Sarcopenia is independently associated with poor preoperative physical fitness in patients undergoing colorectal cancer surgery.

BACKGROUND: Accurate preoperative risk assessment for major colorectal cancer (CRC) surgery remains challenging. Body composition (BC) and cardiopulmonary exercise testing (CPET) can be used to evaluate risk. The relationship between BC and CPET in patients undergoing curative CRC surgery is unclear. METHODS: Consecutive patients undergoing CPET prior to CRC surgery between 2010 and 2020 were identified between two different UK hospitals. Body composition phenotypes such as sarcopenia, myosteatosis, and visceral obesity were defined using widely accepted thresholds using preoperative single axial slice CT image at L3 vertebrae. Relationships between clinicopathological, BC, and CPET variables were investigated using linear regression analysis. RESULTS: Two hundred eighteen patients with stage I-III CRC were included. The prevalence of sarcopenia, myosteatosis, and visceral obesity was 62%, 33%, and 64%, respectively. The median oxygen uptake at anaerobic threshold (VO2 at AT) was 12.2 mL/kg/min (IQR 10.6-14.2), and oxygen uptake at peak exercise (VO2 peak) was 18.8 mL/kg/min (IQR 15.4-23). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 at AT. While ASA grade (P < 0.001) and BMI (P = 0.007) were negatively associated with VO2 at AT, on multivariate linear regression analysis, these variables remained significant (P < 0.05). On univariate linear regression analysis, male sex (P < 0.001) was positively associated with VO2 peak, whereas age (P < 0.001), ASA grade (P < 0.001), BMI (P = 0.003), sarcopenia (P = 0.015), and myosteatosis (P < 0.001) were negatively associated with VO2 peak. On multivariate linear regression analysis age (P < 0.001), ASA grade (P < 0.001), BMI (P < 0.001), and sarcopenia (P = 0.006) were independently and negatively associated with VO2 peak. CONCLUSIONS: The novel finding that sarcopenia is independently associated with reduced VO2 peak performance in CPET supports the supposition that reduced muscle mass relates to poor physical function in CRC patients. Further work should be undertaken to assess whether sarcopenia diagnosed on CT can act as suitable surrogate for CPET to further enhance personalized risk stratification.

The Glasgow Microenvironment Score: an exemplar of contemporary biomarker evolution in colorectal cancer.

Colorectal cancer remains a leading cause of mortality worldwide. Significant variation in response to treatment and survival is evident among patients with similar stage disease. Molecular profiling has highlighted the heterogeneity of colorectal cancer but has had limited impact in daily clinical practice. Biomarkers with robust prognostic and therapeutic relevance are urgently required. Ideally, biomarkers would be derived from H&E sections used for routine pathological staging, have reliable sensitivity and specificity, and require minimal additional training. The biomarker targets would capture key pathological features with proven additive prognostic and clinical utility, such as the local inflammatory response and tumour microenvironment. The Glasgow Microenvironment Score (GMS), first described in 2014, combines assessment of peritumoural inflammation at the invasive margin with quantification of tumour stromal content. Using H&E sections, the Klintrup-Mäkinen (KM) grade is determined by qualitative morphological assessment of the peritumoural lymphocytic infiltrate at the invasive margin and tumour stroma percentage (TSP) calculated in a semi-quantitative manner as a percentage of stroma within the visible field. The resulting three prognostic categories have direct clinical relevance: GMS 0 denotes a tumour with a dense inflammatory infiltrate/high KM grade at the invasive margin and improved survival; GMS 1 represents weak inflammatory response and low TSP associated with intermediate survival; and GMS 2 tumours are typified by a weak inflammatory response, high TSP, and inferior survival. The prognostic capacity of the GMS has been widely validated while its potential to guide chemotherapy has been demonstrated in a large phase 3 trial cohort. Here, we detail its journey from conception through validation to clinical translation and outline the future for this promising and practical biomarker.

Self-reported fitness as a measure of perioperative cardiovascular risk: tension between subjective and objective assessments persists.

Despite recent high-quality international studies, the optimal sum and sequence of subjective and objective assessments that build the complex picture of fitness for surgery remains to be defined. Physicians' subjective assessment of patient fitness after a typical unstructured interview has poor prognostic accuracy in predicting the risk of major cardiovascular events after noncardiac surgery. How does self-reported fitness assessed by structured questionnaire compare as an indicator of perioperative cardiovascular risk? Here we discuss the latest evidence in this evolving and fundamental aspect of perioperative care.

