Long-term scarring outcomes and safety of patients treated with NovoSorbⓇ Biodegradable Temporizing Matrix (BTM): An observational cohort study.

Background/Aim: NovoSorbⓇ Biodegradable Temporizing Matrix (BTM) is a relatively novel, biodegradable polyurethane-based dermal regeneration template. The aim of this study was to evaluate the long-term scarring outcomes and safety of BTM in patients who underwent dermal reconstruction involving ≥5% of the total body surface area. Methods: This was a postmarket, multicenter, observational cohort study involving evaluation of long-term outcomes in patients treated with BTM. A total of 55 patients (35 from Royal Adelaide Hospital, South Australia, and 20 from Victoria Adult Burns Service, The Alfred, Victoria) who underwent dermal repair with BTM between 2011 and 2017 were screened for inclusion in this study. All patients had BTM implanted for ≥18 months. Results: Fifteen eligible patients with a mean (SD) age of 49.1 (14.3) years completed study assessments. These patients had a total of 39 areas treated with BTM. Using the Patient and Observer Scar Assessment Scale, scar quality was reported to be good by both observers and patients, with a mean (SD) observer score across all lesions of 3.6 (1.2) and mean (SD) overall opinion of 3.8 (1.2) as well as a mean (SD) patient score of 3.5 (1.2) and overall opinion of 5.0 (2.2). No adverse events or adverse device effects were reported or identified. Conclusion: The long-term scar quality is comparable to published studies. BTM is safe in the long term with no additional risks or adverse consequences being identified.

Urethro-venous fistula following straddle injury: A case report and image series.

We present a case of a 49-year-old man with an acute traumatic urethral injury after a fall onto a fence post. Retrograde contrast study showed a contrast leak and suspicion of a traumatic urethro-venous fistula. We successfully placed a urethral indwelling catheter (IDC) in the operating room and follow-up urethrocystoscopy showed healing of the injury. The patient remained asymptomatic during further follow-up visits.

The role of cadaveric simulation in talus fracture research: A scoping review.

BACKGROUND: Talus fractures are rare (<1% of all fractures), and their rarity limits the number of studies available to guide management. In instances such as this, cadaveric studies can play an important role. The purpose of this scoping review was to identify and describe the current body of literature on cadaveric studies of fractures of the talus. METHODS: Through multiple electronic database searches (Medline, Embase, Scopus) we identified a broad body of cadaveric research into talus fractures, and these were classified into 4 main themes. Study characteristics were summarised along with any descriptive results and conclusions. RESULTS: The search yielded 484 articles of which 19 met the inclusion criteria. They provide valuable insights into benefits and drawbacks of surgical approaches to the talus, particularly with regard to direct visualisation of anatomic reduction, and risks of neurovascular or tendon compromise. For talar neck fractures it is clear that cannulated screws offer superior fixation over plates, however, are inferior when considering anatomic reduction of the fracture. Direct visualisation of fracture reduction is far superior to intraoperative radiographic assessment, and mal-reduction leads to reduced subtalar joint range of motion, midfoot deformity, and increased joint contact pressures. CONCLUSIONS: This study provides a summary of the existing literature surrounding the use of cadaver studies in fractures of the talus. We have identified gaps in the literature, particularly surrounding strength of fixation of new locking plate fixation techniques.

Anterior cervical osteophytes causing dysphagia and dyspnoea.

A 75-year-old man presents to his general practitioner (GP) with dyspnoea, and dysphagia to liquids and solids, with regurgitation causing recurrent episodes of dyspnoea. He had a background of osteoarthritis, was an ex heavy smoker and had undergone coronary artery bypass graft five years previously. After several emergency admissions, initial investigation by the GP, and referral to ear, nose and throat specialists with no cause for dysphagia found, he underwent computed tomography imaging of the neck and thorax which demonstrated large cervical osteophytes at the level of C3-C4. He was referred to spinal orthopaedics and after multidisciplinary team discussion the cervical osteophytes were removed via an anterior approach, resulting in complete resolution of his symptoms.

Development and Interrogation of a Transcriptomic Resource for the Giant Triton Snail (Charonia tritonis).

