Muscle damage and its relationship with muscle fatigue during a half-iron triathlon

Background

To investigate the cause/s of muscle fatigue experienced during a half-iron distance triathlon.

Methodology/Principal Findings

We recruited 25 trained triathletes (36±7 yr; 75.1±9.8 kg) for the study. Before and just after the race, jump height and leg muscle power output were measured during a countermovement jump on a force platform to determine leg muscle fatigue. Body weight, handgrip maximal force and blood and urine samples were also obtained before and after the race. Blood myoglobin and creatine kinase concentrations were determined as markers of muscle damage.

Results

Jump height (from 30.3±5.0 to 23.4±6.4 cm; P<0.05) and leg power output (from 25.6±2.9 to 20.7±4.6 W · kg⁻¹; P<0.05) were significantly reduced after the race. However, handgrip maximal force was unaffected by the race (430±59 to 430±62 N). Mean dehydration after the race was 2.3±1.2% with high inter-individual variability in the responses. Blood myoglobin and creatine kinase concentration increased to 516±248 µg · L⁻¹ and 442±204 U · L⁻¹, respectively (P<0.05) after the race. Pre- to post-race jump change did not correlate with dehydration (r = 0.16; P>0.05) but significantly correlated with myoglobin concentration (r = 0.65; P<0.001) and creatine kinase concentration (r = 0.54; P<0.001).

Conclusions/significance

During a half-iron distance triathlon, the capacity of leg muscles to produce force was notably diminished while arm muscle force output remained unaffected. Leg muscle fatigue was correlated with blood markers of muscle damage suggesting that muscle breakdown is one of the most relevant sources of muscle fatigue during a triathlon.     

Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage

Background

Completing a marathon is one of the most challenging sports activities, yet the source of running fatigue during this event is not completely understood. The aim of this investigation was to determine the cause(s) of running fatigue during a marathon in warm weather.

Methodology/Principal Findings

We recruited 40 amateur runners (34 men and 6 women) for the study. Before the race, body core temperature, body mass, leg muscle power output during a countermovement jump, and blood samples were obtained. During the marathon (27 °C; 27% relative humidity) running fatigue was measured as the pace reduction from the first 5-km to the end of the race. Within 3 min after the marathon, the same pre-exercise variables were obtained.

Results

Marathoners reduced their running pace from 3.5 ± 0.4 m/s after 5-km to 2.9 ± 0.6 m/s at the end of the race (P<0.05), although the running fatigue experienced by the marathoners was uneven. Marathoners with greater running fatigue (> 15% pace reduction) had elevated post-race myoglobin (1318 ± 1411 v 623 ± 391 µg L⁻¹; P<0.05), lactate dehydrogenase (687 ± 151 v 583 ± 117 U L⁻¹; P<0.05), and creatine kinase (564 ± 469 v 363 ± 158 U L⁻¹; P = 0.07) in comparison with marathoners that preserved their running pace reasonably well throughout the race. However, they did not differ in their body mass change (−3.1 ± 1.0 v −3.0 ± 1.0%; P = 0.60) or post-race body temperature (38.7 ± 0.7 v 38.9 ± 0.9 °C; P = 0.35).

Conclusions/Significance

Running pace decline during a marathon was positively related with muscle breakdown blood markers. To elucidate if muscle damage during a marathon is related to mechanistic or metabolic factors requires further investigation.     

Effects of Dietary Crude Protein Levels and Cysteamine Supplementation on Protein Synthetic and Degradative Signaling in Skeletal Muscle of Finishing Pigs

