The Prospect of Harnessing the Microbiome to Improve Immunotherapeutic Response in Pancreatic Cancer

Pancreatic ductal adenocarcinoma cancer (PDAC) is projected to become the second leading cause of cancer-related death in the United States by 2030. Patients are often diagnosed with advanced disease, which explains the dismal 5-year median overall survival rate of ~12%. Immunotherapy has been successful in improving outcomes in the past decade for a variety of malignancies, including gastrointestinal cancers. However, PDAC is historically an immunologically "cold" tumor, one with an immunosuppressive environment and with restricted entry of immune cells that have limited the success of immunotherapy in these tumors. The microbiome, the intricate community of microorganisms present on and within humans, has been shown to contribute to many cancers, including PDAC. Recently, its role in tumor immunology and response to immunotherapy has generated much interest. Herein, the current state of the interaction of the microbiome and immunotherapy in PDAC is discussed with a focus on needed areas of study in order to harness the immune system to combat pancreatic cancer.

A phase II study of neoadjuvant liposomal irinotecan with 5-FU and oxaliplatin (NALIRIFOX) in pancreatic adenocarcinoma

For patients with localized pancreatic cancer with minimal vascular involvement, optimal survivability requires a multidisciplinary approach of surgical resection and systemic chemotherapy. FOLFIRINOX is a combination chemotherapy regimen that offers promising results in the perioperative and metastatic settings; however, it can cause significant adverse effects. Such toxicity can negatively impact some patients, resulting in chemotherapy discontinuation or surgical unsuitability. In an effort to reduce toxicities and optimize outcomes, this investigation explores the safety and feasibility of substituting liposomal irinotecan (nal-IRI) for nonliposomal irinotecan to improve tumor drug delivery and potentially reduce toxicity. This regimen, NALIRIFOX, has the potential to be both safer and more effective when administered in the preoperative setting.

Development of a computable phenotype using electronic health records for venous thromboembolism in medical inpatients: the Medical Inpatient Thrombosis and Hemostasis study

Background

Accurate and efficient methods to identify venous thromboembolism (VTE) events in hospitalized people are needed to support large-scale studies. Validated computable phenotypes using a specific combination of discrete, searchable elements in electronic health records to identify VTE and distinguish between hospital-acquired (HA)-VTE and present-on-admission (POA)-VTE would greatly facilitate the study of VTE, obviating the need for chart review.

Objectives

To develop and validate computable phenotypes for POA- and HA-VTE in adults hospitalized for medical reasons.

Methods

The population included admissions to medical services from 2010 to 2019 at an academic medical center. POA-VTE was defined as VTE diagnosed within 24 hours of admission, and HA-VTE as VTE identified more than 24 hours after admission. Using discharge diagnosis codes, present-on-admission flags, imaging procedures, and medication administration records, we iteratively developed computable phenotypes for POA-VTE and HA-VTE. We assessed the performance of the phenotypes using manual chart review and survey methodology.

Results

Among 62,468 admissions, 2693 had any VTE diagnosis code. Using survey methodology, 230 records were reviewed to validate the computable phenotypes. Based on the computable phenotypes, the incidence of POA-VTE was 29.4 per 1000 admissions and that of HA-VTE was 3.6 per 1000 admissions. The POA-VTE computable phenotype had positive predictive value and sensitivity of 88.8% (95% CI, 79.8%-94.0%) and 99.1% (95% CI, 94.0%- 99.8%), respectively. Corresponding values for the HA-VTE computable phenotype were 84.2% (95% CI, 60.8%-94.8%) and 72.3% (95% CI, 40.9%-90.8%).

Conclusion

We developed computable phenotypes for HA-VTE and POA-VTE with adequate positive predictive value and sensitivity. This phenotype can be used in electronic health record data-based research.