Gastropod molluscs are among the most abundant species that inhabit coral reef ecosystems. Many are specialist predators, along with the giant triton snail Charonia tritonis (Linnaeus, 1758) whose diet consists of Acanthaster planci (crown-of-thorns starfish), a corallivore known to consume enormous quantities of reef-building coral. C. tritonis are considered vulnerable due to overexploitation, and a decline in their populations is believed to have contributed to recurring A. planci population outbreaks. Aquaculture is considered one approach that could help restore natural populations of C. tritonis and mitigate coral loss; however, numerous questions remain unanswered regarding their life cycle, including the molecular factors that regulate their reproduction and development. In this study, we have established a reference C. tritonis transcriptome derived from developmental stages (embryo and veliger) and adult tissues. This was used to identify genes associated with cell signalling, such as neuropeptides and G protein-coupled receptors (GPCRs), involved in endocrine and olfactory signalling. A comparison of developmental stages showed that several neuropeptide precursors are exclusively expressed in post-hatch veligers and functional analysis found that FFamide stimulated a significant (20.3%) increase in larval heart rate. GPCRs unique to veligers, and a diversity of rhodopsin-like GPCRs located within adult cephalic tentacles, all represent candidate olfactory receptors. In addition, the cytochrome P450 superfamily, which participates in the biosynthesis and degradation of steroid hormones and lipids, was also found to be expanded with at least 91 genes annotated, mostly in gill tissue. These findings further progress our understanding of C. tritonis with possible application in developing aquaculture methods.

Norwich COVID-19 testing initiative pilot: evaluating the feasibility of asymptomatic testing on a university campus.

BACKGROUND: There is a high prevalence of COVID-19 in university-age students, who are returning to campuses. There is little evidence regarding the feasibility of universal, asymptomatic testing to help control outbreaks in this population. This study aimed to pilot mass COVID-19 testing on a university research park, to assess the feasibility and acceptability of scaling up testing to all staff and students. METHODS: This was a cross-sectional feasibility study on a university research park in the East of England. All staff and students (5625) were eligible to participate. All participants were offered four PCR swabs, which they self-administered over two weeks. Outcome measures included uptake, drop-out rate, positivity rates, participant acceptability measures, laboratory processing measures, data collection and management measures. RESULTS: 798 (76%) of 1053 who registered provided at least one swab; 687 (86%) provided all four; 792 (99%) of 798 who submitted at least one swab had all negative results and 6 participants had one inconclusive result. There were no positive results. 458 (57%) of 798 participants responded to a post-testing survey, demonstrating a mean acceptability score of 4.51/5, with five being the most positive. CONCLUSIONS: Repeated self-testing for COVID-19 using PCR is feasible and acceptable to a university population.

Time-frequency approaches to investigating changes in feedback processing during childhood and adolescence.

Processing feedback from the environment is an essential function during development to adapt behavior in advantageous ways. One measure of feedback processing, the feedback negativity (FN), is an ERP observed following the presentation of feedback. Findings detailing developmental changes in the FN have been mixed, possibly due to limitations in traditional ERP measurement methods. Recent work shows that both theta and delta frequency activity contribute to the FN; utilizing time-frequency methods to measure change in power and phase in these frequency bands may provide more accurate representation of feedback processing development in childhood and adolescence. We employ time-frequency power and intertrial phase synchrony measures, in addition to conventional time-domain ERP methods, to examine the development of feedback processing in the theta (4-7 Hz) and delta (.1-3 Hz) bands throughout adolescence. A sample of 54 female participants (8-17 years old) completed a gambling task while EEG was recorded. As expected, time-domain ERP amplitudes showed no association with age. In contrast, significant effects were observed for the time-frequency measures, with theta power decreasing with age and delta power increasing with age. For intertrial phase synchrony, delta synchrony increased with age, while age-related changes in theta synchrony differed for gains and losses. Collectively, these findings highlight the importance of considering time-frequency dynamics when exploring how the processing of feedback develops through late childhood and adolescence. In particular, the role of delta band activity and theta synchrony appear central to understanding age-related changes in the neural response to feedback.

Lipid droplet remodelling and reduced muscle ceramides following sprint interval and moderate-intensity continuous exercise training in obese males.