Different Sources of Fiber Intake and Risk of 17 Specific Cancers and All Cancers Combined: Prospective Study of 364,856 Participants in the UK Biobank.

Inverse associations between dietary fiber (DF) and colorectal cancer risk are well-established. However, evidence is limited in relation to other cancer sites. This study, of 364,856 participants from the UK Biobank, aimed to evaluate the associations between total and source-specific partial DF and risk of 17 specific cancers and all cancers combined. Partial DF was derived from baseline touchscreen questionnaire data on cereal, bread, fruit, and vegetable intake. The outcomes were incident cancer at 17 sites and all cancers combined. Cox proportional hazards models were applied. Over a median 8.8-year follow-up period, 30,725 people were diagnosed with cancer. After adjusting for sociodemographic and lifestyle factors, those in the highest quintile of partial DF compared with the lowest quintile (<9.6 vs ≥19.1 g/day) had 10% lower risk of cancer overall, with the greatest risk reductions observed for cervical (hazard ratio (HR) = 0.33, 95% confidence interval (CI): 0.14; 0.82), esophageal (HR = 0.66, 95% CI: 0.52; 0.84), lung (HR = 0.67, 95% CI: 0.59; 0.76), bladder (HR = 0.72, 95% CI: 0.56; 0.91), and kidney (HR = 0.75, 95% CI: 0.61; 0.92) cancers. Associations between DF and lung cancer were observed only in current and former smokers. Higher DF intake, in particular cereal fiber and fruit and vegetable fiber, was associated with a lower risk of overall and multiple site-specific cancers.

Deformation and Durability of Soft Three-Dimensional-Printed Polycarbonate Urethane Porous Membranes for Potential Use in Pelvic Organ Prolapse.

Pelvic organ prolapse (POP) is the herniation of the pelvic organs into the vaginal space, resulting in the feeling of a bulge and organ dysfunction. Treatment of POP often involves repositioning the organs using a polypropylene mesh, which has recently been found to have relatively high rates of complications. Complications have been shown to be related to stiffness mismatches between the vagina and polypropylene, and unstable knit patterns resulting in mesh deformations with mechanical loading. To overcome these limitations, we have three-dimensional (3D)-printed a porous, monofilament membrane composed of relatively soft polycarbonate-urethane (PCU) with a stable geometry. PCU was chosen for its tunable properties as it is comprised of both hard and soft segments. The bulk mechanical properties of PCU were first characterized by testing dogbone samples, demonstrating the dependence of PCU mechanical properties on its measurement environment and the effect of print pathing. The pore dimensions and load-relative elongation response of the 3D-printed PCU membranes under monotonic tensile loading were then characterized. Finally, a fatigue study was performed on the 3D-printed membrane to evaluate durability, showing a similar fatigue resistance with a commercial synthetic mesh and hence its potential as a replacement.

Mesh deformation: A mechanism underlying polypropylene prolapse mesh complications in vivo.

Polypropylene meshes used in pelvic organ prolapse (POP) repair are hampered by complications. Most POP meshes are highly unstable after tensioning ex vivo, as evidenced by marked deformations (pore collapse and wrinkling) that result in altered structural properties and material burden. By intentionally introducing collapsed pores and wrinkles into a mesh that normally has open pores and remains relatively flat after implantation, we reproduce mesh complications in vivo. To do this, meshes were implanted onto the vagina of rhesus macaques in nondeformed (flat) vs deformed (pore collapse +/- wrinkles) configurations and placed on tension. Twelve weeks later, animals with deformed meshes had two complications, (1) mesh exposure through the vaginal epithelium, and (2) myofibroblast proliferation with fibrosis - a mechanism of pain. The overarching response to deformed mesh was vaginal thinning associated with accelerated apoptosis, reduced collagen content, increased proteolysis, deterioration of mechanical integrity, and loss of contractile function consistent with stress shielding - a precursor to mesh exposure. Regional differences were observed, however, with some areas demonstrating myofibroblast proliferation and matrix deposition. Variable mechanical cues imposed by deformed meshes likely induce these two disparate responses. Utilizing meshes associated with uniform stresses on the vagina by remaining flat with open pores after tensioning is critical to improving outcomes. STATEMENT OF SIGNIFICANCE: Pain and exposure are the two most reported complications associated with the use of polypropylene mesh in urogynecologic procedures. Most meshes have unstable geometries as evidenced by pore collapse and wrinkling after tensioning ex vivo, recapitulating what is observed in meshes excised from women with complications in vivo. We demonstrate that collapsed pores and wrinkling result in two distinct responses (1) mesh exposure associated with tissue degradation and atrophy and (2) myofibroblast proliferation and matrix deposition consistent with fibrosis, a tissue response associated with pain. In conclusion, mesh deformation leads to areas of tissue degradation and myofibroblast proliferation, the likely mechanisms of mesh exposure and pain, respectively. These data corroborate that mesh implantation in a flat configuration with open pores is a critical factor for reducing complications in mesh-augmented surgeries.

