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.

Intestinal dysbiosis contributes to the delayed gastrointestinal transit in high-fat diet fed mice.

BACKGROUND & AIMS: High-fat diet (HFD) feeding is associated with gastrointestinal motility disorders. We recently reported delayed colonic motility in mice fed a HFD mice for 11 weeks. In this study, we investigated the contributing role of gut microbiota in HFD-induced gut dysmotility. METHODS: Male C57BL/6 mice were fed a HFD (60% kcal fat) or a regular/control diet (RD) (18% kcal fat) for 13 weeks. Serum and fecal endotoxin levels were measured, and relative amounts of specific gut bacteria in the feces assessed by real time PCR. Intestinal transit was measured by fluorescent-labeled marker and bead expulsion test. Enteric neurons were assessed by immunostaining. Oligofructose (OFS) supplementation with RD or HFD for 5 weeks was also studied. In vitro studies were performed using primary enteric neurons and an enteric neuronal cell line. RESULTS: HFD-fed mice had reduced numbers of enteric nitrergic neurons and exhibited delayed gastrointestinal transit compared to RD-fed mice. HFD-fed mice had higher fecal Firmicutes and Escherichia coli and lower Bacteroidetes compared to RD-fed mice. OFS supplementation protected against enteric nitrergic neurons loss in HFD-fed mice, and improved intestinal transit time. OFS supplementation resulted in a reductions in fecal Firmicutes and Escherichia coli and serum endotoxin levels. In vitro, palmitate activation of TLR4 induced enteric neuronal apoptosis in a p-JNK1 dependent pathway. This apoptosis was prevented by a JNK inhibitor and in neurons from TLR4-/- mice. CONCLUSIONS: Together our data suggest that intestinal dysbiosis in HFD fed mice contribute to the delayed intestinal motility by inducing a TLR4-dependant neuronal loss. Manipulation of gut microbiota with OFS improved intestinal motility in HFD mice.

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.

Intermittent voiding per urethra as an indicator of cutaneous vesicostomy malfunction.

PURPOSE: To present a new approach for management of cutaneous vesicostomy (CV) prolapse, with special emphasis on normal appearing vesicostomy may be malfunctioning. To introduce the application of temporary stoma-free drainage as a diagnostic and therapeutic tool. MATERIALS AND METHODS: From December 2000 to September 2006, 66 children (61 males and 5 females) with CV were studied. The mean age at vesicostomy was 7 months (range 1-30), and the main underlying disease was posterior urethral valves (in 45 children, 68%). Indications for CV included significant hydroureteronephrosis (HUN) and recurrent urinary tract infection. Patients were followed up for complications and were treated based on our institutional approach. All patients with persistent upper tract dilatation and micturition per urethra underwent temporary bladder (via stoma) free drainage. Patients with stomal stenosis were managed either by a revision surgery or by simple dilatation and intermittent catheterization. Purse string suturing was applied in mucosal prolapses as the first choice. RESULTS: The complications were observed in 21 patients (31%), including twelve stomal stenosis, nine severe mucosal prolapses, and two recurrent urinary infections. HUN and significant voiding per urethra persisted following initial CV in 19 out of 66 patients (29%), eleven of which having normal appearing CVs. Seventeen of these patients were managed by temporary stoma-free drainage (accompanied by purse string suturing in mucosal prolapse), and two patients with severe stenosis underwent surgical revision. Temporary stoma-free drainage improved HUN in 94% of patients (16 of 17). CONCLUSIONS: Voiding per urethra is an indicator of CV malfunction, and temporary stoma-free drainage can be a diagnostic and therapeutic option in such children. A seemingly open CV may still be malfunctioning, and ureterovesical or intravesical obstructions should be considered if HUN does not improve following temporary stoma-free drainage.

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.

Na(+)-H+ exchange inhibition attenuates ischemic injury in rat random pattern skin flap: the role of mitochondrial ATP-sensitive potassium channels.