Role of Bacteria in the Development of Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Once limited to older populations, the incidence of CRC in patients under the age of 50 years is increasing and the etiology for this is uncertain. One hypothesis lies on the impact of the intestinal microbiome. The intestinal microbiome, composed primarily of bacteria but also viruses, fungi, and archaea, has been shown to regulate CRC development and progression both in vitro and in vivo. In this review, the role and intersection of the bacterial microbiome in various stages of clinical CRC development and management are discussed beginning with CRC screening. Various mechanisms whereby the microbiome has been shown to modulate CRC development including the influence of diet on the microbiome, bacterial-induced injury to the colonic epithelium, bacterial-produced toxins, and alteration of normal cancer immunosurveillance by the microbiome are discussed. Finally, the influence of microbiome on the response of CRC to treatment is discussed while highlighting ongoing clinical trials. The complexities of the microbiome and its role in CRC development and progression have become apparent and will require ongoing commitment to translate laboratory findings into meaningful clinical results that will aid more than 150,000 patients that develop CRC every year.

A phase Ib/II study of atezolizumab plus tivozanib in pancreatic, gallbladder, and bile duct malignancies

TPS625

Background: Immune checkpoint inhibitor (ICI) therapy represents a significant advance in cancer care however it is not an effective intervention in the treatment of several immunologically cold tumors including pancreatic, gallbladder, and bile duct malignancies where ICIs have produced objective response rates of 0-6%. VEGF is thought to play a key role in modulating the anti-tumor immune response as it is secreted by tumors and leads to endothelial cell proliferation, vascular permeability, and vasodilation. This in turn leads to the development of an abnormal vasculature with excessive permeability and poor blood flow, thus limiting immune surveillance. In addition, VEGF inhibits dendritic cell differentiation, limiting the presentation of tumor antigens to CD4 and CD8 T cells. Through the inhibition of VEGF, it may be possible to potentiate the effect of ICIs. Combined use of a VEGF receptor tyrosine kinase inhibitor (TKI) and ICI is already approved for advanced kidney and endometrial cancer. Methods: This is a single institution, single arm, open-label phase Ib/II study with the co-primary endpoints of safety and efficacy of the combination of the VEGFR-TKI tivozanib and the ICI atezolizumab. Eligible patients are those with metastatic cancer progressing on at least one line of therapy of the following organs: pancreatic, gallbladder, bile duct, well-differentiated grade 2 and 3 neuroendocrine tumors, ovarian, vulvar, soft tissue sarcoma, castrate resistant prostate, and HER2 positive hormone receptor negative breast. Key exclusion criteria will include patients with known mismatch repair deficiency, microsatellite instability, or high tumor mutational burden. The phase Ib portion will assess the safety profile of the combination of tivozanib and atezolizumab with a potential dose de-escalation of tivozanib using a 3+3 study design. Three patients will be treated with tivozanib 1.34 mg per day (dose level 0) for 21 days of each 28-day cycle and atezolizumab 1680 mg on day 1 of every 28-day cycle. If one dose limiting toxicity (DLT) is found then 3 more patients will be enrolled at dose level 0. If >1 DLT occurs in the first 3 patients or >1 DLT in the first 6, another 3+3 study will begin at dose level -1 (0.89 mg of tivozanib). If 1 DLT occurs in these 3 patients at dose level -1 then another 3 will be enrolled at this dose. The study will be stopped for toxicity if there is >1 DLT in the first 3 patients at dose level -1 or if there are >1 DLT in the 6 patients at dose level -1. A subsequent protocol amendment was made to reduce tivozanib dose level 0 to 0.89 mg per day and dose level -1 to 0.89 mg every other day. The phase II portion will enroll up to 26 patients using the dose of tivozanib found to be safe in the Ib portion. Disease response assessment every 12 weeks with CT Chest, Abdomen, and Pelvis via RECIST 1.1. Treatment will continue until progression or intolerance. Enrollment is ongoing. Clinical trial information: NCT05000294 .