Dietary protein levels and cysteamine (CS) supplementation can affect growth performance and protein metabolism of pigs. However, the influence of dietary protein intake on the growth response of CS-treated pigs is unclear, and the mechanisms involved in protein metabolism remain unknown. Hence, we investigated the interactions between dietary protein levels and CS supplementation and the effects of dietary crude protein levels and CS supplementation on protein synthetic and degradative signaling in skeletal muscle of finishing pigs. One hundred twenty barrows (65.84 ± 0.61 kg) were allocated to a 2 × 2 factorial arrangement with five replicates of six pigs each. The primary variations were dietary crude protein (CP) levels (14% or 10%) and CS supplemental levels (0 or 700 mg/kg). The low-protein (LP) diets (10% CP) were supplemented with enough essential amino acids (EAA) to meet the NRC AA requirements of pigs and maintain the balanced supply of eight EAA including lysine, methionine, threonine, tryptophan, valine, phenylalanine, isoleucine, and leucine. After 41 days, 10 pigs per treatment were slaughtered. We found that LP diets supplemented with EAA resulted in decreased concentrations of plasma somatostatin (SS) (P<0.01) and plasma urea nitrogen (PUN) (P<0.001), while dietary protein levels did not affect other traits. However, CS supplementation increased the average daily gain (P<0.001) and lean percentage (P<0.05), and decreased the feed conversion ratio (P<0.05) and back fat (P<0.05). CS supplementation also increased the concentrations of plasma insulin-like growth factor 1 (IGF-1) (P<0.001), and reduced the concentrations of leptin, SS, and PUN (P<0.001). Increased mRNA abundance of Akt1 and IGF-1 signaling (P<0.001) and decreased mRNA abundance of Forkhead Box O (FOXO) 4 (P<0.01) and muscle atrophy F-box (P<0.001) were observed in pigs receiving CS. Additionally, CS supplementation increased the protein levels for the phosphorylated mammalian target of rapamycin (mTOR), eIF-4E binding protein 1, and ribosomal protein S6 kinase 1 (P<0.001). There were no interactions between dietary protein levels and CS supplementation for all traits. In conclusion, dietary protein levels and CS supplementation influenced growth and protein metabolism through independent mechanisms in pigs. In addition, LP diets supplemented with EAA did not affect growth performance and other traits except the concentrations of SS and PUN probably through maintenance of protein synthesis and degradation signaling. Moreover, CS supplementation improved growth performance by increasing plasma IGF-1 concentrations possibly through alterations of mTOR and Akt/FOXO signaling pathways in skeletal muscle of finishing pigs.     

Post-Prandial Protein Handling: You Are What You Just Ate

Background

Protein turnover in skeletal muscle tissue is highly responsive to nutrient intake in healthy adults.

Objective

To provide a comprehensive overview of post-prandial protein handling, ranging from dietary protein digestion and amino acid absorption, the uptake of dietary protein derived amino acids over the leg, the post-prandial stimulation of muscle protein synthesis rates, to the incorporation of dietary protein derived amino acids in de novo muscle protein.

Design

12 healthy young males ingested 20 g intrinsically [1-¹³C]-phenylalanine labeled protein. In addition, primed continuous L-[ring-²H₅]-phenylalanine, L-[ring-²H₂]-tyrosine, and L-[1-¹³C]-leucine infusions were applied, with frequent collection of arterial and venous blood samples, and muscle biopsies throughout a 5 h post-prandial period. Dietary protein digestion, amino acid absorption, splanchnic amino acid extraction, amino acid uptake over the leg, and subsequent muscle protein synthesis were measured within a single in vivo human experiment.

Results

55.3±2.7% of the protein-derived phenylalanine was released in the circulation during the 5 h post-prandial period. The post-prandial rise in plasma essential amino acid availability improved leg muscle protein balance (from -291±72 to 103±66 μM·min^-1·100 mL leg volume^-1; P<0.001). Muscle protein synthesis rates increased significantly following protein ingestion (0.029±0.002 vs 0.044±0.004%·h^-1 based upon the muscle protein bound L-[ring-²H₅]-phenylalanine enrichments (P<0.01)), with substantial incorporation of dietary protein derived L-[1-¹³C]-phenylalanine into de novo muscle protein (from 0 to 0.0201±0.0025 MPE).

Conclusion

Ingestion of a single meal-like amount of protein allows ~55% of the protein derived amino acids to become available in the circulation, thereby improving whole-body and leg protein balance. About 20% of the dietary protein derived amino acids released in the circulation are taken up in skeletal muscle tissue following protein ingestion, thereby stimulating muscle protein synthesis rates and providing precursors for de novo muscle protein synthesis.

Trial Registration

trialregister.nl 3638     

Alterations of Neuromuscular Function after the World's Most Challenging Mountain Ultra-Marathon

We investigated the physiological consequences of the most challenging mountain ultra-marathon (MUM) in the world: a 330-km trail run with 24000 m of positive and negative elevation change. Neuromuscular fatigue (NMF) was assessed before (Pre-), during (Mid-) and after (Post-) the MUM in experienced ultra-marathon runners (n = 15; finish time  = 122.43 hours ±17.21 hours) and in Pre- and Post- in a control group with a similar level of sleep deprivation (n = 8). Blood markers of muscle inflammation and damage were analyzed at Pre- and Post-. Mean ± SD maximal voluntary contraction force declined significantly at Mid- (−13±17% and −10±16%, P<0.05 for knee extensor, KE, and plantar flexor muscles, PF, respectively), and further decreased at Post- (−24±13% and −26±19%, P<0.01) with alteration of the central activation ratio (−24±24% and −28±34% between Pre- and Post-, P<0.05) in runners whereas these parameters did not change in the control group. Peripheral NMF markers such as 100 Hz doublet (KE: −18±18% and PF: −20±15%, P<0.01) and peak twitch (KE: −33±12%, P<0.001 and PF: −19±14%, P<0.01) were also altered in runners but not in controls. Post-MUM blood concentrations of creatine kinase (3719±3045 Ul·¹), lactate dehydrogenase (1145±511 UI·L⁻¹), C-Reactive Protein (13.1±7.5 mg·L⁻¹) and myoglobin (449.3±338.2 µg·L⁻¹) were higher (P<0.001) than at Pre- in runners but not in controls. Our findings revealed less neuromuscular fatigue, muscle damage and inflammation than in shorter MUMs. In conclusion, paradoxically, such extreme exercise seems to induce a relative muscle preservation process due likely to a protective anticipatory pacing strategy during the first half of MUM and sleep deprivation in the second half.     