The role of surgery in weaning patients from home parenteral support - A cohort study.

AIM: Some patients with intestinal failure requiring home parenteral support (HPS) may be weaned. This study considered all abdominal surgery in a cohort of HPS patients over a 25-year period. Our aim was to identify how many patients can be weaned from HPS and by what means, and to identify what makes weaning more likely. METHOD: A prospectively collected database of HPS patients to December 2018 was analysed for outcomes of care. RESULTS: At 5 years 56% of 205 patients remained on HPS. Fifty eight patients (28%), who had 68 operations, stopped HPS after surgery. Patients stopping HPS had a longer median final small bowel length (155 cm, range 45-350 cm) and were more likely to have colon in circuit (84%) than patients who had reconstructive surgery but did not stop HPS (median small bowel length 50 cm, range 15-135 cm; 50% colon in circuit). The median period between HPS discharge and reconstructive surgery was 238 days. There were no deaths, but 18 Clavien-Dindo grade 3-4 complications occurred within 30 days. Ninety per cent of patients who stopped HPS survived for 5 years from the start of HPS in comparison with 53% of those who remained on HPS. CONCLUSIONS: No previous study has examined surgery in an entire cohort of HPS patients. More than a quarter of HPS patients can be weaned after reconstructive surgery. The length of bowel available for recruitment at surgery is the main determinant of the ability to stop HPS. The possibility of reconstruction should be considered, since patients who stop HPS appear to have a survival advantage.

A soft elastomer alternative to polypropylene for pelvic organ prolapse repair: a preliminary study.

INTRODUCTION AND HYPOTHESIS: We compared the impact of a mesh manufactured from the soft elastomer polydimethylsiloxane (PDMS) to that of a widely used lightweight polypropylene (PP) mesh. To achieve a similar overall device stiffness between meshes, the PDMS mesh was made with more material and therefore was heavier and less porous. We hypothesized that the soft polymer PDMS mesh, despite having more material, would have a similar impact on the vagina as the PP mesh. METHODS: PDMS and PP meshes were implanted onto the vaginas of 20 rabbits via colpopexy. Ten rabbits served as sham. At 12 weeks, mesh-vagina complexes were explanted and assessed for contractile function, histomorphology, total collagen, and glycosaminoglycan content. Outcome measures were compared using one-way ANOVA and Kruskal-Wallis testing with appropriate post-hoc testing. RESULTS: Relative to sham, vaginal contractility was reduced following the implantation of PP (p = 0.035) but not the softer PDMS (p = 0.495). PP had an overall greater negative impact on total collagen and glycosaminoglycan content, decreasing by 53% (p < 0.001) and 54% (p < 0.001) compared to reductions of 35% (p = 0.004 and p < 0.001) with PDMS. However, there were no significant differences in the contractility, collagen fiber thickness, total collagen, and glycosaminoglycan content between the two meshes. CONCLUSIONS: Despite having a substantially higher weight, PDMS had a similar impact on the vagina compared to a low-weight PP mesh, implicating soft polymers as potential alternatives to PP. The notion that heavyweight meshes are associated with a worse host response is not applicable when comparing across materials.

Disease recurrence after right hemicolectomy in Scotland: Is there rationale to adopt complete mesocolic excision (CME)?

