Transcriptomic Profiling of Rectus Abdominis Muscle in Women with Gestational Diabetes-Induced Myopathy: Characterization of Pathophysiology and Potential Muscle Biomarkers of Pregnancy-Specific Urinary Incontinence.

Gestational diabetes mellitus (GDM) is recognized as a "window of opportunity" for the future prediction of such complications as type 2 diabetes mellitus and pelvic floor muscle disorders, including urinary incontinence and genitourinary dysfunction. Translational studies have reported that pelvic floor muscle disorders are due to a GDM-induced-myopathy (GDiM) of the pelvic floor muscle and rectus abdominis muscle (RAM). We now describe the transcriptome profiling of the RAM obtained by Cesarean section from GDM and non-GDM women with and without pregnancy-specific urinary incontinence (PSUI). We identified 650 genes in total, and the differentially expressed genes were defined by comparing three control groups to the GDM with PSUI group (GDiM). Enrichment analysis showed that GDM with PSUI was associated with decreased gene expression related to muscle structure and muscle protein synthesis, the reduced ability of muscle fibers to ameliorate muscle damage, and the altered the maintenance and generation of energy through glycogenesis. Potential genetic muscle biomarkers were validated by RT-PCR, and their relationship to the pathophysiology of the disease was verified. These findings help elucidate the molecular mechanisms of GDiM and will promote the development of innovative interventions to prevent and treat complications such as post-GDM urinary incontinence.

Basal protein synthesis rates differ between vastus lateralis and rectus abdominis muscle.

BACKGROUND: In vivo muscle protein synthesis rates are typically assessed by measuring the incorporation rate of stable isotope labelled amino acids in skeletal muscle tissue collected from vastus lateralis muscle. It remains to be established whether muscle protein synthesis rates in the vastus lateralis are representative of muscle protein synthesis rates of other muscle groups. We hypothesized that post-absorptive muscle protein synthesis rates differ between vastus lateralis and rectus abdominis, pectoralis major, or temporalis muscle in vivo in humans. METHODS: Twenty-four patients (62 ± 3 years, 42% female), scheduled to undergo surgery, participated in this study and underwent primed continuous intravenous infusions with l-[ring-13 C6 ]-phenylalanine. During the surgical procedures, serum samples were collected, and muscle tissue was obtained from the vastus lateralis as well as from the rectus abdominis, pectoralis major, or temporalis muscle. Fractional mixed muscle protein synthesis rates (%/h) were assessed by measuring the incorporation of l-[ring-13 C6 ]-phenylalanine into muscle tissue protein. RESULTS: Serum l-[ring-13 C6 ]-phenylalanine enrichments did not change throughout the infusion period. Post-absorptive muscle protein synthesis rates calculated based upon serum l-[ring-13 C6 ]-phenylalanine enrichments did not differ between vastus lateralis and rectus abdominis (0.032 ± 0.004 vs. 0.038 ± 0.003%/h), vastus lateralis and pectoralis major, (0.025 ± 0.003 vs. 0.022 ± 0.005%/h) or vastus lateralis and temporalis (0.047 ± 0.005 vs. 0.043 ± 0.005%/h) muscle, respectively (P > 0.05). When fractional muscle protein synthesis rates were calculated based upon tissue-free l-[ring-13 C6 ]-phenylalanine enrichments as the preferred precursor pool, muscle protein synthesis rates were significantly higher in rectus abdominis (0.089 ± 0.008%/h) compared with vastus lateralis (0.054 ± 0.005%/h) muscle (P < 0.01). No differences were observed between fractional muscle protein synthesis rates in vastus lateralis and pectoralis major (0.046 ± 0.003 vs. 0.041 ± 0.008%/h) or vastus lateralis and temporalis (0.073 ± 0.008 vs. 0.083 ± 0.011%/h) muscle, respectively. CONCLUSIONS: Post-absorptive muscle protein synthesis rates are higher in rectus abdominis when compared with vastus lateralis muscle. Post-absorptive muscle protein synthesis rates do not differ between vastus lateralis and pectoralis major or temporalis muscle. Protein synthesis rates in muscle tissue samples obtained during surgery do not necessarily represent a good proxy for appendicular skeletal muscle protein synthesis rates.

