Implementation of an evidence-based protocol after appendectomy reduces unnecessary antibiotics

BACKGROUND

Children with acute appendicitis have historically received intravenous antibiotics before and after appendectomy, yet recent literature supports minimizing postoperative antibiotics. In this study, we examined the impact of a standardized protocol that eliminates postoperative antibiotics for nonperforated appendicitis and discontinues antibiotics at discharge for perforated appendicitis.

METHODS

A retrospective review of all pediatric patients who underwent laparoscopic appendectomy for acute appendicitis between May 2013 and March 2017 was performed. Preprotocol patients (5/1/2013-3/31/2015) were compared to postprotocol patients (5/1/2015-3/31/2017), excluding those who underwent surgery during the month of protocol introduction (4/2015). Primary outcomes were postoperative antibiotic doses for nonperforated cases and antibiotics after discharge for perforated cases. Mann-Whitney and Fisher's exact tests were performed.

RESULTS

Laparoscopic appendectomy was performed in 748 children before (PRE) and in 814 children after (POST) protocol implementation. Perforation rates were similar (POST 21.5 vs. PRE 21.8%, p=0.90). For nonperforated appendicitis, postoperative antibiotics were reduced (median 0 [IQR 0-0] vs. 3 [0-5] doses, p<0.001), and more patients were discharged less than 24 h after surgery (65.7 vs. 40.9%, p<0.001). Fewer patients with perforated appendicitis underwent PICC placement (8.6 vs. 21.0%, p=0.002), and fewer patients were prescribed antibiotics on discharge (33.7 vs. 89.0%, p<0.001). There were no differences between groups for complication, readmission, or return to ED rates.

CONCLUSION

For children with acute appendicitis, a standardized protocol can safely reduce unnecessary antibiotics and decrease length of stay. Furthermore, the judicious use of antibiotics does not increase SSI, readmission, or overall complication rates.

LEVEL OF EVIDENCE

III.

Update on pediatric rhabdomyosarcoma: A report from the APSA Cancer Committee

BACKGROUND/PURPOSE

Rhabdomyosarcoma is the most common soft tissue sarcoma in children and young adults and requires multimodality treatment. The purpose of this review is to present an update on risk stratification as well as surgical and medical management strategies in pediatric rhabdomyosarcoma.

METHODS

A comprehensive review of the current literature on pediatric rhabdomyosarcoma, including the most recent Children's Oncology Group studies and several international collaboratives, was performed by the authors and key findings were summarized in the manuscript.

RESULTS

FOXO1 fusion status is a stronger prognostic factor than histology and is now used for risk stratification in treatment protocols. For assessment of regional nodal involvement, FDG-PET-CT shows poor sensitivity and specificity to detect histologically confirmed nodal metastasis. Thus, surgical assessment of regional lymph nodes is required for rhabdomyosarcoma of the extremities or trunk as well as paratesticular rhabdomyosarcoma in patients ≥10 years of age, although adherence to surgical guidelines remains poor. Hemiscrotectomy performed for scrotal violation in paratesticular rhabdomyosarcoma has not shown an improvement in event free survival and is not recommended.

CONCLUSIONS

Surgical and medical treatment strategies for rhabdomyosarcoma in children continue to evolve. This review provides current evidence-based treatment standards with an emphasis on surgical care.

TYPE OF STUDY

Review.

LEVEL OF EVIDENCE

Level IV.

1096. Reducing Unnecessary Postoperative Antibiotic Prophylaxis

Background

National guidelines for the prevention of surgical site infections (SSI) recommend against antibiotic prophylaxis following wound closure for clean and clean-contaminated surgical procedures. Prolonged antibiotic prophylaxis can lead to antibiotic resistance and adverse drug events without reducing SSI rates. The objective was to reduce the rate of antibiotic prophylaxis following surgical incision closure for specified procedures in the Divisions of Neurosurgery (NRS), Otolaryngology (OTO), and General Surgery (GS) at Children’s Hospital of Philadelphia (CHOP).