AIMS: Complete mesocolic excision (CME) has been proposed as a way to improve the oncological outcomes in patients with colon cancer. To investigate whether there is rationale for adopting the technique in Scotland, our aim was to define the incidence of disease recurrence following standard right hemicolectomy and to compare this with published CME outcomes. METHODS: Data was collected on consecutive patients undergoing right or extended right hemicolectomy for colonic adenocarcinoma (2012-2017) at three hospitals in Scotland (Raigmore Hospital, Aberdeen Royal Infirmary and Glasgow Royal Infirmary). Emergency or palliative surgery was excluded. Patients were followed up with CT scans and colonoscopy for a minimum of 3 years. RESULTS: 689 patients (M 340, F 349) were included. 30-day mortality was 1.6%. Final pathological stage was Stage I (14%), Stage II (49.8%) and Stage III (36.1%). During follow-up, 10.5% developed loco-regional recurrence and 12.2% developed distant metastases. The 1, 3 and 5-year disease-free survival (DFS) was 94%, 84% and 82% respectively. Primary determinants of recurrence were T stage (p < 0.001), N stage (p < 0.001), apical node involvement (p < 0.001) and EMVI (p < 0.001). When compared to the literature, 30-day mortality was lower than many published series and DFS rates were similar to the largest CME study to date (4 year DFS 85.8% versus 83%). CONCLUSION: The outcomes of patients undergoing right hemicolectomy in Scotland compare favourably with many published CME studies. The technique demands further evaluation before it can be recommended for adoption into routine surgical practice.

Changes in adult home parenteral nutrition practice over 25 years.

BACKGROUND AND AIMS: Home Parenteral Nutrition (HPN) is the established treatment of intestinal failure. This study considers the changes in practice in a single UK centre over the past twenty-five years. METHODS: Data was culled from a database used for clinical care and maintained prospectively. RESULTS: Two hundred and five patients were included from 1993 to 2018. Patient numbers increased from 22 during 1999-2003 to 158 during 2014-2018. The median age at discharge increased from 52 years during 1999-2003 to 59 years during 2014-2018. Thirty percent of patients discharged during 1999-2003 had Crohn's disease, reducing to 14% during 2014-2018. Fifteen percent of patients discharged during 1999-2003 had small bowel fistula or obstruction in comparison to 44% during 2014-2018. Only 18 patients were treated with palliative intent, the majority in recent years. An increasing number of patients required help with HPN care over the years. Survival in non-palliative patients was 85% at 1 year, 67% at 3 years, 53% at 5 years and 42% at 10 years. The majority of deaths were due to underlying disease and only 5 of 55 deaths were attributed to HPN alone. HPN dependence in non-palliative patients was 73% at 1 year, 59% at 3 years, 56% at 5 years and 43% at 10 years. Fifty eight patients stopped HPN after reconstructive surgery. Patients experienced 5.1 admissions/1000 HPN days (64.7 admission days/1000 HPN days). Admission rate did not change over the years though the percentage due to catheter problems fell from 52% to 40% while the percentage due to underlying disease or unrelated cause rose. CONCLUSIONS: The increase in numbers, age and dependency of HPN patients requires increasing resource and consideration of new models of service. Many patients with short bowel syndrome now survive to old age and the care needs of the HPN patient who has become elderly can be complex. A significant proportion of patients are being referred for HPN as a bridge to reconstructive surgery after surgical complication and this requires close involvement of gastrointestinal surgeons in HPN teams. The need for hospital admissions remains a burden for HPN patients and there is scope for changes in service provision to try to reduce hospital days.

Vascular calcification and response to neoadjuvant therapy in locally advanced rectal cancer: an exploratory study.

PURPOSE: Patients with locally advanced rectal cancer (LARC) may experience a clinical complete response (cCR) to neoadjuvant chemoradiotherapy (NACRT) and opt for non-operative management. Pathological factors that relate to NACRT response have been well described. Host factors associated with response, however, are poorly defined. Calcification of the aortoiliac (AC) vessels supplying the rectum may influence treatment response. METHODS: Patients with LARC having NACRT prior to curative surgery at Glasgow Royal Infirmary (GRI) and St Mark's hospital (SMH) between 2008 and 2016 were identified. AC was scored on pre-treatment CT imaging. NACRT response was assessed using pathologic complete response (pCR) rates, tumour regression grades (TRGs), the NeoAdjuvant Rectal score and T-/N-downstaging. Associations were assessed using Chi-squared, Mantel-Haenszel and Fisher's exact tests. RESULTS: Of 231 patients from GRI, 79 (34%) underwent NACRT for LARC. Most were male (58%), aged over 65 (51%) with mid- to upper rectal tumours (56%) and clinical T3/4 (95%), node-positive (77%) disease. pCR occurred in 10 patients (13%). Trends were noted between higher clinical T stage and poor response by Royal College of Pathologist's TRG (p = 0.021) and tumour height > 5 cm and poor response by Mandard TRG (0.068). In the SMH cohort, 49 of 333 (15%) patients underwent NACRT; 8 (16%) developed a pCR. AC was not associated with NACRT response in either cohort. CONCLUSIONS: AC was not associated with NACRT response in this cohort. Larger contemporary cohorts are required to better assess host determinants of NACRT response and develop predictive models to improve patient selection.

