Outcomes of minimally invasive abdominal sacrocolpopexy with resident operative involvement.

INTRODUCTION AND HYPOTHESIS: Resident involvement in complex surgeries is under scrutiny with increasing attention paid to health care efficiency and quality. Outcomes of urogynecological surgery with resident involvement are poorly described. We hypothesized that resident surgical involvement does not influence perioperative outcomes in minimally invasive abdominal sacrocolpopexy (ASC). METHODS: Using the 2006-2012 National Surgical Quality Improvement Program database, we identified 450 cases of laparoscopic or robotic ASC performed with resident involvement. Resident operative participation was stratified by experience (junior [PGY 1-3] vs senior level [PGY ≥4]). The primary outcome was operative time, and multinomial logistic regression was used to determine the effects of resident involvement and experience. Chi-squared analyses were used to assess the relationship between resident participation with length of stay (LOS) and 30-day complications and readmissions. RESULTS: Residents participated in 74% (n = 334) of these surgeries, and these cases were significantly longer (median 220 vs 195 min, p = 0.03). On multivariate analysis, senior level resident involvement was associated with longer operative times across all time intervals compared with <2 h (2 to ≤4 h relative risk reduction [RRR] 4.1, p = 0.007, CI 1.47-11.40; 4 to ≤6 h RRR 6.6, p = 0.001, CI 2.23-19.44; ≥6 h RRR 4.7, p = 0.020, CI 1.28-17.43). Resident participation was not associated with LOS, readmissions, or complications. CONCLUSIONS: Senior level resident involvement in minimally invasive ASC is associated with longer operative times, with no association with LOS or adverse perioperative outcomes. The educational benefit of surgical training does not adversely affect patient outcomes for ASC.

National Surgical Trends and Perioperative Outcomes of Midurethral Sling Placement for Stress Urinary Incontinence.

OBJECTIVE: To determine contemporary trends, patient characteristics, and outcomes for midurethral sling placement (MUS) at inpatient and ambulatory facilities from a national database. MATERIALS AND METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program database, we identified 7767 women who underwent isolated MUS 2006-2012. We stratified patients by hospitalization type (outpatient vs hospitalization). Primary outcomes were 30-day complications, readmissions, and reoperations. Multivariable logistic regression was used to determine patient and surgery factors associated with adverse perioperative outcomes. RESULTS: Among the 7767 women undergoing MUS, 84.3% underwent outpatient surgery (n = 6547), with greater use of outpatient facilities over time (P < .001). Overall, 3.9% of patients (n = 300) experienced one or more postoperative complications. Complications were more likely among inpatients (7.4% vs 3.2%; odds ratio [OR] 0.48, confidence interval [CI] 0.36-0.64, P < .001), with gynecologists as compared to urologists (4.4% vs 3.1%; OR 1.53, CI 1.16-2.02, P = .003), and with resident participation (5.1% vs 3.7%; OR 1.32, CI 1.01-1.73, P = .04). On multivariable analysis, outpatients were less likely to experience readmissions (0.9% vs 2.8%; OR 0.2, CI 0.09-0.56, P = .002) or undergo reoperation (0.3% vs 3.1%; OR 0.10, CI 0.02-0.38, P = .001). CONCLUSION: Use of outpatient surgical centers for MUS is increasing, with lower rates of complications, readmissions, and reoperations compared to inpatient treatment. Although there is a difference in complications by specialty and with resident involvement, overall incidence of complications is low.

Enterocyte differentiation marker intestinal alkaline phosphatase is a target gene of the gut-enriched Kruppel-like factor.

We have examined the role that the transcription factor gut-enriched Krüppel-like factor (KLF4 or GKLF) plays in activating the enterocyte differentiation marker gene intestinal alkaline phosphatase (IAP). A yeast one-hybrid screen was used to identify proteins interacting with a previously identified cis-element (IF-III) located within the human IAP gene promoter. DNA-protein interactions were determined by using EMSA. Northern blot analysis was used to study RNA expression in human colon cancer RKO cells engineered to overexpress KLF4. Transient transfections with IAP-luciferase reporter constructs were used to characterize the mechanisms by which KLF4 activates IAP transcription. The yeast one-hybrid screen and EMSA identified KLF4 as binding to IF-III. RKO cells induced to overexpress KLF4 demonstrated a corresponding dose-dependent increase in IAP expression, and EMSA with nuclear extract from these cells confirmed that KLF4 binds to the IF-III element. Transient transfections revealed that KLF4 transactivated the IAP gene largely via a critical segment in the IAP promoter that includes the IF-III cis-element. Mutant KLF4 constructs failed to fully activate IAP. We have identified the enterocyte differentiation marker IAP as a KLF4 target gene. IAP transactivation by KLF4 is likely mediated through a critical region located within the proximal IAP promoter region.

Convergence of the thyroid hormone and gut-enriched Krüppel-like factor pathways in the context of enterocyte differentiation.