Myokines in treatment-naïve patients with cancer-associated cachexia.

Cancer-associated cachexia is a complex metabolic syndrome characterized by weight loss and systemic inflammation. Muscle loss and fatty infiltration into muscle are associated with poor prognosis in cancer patients. Skeletal muscle secretes myokines, factors with autocrine, paracrine and/or endocrine action, which may be modified by or play a role in cachexia. This study examined myokine content in the plasma, skeletal muscle and tumor homogenates from treatment-naïve patients with gastric or colorectal stages I-IV cancer with cachexia (CC, N = 62), or not (weight stable cancer, WSC, N = 32). Myostatin, interleukin (IL) 15, follistatin-like protein 1 (FSTL-1), fatty acid binding protein 3 (FABP3), irisin and brain-derived neurotrophic factor (BDNF) protein content in samples was measured with Multiplex technology; body composition and muscle lipid infiltration were evaluated in computed tomography, and quantification of triacylglycerol (TAG) in the skeletal muscle. Cachectic patients presented lower muscle FSTL-1 expression (p = 0.047), higher FABP3 plasma content (p = 0.0301) and higher tumor tissue expression of FABP3 (p = 0.0182), IL-15 (p = 0.007) and irisin (p = 0.0110), compared to WSC. Neither muscle TAG content, nor muscle attenuation were different between weight stable and cachectic patients. Lumbar adipose tissue (AT) index, visceral AT index and subcutaneous AT index were lower in CC (p = 0.0149, p = 0.0455 and p = 0.0087, respectively), who also presented lower muscularity in the cohort (69.2% of patients; p = 0.0301), compared to WSC. The results indicate the myokine profile in skeletal muscle, plasma and tumor is impacted by cachexia. These findings show that myokines eventually affecting muscle wasting may not solely derive from the muscle itself (as the tumor also may contribute to the systemic scenario), and put forward new perspectives on cachexia treatment targeting myokines and associated receptors and pathways.

Preoperative Oral Carbohydrate Reduces Postoperative Insulin Resistance by Activating AMP-Activated Protein Kinase after Colorectal Surgery.

BACKGROUND: Postoperative insulin resistance (PIR) is a common response after colorectal surgery and an independent risk factor for recovery. Preoperative oral carbohydrate (POC) has been known to reduce PIR. Herein, we investigated whether its mechanism of action involves AMP-activated protein kinase (AMPK) and mTOR/S6K1/insulin receptor substrate-1 (IRS-1) pathways. METHODS: Patients undergoing colorectal cancer resection were randomly assigned to a POC, fasting, or placebo group. The exclusion criteria were association with diseases or intake of medication affecting insulin sensitivity. Pre- and postoperative insulin resistance, and protein phosphorylation of AMPK, mTOR, and IRS-1 in the rectus abdominis muscle were evaluated. RESULTS: From January 2017 to December 2017, 70 patients were randomized and 63 were evaluated. No difference was found in the clinical and operative characteristics among the 3 groups. In the POC group, the levels of blood glucose, blood insulin, and homeostasis model assessment of insulin resistance were significantly lower in the POC group than the fasting and placebo groups, and the insulin sensitivity index was significantly higher. The phosphorylation of AMPK in the POC group was significantly higher than that in the other 2 groups, whereas the phosphorylation of mTOR and IRS-1 was significantly lower. CONCLUSION: PIR involves AMPK and mTOR/S6K1/IRS-1 pathways. POC reduces PIR by the stimulation of AMPK, which suppresses the phosphorylation of mTOR/IRS-1 and attenuates PIR after colorectal resection.

Neuromuscular junctions are stable in patients with cancer cachexia.