Multidisciplinary management of anal intraepithelial neoplasia and rate of progression to cancer: A retrospective cohort study.

PURPOSE: To describe the regional burden of AIN and rate of progression to cancer in patients managed in specialist and non-specialist clinic settings. METHODS: Patients with a histopathological diagnosis of AIN between 1994 and 2018 were retrospectively identified. Clinicopathological characteristics including high-risk status (chronic immunosuppressant use or HIV positive), number and type of biopsy (punch/excision) and histopathological findings were recorded. The relationship between clinicopathological characteristics and progression to cancer was assessed using logistic regression. RESULTS: Of 250 patients identified, 207 were eligible for inclusion: 144 from the specialist and 63 from the non-specialist clinic. Patients in the specialist clinic were younger (<40 years 31% vs 19%, p = 0.007), more likely to be male (34% vs 16%, p = 0.008) and HIV positive (15% vs 2%, p = 0.012). Patients in the non-specialist clinic were less likely to have AIN3 on initial pathology (68% vs 79%, p = 0.074) and were more often followed up for less than 36 months (46% vs 28%, p = 0.134). The rate of progression to cancer was 17% in the whole cohort (20% vs 10%, p = 0.061). On multivariate analysis, increasing age (OR 3.02, 95%CI 1.58-5.78, p < 0.001), high risk status (OR 3.53, 95% CI 1.43-8.74, p = 0.006) and increasing number of excisions (OR 4.88, 95%CI 2.15-11.07, p < 0.001) were related to progression to cancer. CONCLUSION: The specialist clinic provides a structured approach to the follow up of high-risk status patients with AIN. Frequent monitoring with specialist assessments including high resolution anoscopy in a higher volume clinic are required due to the increased risk of progression to anal cancer.

Aortic calcification is associated with non-infective rather than infective postoperative complications following colorectal cancer resection: an observational cohort study.

OBJECTIVES: Complications following colorectal cancer resection are common. The degree of aortic calcification (AC) on CT has been proposed as a predictor of complications, particularly anastomotic leak. This study assessed the relationship between AC and complications in patients undergoing colorectal cancer resection. METHODS: Patients from 2008 to 2016 were retrospectively identified from a prospectively maintained database. Complications were classified using the Clavien-Dindo (CD) scale. Calcification was quantified on preoperative CT by visual assessment of the number of calcified quadrants in the proximal and distal aorta. Scores were grouped into categories: none, minor (< median AC score) and major (> median AC score). The relationship between clinicopathological characteristics and complications was assessed using logistic regression. RESULTS: Of 657 patients, 52% had proximal AC (> median score (1)) and 75% had distal AC (> median score (4)). AC was more common in older patients and smokers. Higher burden of AC was associated with non-infective complications (proximal AC 28% vs 16%, p = 0.004, distal AC 26% vs 14% p = 0.001) but not infective complications (proximal AC 28% vs 29%, p = 0.821, distal AC 29% vs 23%, p = 0.240) or anastomotic leak (proximal AC 6% vs 4%, p = 0.334, distal AC 7% vs 3%, p = 0.077). Independent predictors of complications included open surgery (OR 1.99, 95%CI 1.43-2.79, p = 0.001), rectal resection (OR 1.51, 95%CI 1.07-2.12, p = 0.018) and smoking (OR 2.56, 95%CI 1.42-4.64, p = 0.002). CONCLUSIONS: These data suggest that high levels of AC are associated with non-infective complications after colorectal cancer surgery and not anastomotic leak. KEY POINTS: • Aortic calcification measured by visual quantification of the number of calcified quadrants at two aortic levels on preoperative CT is associated with clinical outcome following colorectal cancer surgery. • An increased burden of aortic calcification was associated with non-infective complications but not anastomotic leak. • Assessment of the degree of aortic calcification may help identify patients at risk of cardiorespiratory complications, improve preoperative risk stratification and assign preoperative strategies to improve fitness for surgery.

New Zealand white rabbit: a novel model for prolapse mesh implantation via a lumbar colpopexy.