Methods

We identified all NRS, OTO, and GS procedures conducted at CHOP from July 1, 2016 to June 20, 2017. Collaborative meetings between surgical quality improvement team leads and the antimicrobial stewardship program (ASP) were convened to identify procedures most suitable for the intervention, including Chiari decompressions and tethered cord repair (NRS); tympanoplasty and tracheostomy (OTO); and laparoscopic and thoracoscopic procedures (GS). The intervention, started in March 2018, included (1) education of surgeons on perioperative prescribing guidelines, (2) order set modification, and (3) individualized monthly audit with feedback reports of inappropriate postoperative prescribing (via email copying all surgeons within the division). We monitored rates utilizing SPC charts of postoperative antibiotic use (defined as administration within 24 hours of procedure end) and evaluated SSI rates pre and post-intervention with a Poisson regression.

Results

Following the intervention, postoperative antibiotic use reached special cause resulting in a mean decline for laparoscopy (19.6% to 11.7%), thoracoscopy (35.6% to 17.9%), tympanoplasty (90.5% to 11.4%), tethered cord repair (95% to 25.5%), and Chiari decompression (97% to 45.9%). There was no mean shift in postoperative antibiotic use for tracheostomy (25.5%). 30-day SSI rates did not change pre- and post-intervention (P = 0.36).

Conclusion

A quality improvement initiative conducted to implement national guidelines recommending against postoperative antibiotic prophylaxis showed a significant reduction in postoperative antibiotic prophylaxis without a concomitant rise in SSI rates.

Disclosures

All authors: No reported disclosures.

Maintaining Outstanding Outcomes Using Response- and Biology-Based Therapy for Intermediate-Risk Neuroblastoma: A Report From the Children's Oncology Group Study ANBL0531

PURPOSE

The primary objective of the Children's Oncology Group study ANBL0531 (ClinicalTrials.gov identifier: NCT00499616) was to reduce therapy for subsets of patients with intermediate-risk neuroblastoma using a biology- and response-based algorithm to assign treatment duration while maintaining a 3-year overall survival (OS) of 95% or more for the entire cohort.

PATIENTS AND METHODS

Children younger than age 12 years with intermediate-risk stage 2A/2B or stage 3 tumors with favorable histology; infants younger than age 365 days with stage 3, 4 or 4S disease; and toddlers from 365 to younger than 547 days with favorable histology, hyperdiploid stage 4, or unfavorable histology stage 3 tumors were eligible. Patients with MYCN-amplified tumors were excluded. Patients were assigned to initially receive two (group 2), four (group 3), or eight (group 4) cycles of chemotherapy with or without surgery on the basis of prognostic markers, including allelic status of chromosomes 1p and 11q; ultimate duration of therapy was determined by overall response.

RESULTS

Between 2007 and 2011, 404 evaluable patients were enrolled. Compared with legacy Children's Oncology Group studies, subsets of patients had a reduction in treatment. The 3-year event-free survival and OS rates were 83.2% (95% CI, 79.4% to 87.0%) and 94.9% (95% CI, 92.7% to 97.2%), respectively. Infants with stage 4 tumors with favorable biology (n = 61) had superior 3-year event-free survival compared with patients with one or more unfavorable biologic features (n = 47; 86.9% [95% CI, 78.3% to 95.4%] v 66.8% [95% CI, 53.1% to 80.6%]; P = .02), with a trend toward OS advantage (95.0% [95% CI, 89.5% to 100%] v 86.7% [95% CI, 76.6% to 96.7%], respectively; P = .08). OS for patients with localized disease was 100%.

CONCLUSION

Excellent survival was achieved with this treatment algorithm, with reduction of therapy for subsets of patients. More-effective treatment strategies still are needed for infants with unfavorable biology stage 4 disease.

Outcomes After Proton Therapy for Treatment of Pediatric High-Risk Neuroblastoma

PURPOSE

Patients with high-risk neuroblastoma (HR-NBL) require radiation to the primary tumor site and sites of persistent metastatic disease. Proton radiation therapy (PRT) may promote organ sparing, but long-term outcomes have not been studied.