Cancer cachexia is a major cause of patient morbidity and mortality, with no efficacious treatment or management strategy. Despite cachexia sharing pathophysiological features with a number of neuromuscular wasting conditions, including age-related sarcopenia, the mechanisms underlying cachexia remain poorly understood. Studies of related conditions suggest that pathological targeting of the neuromuscular junction (NMJ) may play a key role in cachexia, but this has yet to be investigated in human patients. Here, high-resolution morphological analyses were undertaken on NMJs of rectus abdominis obtained from patients undergoing upper GI cancer surgery compared with controls (N = 30; n = 1,165 NMJs). Cancer patients included those with cachexia and weight-stable disease. Despite the low skeletal muscle index and significant muscle fiber atrophy (P < 0.0001) in patients with cachexia, NMJ morphology was fully conserved. No significant differences were observed in any of the pre- and postsynaptic variables measured. We conclude that NMJs remain structurally intact in rectus abdominis in both cancer and cachexia, suggesting that denervation of skeletal muscle is not a major driver of pathogenesis. The absence of NMJ pathology is in stark contrast to what is found in related conditions, such as age-related sarcopenia, and supports the hypothesis that intrinsic changes within skeletal muscle, independent of any changes in motor neurons, represent the primary locus of neuromuscular pathology in cancer cachexia.

Decreased placental and muscular expression of the fibroblast growth factor 19 in gestational diabetes mellitus.

AIMS/INTRODUCTION: Fibroblast growth factor (FGF)19 has been shown to improve glycemic homeostasis and lipid metabolism in animal models. In humans, decreased FGF19 level has been described in diabetes. The present study aimed to investigate the expression of FGF19 in gestational diabetes mellitus (GDM) patients. MATERIALS AND METHODS: Samples for measurement were obtained from 20 women with GDM and 25 healthy controls. The messenger ribonucleic acid (mRNA) and protein expression levels of FGF19, FGF21 and co-receptor ß-klotho (KLB) in the placenta, rectus muscle and subcutaneous fat tissues were quantified by real-time quantitative polymerase chain reaction, western blot and immunohistochemistry, respectively. RESULTS: Women with GDM had significantly lower mRNA and protein expressions of FGF19 than control women in the placenta (mRNA 0.33 ± 0.05 vs 0.72 ± 0.09; protein 0.34 ± 0.13 vs 0.85 ± 0.20) and rectus muscle (mRNA 0.83 ± 0.11 vs 1.28 ± 0.19; protein 0.78 ± 0.24 vs 1.23 ± 0.39). However, there were no significant differences between GDM women and controls with respect to the expression levels of FGF21 and ß-klotho in the placenta and rectus muscle. There were almost no detectable FGF19 and FGF21 expressions in subcutaneous fat tissue. Furthermore, ß-klotho expression levels were not different between the GDM and control group in subcutaneous fat. CONCLUSIONS: FGF19 expressions are decreased in the placenta and rectus muscle of women with GDM. This might contribute to the pathophysiology or development of GDM.

The relationship between muscle protein content and CT-derived muscle radio-density in patients with upper GI cancer.

INTRODUCTION: Cancer cachexia is a multifactorial syndrome characterized by skeletal muscle loss. Cross-sectional analysis of CT scans is a recognized research method for assessing skeletal muscle volume. However, little is known about the relationship between CT-derived estimates of muscle radio-density (SMD) and muscle protein content. We assessed the relationship between CT-derived body composition variables and the protein content of muscle biopsies from cancer patients. METHODS: Rectus abdominis biopsies from cancer patients (n = 32) were analysed for protein content and correlated with phenotypic data gathered using CT body composition software. RESULTS: Skeletal muscle protein content varied widely between patients (median µg/mg wet weight = 89.3, range 70-141). There was a weak positive correlation between muscle protein content and SMD (r = 0.406, p = 0.021), and a weak positive correlation between protein content and percentage weight change (r = 0.416, p = 0.018). CONCLUSION: The protein content of skeletal muscle varies widely in cancer patients and cannot be accurately predicted by CT-derived muscle radio-density.

Increased Methylene Diphosphonate Uptake in the Rectus Abdominis After Strenuous Exercise.

A 28-year-old man with papillary thyroid cancer underwent bone scintigraphy to assess possible osseous metastasis. He had vigorous workouts 5 days prior, which involved pectorals, rectus abdominis, quadriceps, and glutei. However, the images only showed increased activity in the rectus abdominis, whereas other involved muscles had no obvious uptake. No lesion in the bone was identified.

