Western diet induces colonic nitrergic myenteric neuropathy and dysmotility in mice via saturated fatty acid- and lipopolysaccharide-induced TLR4 signalling.

KEY POINTS: A high-fat diet (60% kcal from fat) is associated with motility disorders inducing constipation and loss of nitrergic myenteric neurons in the proximal colon. Gut microbiota dysbiosis, which occurs in response to HFD, contributes to endotoxaemia. High levels of lipopolysaccharide lead to apoptosis in cultured myenteric neurons that express Toll-like receptor 4 (TLR4). Consumption of a Western diet (WD) (35% kcal from fat) for 6 weeks leads to gut microbiota dysbiosis associated with altered bacterial metabolites and increased levels of plasma free fatty acids. These disorders precede the nitrergic myenteric cell loss observed in the proximal colon. Mice lacking TLR4 did not exhibit WD-induced myenteric cell loss and dysmotility. Lipopolysaccharide-induced in vitro enteric neurodegeneration requires the presence of palmitate and may be a result of enhanced NO production. The present study highlights the critical role of plasma saturated free fatty acids that are abundant in the WD with respect to driving enteric neuropathy and colonic dysmotility. ABSTRACT: The consumption of a high-fat diet (HFD) is associated with myenteric neurodegeneration, which in turn is associated with delayed colonic transit and constipation. We examined the hypothesis that an inherent increase in plasma free fatty acids (FFA) in the HFD together with an HFD-induced alteration in gut microbiota contributes to the pathophysiology of these disorders. C57BL/6 mice were fed a Western diet (WD) (35% kcal from fat enriched in palmitate) or a purified regular diet (16.9% kcal from fat) for 3, 6, 9 and 12 weeks. Gut microbiota dysbiosis was investigated by fecal lipopolysaccharide (LPS) measurement and metabolomics (linear trap quadrupole-Fourier transform mass spectrometer) analysis. Plasma FFA and LPS levels were assessed, in addition to colonic and ileal nitrergic myenteric neuron quantifications and motility. Compared to regular diet-fed control mice, WD-fed mice gained significantly more weight without blood glucose alteration. Dysbiosis was exhibited after 6 weeks of feeding, as reflected by increased fecal LPS and bacterial metabolites and concomitant higher plasma FFA. The numbers of nitrergic myenteric neurons were reduced in the proximal colon after 9 and 12 weeks of WD and this was also associated with delayed colonic transit. WD-fed Toll-like receptor 4 (TLR4)-/- mice did not exhibit myenteric cell loss or dysmotility. Finally, LPS (0.5-2 ng·ml-1 ) and palmitate (20 and 30 µm) acted synergistically to induce neuronal cell death in vitro, which was prevented by the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester. In conclusion, WD-feeding results in increased levels of FFA and microbiota that, even in absence of hyperglycaemia or overt endotoxaemia, synergistically induce TLR4-mediated neurodegeneration and dysmotility.

Glial cell line-derived neurotrophic factor protects against high-fat diet-induced hepatic steatosis by suppressing hepatic PPAR-γ expression.

Glial cell line-derived neurotrophic factor (GDNF) protects against high-fat diet (HFD)-induced hepatic steatosis in mice, however, the mechanisms involved are not known. In this study we investigated the effects of GDNF overexpression and nanoparticle delivery of GDNF in mice on hepatic steatosis and fibrosis and the expression of genes involved in the regulation of hepatic lipid uptake and de novo lipogenesis. Transgenic overexpression of GDNF in liver and other metabolically active tissues was protective against HFD-induced hepatic steatosis. Mice overexpressing GDNF had significantly reduced P62/sequestosome 1 protein levels suggestive of accelerated autophagic clearance. They also had significantly reduced peroxisome proliferator-activated receptor-γ (PPAR-γ) and CD36 gene expression and protein levels, and lower expression of mRNA coding for enzymes involved in de novo lipogenesis. GDNF-loaded nanoparticles were protective against short-term HFD-induced hepatic steatosis and attenuated liver fibrosis in mice with long-standing HFD-induced hepatic steatosis. They also suppressed the liver expression of steatosis-associated genes. In vitro, GDNF suppressed triglyceride accumulation in Hep G2 cells through enhanced p38 mitogen-activated protein kinase-dependent signaling and inhibition of PPAR-γ gene promoter activity. These results show that GDNF acts directly in the liver to protect against HFD-induced cellular stress and that GDNF may have a role in the treatment of nonalcoholic fatty liver disease.