METHODS AND MATERIALS

Sequential patients with HR-NBL received PRT: 2160 cGy (relative biological effectiveness) to primary tumor bed and persistent metastatic sites, with 3600 cGy (relative biological effectiveness) to gross residual disease.

RESULTS

From September 2010 through September 2015, 45 patients with HR-NBL received PRT after systemic therapy, primary tumor resection, and high-dose chemotherapy with stem cell rescue. Median age was 46 months at the time of PRT (range, 10 months to 12 years); 23 patients (51%) were male. Primary tumors were adrenal in 40 (89%); 11 (24%) received boost. Ten metastatic sites in 8 patients were radiated. Double scattered proton beams were used for 19 (42%) patients, in combination with x-rays for 2 (5%). The remaining 26 (58%) received pencil beam scanning, available since January 2013. We observed 97% freedom from primary site recurrence at 3, 4, and 5 years. Overall survival rates were 89%, 80%, and 80% and disease-free survival rates were 77%, 70%, and 70%, at 3, 4, and 5 years, respectively. With median follow-up of 48.7 months from diagnosis (range, 11-90 months) for all patients (57.4 months for those alive), 37 (82%) patients are alive, and 32 (71%) are without evidence of disease. One patient experienced locoregional recurrence; the remaining 12 (27%) experienced relapse at distant, nonradiated sites. Acute toxicities during treatment were mainly grade 1. No patient has experienced World Health Organization grade 3 or 4 long-term renal or hepatic toxicity. Pencil beam scanning plans required less planning time and resources than double scattered plans.

CONCLUSIONS

We observe excellent outcomes in patients treated with PRT for HR-NBL from 2010 through 2015, with 82% of patients alive and 97% free of primary site recurrence. No patient has experienced long-term renal or liver toxicity. This treatment maximizes normal tissue preservation and is appropriate for this patient population.

Defining Risk Factors for Chemotherapeutic Intervention in Infants With Stage 4S Neuroblastoma: A Report From Children's Oncology Group Study ANBL0531

PURPOSE

Infants with stage 4S neuroblastoma usually have favorable outcomes with observation or minimal chemotherapy. However, young infants with symptoms secondary to massive hepatomegaly or with unfavorable tumor biology are at high risk of death. Our aim was to improve outcomes for patients with symptomatic and/or unfavorable biology 4S neuroblastoma with a uniform treatment approach using a biology- and response-based algorithm.

PATIENTS AND METHODS

The subset of patients with 4S disease with MYCN-not amplified tumors with impaired or impending organ dysfunction, or with unfavorable histology and/or diploid DNA index, were eligible. Patients were assigned to receive two, four, or eight cycles of chemotherapy on the basis of histology, diploid DNA index, chromosome arm 1p or 11q loss of heterozygosity (LOH) status, and symptoms.

RESULTS

Forty-nine eligible patients were enrolled: 41 were symptomatic and 28 had unfavorable biology. Seventeen patients (symptomatic, favorable biology) were assigned two cycles, 21 patients (any unfavorable biologic feature without 1p or 11q LOH) were assigned four cycles, and 11 patients (unfavorable biology including 1p and/or 11q LOH [n = 7] or symptomatic with unknown biology [n = 4]), were assigned eight cycles. The 3-year overall survival was 81.4% ± 5.8%. Eight of nine deaths were in patients younger than 2 months of age at diagnosis (median, 9 days [range, 1 to 68 days]): five acute deaths were a result of hepatomegaly and associated toxicities; two were a result of late relapse in patients with unfavorable biology; and two were a result of treatment complications. No deaths occurred after protocol-mandated pre-emptive treatment of infants younger than 2 months with hepatomegaly, regardless of symptoms. A new scoring algorithm for emergent chemotherapy in patients with 4S disease was developed on the basis of this experience.

CONCLUSION

The outcome for 4S neuroblastoma can be improved with pre-emptive chemotherapy for evolving hepatomegaly or other baseline comorbidities in infants younger than 2 months of age.