INTRODUCTION AND HYPOTHESIS: New Zealand white rabbits are an inexpensive large-animal model. This study explored the rabbit as a model for mesh-augmented colpopexy using the intra-abdominal vagina. We hypothesized that polypropylene mesh would negatively impact rabbit vaginal smooth muscle (VSM) morphology and contractile function, similar to the nonhuman primate (NHP)-the established model for prolapse mesh evaluation. METHODS: Restorelle was implanted onto the vagina of ten rabbits via lumbar colpopexy after a hysterectomy. Ten rabbits served as sham. Twelve weeks post-implantation, the vagina was excised and VSM morphology and vaginal contractility were assessed. Outcome measures were compared using independent samples t and Mann-Whitney U tests with a Bonferroni correction, where appropriate. Results from the rabbits were compared with published NHP data. RESULTS: Animals had similar age, parity and BMI. VSM was 18% thinner after Restorelle implantation, P = 0.027. Vaginal contractility was 43% decreased in response to 120 mM KCl (P = 0.003), similar to the 46% reduction observed in the NHP vagina implanted with Restorelle (P = 0.027). Three meshes wrinkled in vivo, resulting in dramatic thinning of the underlying vagina in the area of the mesh causing a mesh exposure. CONCLUSIONS: Polypropylene mesh negatively impacts VSM morphology and vaginal contractility in the rabbit, similar to the NHP, suggesting that the rabbit may serve as an alternative large-animal model. The vaginal thinning and appearance of a mesh exposure in the area of a mesh wrinkle suggest the rabbit may also serve as a model for understanding the pathophysiology of mesh exposure.

Impact of polypropylene prolapse mesh on vaginal smooth muscle in rhesus macaque.

BACKGROUND: The use of polypropylene prolapse mesh to treat pelvic organ prolapse has been limited by mesh-related complications. Gynemesh PS mesh, implanted via sacrocolpopexy in rhesus macaques, had a negative impact on the vagina with thinning of vaginal muscularis and decreased vaginal smooth muscle contractility. The negative effect was attenuated when a bioscaffold derived from urinary bladder extracellular matrix was used as a composite with Gynemesh PS. OBJECTIVE: The objective of the study was to further elucidate the impact of Gynemesh PS polypropylene mesh and MatriStem extracellular matrix bioscaffolds on the vaginal smooth muscle in terms of micromorphology of vaginal smooth muscle (muscle bundles and individual myocytes), innervation, and nerve-mediated contractile function following their implantations in a rhesus macaque model via sacrocolpopexy. STUDY DESIGN: Thirty-two middle-aged rhesus macaques were randomized to undergo either a sham surgery (sham, n = 8), or the implantation of Gynemesh PS alone (n = 8) vs composite mesh comprised of Gynemesh PS plus 2-ply MatriStem (n = 8) vs 6-ply MatriStem alone (n = 8) via sacrocolpopexy. The graft-vagina complexes were harvested 3 months later. Histomorphometrics of smooth muscle bundles and myocytes were performed by immunofluorescent labeling of alpha smooth muscle actin, caveolin-3 (membrane protein), and cell nuclei followed by confocal imaging. The cross-sectional diameters of smooth muscle bundles and individual myocytes were quantified using images randomly taken in at least 5 areas of each section of sample. Contractile proteins alpha smooth muscle actin and smoothelin were quantified by Western immunoblotting. Nerve density was measured by immunohistochemical labeling of a pan-neuron marker, PGP9.5. Nerve-mediated smooth muscle contractility was quantified using electrical field stimulation. One-way analysis of variance and appropriate post hoc tests were used for statistical comparisons. RESULTS: Compared with sham, the implantation of Gynemesh PS alone resulted in a disorganized smooth muscle morphology with the number of small muscle bundles (cross-sectional diameter less than 20 µm) increased 67% (P = .004) and the myocyte diameter decreased 22% (P < .001). Levels of contractile proteins were all decreased vs sham with alpha smooth muscle actin decreased by 68% (P = .009), low-molecular-weight smoothelin by 51% (P = .014), and high-molecular-weight smoothelin by 40% (P = .015). Nerve density was decreased by 48% (P = .03 vs sham) paralleled by a 63% decrease of nerve-mediated contractility (P = .02). Following the implantation of composite mesh, the results of measurements were similar to sham (all P > .05), with a 39% increase in the myocyte diameter (P < .001) and a 2-fold increase in the level of alpha smooth muscle actin relative to Gynemesh (P = .045). Following the implantation of MatriStem alone, the number of small muscle bundles were increased 54% vs sham (P = .002), while the other parameters were not significantly different from sham (all P > .05). CONCLUSION: The implantation of Gynemesh PS had a negative impact on the structural and functional integrity of vaginal smooth muscle evidenced by atrophic macro- and microscopic muscle morphology, decreased innervation, and impaired contractile property, consistent with a maladaptive remodeling response. The extracellular matrix bioscaffold (MatriStem), when used with Gynemesh PS as a composite (2 ply), attenuated the negative impact of Gynemesh PS; when used alone (6 ply), it induced adaptive remodeling as evidenced by an increased fraction of small smooth muscle bundles with normal contractility.