Toll-like receptor 4 signalling mediates inflammation in skeletal muscle of patients with chronic kidney disease.

BACKGROUND: Inflammation in skeletal muscle is implicated in the pathogenesis of insulin resistance and cachexia but why uremia up-regulates pro-inflammatory cytokines is unknown. Toll-like receptors (TLRs) regulate locally the innate immune responses, but it is unknown whether in chronic kidney disease (CKD) TLR4 muscle signalling is altered. The aim of the study is to investigate whether in CKD muscle, TLRs had abnormal function and may be involved in transcription of pro-inflammatory cytokine. METHODS: TLR4, phospho-p65, phospho-ikBα, tumour necrosis factor (TNF)-α, phospho p38, Murf 1, and atrogin were studied in skeletal muscle from nondiabetic CKD stage 5 patients (n = 29) and controls (n = 14) by immunohistochemistry, western blot, and RT-PCR. Muscle cell cultures (C2C12) exposed to uremic serum were employed to study TLR4 expression (western blot and RT-PCR) and TLR-driven signalling. TLR4 signalling was abrogated by a small molecule chemical inhibitor or TLR4 siRNA. Phospho AKT and phospho p38 were evaluated by western blot. RESULTS: CKD subjects had elevated TLR4 gene and protein expression. Also expression of NFkB, p38 MAPK and the NFkB-regulated gene TNF-α was increased. At multivariate analysis, TLR4 protein content was predicted by eGFR and Subjective Global Assessment, suggesting that the progressive decline in renal function and wasting mediate TLR4 activation. In C2C12, uremic serum increased TLR4 as well as TNF-α and down-regulated pAkt. These effects were prevented by blockade of TLR4. CONCLUSIONS: CKD promotes muscle inflammation through an up-regulation of TLR4, which may activate downward inflammatory signals such as TNF-α and NFkB-regulated genes.

Premorbid obesity, but not nutrition, prevents critical illness-induced muscle wasting and weakness.

BACKGROUND: The 'obesity paradox' of critical illness refers to better survival with a higher body mass index. We hypothesized that fat mobilized from excess adipose tissue during critical illness provides energy more efficiently than exogenous macronutrients and could prevent lean tissue wasting. METHODS: In lean and premorbidly obese mice, the effect of 5 days of sepsis-induced critical illness on body weight and composition, muscle wasting, and weakness was assessed, each with fasting and parenteral feeding. Also, in lean and overweight/obese prolonged critically ill patients, markers of muscle wasting and weakness were compared. RESULTS: In mice, sepsis reduced body weight similarly in the lean and obese, but in the obese with more fat loss and less loss of muscle mass, better preservation of myofibre size and muscle force, and less loss of ectopic lipids, irrespective of administered feeding. These differences between lean and obese septic mice coincided with signs of more effective hepatic fatty acid and glycerol metabolism, and ketogenesis in the obese. Also in humans, better preservation of myofibre size and muscle strength was observed in overweight/obese compared with lean prolonged critically ill patients. CONCLUSIONS: During critical illness premorbid obesity, but not nutrition, optimized utilization of stored lipids and attenuated muscle wasting and weakness.

Abdominal Wall Endometriosis: Myofibroblasts as a Possible Evidence of Metaplasia: A Case Report.

In this study, we report about a patient with extra-uterine endometriosis (EM) in the abdominal wall muscle with evident metaplasia based on the abundant alpha smooth muscle actin (ASMA)-expressing myofibroblasts. Laparotomy excision of the abdominal wall EM was done following ultrasonographic evidence of a hypodense swelling in the right rectus abdominis, which was confirmed by MRI. Immunohistochemistry staining for ASMA and collagen I was done, with the results confirming that endometriotic stromal cells expressed both. Anterior abdominal wall endometriosis was suspected because of the patient's history of recurrent EM combined with the cyclic nature of symptoms. MRI is useful in determining the extent of the disease. In case of persisting symptoms even under hormonal treatment, surgical excision is mandatory. The expression of both ASMA and collagen I in and around EM lesions supports the notion of the metaplastic process in the course of disease development.

Congenital Partial Absence of Trapezius with Variant Pattern of Rectus Sheath.