Retinal Nerve Fiber Layer Thickness. The Beijing Eye Study 2011

Purpose

To measure retinal nerve fiber layer (RNFL) thickness in a population-based setting.

Methods

In the population-based Beijing Eye Study 2011 with 3468 individuals, RNFL thickness was measured in a subgroup of 1654 (47.7%) study participants by spectral domain optical coherence tomography (iVue SD-OCT).

Results

Mean RNFL thickness was significantly (P<0.001) higher in the inferior sector (131.4±20.6 µm) than the superior sector (126.1±19.1 µm), where it was higher than in the temporal sector (79.8±12.2 µm;P<0.001), where it was higher than in the nasal sector (75.1±12.6 µm;P<0.001). In multivariate analysis, mean global RNFL thickness (103.2±12.6 µm) increased significantly with younger age (standardized correlation coefficient beta:−0.30;P<0.001), larger neuroretinal rim area (beta:0.26;P<0.001), shorter axial length (beta:−0.21;P<0.001), thicker subfoveal choroidal thickness (beta:0.15;P<0.001), larger optic disc area (beta:0.10;P<0.001), less refractive lens power (beta:0.10;P<0.001), flatter anterior cornea (beta:0.07;P = 0.01) and female gender (beta:0.05;P = 0.03). In this population with an age of 50+ years, the age-related decline in RNFL thickness was 0.5 µm per year of life or 0.36% of an original RNFL thickness of 137 µm at baseline of the study at 50 years of age. Mean global RNFL thickness decreased by 2.4 µm for each mm enlargement of axial length.

Conclusions

The RNFL profile shows a double hump configuration with the thickest part in the inferior sector, followed by the superior sector, temporal sector and nasal sector. Factors influencing global RNFL thickness were younger age, larger neuroretinal rim, shorter axial length, thicker subfoveal choroid, larger optic disc, less refractive lens power, flatter anterior cornea and female gender. Beyond an age of 50+ years, RNFL decreased by about 0.3% per year of life at an age of 50+ years and by 2.4 µm per mm of axial elongation. These findings may be of interest for the knowledge of the normal anatomy of the eye and may be of help to diagnose diseases affecting the RNFL.     

Training,psychometric status,biological markers and neuromuscular fatigue in soccer

The study examined the relationship between psychometric status, neuromuscular, and biochemical markers of fatigue in response to an intensified training (IT) period in soccer. Fifteen professional soccer players volunteered to participate in the study (mean ± SD: age: 25 ± 1 years; body height: 179 ± 7 cm, body mass: 73.7 ± 16.2 kg, experience: 13.2 ± 3 years). Training load, monotony, strain, Hooper index and total quality recovery (TQR) were determined for each training session during a 2-week of IT. Counter-movement jump (CMJ) and biochemical responses [testosterone, cortisol, testosterone-to-cortisol ratio (T/C ratio), creatine kinase, and C-reactive protein] were collected before and after IT. Results showed that IT induced significant increases in cortisol, creatine kinase and C-reactive protein and significant decreases in T/C ratio and CMJ performance from before to after IT (p < 0.01, p < 0.001, p < 0.001, p < 0.01, p < 0.05, respectively). However, testosterone did not differ from before to after IT (p > 0.05). Training loads were positively correlated with Hooper index (p < 0.05) and negatively correlated with total quality recovery (p < 0.05). Hooper index was positively correlated with cortisol (p < 0.05), T/C ratio (p < 0.01), and creatine kinase (p < 0.01), and negatively correlated with CMJ (p < 0.05). Furthermore, TQR was negatively correlated with T/C ratio (p < 0.01), creatine kinase (p < 0.001), and C-reactive protein (p < 0.05), and positively correlated with CMJ (p < 0.01). Neuromuscular fatigue, muscle damage, and change in the anabolic/catabolic state induced by the IT were related to well-being and perceived recovery state among professional soccer players.     