Towards rebuilding vaginal support utilizing an extracellular matrix bioscaffold.

As an alternative to polypropylene mesh, we explored an extracellular matrix (ECM) bioscaffold derived from urinary bladder matrix (MatriStem™) in the repair of vaginal prolapse. We aimed to restore disrupted vaginal support simulating application via transvaginal and transabdominal approaches in a macaque model focusing on the impact on vaginal structure, function, and the host immune response. In 16 macaques, after laparotomy, the uterosacral ligaments and paravaginal attachments to pelvic side wall were completely transected (IACUC# 13081928). 6-ply MatriStem was cut into posterior and anterior templates with a portion covering the vagina and arms simulating uterosacral ligaments and paravaginal attachments, respectively. After surgically exposing the correct anatomical sites, in 8 animals, a vaginal incision was made on the anterior and posterior vagina and the respective scaffolds were passed into the vagina via these incisions (transvaginal insertion) prior to placement. The remaining 8 animals underwent the same surgery without vaginal incisions (transabdominal insertion). Three months post implantation, firm tissue bands extending from vagina to pelvic side wall appeared in both MatriStem groups. Experimental endpoints examining impact of MatriStem on the vagina demonstrated that vaginal biochemical and biomechanical parameters, smooth muscle thickness and contractility, and immune responses were similar in the MatriStem no incision group and sham-operated controls. In the MatriStem incision group, a 41% decrease in vaginal stiffness (P=0.042), a 22% decrease in collagen content (P=0.008) and a 25% increase in collagen subtypes III/I was observed vs. Sham. Active MMP2 was increased in both Matristem groups vs. Sham (both P=0.002). This study presents a novel application of ECM bioscaffolds as a first step towards the rebuilding of vaginal support. STATEMENT OF SIGNIFICANCE: Pelvic organ prolapse is a common condition related to failure of the supportive soft tissues of the vagina; particularly at the apex and mid-vagina. Few studies have investigated methods to regenerate these failed structures. The overall goal of the study was to determine the feasibility of utilizing a regenerative bioscaffold in prolapse applications to restore apical (level I) and lateral (level II) support to the vagina without negatively impacting vaginal structure and function. The significance of our findings is two fold: 1. Implantation of properly constructed extracellular matrix grafts promoted rebuilding of level I and level II support to the vagina and did not negatively impact the overall functional, morphological and biochemical properties of the vagina. 2. The presence of vaginal incisions in the transvaginal insertion of bioscaffolds may compromise vaginal structural integrity in the short term.

Extracellular matrix regenerative graft attenuates the negative impact of polypropylene prolapse mesh on vagina in rhesus macaque.