The gut-enriched Krüppel-like factor (KLF4) and the ligand-bound thyroid hormone receptor (TR) have each been shown to play a critical role in mammalian gut development and differentiation. We investigated an interrelationship between these two presumably independent pathways using the differentiation marker gene, intestinal alkaline phosphatase (IAP). Transient transfections were performed in Cos-7 cells using luciferase reporter plasmids containing a 2.5 kb segment of the proximal human IAP 5' regulatory region, as well as multiple deletions. Cells were cotransfected with TR and/or KLF4 expression vectors and treated+/-100 nmol/L thyroid hormone (T3). IAP reporter gene transactivation was increased independently by KLF4 (ninefold) and ligand-bound TR beta 1 (sevenfold). Cells cotransfected with KLF4 and TR beta 1 in the presence of T3 showed synergistic activation (70-fold). A similar pattern was seen with the other T3 receptor isoform, TR alpha 1. The synergistic effect was lost with deletions of the T3 and KLF4 response elements in the IAP promoter and was completely or partially abolished in the case of mutant KLF4 expression vectors. The thyroid hormone receptor complex and KLF4 synergistically activate the enterocyte differentiation marker gene IAP, suggesting a previously unrecognized interrelationship between these two transcription factor pathways.

Transcriptional activation of the enterocyte differentiation marker intestinal alkaline phosphatase is associated with changes in the acetylation state of histone H3 at a specific site within its promoter region in vitro.

Enterocyte differentiation is thought to occur through the transcriptional regulation of a small subset of specific genes. A recent growing body of evidence indicates that post-translational modifications of chromatin proteins (histones) play an important role in the control of gene transcription. Previous work has demonstrated that one such modification, histone acetylation, occurs in an in vitro model of enterocyte differentiation, butyrate-treated HT-29 cells. In the present work, we sought to determine if the epigenetic signal of histone acetylation occurs in an identifiable pattern in association with the transcriptional activation of the enterocyte differentiation marker gene intestinal alkaline phosphatase (IAP). HT-29 cells were maintained under standard culture conditions and differentiated with sodium butyrate. The chromatin immunoprecipitation (ChIP) assay was used to compare the acetylation state of histones associated with specific regions of the IAP promoter in the two cell populations (undifferentiated vs. differentiated). Chromatin was extracted from cells and cleaved by sonication or enzymatic digestion to obtain fragments of approximately 200 to 600 base-pairs, as confirmed by polymerase chain reaction using primers designed to amplify the IAP segments of interest. The ChIP assay selects DNA sequences that are associated with acetylated histones by immunoprecipitation. Unbound segments represent DNA sequences whose histones are not acetylated. After immunoprecipitation, sequences were detected by radiolabeled polymerase chain reaction, and the relative intensity of the bands was quantified by densitometry. The relative acetylation state of histones at specific sites was determined by comparing the ratios of bound/unbound segments. We determined that in a segment of the IAP promoter between -378 and -303 base-pairs upstream from the transcriptional start site, the acetylation state of histone H3 increased twofold in the differentiated, IAP expressing cells, whereas that of histone H4 remained essentially constant. Additionally, at a distant site, between -1378 and -1303 base-pairs, the acetylation state of H3 and H4 did not change appreciably between the undifferentiated and differentiated cells. We conclude that butyrate-induced differentiation is associated with specific and localized changes in the histone acetylation state within the IAP promoter. These changes within the endogenous IAP gene may underlie its transcriptional activation in the context of the enterocyte differentiation program.

Enterocyte response to ischemia is dependent on differentiation state.

Enterocytes at the tips of microvilli are more sensitive to an ischemic insult than those cells residing in the crypts, an effect thought to be due to a relative lack of collateral flow. We speculated that this increased cellular sensitivity to ischemia might be an intrinsic feature of the cells related to their differentiated phenotype. To test this hypothesis, enterocyte response to ischemia was determined using both in vivo and in vitro models. For the in vivo studies, male Sprague-Dawley rats underwent laparotomy, and small intestinal ischemia was induced by clamping the superior mesenteric artery for 30 or 60 minutes, after which reperfusion was allowed for various time points up to 4 days. Injury was assessed histologically, as well as with Northern blots, probing for the enterocyte differentiation markers intestinal alkaline phosphatase and lactase, as well as the gut-epithelial marker villin. Mucosal changes consistent with ischemia/reperfusion injury were evident--that is, a rapid inflammatory response followed by progressive villus cell loss beginning at the tips and progressing to the crypts, depending on the degree of insult, with an eventual return to normal microanatomy. Intestinal alkaline phosphatase and lactase were lost immediately after ischemia and returned with reperfusion, confirming that the differentiated cells are particularly sensitive to ischemic injury. The in vitro studies employed two separate models of enterocyte differentiation: sodium butyrate-treated HT-29 cells and Caco-2 cells maintained for 7 days after confluence. In both models, undifferentiated and differentiated cells were subjected to treatment with 2-deoxyglucose and oligomycin-A (in vitro model of ischemia) and apoptosis was assessed by fluorescence-activated cell sorting analysis. Differentiation of both cell lines resulted in a significantly greater apoptotic response to ischemia compared to undifferentiated cells exposed to an identical insult. We conclude that differentiated enterocytes may be inherently more sensitive to ischemia-induced injury than their undifferentiated counterparts. These findings call into question the popularly held belief that villus tip cells are more susceptible to ischemia because of their location relative to the microvascular anatomy.