Successful treatment of pulmonary mucormycosis in two pediatric hematopoietic stem cell transplant patients

Pulmonary mucormycosis diagnosed immediately after hematopoietic stem cell transplantation frequently portends a poor prognosis. However, here we describe two cases in children that were treated successfully to highlight the efficacy of a multidisciplinary approach. Despite diagnosis in the immediate post-transplant period and requirement for ongoing immunosuppression to prevent or treat GVHD, both are long-term survivors due to early surgical debridement with transfusion support and prompt initiation of targeted antifungal therapy. In the absence of evidence-based treatment guidelines, survival of pulmonary mucormycosis is achievable even in high-risk patients with a multidisciplinary team to guide management.

Single-site robotic-assisted laparoscopic cholecystectomy in children and adolescents: a report of 20 cases

BACKGROUND

Single-site laparoscopy is increasingly popular for straightforward operations like appendectomy. Due to limited triangulation and maneuverability, single-site cholecystectomy is riskier and more difficult. Robotics offer to make it easier and safer.

METHODS

Twenty children and adolescents underwent robotic-assisted single-site cholecystectomy at a large academic children's hospital. Patients were not randomized; patients were offered the option of robotic-assisted single-site (SSR) or standard four-incision laparoscopic (LAP) cholecystectomy. Demographics and perioperative details were compared with those of a comparable cohort who underwent LAP during the same period.

RESULTS

The two groups were similar in physical characteristics and indications for operation. The robotic operations took longer but both groups received similar PRN doses of parenteral opiates. Patients in the SSR group were all discharged on the first postoperative day. There were no major complications in either group but a slightly higher incidence of minor wound complications in the SSR group.

CONCLUSION

Robotic-assisted single-site cholecystectomy appears to be a safe alternative to standard laparoscopy with a similar postoperative pain profile, short postoperative lengths of stay, and, for some, a superior cosmetic result. Nevertheless, it comes with longer set-up and operative times, a higher incidence of minor wound complications, an unknown but possibly higher risk of incisional hernia, and higher costs.

Developing a Hospital-Wide Fertility Preservation Service for Pediatric and Young Adult Patients

PURPOSE

Gonadal damage is a common consequence of treatment for pediatric malignancies. Nononcologic conditions may also utilize treatments with potential impact on fertility. Models for oncology fertility preservation programs have emerged and demonstrate that a multidisciplinary team approach can have a positive impact on referral patterns, appropriate risk counseling, and access to fertility preservation options. Expansion of programmatic breadth is needed, providing improved care to nonmalignant conditions where the disease itself may impact reproductive health or treatment modalities.

METHODS

With support from the Department of Pediatrics Chair's Initiative, a multidisciplinary, hospital-wide Fertility Preservation Service was created at the Children's Hospital of Philadelphia. A centralized team provides fertility consults across the institution, allowing for risk-based counseling and facilitation of fertility preservation options (both standard care and experimental).

RESULTS

Team structure, consult process, and available fertility options for prepubertal and pubertal males and females are described. Preinitiative and postinitiative referral patterns were analyzed. Postinitiative referrals from divisions outside oncology more than doubled (34% vs. 15% at baseline).

CONCLUSIONS

A comprehensive model for fertility counseling provides accessible, high-value fertility preservation care to pediatric and young adult patients with a wide variety of diagnoses. A centralized point of contact ensures timely referrals and risk-based counseling and streamlines access to fertility preservation procedures.

Diverting Ileostomy for the Treatment of Severe, Refractory, Pediatric Inflammatory Bowel Disease

OBJECTIVES

Diverting ileostomy is used as a temporizing therapy in patients with perianal Crohn disease; however, little data exist regarding its use for colonic disease. The primary aim of the present study was to determine the role of diversion in severe refractory colonic inflammatory bowel disease (IBD) in a pediatric population.

METHODS

Retrospective study of patients who underwent diverting ileostomy at The Children's Hospital of Philadelphia from 2000 to 2014 for the management of severe, refractory colonic IBD. Clinical variables were compared in the 1 year before ileostomy and 1 year after diversion. Surgical and disease outcomes including changes in diagnosis were reviewed through 2015.