Musculocutaneous pedicled/free flaps are an essential prerequisite for reconstructive surgery. Amongst the trunk muscles commonly harvested for flaps, the trapezius and rectus abdominis provide satisfactory coverage for cranial and trunk defects. unilateral/bilateral or partial congenital absence of trapezius muscle is well documented and may result in muscular imbalances compromising posture and limb movements. During routine cadaveric dissection, we encountered a case of bilateral partial absence of occipital part of the trapezius muscle. Concurrently, the ventral abdominal musculature displayed the aponeurosis of transversus abdominis muscle solely forming the posterior wall of the rectus sheath. These conjointly occurring anomalies advocate a compensatory strengthening of the anterior wall of rectus sheath in response to the congenital absence of occipital part of the trapezius, probably to counteract the postural instability. The present study focuses on recognition of compensatory mechanisms resulting from congenital variations as identification of such processes may prevent chronic debilitating conditions.

Impaired mitochondrial oxidative phosphorylation and supercomplex assembly in rectus abdominis muscle of diabetic obese individuals.

AIMS/HYPOTHESIS: Skeletal muscle mitochondrial dysfunction has been documented in patients with type 2 diabetes mellitus; however, specific respiratory defects and their mechanisms are poorly understood. The aim of the current study was to examine oxidative phosphorylation and electron transport chain (ETC) supercomplex assembly in rectus abdominis muscles of 10 obese diabetic and 10 obese non-diabetic individuals. METHODS: Twenty obese women undergoing Roux-en-Y gastric bypass surgery were recruited for this study. Muscle samples were obtained intraoperatively and subdivided for multiple analyses, including high-resolution respirometry and assessment of supercomplex assembly. Clinical data obtained from referring physicians were correlated with laboratory findings. RESULTS: Participants in both groups were of a similar age, weight and BMI. Mitochondrial respiration rates were markedly reduced in diabetic vs non-diabetic patients. This defect was observed during maximal ADP-stimulated respiration in the presence of complex I-linked substrates and complex I- and II-linked substrates, and during maximal uncoupled respiration. There were no differences in fatty acid (octanoyl carnitine) supported respiration, leak respiration or isolated activity of cytochrome c oxidase. Intriguingly, significant correlations were found between glycated haemoglobin (HbA1c) levels and maximal respiration or respiration supported by complex I, complex I and II or fatty acid. In the muscle of diabetic patients, blue native gel electrophoresis revealed a striking decrease in complex I, III and IV containing ETC supercomplexes. CONCLUSIONS/INTERPRETATION: These findings support the hypothesis that ETC supercomplex assembly may be an important underlying mechanism of muscle mitochondrial dysfunction in type 2 diabetes mellitus.

The effect of age and medical comorbidities on in vitro myoblast expansion in women with and without pelvic organ prolapse.

INTRODUCTION: This is an observational study is designed to assess the influence of age, prolapse and medical co-morbidities on myogenic stem cells growth in-vitro. METHODS: A biopsy of the rectus abdominus muscle was obtained during surgery in patients with and without pelvic organ prolapse (POP). Nuclei number and fiber count were correlated with patient's age, presence of POP, and medical comorbidities. Efficiency of expansion of myogenic stem cells in vitro was calculated. The percentage of Pax7-, MyoD-, and desmin-positive cells was correlated with age, POP status, and medical comorbidities. RESULTS: A total of 17 specimens were obtained; 13 specimens were available for histologic analysis. There was no correlation between patient's age, POP status or medical comorbidities and nuclei or fiber count, growth rate, or the percentage of Pax7- and MyoD-positive cells. Patients with 2 to 4 medical comorbidities were noted to have a significantly lower percentage of desmin-positive cells. Specimens with a higher nuclear count had significantly better cellular expansion. Data were analyzed using Kruskal-Wallis or Wilcoxon rank sum statistics. CONCLUSIONS: Multiple medical comorbidities but not patient's age or POP status influenced in vitro myogenic stem cell growth. These data suggest that patients with advancing age or POP may be acceptable autologous donors if treatment of urinary or anal incontinence requires myoblast transplantation.