Glial cell line-derived neurotrophic factor-induced mice liver defatting: A novel strategy to enable transplantation of steatotic livers.

Moderate macrovesicular steatosis (>30%), which is present in almost 50% of livers considered for transplantation, increases the risk of primary graft dysfunction. Our previously published data showed that glial cell line-derived neurotrophic factor (GDNF) is protective against high-fat diet (HFD)-induced hepatic steatosis in mice. Hence, we hypothesized that perfusion of steatotic livers with GDNF may reduce liver fat content before transplantation. Livers from 8 weeks of regular diet (RD) and of HFD-fed mice were perfused ex vivo for 4 hours with either vehicle, GDNF, or a previously described defatting cocktail. The liver's residual fat was quantified colorimetrically using a triglyceride (TG) assay kit and by Oil Red O (ORO) and Nile red/Hoechst staining. Liver tissue injury was assessed by using a lactate dehydrogenase (LDH) activity assay. In vitro induction of lipolysis in HepG2 cells was assessed by measuring glycerol and free fatty acid release. ORO staining showed significantly more steatosis in livers from HFD-fed mice compared with RD-fed mice (P < 0.001). HFD livers perfused with GDNF had significantly less steatosis than those not perfused (P = 0.001) or perfused with vehicle (P < 0.05). GDNF is equally effective in steatotic liver defatting compared to the defatting cocktail; however, GDNF induces less liver damage than the defatting cocktail. These observations were consistent with data obtained from assessment of liver TG content. Assessment of liver injury revealed significant hepatocyte injury in livers perfused with the control defatting cocktail but no evidence of injury in livers perfused with either GDNF or vehicle. In vitro, GDNF reduced TG accumulation in HepG2 cells and stimulated increased TG lipolysis. In conclusion, GDNF can decrease mice liver fat content to an acceptable range and could be a potential defatting agent before liver transplantation.

MicroRNA 375 mediates palmitate-induced enteric neuronal damage and high-fat diet-induced delayed intestinal transit in mice.

BACKGROUND & AIMS: A high-fat diet (HFD) can cause serious health problems, including alteration of gastrointestinal transit, the exact mechanism of which is not clear. Several microRNAs (miRNAs) are involved in energy homeostasis, lipid metabolism, and HFD-induced weight gain. We investigated the role of miRNAs in HFD-induced damage to the enteric nervous system. METHODS: Male mice were fed a HFD (60% calories from fat) or regular diets (18% calories from fat) for 11 weeks. Mice on regular diets and HFDs were given intraperitoneal injections of Mir375 inhibitor or a negative control. Body weights, food intake, stool indices, and gastrointestinal transit (following Evans blue gavage) were measured. An enteric neuronal cell line (immorto-fetal enteric neuronal) and primary enteric neurons were used for in vitro studies. RESULTS: HFD delayed intestinal transit, which was associated with increased apoptosis and loss of colonic myenteric neurons. Mice fed a low-palmitate HFD did not develop a similar phenotype. Palmitate caused apoptosis of enteric neuronal cells associated with mitochondrial dysfunction and endoplasmic reticulum stress. Palmitate significantly increased the expression of Mir375 in vitro; transfection of cells with a Mir375 inhibitor prevented the palmitate-induced enteric neuronal cell apoptosis. Mir375 expression was increased in myenteric ganglia of mice fed HFD and associated with decreased levels of Mir375 target messenger RNAs, including Pdk1. Systemic injection of a Mir375 inhibitor for 5 weeks prevented HFD-induced delay in intestinal transit and morphologic changes. CONCLUSIONS: HFDs delay colonic transit, partly by inducing apoptosis in enteric neuronal cells. This effect is mediated by Mir375 and is associated with reduced levels of Pdk1. Mir375 might be targeted to increase survival of enteric neurons and gastrointestinal motility.

Glial cell line-derived neurotrophic factor protects against high-fat diet-induced obesity.