BACKGROUND/OBJECTIVES: In obesity, improved muscle insulin sensitivity following exercise training has been linked to the lowering of diacylglycerol (DAG) and ceramide concentrations. Little is known, however, about how improved insulin action with exercise training in obese individuals relates to lipid droplet (LD) adaptations in skeletal muscle. In this study we investigated the hypothesis that short-term sprint interval training (SIT) and moderate-intensity continuous training (MICT) in obese individuals would increase perilipin (PLIN) expression, increase the proportion of LDs in contact with mitochondria and reduce muscle concentrations of DAGs and ceramides. METHODS: Sixteen sedentary obese males performed 4 weeks of either SIT (4-7 × 30 s sprints at 200% Wmax, 3 days week) or MICT (40-60 min cycling at ~65% VO2peak, 5 days per week), and muscle biopsies were obtained pre- and post-training. RESULTS: Training increased PLIN2 (SIT 90%, MICT 68%) and PLIN5 (SIT 47%, MICT 34%) expression in type I fibres only, and increased PLIN3 expression in both type I (SIT 63%, MICT 67%) and type II fibres (SIT 70%, MICT 160%) (all P<0.05). Training did not change LD content but increased the proportion of LD in contact with mitochondria (SIT 12%, MICT 21%, P<0.01). Ceramides were reduced following training (SIT -10%, MICT -7%, P<0.05), but DAG was unchanged. No training × group interactions were observed for any variables. CONCLUSIONS: These results confirm the hypothesis that SIT and MICT results in remodelling of LDs and lowers ceramide concentrations in skeletal muscle of sedentary obese males.

Well-posed continuum equations for granular flow with compressibility and µ(I)-rheology.

Continuum modelling of granular flow has been plagued with the issue of ill-posed dynamic equations for a long time. Equations for incompressible, two-dimensional flow based on the Coulomb friction law are ill-posed regardless of the deformation, whereas the rate-dependent µ(I)-rheology is ill-posed when the non-dimensional inertial number I is too high or too low. Here, incorporating ideas from critical-state soil mechanics, we derive conditions for well-posedness of partial differential equations that combine compressibility with I-dependent rheology. When the I-dependence comes from a specific friction coefficient µ(I), our results show that, with compressibility, the equations are well-posed for all deformation rates provided that µ(I) satisfies certain minimal, physically natural, inequalities.

Female rats display fewer optimistic responses in a judgment bias test in the absence of a physiological stress response.

Metabolic cages are a type of housing used in biomedical research. Metabolic cage housing has been demonstrated to elicit behavioural and physiological changes in rodents housed within them. The nature of this effect has been characterized as anxiogenic. However, few studies have evaluated positive affect in response to metabolic cage housing and the interaction between this, sex and traditional physiological measures of stress. Cognitive biasing, as measured through a judgment bias paradigm has proven a reliable measure of animal affective state, particularly through its ability to measure positive affect. The current study investigated differences in cognitive biasing between male and female rats when transferred from open-top, grouped housing to a metabolic cage. Rats (Rattus norvegicus) (n=60) were trained in a judgment bias paradigm previously validated for use in the rat model. Upon exposure to an intermediate, ambiguous probe rats responded with either an optimistic or pessimistic decision. The animals were also subjected to the sucrose preference test to identify the presence of anhedonia. Faecal corticosterone and changes in adrenal tyrosine hydroxylase were also measured to establish whether a stress-like state was experienced. There was a significant interaction between sex and metabolic cage housing on the number of optimistic decisions made F (1, 56)=7.461, p=0.008. Female rats that remained in control housing responded with a reduced number of days featuring an optimistic decision compared to males in control housing (p=0.036). However, both males and females responded with significantly fewer optimistic decisions in the metabolic cage compared to control (p<0.001). There was a significant negative correlation between treatment and sucrose consumption (rpb=-0.654, n=195, p<0.001). There was also a significant sex effect for faecal corticosterone concentrations F (1, 30)=6.305, p=0.018) with female rats (4.050±1.285), displaying greater corticosterone concentrations than males (2.291±0.495). No differences between treatment were observed for either corticosterone or tyrosine hydroxylase levels. This data demonstrates that movement into a metabolic cage resulted in rats displaying significantly greater pessimistic cognitive biases as determined through the judgment bias test. Interestingly, male rats that remained in control housing demonstrated cognitive biases that were not equivalent to female rats. Furthermore, despite a behavioural change being evident, a physiological change in corticosterone or tyrosine hydroxylase levels was not observed.