Increased Circulating Cathepsin K in Patients with Chronic Heart Failure

Cysteinyl cathepsin K (CatK) is one of the most potent mammalian collagenases involved in cardiovascular disease. Here, we investigated the clinical predictive value of serum CatK levels in patients with chronic heart failure (CHF). We examined 134 patients with CHF, measuring their serum CatK, troponin I, high-sensitive C-reactive protein, and pre-operative N-terminal pro-brain natriuretic peptide levels. The patients were divided into two groups: the 44 patients who showed a left ventricular (LV) ejection fraction (LVEF) < 40% (the “lowLVEF” group) and the 90 patients showing LVEF values ≥ 40% (the “highLVEF” group). The lowLVEF patients had significantly higher serum CatK levels compared to the highLVEF patients (58.4 ± 12.2 vs. 44.7 ± 16.4, P < 0.001). Overall, a linear regression analysis showed that CatK levels correlated negatively with LVEF (r = −0.4, P < 0.001) and positively with LV end-diastolic dimensions (r = 0.2, P < 0.01), LV end-systolic dimensions (r = 0.3, P < 0.001), and left atrial diameters (r = 0.3, P < 0.01). A multiple logistic regression analysis showed that CatK levels were independent predictors of CHF (odds ratio, 0.90; 95% confidence interval, 0.84–0.95; P < 0.01). These data indicate that elevated levels of CatK are closely associated with the presence of CHF and that the measurement of circulating CatK provides a noninvasive method of documenting and monitoring the extent of cardiac remodeling and dysfunction in patients with CHF.     

Mesangial Cell-Binding Activity of Serum Immunoglobulin G in Patients with Lupus Nephritis

In vitro data showed that immunoglobulin G (IgG) from patients with lupus nephritis (LN) could bind to cultured human mesangial cells (HMC). The clinical relevance of such binding was unknown. Binding of IgG and subclasses was measured in 189 serial serum samples from 23 patients with Class III/IV±V LN (48 during renal flares, 141 during low level disease activity (LLDA)). 64 patients with non-lupus glomerular diseases (NLGD) and 23 healthy individuals were used as controls. HMC-binding was measured with cellular ELISA and expressed as OD index. HMC-binding index of total IgG was 0.12±0.09, 0.36±0.25, 0.59±0.37 and 0.74±0.42 in healthy subjects, NLGD, LN patients during LLDA, and LN flares respectively (P = 0.046, LN flare vs. LLDA; P<0.001, for healthy controls or NLGD vs. LN during flare or LLDA). Binding of serum IgG₁ to HMC was 0.05±0.05, 0.15±0.11, 0.41±0.38 and 0.55±0.40 for the corresponding groups respectively (P = 0.007, LN flare vs. remission; P<0.001, for healthy controls or NLGD vs. LN during flare or remission). IgG₂, IgG₃ and IgG₄ from patients and controls did not show significant binding to HMC. Total IgG and IgG₁ HMC-binding index correlated with anti-dsDNA level (r = 0.26 and 0.39 respectively, P<0.001 for both), and inversely with C3 (r = −0.17 and −0.45, P<0.05 for both). Sensitivity/specificity of total IgG or IgG₁ binding to HMC in predicting renal flares were 81.3%/39.7% (ROC AUC 0.61, P = 0.03) and 83.8%/41.8% (AUC 0.63, P = 0.009) respectively. HMC-binding by IgG_1, but not total IgG, correlated with mesangial immune deposition in LN renal biopsies under electron microscopy. Our results showed that binding of serum total IgG and IgG₁ in LN patients correlates with disease activity. The correlation between IgG₁ HMC-binding and mesangial immune deposition suggests a potential pathogenic significance.     

The Association of Brachial-Ankle Pulse Wave Velocity with Coronary Artery Disease Evaluated by Coronary Computed Tomography Angiography

The aim of this study was to investigate whether brachial-ankle pulse wave velocity (baPWV) is associated with the severity of coronary artery disease (CAD) assessed by coronary computed tomography angiography (CCTA), and to evaluate baPWV as a predictor of obstructive CAD on CCTA. A total of 470 patients who underwent both baPWV and CCTA were included. We evaluated stenosis degree and plaque characteristics on CCTA. To estimate the severity of CAD, we calculated the number of segment with plaque (segment involvement score; SIS), stenosis degree-weighted plaque score (segment stenosis score; SSS), and coronary artery calcium score (CACS). The mean baPWV was 1,485 ± 315 cm/s (range, 935-3,175 cm/s). Non-obstructive (stenosis < 50%) and obstructive (stenosis ≥ 50%) CAD was found in 129 patients (27.4%) and 144 (30.6%), respectively. baPWV in patients with obstructive CAD was higher than that of patients with non-obstructive (1,680 ± 396 cm/s versus 1,477 ± 244 cm/s, P < 0.001) or no CAD (1,680 ± 396 cm/s versus ± 196 1,389 cm/s, P < 0.001). baPWV showed significant correlation with SSS (r = 0.429, P < 0.001), SIS (r = 0.395, P < 0.001), CACS (r 0.346, P < 0.001), and the number of segment with non-calcified plaque (r 0.092, P = 0.047), mixed plaque (r = 0.267, P < 0.001), and calcified plaque (r = 0.348, P < 0.001), respectively. The optimal baPWV cut-off value for the detection of obstructive CAD was 1,547 cm/s. baPWV ≥ 1,547 cm/s was independent predictor for the obstructive CAD. In conclusion, baPWV is well correlated with the severity of CAD evaluated by CCTA. baPWV has the potential to predict severity of coronary artery atherosclerosis.     