Obesity is a growing epidemic with limited effective treatments. The neurotrophic factor glial cell line-derived neurotrophic factor (GDNF) was recently shown to enhance ß-cell mass and improve glucose control in rodents. Its role in obesity is, however, not well characterized. In this study, we investigated the ability of GDNF to protect against high-fat diet (HFD)-induced obesity. GDNF transgenic (Tg) mice that overexpress GDNF under the control of the glial fibrillary acidic protein promoter and wild-type (WT) littermates were maintained on a HFD or regular rodent diet for 11 wk, and weight gain, energy expenditure, and insulin sensitivity were monitored. Differentiated mouse brown adipocytes and 3T3-L1 white adipocytes were used to study the effects of GDNF in vitro. Tg mice resisted the HFD-induced weight gain, insulin resistance, dyslipidemia, hyperleptinemia, and hepatic steatosis seen in WT mice despite similar food intake and activity levels. They exhibited significantly (P<0.001) higher energy expenditure than WT mice and increased expression in skeletal muscle and brown adipose tissue of peroxisome proliferator activated receptor-α and ß1- and ß3-adrenergic receptor genes, which are associated with increased lipolysis and enhanced lipid ß-oxidation. In vitro, GDNF enhanced ß-adrenergic-mediated cAMP release in brown adipocytes and suppressed lipid accumulation in differentiated 3T3L-1 cells through a p38MAPK signaling pathway. Our studies demonstrate a novel role for GDNF in the regulation of high-fat diet-induced obesity through increased energy expenditure. They show that GDNF and its receptor agonists may be potential targets for the treatment or prevention of obesity.

Emerging neuropeptide targets in inflammation: NPY and VIP.

The enteric nervous system (ENS), referred to as the "second brain," comprises a vast number of neurons that form an elegant network throughout the gastrointestinal tract. Neuropeptides produced by the ENS play a crucial role in the regulation of inflammatory processes via cross talk with the enteric immune system. In addition, neuropeptides have paracrine effects on epithelial secretion, thus regulating epithelial barrier functions and thereby susceptibility to inflammation. Ultimately the inflammatory response damages the enteric neurons themselves, resulting in deregulations in circuitry and gut motility. In this review, we have emphasized the concept of neurogenic inflammation and the interaction between the enteric immune system and enteric nervous system, focusing on neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP). The alterations in the expression of NPY and VIP in inflammation and their significant roles in immunomodulation are discussed. We highlight the mechanism of action of these neuropeptides on immune cells, focusing on the key receptors as well as the intracellular signaling pathways that are activated to regulate the release of cytokines. In addition, we also examine the direct and indirect mechanisms of neuropeptide regulation of epithelial tight junctions and permeability, which are a crucial determinant of susceptibility to inflammation. Finally, we also discuss the potential of emerging neuropeptide-based therapies that utilize peptide agonists, antagonists, siRNA, oligonucleotides, and lentiviral vectors.

Hypothyroidism improves random-pattern skin flap survival in rats.

BACKGROUND: The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps. MATERIALS AND METHODS: Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 µg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent. RESULTS: Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival. CONCLUSION: This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.

The timing of established detrusor hyperreflexia in a rat model of neuropathic bladder.

BACKGROUND: Proper timing of catheter insertion and the use of a suitable surgical method are essential parts of producing rat models to evaluate neuropathic bladder following spinal cord injury (SCI). METHODS: Thirty-two female Sprague-Dawley rats were randomly allocated into four groups. Group 1 underwent surgical laminectomy using the classic method. Group 2 underwent SCI 7 d following insertion of the catheter, and group 3 underwent sham operation. For bladder catheterization, a 4.5 Fr catheter was fixed into the bladder and tunneled beneath the skin to reach out at the nape of the neck. Group 4 underwent urodynamic study via bladder catheter prior to surgery and every 10 d following the operation to determine the exact time of establishing neuropathic bladder following spinal shock. The animals' survival rate and bladder wall's histopathologic changes were assessed 30 d following the operation. RESULTS: Simultaneous suprapubic catheter placement raised the mortality rate in group 1 in comparison with group 2. Repeated urodynamic study in group 4 showed hypertonic behavior in the bladder 10 d after SCI, with significantly increased leak point pressure and bladder capacity; however, the end filling pressure and constant neuropathic bladder on cystometric indices are attained from 20 d after the operation. CONCLUSIONS: Insertion of a bladder catheter 1 wk prior to SCI provides an applicable route for repeated cystometric studies in rats. The results demonstrate that sustained bladder overactivity is established in rats 20 d after SCI and animals are ready for further experiments on neuropathic bladder dysfunction following this period.

Chronic lithium impairs skin tolerance to ischemia in random-pattern skin flap of rats.