The Reliability of a Pre-Loaded Treadmill Time-Trial in Moderate Normobaric Hypoxia.

The purpose of this study was to assess the reliability of a pre-loaded 1 500-m treadmill time trial, conducted in moderate normobaric hypoxia. 8 trained runners/triathletes (24±3 years, 73.2±8.1 kg, 182.5±6.5 cm, altitude specific V˙O2max: 52.9±5.5 ml·kg(-1)·min(-1)) completed 3 trials (the first as a familiarisation), involving 2, 15-min running bouts at 45% and 65% V˙O2max, respectively, and a 1 500-m time trial in moderate normobaric hypoxia equivalent to a simulated altitude of 2 500 m (FiO2~15%). Heart rate, arterial oxygen saturation, skeletal muscle and cerebral tissue oxygenation (StO2), expired gas ( V˙O2 and V˙CO2), and ratings of perceived exertion were monitored. Running performance (Trial 1: 352.7±40; Trial 2: 353.9±38.2 s) demonstrated a low CV (0.9%) and high ICC (1). All physiological variables demonstrated a global CV≤4.2%, and ICC≥0.87, with the exception of muscle (CV 10.4%; ICC 0.70) and cerebral (CV 4.1%; ICC 0.82) StO2. These data demonstrate good reliability of the majority of physiological variables and indicate that a pre-loaded 1 500-m time trial conducted in moderate normobaric hypoxia is a highly reliable test of performance.

Management and closure of the open abdomen after damage control laparotomy for trauma. A systematic review and meta-analysis.

INTRODUCTION: Damage control laparotomy for trauma (DCL) entails immediate control of haemorrhage and contamination, temporary abdominal closure (TAC), a period of physiological stabilisation, then definitive repair of injuries. Although immediate primary fascial closure is desired, fascial retraction and visceral oedema may dictate an alternate approach. Our objectives were to systematically identify and compare methods for restoration of fascial continuity when primary closure is not possible following DCL for trauma, to simplify these into a standardised map, and describe the ideal measures of process and outcome for future studies. METHODS: Cochrane, OVID (Medline, AMED, Embase, HMIC) and PubMed databases were accessed using terms: (traum*, damage control, abbreviated laparotomy, component separation, fascial traction, mesh closure, planned ventral hernia (PVH), and topical negative pressure (TNP)). Randomised Controlled Trials, Case Series and Cohort Studies reporting TAC and early definitive closure methods in trauma patients undergoing DCL were included. Outcomes were mortality, days to fascial closure, hospital length of stay, abdominal complications and delayed ventral herniation. RESULTS: 26 studies described and compared early definitive closure methods; delayed primary closure (DPC), component separation (CS) and mesh repair (MR), among patients with an open abdomen after DCL for trauma. A three phase map was developed to describe the temporal and sequential attributes of each technique. Significant heterogeneity in nomenclature, terminology, and reporting of outcomes was identified. Estimates for abdominal complications in DPC, MR and CS groups were 17%, 41% and 17% respectively, while estimates for mortality in DPC and MR groups were 6% and 0.5% (data heterogeneity and requirement of fixed and random effects models prevented significance assessment). Estimates for abdominal closure in the MR and DPC groups differed; 6.30 (95% CI=5.10-7.51), and 15.90 (95% CI=9.22-22.58) days respectively. Reporting poverty prevented subgroup estimate generation for ventral hernia and hospital length of stay. CONCLUSION: Component separation or mesh repair may be valid alternatives to delayed primary closure following a trauma DCL. Comparisons were hampered by the lack of uniform reporting and bias. We propose a new system of standardised nomenclature and reporting for further investigation and management of the post-DCL open abdomen.

Influence of pedal cadence on the respiratory compensation point and its relation to critical power.