BACKGROUND: The use of wide pore lightweight polypropylene mesh to improve anatomical outcomes in the surgical repair of prolapse has been hampered by mesh complications. One of the prototype prolapse meshes has been found to negatively impact the vagina by inducing a decrease in smooth muscle volume and contractility and the degradation of key structural proteins (collagen and elastin), resulting in vaginal degeneration. Recently, bioscaffolds derived from extracellular matrix have been used to mediate tissue regeneration and have been widely adopted in tissue engineering applications. OBJECTIVE: Here we aimed to: (1) define whether augmentation of a polypropylene prolapse mesh with an extracellular matrix regenerative graft in a primate sacrocolpopexy model could mitigate the degenerative changes; and (2) determine the impact of the extracellular matrix graft on vagina when implanted alone. STUDY DESIGN: A polypropylene-extracellular matrix composite graft (n = 9) and a 6-layered extracellular matrix graft alone (n = 8) were implanted in 17 middle-aged parous rhesus macaques via sacrocolpopexy and compared to historical data obtained from sham (n = 12) and the polypropylene mesh (n = 12) implanted by the same method. Vaginal function was measured in passive (ball-burst test) and active (smooth muscle contractility) mechanical tests. Vaginal histomorphologic/biochemical assessments included hematoxylin-eosin and trichrome staining, immunofluorescent labeling of α-smooth muscle actin and apoptotic cells, measurement of total collagen, collagen subtypes (ratio III/I), mature elastin, and sulfated glycosaminoglycans. Statistical analyses included 1-way analysis of variance, Kruskal-Wallis, and appropriate post-hoc tests. RESULTS: The host inflammatory response in the composite mesh-implanted vagina was reduced compared to that following implantation with the polypropylene mesh alone. The increase in apoptotic cells observed with the polypropylene mesh was blunted in the composite (overall P < .001). Passive mechanical testing showed inferior parameters for both polypropylene mesh alone and the composite compared to sham whereas the contractility and thickness of smooth muscle layer in the composite were improved with a value similar to sham, which was distinct from the decreases observed with polypropylene mesh alone. Biochemically, the composite had similar mature elastin content, sulfated glycosaminoglycan content, and collagen subtype III/I ratio but lower total collagen content when compared to sham (P = .011). Multilayered extracellular matrix graft alone showed overall comparable values to sham in aspects of the biomechanical, histomorphologic, or biochemical endpoints of the vagina. The increased collagen subtype ratio III/I with the extracellular matrix graft alone (P = .033 compared to sham) is consistent with an ongoing active remodeling response. CONCLUSION: Mesh augmentation with a regenerative extracellular matrix graft attenuated the negative impact of polypropylene mesh on the vagina. Application of the extracellular matrix graft alone had no measurable negative effects suggesting that the benefits of this extracellular matrix graft occur when used without a permanent material. Future studies will focus on understanding mechanisms.

Exploring the basic science of prolapse meshes.

PURPOSE OF REVIEW: Polypropylene mesh has been widely used in the surgical repair of pelvic organ prolapse. However, low but persistent rates of complications related to mesh, most commonly mesh exposure and pain, have hampered its use. Complications are higher following transvaginal implantation prompting the Food and Drug Administration to release two public health notifications warning of complications associated with transvaginal mesh use (PHN 2008 and 2011) and to upclassify transvaginal prolapse meshes from Class II to Class III devices. Although there have been numerous studies to determine the incidence and management of mesh complications as well as impact on quality of life, few studies have focused on mechanisms. RECENT FINDINGS: In this review, we summarize the current understanding of how mesh textile properties and mechanical behavior impact vaginal structure and function, as well as the local immune response. We also discuss how mesh properties change in response to loading. SUMMARY: We highlight a few areas of current and future research to emphasize collaborative strategies that incorporate basic science research to improve patient outcomes.

Colorectal cancer in the elderly and the influence of lead time bias: better survival does not equate with improved life expectancy.

AIMS: Poorer outcomes in those aged ≥80 years who undergo colorectal cancer surgery have been previously reported. Little is known about the natural history of those managed non-operatively. We explored outcomes in all patients with colorectal cancer aged ≥80 years at time of diagnosis based on treatment received. METHODS: Patients ≥80 years diagnosed with colorectal cancer in one hospital trust between 1998 and 2011 were identified from a prospectively maintained database. Primary endpoints were age at diagnosis, age at death/censor and mortality at 30, 90 and 365 days. RESULTS: Six hundred sixty-eight patients were identified. Four hundred twelve (61.7%) underwent surgery, 44 (6.6%) received endoscopic therapy and 212 (31.7%) had no active treatment. Of those who underwent surgery, 359 (87.1%) had resectional surgery, 34 (8.3%) defunctioning only, 13 (3.2%) received bypass surgery and 6 (1.5%) had an open and close laparotomy. The mean age at diagnosis was younger in those who underwent surgical resection (83.7 years) compared to those having defunctioning surgery (84.9 years, P = 0.043), endoscopic therapy (85.1 years, P = 0.008) or no surgical intervention (85.6 years, P < 0.001). There was no significant difference in the mean age of death or censor between groups. CONCLUSIONS: There was no significant difference in age at death or censor between treatment groups among patients aged ≥80 years presenting with colorectal cancer, suggesting that differences in the observed survival time are heavily influenced by lead time bias. Age at death or censor should be reported in addition to survival times in this age group to enable fair comparison of outcomes.