Elevated serum squalene and cholesterol synthesis markers in pregnant obese women with gestational diabetes mellitus

We examined serum cholesterol synthesis and absorption markers and their association with neonatal birth weight in obese pregnancies affected by gestational diabetes mellitus (GDM). Pregnant women at risk for GDM (BMI >30 kg/m²) were enrolled from maternity clinics in Finland. GDM was determined from the results of an oral glucose tolerance test. Serum samples were collected at six time-points, one in each trimester of pregnancy, and at 6 weeks, 6 months, and 12 months postpartum. Analysis of serum squalene and noncholesterol sterols by gas-liquid chromatography revealed that in subjects with GDM (n = 22), the serum Δ8-cholestenol concentration and lathosterol/sitosterol ratio were higher (P < 0.05) than in the controls (n = 30) in the first trimester, reflecting increased cholesterol synthesis. Also, subjects with GDM had an increased ratio of squalene to cholesterol (100 × μmol/mmol of cholesterol) in the second (11.5 ± 0.5 vs. 9.1 ± 0.5, P < 0.01) and third (12.1 ± 0.8 vs. 10.0 ± 0.7, P < 0.05) trimester. In GDM, the second trimester maternal serum squalene concentration correlated with neonatal birth weight (r = 0.70, P < 0.001). In conclusion, in obesity, GDM associated with elevated serum markers of cholesterol synthesis. Correlation of maternal serum squalene with neonatal birth weight suggests a potential contribution of maternal cholesterol synthesis to newborn weight in GDM.     

Serum Testosterone Levels and Androgen Receptor CAG Polymorphism Correlate with Hepatitis B Virus (HBV)-Related Acute Liver Failure in Male HBV Carriers

Background

Augmentation of androgen/androgen receptor (AR) pathway may influence chronic hepatitis B (CHB) more likely in males. AR activity is modulated by a polymorphic CAG repeat sequence in AR exon 1. This study aimed to investigate the relationship between serum testosterone levels, CAG repeat numbers and hepatitis B virus (HBV)-related acute liver failure (ALF).

Methods

Three hundred and seventy eight male CHB patients with ALF and 441 asymptomatic HBV carriers (AsCs) were recruited. AR CAG repeats numbers were analyzed. The serum testosterone levels of AsCs, ALFs and patients with hepatitis B flare groups, and sequential serum samples, were assessed quantitatively.

Results

The median CAG repeat (M-CAG) frequency was significantly higher in ALF patients than AsCs (P<0.001). Patients with M-CAG alleles (P<0.001, OR 3.0, 95% CI 2.1–4.2) had the highest risk for ALF. Serum testosterone levels were significantly higher (P<0.001) at hepatitis flare point (8.2±3.0 ng/mL) than inactive phase (6.4±2.0 ng/mL). CHB (8.30±2.71 ng/mL, P = 7.6×10⁻⁶) and ALF group (2.61±1.83 ng/mL, P = 1.7×10⁻¹⁷) had significantly different levels of testosterone in comparison with AsCs group (6.56±2.36 ng/mL). The serum testosterone levels sharply decreased from hepatitis flare phase to liver failure phase, and tended to be normal at the recovery phase. Male AsCs with M-CAG alleles had significantly lower serum testosterone levels (P<0.05).

Conclusions

There was a serum testosterone fluctuation during hepatitis B flare and HBV-related ALF, and the median CAG repeats in AR gene exon 1 were associated with lower serum testosterone levels in asymptomatic HBV carriers and an increased susceptibility to HBV-related ALF.     