It is not known if the respiratory compensation point (RCP) is a distinct work rate (Watts (W)) or metabolic rate V̇(O2) and if the RCP is mechanistically related to critical power (CP). To examine these relationships, 10 collegiate men athletes performed cycling incremental and constant-power tests at 60 and 100 rpm to determine RCP and CP. RCP work rate was significantly (p≤0.05) lower for 100 than 60 rpm (197±24 W vs. 222±24 W), while RCP V̇(O2) was not significantly different (3.00±0.33 l min(-1) vs. 3.12±0.41 l min(-1)). CP at 60 rpm (214±51 W; V̇(O2): 3.01±0.69 l min(-1)) and 100 rpm (196±46 W; V̇(O2): 2.95±0.54 l min(-1)) were not significantly different from RCP. However, RCP and CP were not significantly correlated. These findings demonstrate that RCP represents a distinct metabolic rate, which can be achieved at different power outputs, but that RCP and CP are not equivalent parameters and should not, therefore, be used synonymously.

Predictors of vitamin D status in subjects that consume a vitamin D supplement.

BACKGROUND/OBJECTIVE: Although dietary supplement use has increased significantly among the general population, the interplay between vitamin D supplementation and other factors that influence vitamin D status remains unclear. The objective of this study was to identify predictor variables of vitamin D status in free-living subjects to determine the extent to which vitamin D supplements and other factors influence vitamin D status. SUBJECTS/METHODS: This was a retrospective, cross-sectional study involving 743 volunteers. Serum 25-hydroxy-vitamin D (25(OH)D) level and the variables diet, supplement usage, latitude of residence, ethnicity, age and body mass index (BMI) were used to predict vitamin D status in a summer and winter cohort. RESULTS: Supplemental vitamin D3 consumption was the most significant positive predictor, whereas BMI was the most significant negative predictor, of vitamin D status in each cohort. Other positive predictors were fortified beverage and dairy consumption in the summer and winter cohort, respectively. Negative predictors were: African American, Asian and Hispanic race in the summer; latitude of residence >36°N, Asian and Hispanic ethnicity in the winter. Mean(± s.d.) 25(OH)D levels were 101.1 (± 42.1) and 92.6 (± 39.0) nmol/l in summer and winter, respectively. Comparing non-supplement vs supplement users, approximately 38 vs 2.5% in the winter and 18 vs 1.4% in the summer had vitamin D levels <50 nmol/l. CONCLUSIONS: Vitamin D supplementation was the most significant positive predictor of vitamin D status. Collectively, these data point to the practicality of utilizing vitamin D supplements to reduce hypovitaminosis D in adults throughout the United States.

Use of pelleted sericea lespedeza (Lespedeza cuneata) for natural control of coccidia and gastrointestinal nematodes in weaned goats.

Infection with Eimeria spp. (coccidia) can be devastating in goats, particularly for young, recently-weaned kids, resulting in diarrhea, dehydration, and even death. Feeding dried sericea lespedeza [SL; Lespedeza cuneata (Dum.-Cours.) G. Don.] to young goats has been reported to reduce the effects of internal parasites, including gastrointestinal nematodes (GIN) but there have been no reports of the effects of feeding this forage on Eimeria spp. in goats. Two confinement feeding experiments were completed on recently-weaned intact bucks (24 Kiko-cross, Exp. 1; 20 Spanish, Exp. 2) to determine effects of SL pellets on an established infection of GIN and coccidia. The bucks were assigned to 1 of 2 (Exp. 1) or 3 (Exp. 2) treatment groups based upon the number of Eimeria spp. oocysts per gram (OPG) of feces. In Exp. 1, the kids were fed 1 of 2 pelleted rations ad libitum; 90% SL leaf meal+10% of a liquid molasses/lignin binder mix and a commercial pellet with 12% crude protein (CP) and 24% acid detergent fiber (n=12/treatment group, 2 animals/pen). For Exp. 2, treatment groups were fed (1) 90% SL leaf meal pellets from leaves stored 3 years (n=7), (2) 90% SL pellets from leaf meal stored less than 6 months, (n=7), and the commercial pellets (n=6) ad libitum. For both trials, fecal and blood samples were taken from individual animals every 7 days for 28 days to determine OPG and GIN eggs per gram (EPG) and packed cell volume (PCV), respectively. In Exp. 2, feces were scored for consistency (1=solid pellets, 5=slurry) as an indicator of coccidiosis. In Exp. 1, EPG (P<0.001) and OPG (P<0.01) were reduced by 78.7% and 96.9%, respectively, 7 days after initiation of feeding in goats on the SL pellet diet compared with animals fed the control pellets. The OPG and EPG remained lower in treatment than control animals until the end of the trial. In Exp. 2, goats fed new and old SL leaf meal pellets had 66.2% and 79.2% lower (P<0.05) EPG and 92.2% and 91.2% lower (P<0.05) OPG, respectively, than control animals within 7 days, and these differences were maintained or increased throughout the trial. After 4 weeks of pellet feeding in Exp. 2, fecal scores were lower (P<0.01) in both SL-fed groups compared with control animals, indicating fewer signs of coccidiosis. There was no effect of diet on PCV values throughout either experiment. Dried, pelleted SL has excellent potential as a natural anti-coccidial feed for weaned goats.