BACKGROUND: Despite its apparent anti-apoptotic effect, lithium impairs endothelium-dependent vasorelaxation in various tissues. In this study, we assessed the effect of lithium treatment on ischemic skin flap survival and its interaction with nitric oxide pathway. MATERIALS AND METHODS: Seventy-six male Sprague-Dawley rats were randomly assigned into 13 groups. For skin flap surgery, dorsal skin flap measuring 8 × 2 cm was elevated on the midline. After local injections (if needed), the cranial pedicle was cut and flap was sutured back. Flap survival was assessed after 7 d. Animals in the chronic lithium group received lithium chloride in tap water for 4 wk preoperatively and 7 d postoperatively. Acute lithium groups received 3 nmol, 10 nmol and 3 µmol/flap lithium locally. In another experiment, interaction with nitric oxide synthase inhibitor L-NAME as well as nitric oxide precursor L-arginine was studied, and the effect of ischemic preconditioning on skin flap survival in lithium treated rats was investigated. RESULTS: Chronic lithium group had mean flap survival value of 32.6% ± 5.2% (mean ± SD), which was significantly lower than normal subjects (52.7% ± 6.1%, P < 0.001), while acute local lithium treatment had no effect. In chronic lithium group, systemic L-NAME (10 mg/kg, 30 min before flap elevation) failed to significantly decrease the survival, while sub-effective systemic L-arginine (100 mg/kg) and ischemic preconditioning significantly increased flap survival (P < 0.001 and P < 0.01, respectively). CONCLUSIONS: We conclude that long-term lithium treatment impairs the skin tolerance to ischemia in rats, which seems to be nitric oxide mediated. This effect is prevented by ischemic preconditioning or L-arginine treatment. The results suggest that skin-involving interventions should be applied more cautiously in patients who are on lithium treatment.

Early Bone Metastases are Associated with Worse Outcomes in Metastatic Urothelial Carcinoma.

BACKGROUND: Outcomes of patients with metastatic urothelial carcinoma (mUC) with early bone metastases (eBM) vs no early bone metastases (nBM) have not thoroughly been described in the age of immuno-oncology. OBJECTIVE: To compare survival and other clinical outcomes in patients with eBM and nBM. METHODS: We used a multi-institutional database of patients with mUC treated with systemic therapy. Demographic, metastatic site, treatment patterns, and clinical outcomes were recorded. Wilcoxon rank-sum, chi-square tests were performed. Survival was estimated by Kaplan-Meier method; multivariable Cox analysis was performed. RESULTS: We identified 270 pts, 67% men, mean age 69±11 years. At metastatic diagnosis, 27% had≥1 eBM and were more likely to have de novo vs. recurrent metastases (42% vs 19%, p < 0.001). Patients with eBM had shorter overall survival (OS) vs. those with nBM, (6.1 vs 13.7 months, p < 0.0001). On multivariable analysis, eBM independently associated with higher risk of death, HR = 2.52 (95% CI: 1.75-3.63, p < 0.0001). OS was shorter for patients with eBM who received initial immune checkpoint inhibitor vs platinum-based chemotherapy, (1.6 vs 9.1 months, p = 0.02). Patients with eBM received higher opioid analgesic doses compared to patients with nBM and received quantitatively more palliative radiation. CONCLUSIONS: Patients with mUC and eBM have poorer outcomes, may benefit less from anti-PD-1/PD-L1 therapy and represent an unmet need for novel therapeutic interventions. Dedicated clinical trials, biomarker validation to assist in patient selection, as well as consensus on reporting of non-measurable disease are required.

Single incision miniature pyeloplasty and ipsilateral inguinal herniorrhaphy in infants.