RESULTS

Twenty-four patients underwent diverting ileostomy for refractory colonic disease. Initial diagnoses were Crohn disease in 10 (42%), ulcerative colitis in 1 (4%), and IBD-unclassified in 13 patients (54%). Comparing data before and after surgery, there were statistically significant improvements in height and weight velocities, height velocity z score, blood transfusion requirement, hemoglobin, and hospitalization rates. Chronic steroid use decreased from 71% to 22%. At the conclusion of the study, 10 patients had undergone subsequent colectomy, 7 had successful bowel reanastomosis, and 7 remain diverted. Seven patients (29%) had a change in diagnosis. There were 13 surgical complications in 7 subjects, including prolapse reduction, stoma revision, and resection of ischemic bowel.

CONCLUSIONS

In pediatric patients with refractory colonic IBD, diverting ileostomy can be a successful intervention to induce clinical stability. Importantly, diversion is a steroid-sparing therapy and allows additional time to clarify the diagnosis.

Mortality and Morbidity after Laparoscopic Surgery in Children with and without Congenital Heart Disease

OBJECTIVES

To determine the risk of morbidity and mortality after laparoscopic surgery among children with congenital heart disease (CHD).

STUDY DESIGN

Cohort study using the 2013-2014 National Surgical Quality Improvement Program-Pediatrics, which prospectively collected data at 56 and 64 hospitals in 2013 and 2014, respectively. Primary exposure was CHD. Primary outcome was overall in-hospital postoperative mortality. Secondary outcomes included 30-day mortality and 30-day morbidity (any nondeath adverse event). Among 34?543 children who underwent laparoscopic surgery, 1349, 1106, and 266 had minor, major, and severe CHD, respectively. After propensity score matching within each stratum of CHD severity, morbidity and mortality were compared between children with and without CHD.

RESULTS

Children with severe CHD had higher overall mortality and 30-day morbidity (OR 12.31, 95% CI 1.59-95.01; OR 2.51, 95% CI 1.57-4.01, respectively), compared with matched controls. Overall mortality and 30-day morbidity were also higher among children with major CHD compared with children without CHD (OR 3.46, 95% CI 1.49-8.06; OR 2.07, 95% CI 1.65-2.61, respectively). Children with minor CHD had similar mortality outcomes, but had higher 30-day morbidity compared with children without CHD (OR 1.71, 95% CI 1.37-2.13).

CONCLUSIONS

Children with major or severe CHD have higher morbidity and mortality after laparoscopic surgery. Clinicians should consider the increased risks of laparoscopic surgery for these children during medical decision making.

Analysis of surgical interruption of the enterohepatic circulation as a treatment for pediatric cholestasis

To evaluate the efficacy of nontransplant surgery for pediatric cholestasis, 58 clinically diagnosed children, including 20 with Alagille syndrome (ALGS), 16 with familial intrahepatic cholestasis-1 (FIC1), 18 with bile salt export pump (BSEP) disease, and 4 others with low γ-glutamyl transpeptidase disease (levels <100 U/L), were identified across 14 Childhood Liver Disease Research Network (ChiLDReN) centers. Data were collected retrospectively from individuals who collectively had 39 partial external biliary diversions (PEBDs), 11 ileal exclusions (IEs), and seven gallbladder-to-colon (GBC) diversions. Serum total bilirubin decreased after PEBD in FIC1 (8.1 ± 4.0 vs. 2.9 ± 4.1 mg/dL, preoperatively vs. 12-24 months postoperatively, respectively; P = 0.02), but not in ALGS or BSEP. Total serum cholesterol decreased after PEBD in ALGS patients (695 ± 465 vs. 457 ± 319 mg/dL, preoperatively vs. 12-24 months postoperatively, respectively; P = 0.0001). Alanine aminotransferase levels increased in ALGS after PEBD (182 ± 70 vs. 260 ± 73 IU/L, preoperatively vs. 24 months; P = 0.03), but not in FIC1 or BSEP. ALGS, FIC1, and BSEP patients experienced less severely scored pruritus after PEBD (ALGS, 100% vs. 9% severe; FIC1, 64% vs. 10%; BSEP, 50% vs. 20%, preoperatively vs. >24 months postoperatively, respectively; P < 0.001). ALGS patients experienced a trend toward greater freedom from xanthomata after PEBD. There was a trend toward decreased pruritus in FIC1 after IE and GBC. Vitamin K supplementation increased in ALGS after PEBD (33% vs. 77%; P = 0.03). Overall, there were 15 major complications after surgery. Twelve patients (3 ALGS, 3 FIC1, and 6 BSEP) subsequently underwent liver transplantation.