Resistance training increases skeletal muscle oxidative capacity and net intramuscular triglyceride breakdown in type I and II fibres of sedentary males.

Recent in vitro and in vivo experimental observations suggest that improvements in insulin sensitivity following endurance training are mechanistically linked to increases in muscle oxidative capacity, intramuscular triglyceride (IMTG) utilization during endurance exercise and increases in the content of the lipid droplet-associated perilipin 2 (PLIN2) and perilipin 5 (PLIN5). This study investigated the hypothesis that similar adaptations may also underlie the resistance training (RT)-induced improvements in insulin sensitivity. Thirteen sedentary men (20 ± 1 years old; body mass index 24.8 ± 0.8 kg m(-2)) performed 6 weeks of whole-body RT (three times per week), and changes in peak O2 uptake (in millilitres per minute per kilogram) and insulin sensitivity were assessed. Muscle biopsies (n = 8) were obtained before and after 60 min steady-state cycling at ~65% peak O2 uptake. Immunofluorescence microscopy was used to assess changes in oxidative capacity (measured as cytochrome c oxidase protein content), IMTG and PLIN2 and PLIN5 protein content. Resistance training increased peak O2 uptake (by 8 ± 3%), COX protein content (by 46 ± 13 and 61 ± 13% in type I and II fibres, respectively) and the Matsuda insulin sensitivity index (by 47 ± 6%; all P < 0.05). In type I fibres, IMTG (by 52 ± 11%; P < 0.05) and PLIN2 content (by 107 ± 19%; P < 0.05) were increased and PLIN5 content tended to increase (by 54 ± 22%; P = 0.054) post-training. In type II fibres, PLIN2 content increased (by 57 ± 20%; P < 0.05) and IMTG (by 46 ± 17%; P = 0.1) and PLIN5 content (by 44 ± 24%; P = 0.054) tended to increase post-training. Breakdown of IMTG during moderate-intensity exercise was greater in both type I and type II fibres (by 43 ± 5 and 37 ± 5%, respectively; P < 0.05) post-RT. The results confirm the hypothesis that RT enhances muscle oxidative capacity and increases IMTG breakdown and the content of PLIN2 and PLIN5 in both type I and type II fibres during endurance-type exercise.

Vertical rectus abdominis myocutaneous flap reconstruction of the perineal defect after abdominoperineal excision is associated with low morbidity.

AIM: To examine the short-term outcomes of perineal reconstruction with a vertical rectus abdominis myocutaneous (VRAM) flap following abdominoperineal excision (APE). METHOD: Retrospective case note review of all patients undergoing APE and primary VRAM reconstruction between July 2001 and February 2012 in a district general hospital tertiary referral centre for APE. Complications were categorized using the Clavien-Dindo classification, which grades complications from I to V in order of increasing severity. RESULTS: Fifty-five consecutive patients (31 men, median age 65, range 38-84 years) underwent APE with VRAM flap reconstruction, 15 for anal cancer and 40 for rectal cancer. Median length of stay was 11 days but was significantly shorter in the laparoscopic group compared with the open group (8 vs 12 days; P < 0.01) and in patients who did not experience any complications (P < 0.05). Four patients (7%) had major complications (Grade 3 and above) directly related to the flap or donor site. CONCLUSION: VRAM reconstruction of the perineum can be safely performed following APE with results that compare favourably with other techniques. Most flap complications are minor, although these are still associated with an increase in the length of hospital stay.