PURPOSE: We describe a single incision miniature open pyeloplasty and retroperitoneal herniorrhaphy technique in infants. MATERIALS AND METHODS: A total of 22 patients with ureteropelvic junction obstruction and concomitant inguinal hernia were referred to our center between November 2003 and November 2008. A total of 13 patients (mean age 5 months) with extensively dilated pelves (extending down to pelvic cavity) and ipsilateral inguinal hernia underwent single incision miniature open pyeloplasty and retroperitoneal herniorrhaphy. All patients had decreased differential renal function (less than 40%), urinary tract infection, palpable kidney and obstructive pattern on renal diethylenetriamine pentaacetic acid scan. The incision was made along the most dependent part of the lower quadrant. After dissection of the ureteropelvic junction component, we pulled out the affected section and performed classic dismembered pyeloplasty without renal pelvis reduction. Next, we performed retroperitoneal herniorrhaphy from the same incision. Surgical incision size, operative time, hospital stay, postoperative analgesic use and complication rate were recorded for further evaluation. RESULTS: The operation was uneventful in all patients. Mean operative time was 64 minutes (range 47 to 93) and patients were discharged home after a mean +/- SD of 19 +/- 3 hours (15 to 24). Incision size was 12 to 18 mm and the incision was closed by inserting a mini Hemovac closed drain. No narcotic supplementation was required postoperatively and there were no complications during followup. CONCLUSIONS: Single incision miniature pyeloplasty with ipsilateral inguinal herniorrhaphy in an extensively dilated pelvis and ipsilateral inguinal hernia is technically feasible and safe in selected cases. The exact incision site must be reconfirmed intraoperatively by physical examination or renal ultrasound. The technique adds the advantages of minimally invasive procedures (small incision, negligible postoperative pain) to the short operative time and high success rate of the open approach.

Teapot ureterocystoplasty and ureteral Mitrofanoff channel for bilateral megaureters: technical points and surgical results of neurogenic bladder.

PURPOSE: We present the long-term results of simultaneous "teapot" ureterocystoplasty and ureteral Mitrofanoff in patients with bilateral megaureters due to neurogenic bladder, and compare urodynamic results before and after the procedure. MATERIALS AND METHODS: We treated 13 children (mean age 7.3 years) with end stage neurogenic bladder and refluxing megaureters (mean diameter 5.5 cm) with simultaneous teapot ureterocystoplasty and Mitrofanoff appendicovesicostomy between April 1995 and May 2001. The larger ureter was used for teapot bladder augmentation while keeping its distal 2 cm tubularized. The Mitrofanoff channel was then created using the opposite ureter. RESULTS: Followup ranged from 109 to 169 months (median 121). At the end of the followup period all patients were dry with clean intermittent catheterization and/or voiding. No repeat augmentation was needed and there were no bladder calculi during followup. Median postoperative bladder capacity was 430 ml (IQR 380 to 477), which was increased significantly compared to preoperative evaluations (210 ml, IQR 181 to 230, p = 0.001). During followup bladder compliance also improved significantly (p = 0.001) and serum creatinine level decreased (p = 0.021). CONCLUSIONS: Although neurogenic bladder and high grade reflux are poor prognostic factors for ureterocystoplasty, the present modification resulted in enduring bladder augmentation with no calculus formation. Bladders remained compliant with good capacity, presumably because sufficient tissue and blood supply were provided for the augmented flap.

Enteric nervous system in the small intestine: pathophysiology and clinical implications.

The digestive system is endowed with its own, local nervous system, referred to as the enteric nervous system (ENS). Given the varied functions of small intestine, its ENS has developed individualized characteristics relating to motility, secretion, digestion, and inflammation. The ENS regulates the major enteric processes such as immune response, detecting nutrients, motility, microvascular circulation, intestinal barrier function, and epithelial secretion of fluids, ions, and bioactive peptides. Remarkable progress has been made in understanding the signaling pathways in this complex system and how they work. In this article, we focus on recent advances that have led to new insights into small intestinal ENS function and the development of new therapies.

Hypospadias repair and glans augmentation using a modified Mathieu technique.

PURPOSE: To describe a modification in Mathieu (perimeatal-based flap urethroplasty) technique that incorporates glans augmentation into the procedure and is applicable for hypospadias patients with small glans and shallow urethral grooves. PATIENTS AND METHODS: Fifty-four children with primary hypospadias and small glans underwent either the new double-faced Mathieu (DF-Mathieu) technique (33 patients) or tubularized incised plate (TIP) procedure (21 patients). DF-Mathieu perimeatal-based skin flap was meant to cover the distance from urethral orifice to the tip of the glans and flip back to fill the gap between glans wings. Patients were followed up for 20 months (12-30). TIP group underwent the conventional procedure. RESULTS: The mean age in DF-Mathieu and TIP group was 43.1 and 39.8 months, respectively. Post-operative results in DF-Mathieu group revealed one urethral fistula and no urethral break down or necrosis. In TIP group, there were one glans fistula (4.7%) and one meatal stenosis (4.7%). Overall success rate was 97% in DF-Mathieu and 90.5% in TIP operation. After 6 months, all DF-Mathieu patients had slit-like meatus and their cosmetic results were satisfactory. CONCLUSION: Double-faced Mathieu technique seems applicable in patients with shallow urethral grooves when TIP procedure may increase the risk of complications. Unlike its predecessor, this technique eliminates the tension on glans wing sutures and the risk of subsequent neo-urethral break down.