CONCLUSION

This was a multicenter analysis of nontransplant surgical approaches to intrahepatic cholestasis. Approaches vary, are well tolerated, and generally, although not uniformly, result in improvement of pruritus and cholestasis. (Hepatology 2017;65:1645-1654).

Radiologist performance in the interpretation of contrast enemas performed for Hirschsprung's disease in children >1 year of age

AIM

To evaluate the diagnostic performance of contrast enemas (CEs) for the diagnosis of Hirschsprung's disease (HD).

METHODS AND MATERIALS

CE studies performed as part of an HD workup in patients 1-18 years of age over a 10-year period were identified. All abnormal CE studies and an equal number of age-matched controls were included in the final study group. Two radiologists independently and blindly reviewed all CE studies for quality (scale of 0-3) and the presence of large colon calibre, colon redundancy, transition zone, rectosigmoid ratio, and abnormal contractions. Readers also determined whether a rectal biopsy would be recommended to confirm an HD diagnosis. Discrepancies were resolved in consensus. Findings were correlated with surgery and biopsy data.

RESULTS

Out of 834 CE studies, 38 abnormal CE studies were identified (mean age 5.9 years) and included 38 matched controls. Seventeen of 76 patients were recommended for rectal biopsy, of which five were confirmed to have HD. Twelve of 70 (17.1%) were false positives, and were clinically confirmed not to have HD. The proportion of HD in the present population was 6/834 (0.72%). Of the 17 recommended for biopsy, CE studies showed 17/17 (100%) with an abnormal rectosigmoid ratio, 16/17 (94.1%) with redundant colon, and 15/17 (88%) with large colon. Of patients not recommended for biopsy, one was diagnosed with HD, (false negative, 16.7%). The diagnostic performance of CE was 83.3% sensitivity and 82.9% specificity.

CONCLUSION

Few children >1 year of age were found to have HD and the diagnostic performance of the CE is moderately high. The CE examination is a valuable non-invasive imaging study to help exclude older children who may not have HD, thereby obviating the need for invasive rectal biopsy and surgery.

Relação entre os níveis de metabólitos sanguíneos e a qualidade de lã

O tipo de alimentação altera diretamente os níveis dos metabólitos sanguíneos e as características da lã. Neste sentido o objetivo deste trabalho é relacionar os níveis de metabólitos sanguíneos com a qualidade da lã. Foram utilizadas 25 ovelhas com três anos de idade da raça Corriedale, em um período experimental de 98 dias, onde se avaliou os níveis dos metabolitos sanguíneos e os dados objetivos de qualidade de lã. Para as análises objetivas de qualidade de lã ocorreu uma diminuição no diâmetro médio das fibras (do inicio ao fim do experimento) e um crescimento diário médio da mecha de lã de 0,40 mm. Somente foi encontrada correlação entre os níveis séricos de glicose com a variação do diâmetro médio das fibras, a variação do comprimento da mecha de lã e com a variação do diâmetro no ponto em que apresentou maiores valores. As variáveis sanguíneas referentes à albumina e proteínas plasmáticas totais não tiveram correlação significativa com as aferições de qualidade de lã.