Human Muscle Protein Synthetic Responses during Weight-Bearing and Non-Weight-Bearing Exercise: A Comparative Study of Exercise Modes and Recovery Nutrition

Effects of conventional endurance (CE) exercise and essential amino acid (EAA) supplementation on protein turnover are well described. Protein turnover responses to weighted endurance exercise (i.e., load carriage, LC) and EAA may differ from CE, because the mechanical forces and contractile properties of LC and CE likely differ. This study examined muscle protein synthesis (MPS) and whole-body protein turnover in response to LC and CE, with and without EAA supplementation, using stable isotope amino acid tracer infusions. Forty adults (mean ± SD, 22 ± 4 y, 80 ± 10 kg, VO_2peak 4.0 ± 0.5 L∙min^-1) were randomly assigned to perform 90 min, absolute intensity-matched (2.2 ± 0.1 VO₂ L∙m^-1) LC (performed on a treadmill wearing a vest equal to 30% of individual body mass, mean ± SD load carried 24 ± 3 kg) or CE (cycle ergometry performed at the same absolute VO₂ as LC) exercise, during which EAA (10 g EAA, 3.6 g leucine) or control (CON, non-nutritive) drinks were consumed. Mixed-muscle and myofibrillar MPS were higher during exercise for LC than CE (mode main effect, P < 0.05), independent of dietary treatment. EAA enhanced mixed-muscle and sarcoplasmic MPS during exercise, regardless of mode (drink main effect, P < 0.05). Mixed-muscle and sarcoplasmic MPS were higher in recovery for LC than CE (mode main effect, P < 0.05). No other differences or interactions (mode x drink) were observed. However, EAA attenuated whole-body protein breakdown, increased amino acid oxidation, and enhanced net protein balance in recovery compared to CON, regardless of exercise mode (P < 0.05). These data show that, although whole-body protein turnover responses to absolute VO₂-matched LC and CE are the same, LC elicited a greater muscle protein synthetic response than CE.     

Blockade of Thrombopoietin Reduces Organ Damage in Experimental Endotoxemia and Polymicrobial Sepsis

Background and Purpose

Thrombopoietin (TPO), a growth factor primarily involved in thrombopoiesis may also have a role in the pathophysiology of sepsis. In patients with sepsis, indeed, TPO levels are markedly increased, with disease severity being the major independent determinant of TPO concentrations. Moreover, TPO increases and correlates with ex vivo indices of platelet activation in patients with burn injury upon sepsis development, and may contribute to depress cardiac contractility in septic shock. Still, the role of TPO in sepsis pathophysiology remains controversial, given the protective role of TPO in other experimental disease models, for instance in doxorubicin-induced cardiotoxicity and myocardial ischemia/reperfusion injury. The aim of our study was to define the contribution of TPO in the development of organ damage induced by endotoxemia or sepsis, and to investigate the effects of inhibiting TPO in these conditions.

Methods

We synthesized a chimeric protein able to inhibit TPO, mTPOR-MBP, and studied its effect in two murine experimental models, acute endotoxemia and cecal ligation and puncture (CLP) model.

Results

In both models, TPO levels markedly increased, from 289.80±27.87 pg/mL to 465.60±45.92 pg/mL at 3 hours in the LPS model (P<0.01), and from 265.00±26.02 pg/mL to 373.70±26.20 pg/mL in the CLP model (P<0.05), respectively. Paralleling TPO levels, also platelet-monocyte aggregates increased, from 32.86±2.48% to 46.13±1.39% at 3 hours in the LPS model (P<0.01), and from 43.68±1.69% to 56.52±4.66% in the CLP model (P<0.05). Blockade of TPO by mTPOR-MBP administration reduced histological damage in target organs, namely lung, liver, and gut. In particular, neutrophil infiltration and lung septal thickening were reduced from a score of 1.86±0.34 to 0.60±0.27 (P<0.01) and from 1.43±0.37 to 0.40±0.16 (P<0.05), respectively, in the LPS model at 3 hours, and from a score of 1.75±0.37 to 0.38±0.18 (P<0.01) and from 1.25±0.31 to 0.13±0.13 (P<0.001), respectively, in the CLP model. Similarly, the number of hepatic microabscesses was decreased from 14.14±1.41 to 3.64±0.56 in the LPS model at 3 hours (P<0.001), and from 1.71±0.29 to 0.13±0.13 in the CLP model (P<0.001). Finally, the diameter of intestinal villi decreased from 90.69±3.95 μm to 70.74±3.60 μm in the LPS model at 3 hours (P<0.01), and from 74.29±4.29 μm to 57.50±1.89 μm in the CLP model (P<0.01). This protective effect was associated with the blunting of the increase in platelet-monocyte adhesion, and, on the contrary, with increased platelet-neutrophil aggregates in the circulation, which may be related to decreased neutrophil sequestration into the inflamed tissues. Conversely, circulating cytokine levels were not significantly changed, in both models, by mTPOR-MBP administration.

Conclusion

Our results demonstrate that TPO participates in the development of organ damage induced by experimental endotoxemia or polymicrobial sepsis via a mechanism involving increased platelet-leukocyte adhesion, but not cytokine release, and suggest that blocking TPO may be useful in preventing organ damage in patients affected by systemic inflammatory response or sepsis.     