Sildenafil decreased cardiac cell apoptosis in diabetic mice: reduction of oxidative stress as a possible mechanism.

Oxidative stress plays a dominant role in the pathogenesis of cardiac cell apoptosis in diabetic patients. Sildenafil has been demonstrated to have antioxidant effects. In this study, the effects of sildenafil on diabetes-induced cardiac cell apoptosis and the antioxidant status of diabetic mouse hearts were investigated. Diabetic mice showed lower body weight gains and heart weights compared with control mice, and sildenafil treatment did not increase these parameters in diabetic mice. Although apoptotic rates, caspase-3 enzyme activity, and malondialdehyde levels were significantly higher in diabetic mouse hearts than in controls, they were reduced in diabetic mice after sildenafil treatment. At the end of the first week, we observed no significant differences in antioxidant enzyme activities (CAT, GSH-Px, and SOD) in diabetic and control groups, whereas at the end of the second week of sildenafil treatment, antioxidant enzyme activities were higher in the diabetic group. In conclusion, our study indicated that sildenafil was beneficial to hearts of diabetic mice by reducing cardiac cell apoptosis, partially because of its antioxidant effects in the heart.

Chronic upregulation of the endogenous opioid system impairs the skin flap survival in rats.

Recent studies suggest a detrimental role for long-term opioid receptor stimulation in different tissues. In this study, we investigated the effect of chronic over production of endogenous opioids on skin tolerance to ischemia in a rat model of cholestasis. Sixty-six rats were randomly divided into 11 groups, 6 animals each. First group served as surgical control. In first experiment, 1, 2, and 3 weeks bile duct ligation (BDL) rats and SHAM-operated controls underwent random-pattern skin-flaps by elevating a caudally based dorsal flap (2 x 8 cm). BDL was performed by midline laparotomy and ligating the common bile duct under general anesthesia. Flap survival was assessed after 7 days (14-, 21-, and 28-day cholestatic rats, respectively). In another experiment, the first effective duration of BDL on flap survival (21 days) was chosen to receive either chronic (20 mg/kg/day) or acute (20 mg/kg, 30 minutes before flap surgery) intraperitoneal naltrexone (NTX). In the first experiment, flap survival was 56.6% +/- 2.6% (mean +/- SEM) in control group and 50.2% +/- 3.9%, 37.4% +/- 3.4%, and 35.4% +/- 6.9% in groups of 14-, 21-, and 28-day cholestatic rats, which were significantly impaired in 21- and 28-day group. In the second experiment, skin flap survival was completely reversed to their SHAM control level after chronic and acute NTX treatment (63.6% +/- 7.6% and 61.9% +/- 5.6% vs. 55.1% +/- 4.2% and 54.9% +/- 4.3%, respectively, P < 0.05). Chronic cholestasis (longer than 2 weeks) decreases the skin flap survival, which is reversed by systemic NTX. This study provides evidence, for the first time, that long-term elevated opioidergic tone impairs the skin tolerance to ischemia.

Detubularized pedicled vaginal onlay flap urethroplasty: a new method for hypospadias repair of ambiguous genitalia.

PURPOSE: We introduce the detubularized pedicled vaginal onlay flap urethroplasty for single stage repair in ambiguous genitalia with perineoscrotal hypospadias and accompanying vagina, and report its preliminary surgical outcome. MATERIALS AND METHODS: A total of 10 children with severe perineoscrotal hypospadias and genital ambiguity presenting with vagina and urogenital opening underwent single stage reconstruction with vaginal onlay urethroplasty. Through the posterior sagittal or abdominoperineal approach the vagina was released and pulled out, with care taken to preserve its vascular pedicle. Two incisions were made along the lateral margins of the vagina, reaching each other on the upper surface of the vaginal base, converting the vagina into a longitudinal flap twice as long as its original length. The vagina was then trimmed and reconfigured into a suitable sized flap to cover the urethral plate and form a neourethra with the onlay technique. The onlay-tube-onlay technique was also used in 2 patients with insufficient urethral plate. In 5 cases severe ventral chordee was also corrected concurrently with free vaginal graft to the ventral corpus cavernosum without further dorsal plication. RESULTS: The first 3 operations using the posterior sagittal approach failed due to improper surgical access, and the vagina was discarded. However, we achieved a satisfactory outcome with no failure after switching to an abdominoperineal approach. Immediate postoperative and short-term results revealed no urethrocutaneous fistula, urethral breakdown or necrosis at the distal end of the neourethra. Only 1 patient presented with severe mid shaft ring stricture, which required surgical revision. CONCLUSIONS: Incorporating the vagina of intersex patients into urethroplasty using detubularized pedicled vaginal onlay flap seems to provide a safe and practical method to treat severe hypospadias with genital ambiguity. Short-term satisfactory results are achievable by choosing the proper surgical approach and preserving the vaginal blood supply. However, longer followup in a large series of patients is needed before applying this method to clinical practice.