Moderate intra-abdominal hypertension leads to anaerobic metabolism in the rectus abdominis muscle tissue of critically ill patients: a prospective observational study.

PURPOSE: We hypothesize that intra-abdominal hypertension (IAH) is associated with the presence of anaerobic metabolism in the abdominal rectus muscle (RAM) tissue of critically ill patients. METHODS: We included 10 adult, critically ill patients with intra-abdominal pressure (IAP) above 12 mmHg. Microdialysis catheters (CMA 60) were inserted into the RAM tissue. The samples were collected up to 72 hours after enrollment. RESULTS: The patients' median (IQR) APACHE II at inclusion was 29 (21-37); 7 patients were in shock. IAP was 14.5 (12.5-17.8) mmHg at baseline and decreased significantly over time, concomitantly with arterial lactate and vasopressors requirements. The tissue lactate-to-pyruvate (L/P) ratio was 49 (36-54) at the beginning of the study and decreased significantly throughout the study. Additionally, the tissue lactate, lactate-to-glucose (L/G) ratio, and glutamate concentrations changed significantly during the study. The correlation analysis showed that lower levels of pyruvate and glycerol were associated with higher MAP and abdominal perfusion pressures (APP) and that higher levels of glutamate were correlated to elevated IAP. CONCLUSIONS: Moderate IAH leads to RAM tissue anaerobic metabolism suggestive for hypoperfusion in critically ill patients. Correlation analysis supports the concept of using APP as the primary endpoint of resuscitation in addition to MAP and IAP.

[The role of Foxo1 and ubiquitin-proteasome system markers in muscle atrophy caused by chronic kidney disease].

OBJECTIVE: To identity whether there is muscle atrophy phenomenon in end-stage kidney disease patients and to detect the level of transcription factor Foxo1 and the activity of ubiquitin-proteasome system. METHODS: Twenty-two patients in chronic kidney disease (CKD) stage 5 were selected and their mean muscle cross sectional area was measured. mRNA and protein levels of Foxo1, Atrogin-1, MuRF1 in rectus abdominis biopsies obtained from consecutive patients were detected. Control biopsies were obtained from 8 healthy subjects during elective surgery for abdominal wall hernias and 6 subjects during elective surgery for adenomyosis. RESULTS: Compared with the control group, cross sectional area of muscle fibers decreased and the transcription and protein levels of Foxo1, Atrogin-1, MuRF1 were upregulated in CKD group (P < 0.05). Protein level of p-Foxo1 decreased in CKD group (P < 0.05). CONCLUSION: There exist muscle atrophy phenomenon in CKD patients, which may associate with the upregulation of Foxo1 and activation of ubiquitin-proteasome system.

Muscle glucose metabolism in chronic obstructive pulmonary disease patients.

INTRODUCTION: Muscle dysfunction is one of the most extensively studied manifestations of COPD. Metabolic changes in muscle are difficult to study in vivo, due to the lack of non-invasive techniques. Our aim was to evaluate metabolic activity simultaneously in various muscle groups in COPD patients. METHODS: Thirty-nine COPD patients and 21 controls with normal lung function, due to undergo computed axial and positron emission tomography for staging of localized lung lesions were included. After administration of 18-fluordeoxyglucose, images of 2 respiratory muscles (costal and crural diaphragm, and rectus abdominus) and 2 peripheral muscles (brachial biceps and quadriceps) were obtained, using the standard uptake value as the glucose metabolism index. RESULTS: Standard uptake value was higher in both portions of the diaphragm than in the other muscles of all subjects. Moreover, the crural diaphragm and rectus abdominus showed greater activity in COPD patients than in the controls (1.8±0.7 vs 1.4±0.8; and 0.78±0.2 vs 0.58±0.1; respectively, P<.05). A similar trend was observed with the quadriceps. In COPD patients, uptake in the two respiratory muscles and the quadriceps correlated directly with air trapping (r=0.388, 0.427 and 0.361, respectively, P<.05). CONCLUSIONS: There is greater glucose uptake and metabolism in the human diaphragm compared to other muscles when the subject is at rest. Increased glucose metabolism in the respiratory muscles (with a similar trend in their quadriceps) of COPD patients is confirmed quantitatively, and is directly related to the mechanical loads confronted.