Association between Low-Grade Albuminuria and Cardiovascular Risk in Korean Adults: The 2011–2012 Korea National Health and Nutrition Examination Survey

Background

Recent studies have indicated that low UACR levels (<30 μg/mg) previously considered to be in the normal range (‘low-grade albuminuria’) are associated with cardiovascular morbidity and mortality in the general population.

Methods

We studied 9,736 participants with albuminuria in the normal range from the 2011–2012 Korea National Health and Nutrition Examination Survey (KNHANES).

Results

The weighted prevalences of metabolic syndrome (MS) and the 10-year risk for coronary heart disease measured using the Framingham risk score (FRS) ≥ 20% (high risk) were 22.5 ± 0.7% and 14.5 ± 0.7%, respectively, in males and 23.3 ± 0.8% and 8.5 ± 0.4%, respectively in females. Weighted comparisons among the tertiles of UACR revealed that the prevalences of MS and high-risk FRS increased with increasing UACR (MS: males, 15.9 ± 1.1, 20.2 ± 1.2, 32.4 ± 1.5%, respectively; P < 0.001; and females, 17.6 ± 1.0, 22.7 ± 1.0, 30.2 ± 1.4%, respectively; P < 0.001. High-risk FRS: males, 9.5 ± 0.7, 12.3 ± 0.9, 22.5 ± 1.2, respectively; P < 0.001; and females, 5.8 ± 0.6, 7.9 ± 0.7, 12.0 ± 0.9%, respectively; P < 0.001). The positive association persisted after adjusting for hypertension and diabetes. The weighted comparisons among the deciles of UACR revealed that the prevalences of MS and high-risk FRS began to increase at the ranges of 3.89–5.15 and 5.16–7.36 mg/g Cr, respectively.

Conclusion

Low-grade albuminuria was significantly associated with estimated cardiovascular risk and MS in a nationally representative sample of Koreans.     

Inhibition of Lymphocyte Cytotoxicity by Serum from Patients with Alcoholic Liver Disease: Partial Characterization of Serum Inhibitors

Studies were performed to explore the effect on normal lymphocyte function of serum derived from patients with alcohol-induced liver injury and healthy controls. We examined the effect of such serum on the generation of both spontaneous and Concanavalin A (Con A)-induced lymphocyte cytotoxicity for Chang target cells. Normal lymphocytes, when incubated in the presence of 5% serum from patients with alcoholic liver disease, showed a marked (20.75 ± 5.1% mean ± SEM) reduction in the capacity to generate spontaneously cytotoxic cells compared to 5% control serum (3.2 ± 1.9%) (p < 0.001). Similar results were found in studies of Con A-stimulated cytotoxicity (36 ± 7.2% vs. 5 ± 2.3%; p < 0.001). Fractionation of serum by gel chromatography demonstrated the presence of inhibitory activity of various molecular weights, although a major peak of inhibitory activity (approximately 270,000 daltons) was identified in severe alcoholic hepatitis. Thus, this study demonstrates the presence of serum inhibitors in alcoholic liver disease which influence normal lymphocyte function.     

Changes in aminoacidergic and monoaminergic neurotransmission in the hippocampus and amygdala of rats after ayahuasca ingestion

AIM: To evaluate changes in neurotransmission induced by a psychoactive beverage ayahuasca in the hippocampus and amygdala of naive rats. METHODS: The level of monoamines, their main metabolites and amino acid neurotransmitters concentrations were quantified using high performance liquid chromatography(HPLC). Four groups of rats were employed: saline-treated and rats receiving 250, 500 and 800 mg/kg of ayahuasca infusion(gavage). Animals were killed 40 min after drug ingestion and the structures stored at-80 ℃ until HPLC assay. The data from all groups were compared using Analysis of variance and Scheffé as post test and P 0.05 was accepted as significant. RESULTS: The results showed decreased concentrations of glycine(GLY)(0.13 ± 0.03 vs 0.29 ± 0.07, P 0.001) and γ-aminobutyric acid(GABA)(1.07 ± 0.14 vs 1.73 ± 0.25, P 0.001) in the amygdala of rats that received 500 of ayahuasca. Animals that ingested 800 mg/kg of ayahuasca also showed a reduction of GLY level(0.11 ± 0.01 vs 0.29 ± 0.07, P 0.001) and GABA(0.98 ± 0.06 vs 1.73 ± 0.25, P 0.001). In the hippocampus, increased GABA levels were found in rats that received all ayahuasca doses: 250 mg/kg(1.29 ± 0.19 vs 0.84 ± 0.21, P 0.05); 500 mg/kg(2.23 ± 038 vs 084 ± 0.21, P 0.05) and 800 mg/kg(1.98 ± 0.92 vs 0.84 ± 0.21, P 0.05). In addition, an increased utilization rate of all monoamines was found in the amygdala after ayahuasca administration in doses: 250 mg/kg(noradrenaline: 0.16 ± 0.02 vs 0.36 ± 0.06, P 0.01; dopamine: 0.39 ± 0.012 vs 2.39 ± 0.84, P 0.001; serotonin: 1.02 ± 0.22 vs 4.04 ± 0.91, P 0.001), 500 mg/kg(noradrenaline: 0.08 ± 0.02 vs 0.36 ± 0.06, P 0.001; dopamine: 0.33 ± 0.19 vs 2.39 ± 0.84, P 0.001; serotonin: 0.59 ± 0.08 vs 4.04 ± 0.91, P 0.001) and 800 mg/kg(noradrenaline: 0.16 ± 0.04 vs 0.36 ± 0.06, P 0.001; dopamine: 0.84 ± 0.65 vs2.39 ± 0.84, P 0.05; serotonin: 0.36 ± 0.02 vs 4.04 ± 0.91, P 0.001). CONCLUSION: Our data suggest increased release of inhibitory amino acids by the hippocampus and an increased utilization rate of monoamines by the amygdala after different doses of ayahuasca ingestion.     

