family of proteinase-activated receptors (PARs). The signaling mechanism involves the proteolytic unmasking of an N-terminal receptor sequence that acts as a tethered receptor-activating ligand. To date, the recognized targets of thrombin cleavage and activation for signaling are PAR1 and PAR4, in which thrombin cleaves at a conserved target arginine to reveal a tethered ligand. PAR2, which like PAR1 is also cleaved at an N-terminal arginine to unmask its tethered ligand, is generally regarded as a target for trypsin but not for thrombin signaling. We now show that thrombin, at concentrations that can be achieved at sites of acute injury or in a tumor microenvironment, can directly activate PAR2 vasorelaxation and signaling, stimulating calcium and mitogen-activated protein kinase responses along with triggeringß-arrestin recruitment. Thus, PAR2 can be added alongside PAR1 and PAR4 to the targets, whereby thrombin can affect tissue function.