Sacrococcygeal pilonidal sinus treated by a new fascio-cutaneous flap.

PURPOSE: This study reported the technical details and preliminary clinical outcomes of a new fascio-cutaneous transposition flap for the surgical treatment of pilonidal sinus. METHODS: Fifty-two patients with pilonidal sinus were surgically treated. During the surgical procedure, an inferiorly pedicled, fascio-cutaneous flap with specific geometric characteristics was prepared and transposed. Postoperative pain, complications, duration of hospital stay, and time off worked were assessed. Patients were followed for eighteen months after surgery. RESULTS: The mean hospital stay was 2 days. Drains and sutures were removed after 3 and 12 days, respectively. No flap ischemia, wound dehiscence or major complications were observed. Tension on suture lines and pain after surgery were negligible. Wound infections occurred in 4 patients (7.7 percent) and were managed by removing a few sutures. Seroma was detected in 6 patients (11.5 percent). The mean time patients missed work was 7 days. No recurrence was observed during the follow-up period of 18 months. CONCLUSIONS: With no disease recurrence, minimal complication rate, time off work, and acceptable aesthetic outcome, this fascio-cutaneous transposition flap technique is a safe and effective method for surgically treating pilonidal sinus.

The effects of N-acetylcysteine on the expression of matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase-2 in hepatic fibrosis in bile duct ligated rats.

AIM: N-acetylcysteine can inhibit the formation of intracellular reactive oxygen intermediates. Cellular redox state plays a role in regulating the secretion of matrix metalloproteinase-2. We investigated the effects of N-acetylcysteine on the expression of matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase-2. METHODS: Bile duct ligated rats were used as a model of hepatic fibrosis. We compared the level of gene expression (using real-time reverse transcription polymerase chain reaction [RT-PCR]), liver function parameters, hepatic reactive oxygen production, lipid peroxidation and glutathione state in experimental groups. RESULTS: N-acetylcysteine treatment significantly improved liver function parameters including the plasma levels of aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase and bilirubin. In addition, significant improvement of glutathione state and reactive oxygen production were observed. Hepatic lipid peroxidation was reversed by N-acetylcysteine treatment. Although N-acetylcysteine treatment did not completely normalize the increased matrix metalloproteinase-2 expression, it significantly decreased its level by 65%. N-acetylcysteine treatment also significantly decreased matrix metalloproteinase-2 activity and normalized tissue inhibitor of matrix metalloproteinase-2 expression. CONCLUSION: Collectively, N-acetylcysteine showed inhibition of matrix metalloproteinase-2 expression and activity. In addition, administration of N-acetylcysteine was associated with downregulation of the expression of tissue inhibitor of matrix metalloproteinase-2 and amelioration of oxidative stress in the liver of bile duct ligated rats.

Role of nitric oxide in the anticonvulsive effect of progesterone.

Described here is an investigation of the potential interaction of the nitric oxide signaling pathway with the anticonvulsant effects of progesterone. In ovariectomized Swiss mice, the threshold for seizures induced by intravenous infusion of pentylenetetrazole was determined after treatment with progesterone (25, 50, or 75 mg/kg, given subcutaneously 6h before seizure testing) or vehicle. Progesterone induced significant anticonvulsive activity at moderate (50 mg/kg) and high (75 mg/kg) doses. This effect of progesterone was abolished by the NO precursor compound L-arginine (200 mg/kg). Moreover, when subeffective doses of progesterone (25 mg/kg) and the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (10 mg/kg) were injected, a strong anticonvulsant effect was observed. These findings suggest a potential role for NO signaling as an anticonvulsant target in females.