Association of Serum Uric Acid with 2-Hour Postload Glucose in Chinese with Impaired Fasting Plasma Glucose and/or HbA1c

Objective

To examine whether serum uric acid (SUA) is associated with 2-hour postload glucose (2-h PG) in Chinese with impaired fasting plasma glucose (IFG) and/or HbA1c (IA1C).

Research Design and Methods

Anthropometric and biochemical examinations, such as SUA concentration, were performed in 3763 individuals from all the villages in Baqiao County, China. A 75-g oral glucose tolerance test (OGTT) was conducted in 1197 Chinese with prediabetes as having IFG (110≤ fasting plasma glucose [FPG] <126 mg/dl and HbA1c <6.5%), IA1C (5.7% ≤ HbA1c <6.5% and FPG <126 mg/dl), or both.

Results

The present study included 1197 participants with IFG and/or IA1C (mean age 56.5±10.3 years; 50.6% men). In multivariate linear regression, after adjustment for gender, age, smoking and drinking, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), lipid profiles, logarithmic transformed C-reactive protein (log-CRP), estimated glomerular filtration rate (e-GFR), FPG and HbA1c, with a 1-mg/dl increment of SUA, 2-h PG increased by 5.04±0.72 (P<0.001), 3.06±1.08 (P = 0.001), 5.40±1.26 (P<0.001), and 2.34±2.16 mg/dl (P = 0.056) in all participants, in participants with normal glucose tolerance (NGT), with impaired glucose tolerance (IGT), and with 2-h newly diagnosed diabetes (2-h NDM, with 2-h PG ≥200 mg/dl), respectively. In both men and women, 2-h PG increased progressively and significantly from the lower to the upper SUA tertiles (P<0.001). Moreover, in multivariate logistic regression, 1-standard deviation (SD; 1.53 mg/dl) increment of SUA was significantly associated with a 36% higher risk for 2-h NDM (Odds ratio [CI 95%]: 1.36 [1.09–1.99]; P = 0.03).

Conclusions

SUA is significantly associated with 2-h PG in Chinese with IFG and/or IA1C.     

Hydroxyurea affects in vitro porcine oocyte maturation through increased apoptosis and oxidative stress

Hydroxyurea (HU) is an FDA-approved drug used to treat a variety of diseases, especially malignancies, but is harmful to fertility. We used porcine oocytes as an experimental model to study the effect of HU during oocyte maturation. Exposure of cumulus–oocyte complexes (COCs) to 20 µM (P<0.01) and 50 µM (P<0.001) HU reduced oocyte maturation. Exposure to 20 µM HU induced approximately 1.5- and 2-fold increases in Caspase-3 (P<0.001) and P53 (P<0.01) gene expression levels in cumulus cells, respectively, increased Caspase-3 (P<0.01) and P53 (P<0.001) protein expression levels in metaphase II (MII) oocytes and increased the percentage of apoptotic cumulus cells (P<0.001). In addition, HU decreased the mitochondrial membrane potential (Δφm) (P<0.01 and P<0.001) and glutathione (GSH) levels (P<0.01 and P<0.001) of both cumulus cells and MII oocytes, while increasing their reactive oxygen species (ROS) levels (P<0.001). Following parthenogenetic activation of embryos derived from MII oocytes, exposure to 20 µM HU significantly reduced total blastocyst cell numbers (P<0.001) and increased apoptosis of blastocyst cells (P<0.001). Moreover, HU exposure reduced the rate of development of two-celled, four- to eight-celled, blastocyst, and hatching stages after parthenogenetic activation (P<0.05). Our findings indicate that exposure to 20 µM HU caused significant oxidative stress and apoptosis of MII oocytes during maturation, which affected their developmental ability. These results provide valuable information for safety assessments of HU.