Reclamation of river dredged sediments polluted by PAHs by co-composting with green waste

Polluted dredged sediments are classified as waste and cannot be re-used in civil and environmental engineering nor in agriculture, posing serious logistical, economic and environmental problems for their management. We tested co-composting of sediments (S) slightly polluted by PAHs with urban green waste (GW), as a sustainable technique to both degrade the organic pollutants and lend to sediments suitable properties to be reused as technosol. Four treatments were tested: sediments only (S), GW only (GW), 1:1 w:w S:GW (SGW1:1), and 3:1 w:w S:GW (SGW3:1) for a co-composting period of one year. The co-composting materials underwent to an initial short and moderate thermophilic phase. However, at the end of the co-composting process, SGW3:1 and SGW1:1 achieved suitable physical and chemical properties as plant substrate in terms of organic C, N and humic substances contents, electrical conductivity and bulk density. In the first six months of treatment, the PAHs concentration in SGW3:1 and SGW1:1 was reduced by 26% and 57%, respectively, reaching values below under 1mgg(-1), whereas such a reduction in S alone was observed only after nine months. We concluded that co-composting with green waste can be a suitable approach for reclamation of dredged sediments opening opportunities for their use as technosol or as plant growing substrate.

Ganho de peso, níveis de glicose sanguínea e qualidade da lã de ovelhas manejadas no terço final de gestação em pastagens hibernais

O conhecimento acerca da produção de lã a nível internacional é sustentado por dois pilares. O mercado e aspectos produtivos. Assim devemos ser conhecedores das prospecções comerciais, porém não podemos negligenciar alguns fatores de produção, que podem refletir diretamente no aumento da quantidade e qualidade do produto lanoso. O objetivo deste trabalho é comparar as características de ganho de peso, níveis séricos de glicose sanguínea e características qualitativas da lã, em diferentes ofertas forrageiras de pastagens consorciadas de Avena strigosa Schreb. e Lolium multiflorum Lam. O experimento foi conduzido nas coordenadas 31º52’00”S, 52º 21’24”W, altitude 13,24 m. Foram utilizadas 29 ovelhas de seis dentes (estimativa de três anos de idade) prênhes, da raça Corriedale. Foi avaliado o ganho de peso no período e também, foram coletadas amostras de sangue e de lã. As amostras de sangue foram coletadas via punção da veia jugular em cinco momentos: uma coleta mensal, em que a primeira foi feita no mês que antecedeu o inicio do experimento e a ultima no final do mesmo. As amostras de lã foram tomadas na região do costilhar esquerdo nos dias 18 de junho e 24 de setembro. Somente foi encontrada diferença significativa (p

Systemic bile acid sensing by G protein-coupled bile acid receptor 1 (GPBAR1) promotes PYY and GLP-1 release

BACKGROUND AND PURPOSE

Nutrient sensing in the gut is believed to be accomplished through activation of GPCRs expressed on enteroendocrine cells. In particular, L-cells located predominantly in distal regions of the gut secrete glucagon-like peptide 1 (GLP-1) and peptide tyrosine-tyrosine (PYY) upon stimulation by nutrients and bile acids (BA). The study was designed to address the mechanism of hormone secretion in L-cells stimulated by the BA receptor G protein-coupled bile acid receptor 1 (GPBAR1).

EXPERIMENTAL APPROACH

A novel, selective, orally bioavailable, and potent GPBAR1 agonist, RO5527239, was synthesized in order to investigate L-cell secretion in vitro and in vivo in mice and monkey. In analogy to BA, RO5527239 was conjugated with taurine to reduce p.o. bioavailability yet retaining its potency. Using RO5527239 and tauro-RO5527239, the acute secretion effects on L-cells were addressed via different routes of administration.

KEY RESULTS

GPBAR1 signalling triggers the co-secretion of PYY and GLP-1, and leads to improved glucose tolerance. The strong correlation of plasma drug exposure and plasma PYY levels suggests activation of GPBAR1 from systemically accessible compartments. In contrast to the orally bioavailable agonist RO5527239, we show that tauro-RO5527239 triggers PYY release only when applied intravenously. Compared to mice, a slower and more sustained PYY secretion was observed in monkeys.

CONCLUSION AND IMPLICATIONS

Selective GPBAR1 activation elicits a strong secretagogue effect on L-cells, which primarily requires systemic exposure. We suggest that GPBAR1 is a key player in the intestinal proximal-distal loop that mediates the early phase of nutrient-evoked L-cell secretion effects.