Necrosis of distal portion of skin flaps due to ischemia still remains a problem in plastic surgery. Following ischemia, a cascade of deleterious events including over-activity of Na(+)-H(+) Exchanger (NHE) takes place. In present study we evaluated the effect of the potent NHE inhibitor, 5-(N-ethyl-N-isopropyl) amiloride (EIPA) on ischemic tissue injury in a skin flap model, and investigated the role of mitochondrial ATP-sensitive K(+) channels (K(ATP)) in this phenomenon. Seventy-eight rats were randomly divided into thirteen treatment groups (6 rats each). Four groups received different doses of EIPA in the flap. EIPA/GLY group received an effective dose of a K(ATP) channel blocker, glibenclamide (GLY, 0.3mg/kg) intraperitoneally (i.p.) 30 min before raising the flap, and a local effective dose of EIPA (0.1mM) immediately after raising the flap. EIPA/diazoxide group (EIPA/DIA) received a sub-effective dose of diazoxide (7.5mg/kg i.p.) 30 min before raising the flap and a local sub-effective dose of EIPA (0.075 mM). EIPA 0.1 and 0.2mM significantly increased flap survival area compared to control group (56.01 ± 6.1%, P<0.001). The protective effect of EIPA (0.1mM) was abolished by administration of glibenclamide (0.3mg/kg i.p.). Co-administration of a sub-effective dose of EIPA (0.075 mM), with a sub-effective dose of diazoxide (7.5mg/kg i.p.) significantly improved flap survival (P<0.05). We demonstrated that the NHE inhibitor, EIPA can increase random pattern skin flap survival. Administration of diazoxide potentiates this effect, while glibenclamide abolishes that, implicating that the protective effect of EIPA is mediated through mitochondrial-K(ATP) channels.

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.

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.

Protective effects of acute lithium preconditioning against renal ischemia/reperfusion injury in rat: role of nitric oxide and cyclooxygenase systems.

Delayed graft function secondary to ischemia/reperfusion injury has been shown to be associated with increased rate of allograft failure following kidney transplantation. Previously, we have shown that chronic lithium pretreatment protects kidney against ischemia/reperfusion injury. In the present study we aimed to examine the effects of acute lithium administration on the renal ischemia/reperfusion injury in rat. Ischemia/reperfusion injury was induced by clamping left renal pedicle for 60 min, two weeks after right nephrectomy. The mechanism of lithium-mediated renoprotection was explored by combined use of lithium and nitro-l-arginine methyl ester (L-NAME) (non-selective nitric oxide synthase inhibitor) and/or indomethacin (non-selective cyclooxygenase pathway inhibitor). Lithium-treated animals were given 40 mg/kg lithium chloride intraperitoneally, 30 min before ischemia. To investigate the role of nitric oxide and cyclooxygenase pathways in renoprotective effect of lithium, L-NAME and/or indomethacin were administered before lithium injection. Serum creatinine, blood urea nitrogen, and renal histology were assessed after 24h of reperfusion. Lithium preconditioning significantly reduced creatinine and blood urea nitrogen (P<0.001) and improved renal histology. Administration of L-NAME completely reversed renoprotective effect of lithium. In contrast indomethacin significantly potentiated the lithium renoprotection. Moreover, co-administration of L-NAME and indomethacin completely abolished the protective effects of lithium. The results show that a single dose of lithium significantly improves renal function following ischemia/reperfusion injury. In conclusion, the ability of lithium to enhance renal tissue tolerance against ischemia/reperfusion injury suggests a potential clinical application in the setting of kidney transplantation. However, more detailed investigations are required before any definite conclusion.

Miniature pyeloplasty as a minimally invasive surgery with less than 1 day admission in infants.