Effects of sample size on differential gene expression, rank order and prediction accuracy of a gene signature.

Top differentially expressed gene lists are often inconsistent between studies and it has been suggested that small sample sizes contribute to lack of reproducibility and poor prediction accuracy in discriminative models. We considered sex differences (69♂, 65 ♀) in 134 human skeletal muscle biopsies using DNA microarray. The full dataset and subsamples (n = 10 (5 ♂, 5 ♀) to n = 120 (60 ♂, 60 ♀)) thereof were used to assess the effect of sample size on the differential expression of single genes, gene rank order and prediction accuracy. Using our full dataset (n = 134), we identified 717 differentially expressed transcripts (p<0.0001) and we were able predict sex with ~90% accuracy, both within our dataset and on external datasets. Both p-values and rank order of top differentially expressed genes became more variable using smaller subsamples. For example, at n = 10 (5 ♂, 5 ♀), no gene was considered differentially expressed at p<0.0001 and prediction accuracy was ~50% (no better than chance). We found that sample size clearly affects microarray analysis results; small sample sizes result in unstable gene lists and poor prediction accuracy. We anticipate this will apply to other phenotypes, in addition to sex.

Pathological effects of processed bovine pericardial scaffolds--a comparative in vivo evaluation.

The objective of the present study was to assess the biocompatibility and regenerative potential of decellularized bovine pericardial scaffold in comparison with glutaraldehyde-treated and fresh bovine pericardial implants using short-term intramuscular implantation testing in a rat model. The inflammatory and immune responses were assessed using histopathological examination, special stains for connective tissue, histomorphometric evaluation, and immunohistochemistry. The decellularized pericardium showed an active tissue remodeling response with complete cellular invasion, minimum connective tissue encapsulation, extensive fibrovascular tissue formation, and collagen deposition. On the contrary, the glutaraldehyde-treated pericardial implants showed incomplete degradation and cellular invasion, while the fresh pericardial implants elicited a severe foreign body reaction. The results of immunohistochemical staining revealed a minimum T helper (CD4+) lymphocyte response in decellularized pericardial implants compared with its glutaraldehyde-treated and fresh counterparts. The decellularized bovine pericardium was better accepted as a prosthetic scaffold, which permitted maximum collagen deposition and active tissue remodeling by invading host cells and showed good tissue integration in vivo compared with glutaraldehyde-treated and fresh/untreated pericardium.

MuRF-1 and p-GSK3ß expression in muscle atrophy of cirrhosis.

BACKGROUND: Chronic diseases, including cirrhosis, are often accompanied by protein-energy malnutrition and muscle loss, which in turn negatively affect quality of life, morbidity and mortality. Unlike other chronic conditions, few data are available on the molecular mechanisms underlying muscle wasting in this clinical setting. AIMS: To assess mechanisms of muscle atrophy in patients with cirrhosis. METHODS: Nutritional [subjective global assessment (SGA) and anthropometry] and metabolic assessment was performed in 30 cirrhotic patients awaiting liver transplantation. Rectus abdominis biopsies were obtained intraoperatively in 22 cirrhotic patients and in 10 well-nourished subjects undergoing elective surgery for non-neoplastic disease, as a control group. Total RNA was extracted and mRNA for atrogenes (MuRF-1, Atrogin-1/MAFbx), myostatin (MSTN), GSK3ß and IGF-1 was assayed. RESULTS: A total of 50% of cirrhotic patients were malnourished based on SGA, while 53% were muscle-depleted according to mid-arm muscle area (MAMA<5th percentile). MuRF-1 RNA expression was significantly increased in malnourished cirrhotic patients (SGA-B/C) vs. well-nourished patients (SGA-A) (P = 0.01). The phosphorylation of GSK3ß was up-regulated in cirrhotic patients with hepatocellular carcinoma (HCC) vs. patients without tumour (P < 0.05). CONCLUSIONS: Muscle loss is frequently found in end-stage liver disease patients. Molecular factors pertaining to signalling pathways known to be involved in the regulation of muscle mass are altered during cirrhosis and HCC.