Sprint interval and traditional endurance training increase net intramuscular triglyceride breakdown and expression of perilipin 2 and 5.

Intramuscular triglyceride (IMTG) utilization is enhanced by endurance training (ET) and is linked to improved insulin sensitivity. This study first investigated the hypothesis that ET-induced increases in net IMTG breakdown and insulin sensitivity are related to increased expression of perilipin 2 (PLIN2) and perilipin 5 (PLIN5). Second, we hypothesized that sprint interval training (SIT) also promotes increases in IMTG utilization and insulin sensitivity. Sixteen sedentary males performed 6 weeks of either SIT (4-6, 30 s Wingate tests per session, 3 days week(-1)) or ET (40-60 min moderate-intensity cycling, 5 days week(-1)). Training increased resting IMTG content (SIT 1.7-fold, ET 2.4-fold; P < 0.05), concomitant with parallel increases in PLIN2 (SIT 2.3-fold, ET 2.8-fold; P < 0.01) and PLIN5 expression (SIT 2.2-fold, ET 3.1-fold; P < 0.01). Pre-training, 60 min cycling at ∼65% pre-training decreased IMTG content in type I fibres (SIT 17 ± 10%, ET 15 ± 12%; P < 0.05). Following training, a significantly greater breakdown of IMTG in type I fibres occurred during exercise (SIT 27 ± 13%, ET 43 ± 6%; P < 0.05), with preferential breakdown of PLIN2- and particularly PLIN5-associated lipid droplets. Training increased the Matsuda insulin sensitivity index (SIT 56 ± 15%, ET 29 ± 12%; main effect P < 0.05). No training × group interactions were observed for any variables. In conclusion, SIT and ET both increase net IMTG breakdown during exercise and increase in PLIN2 and PLIN5 protein expression. The data are consistent with the hypothesis that increases in PLIN2 and PLIN5 are related to the mechanisms that promote increased IMTG utilization during exercise and improve insulin sensitivity following 6 weeks of SIT and ET.

Preferential utilization of perilipin 2-associated intramuscular triglycerides during 1 h of moderate-intensity endurance-type exercise.

The lipid droplet (LD)-associated protein perilipin 2 (PLIN2) appears to colocalize with LDs in human skeletal muscle fibres, although the function of PLIN2 in the regulation of intramuscular triglyceride (IMTG) metabolism is currently unknown. Here we investigated the hypothesis that the presence of PLIN2 in skeletal muscle LDs is related to IMTG utilisation during exercise. We therefore measured exercise-induced changes in IMTG and PLIN2 distribution and changes in their colocalization. Muscle biopsies from the vastus lateralis were obtained from seven lean, untrained men (22 ± 2 years old, body mass index 24.2 ± 0.9 kg m(-2) and peak oxygen uptake 3.35 ± 0.13 l min(-1)) before and after 1 h of moderate-intensity cycling at ~65% peak oxygen uptake. Cryosections were stained for perilipin 2, IMTG and myosin heavy chain type I and viewed using wide-field and confocal fluorescence microscopy. Exercise induced a 50 ± 7% decrease in IMTG content in type I fibres only (P < 0.05), but no change in PLIN2 content. Colocalization analysis showed that the fraction of PLIN2 associated with IMTG was 0.67 ± 0.03 before exercise, which was reduced to 0.51 ± 0.01 postexercise (P < 0.05). Further analysis revealed that the number of PLIN2-associated LDs was reduced by 31 ± 10% after exercise (P < 0.05), whereas the number of PLIN2-null LDs was unchanged. No such changes were seen in type II fibres. In conclusion, this study shows that PLIN2 content in skeletal muscle is unchanged in response to a single bout of endurance exercise. Furthermore, the PLIN2 and IMTG association is reduced postexercise, apparently due to preferential utilization of PLIN2-associated LDs. These results confirm the hypothesis that the PLIN2 association with IMTG is related to the utilization of IMTG as a fuel during exercise.