PURPOSE: Open dismembered pyeloplasty is usually performed through flank, anterior subcostal or posterior lumbotomy incisions. These incisions are cosmetically less acceptable and may produce significant postoperative pain. We present the smallest incision for open pyeloplasty, called a 'miniature pyeloplasty'. The aim of this study was to reduce hospital stay and postoperative pain, along with enhanced cosmetic results. PATIENTS AND METHOD: 373 infants (mean age 4 months) with hugely dilated pelvises underwent the miniature pyeloplasty. The exact site of incision was determined by intraoperative renal ultrasonography and palpation. A muscle-splitting incision was made in the most dependent part of the lower quadrant. After meticulous dissection of the ureteropelvic junction component, the affected section was pulled out and underwent classic dismembered pyeloplasty without renal pelvis reduction. All children had long-duration stented anastomoses. Surgical incision size, operative time, hospital stay, postoperative analgesic use and complication rate were recorded. RESULTS: The operation was successful in all patients. The mean operative time was 53 min (range 43-75) and patients were discharged after 18 ± 3 (mean ± SD) h. Incision size ranged from 11 to 15 mm (mean 13). No narcotic analgesic was required postoperatively and there were no major complications during follow up. CONCLUSIONS: Miniature pyeloplasty is a safe and successful technique for ureteropelvic junction obstruction that avoids long operative time with negligible postoperative pain compared to the classic open pyeloplasty in infants. The exact incision site must be reconfirmed intraoperatively by physical examination or renal ultrasonography.

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.

Chronic lithium treatment protects the rat kidney against ischemia/reperfusion injury: the role of nitric oxide and cyclooxygenase pathways.

Ischemia/reperfusion injury is a major problem in renal transplantation. Several evidences represent lithium preconditioning effect against ischemia/reperfusion injury in various tissues. In this study our aim was to investigate the protective effect of chronic lithium administration on renal ischemia/reperfusion injury in rats. Ischemia/reperfusion injury was induced by clamping left renal pedicle for 60 min, 2 weeks after right nephrectomy. Lithium-treated animals received lithium-chloride in drinking water for 30days. In order to investigate the role of nitric oxide (NO) and cyclooxygenase (COX) pathways in renoprotective effect of lithium, N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME, NO synthase inhibitor) and indomethacin (COX inhibitor) were used, respectively. Serum creatinine, blood urea nitrogen and renal histology were assessed 24h after inducing ischemia/reperfusion injury. Dimercaptosuccinic acid scan was also performed 48 h following operation. Chronic lithium treatment in ischemia/reperfusion injury groups significantly decreased creatinine (1.09±0.16 mg/dl), blood urea nitrogen (59.0±13.38 mg/dl), histological damage (7.83%±4.02%) and improved cortical function compared with non-lithium treated animals (4.45±0.44, 176.66±12.24 mg/dl and 83.5%±3.5%, respectively) (P<0.001). Either L-NAME or indomethacin administration partially reversed the protective effect of lithium, while simultaneous blockade of NO and COX pathways completely abolished lithium renoprotective effect. Our results indicate that lithium ameliorates renal ischemia/reperfusion injury through NO and/or COX pathways. We propose that lithium pre-treatment as a simple and practical intervention to boost the renal viability and function after ischemia/reperfusion injury may be promising in the setting of transplantation.

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.

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.

Cholestasis induced nephrotoxicity: the role of endogenous opioids.

AIMS: Elevated levels of endogenous opioids play a pivotal role in several deleterious consequences of cholestasis. Renal dysfunction occurs in cholestasis but its exact mechanism is still unknown. In this study, we investigated the role of endogenous opioids in cholestasis induced nephrotoxicity. MAIN METHODS: Thirty-five rats were divided into five groups. In groups 1 and 2 BDL rats received either daily subcutaneous 20mg/kg of naltrexone or its vehicle, for 7days after BDL. In groups 3 and 4, BDL or Sham rats received no injections. In group 5, normal rats received subcutaneous injections of 20mg/kg/day of naltrexone for 7days. At the 7th day, 24h urine was collected to measure urinary N-acetyl-beta-D-glucosaminidase (NAG) as an early marker of renal tubular injury. Kidney samples were then collected for light and electron microscopic studies. KEY FINDINGS: BDL significantly increased NAG activity compared to sham groups. Naltrexone significantly reversed NAG activity to normal levels in BDL animals. Naltrexone treatment in BDL animals also significantly reversed ALT and AST to their normal levels. In light and electron microscopic studies, there were significant structural alterations in BDL samples, which were mostly prevented in naltrexone treated BDL animals. SIGNIFICANCE: Significant changes in urinary NAG activity and renal morphology of cholestatic rats were reversed by naltrexone treatment. These results suggest a possible role for endogenous opioids in inducing cholestatic nephrotoxicity.

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.

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.