The Influence of the microbiome on the innate immune microenvironment of solid tumors

Cancer remains a leading cause of death despite many advances in medical and surgical therapy. In recent decades, the investigation for novel therapeutic strategies with greater efficacy and reduced side effects has led to a deeper understanding of the relationship between the microbiome and the immune system in the context of cancer. The ability of the immune system to detect and kill cancer is now recognized to be greatly influenced by the microbial ecosystem of the host. While most of these studies, as well as currently used immunotherapeutics, focus on the adaptive immune system, this minimizes the impact of the innate immune system in cancer surveillance and its regulation by the host microbiome. In this review, known influences of the microbiome on the innate immune cells in the tumor microenvironment will be discussed in the context of individual innate immune cells. Current and needed areas of investigation will highlight the field and its potential impact in the clinical treatment of solid malignancies.

Atezolizumab plus tivozanib for immunologically cold tumor types: the IMMCO-1 trial

Immune checkpoint inhibitor therapy represents a significant advance in cancer care. The interaction between PD-1 and PD-L1 induces immune tolerance and the inhibition of this interaction is an effective treatment strategy for numerous malignancies. Despite its demonstrated potential, immunotherapy is not clinically effective in immunogenically 'cold' tumors such as pancreatic cancer, prostate cancer and neuroendocrine tumors. Through the inhibition of VEGF, it may be possible to potentiate the effect of immune checkpoint blockade in tumors that have traditionally shown a lack of clinical response to immunotherapy. This signal-seeking, single-arm, prospective clinical trial aims to determine the objective response of tivozanib and atezolizumab in advanced immunogenically cold solid tumors. Clinical Trial Registration: NCT05000294 (ClinicalTrials.gov).

Intestinal microbiota modulates pancreatic carcinogenesis through intratumoral natural killer cells

Preclinical data demonstrate that the gut microbiota can promote pancreatic ductal adenocarcinoma (PDAC), but mechanisms remain unclear. We hypothesized that intestinal microbiota alters anti-tumor innate immunity response to facilitate PDAC progression. Human PDAC L3.6pl cells were heterotopically implanted into Rag1^-/- mice after microbiota depletion with antibiotics, while syngeneic murine PDAC Pan02 cells were implanted intrapancreatic into germ-free (GF) C57BL/6 J mice. Natural killer (NK) cells and their IFNγ expression were quantitated by flow cytometry. NK cells were depleted in vivo using anti-Asialo GM1 antibody to confirm the role of NK cells. Bacteria-free supernatant from SPF and GF mice feces was used to test its effect on NK-92MI cell anti-tumor response in vitro. SPF and ex-GF mice (reconstituted with SPF microbiota) developed larger PDAC tumors with decreased NK cell tumor infiltration and IFNγ expression versus GF-Rag1^-/-. Microbiota-induced PDAC tumorigenesis was attenuated by antibiotic exposure, a process reversed following NK cell depletion in both Rag1^-/- and C57BL/6 J mice. Compared to GF, SPF-Rag1^-/- abiotic stool culture supernatant inhibited NK-92MI cytotoxicity, migration, and anti-cancer related gene expression. Gut microbiota promotes PDAC tumor progression through modulation of the intratumoral infiltration and activity of NK cells.

Sex differences associate with late microbiome alterations after murine surgical sepsis

BACKGROUND

Sepsis-induced gut microbiome alterations contribute to sepsis-related morbidity and mortality. Given evidence for improved postsepsis outcomes in females compared with males, we hypothesized that female mice maintain microbiota resilience versus males.

METHODS

Mixed-sex C57BL/6 mice underwent cecal ligation and puncture (CLP) with antibiotics, saline resuscitation, and daily chronic stress and were compared with naive (nonsepsis/no antibiotics) controls. For this work, the results of young (3-5 months) and old (18-22 months) adult mice were analyzed by sex, independent and dependent of age. Mice were sacrificed at days 7 and 14, and 16S rRNA gene sequencing was performed on fecal bacterial DNA. α and β diversity were determined by Shannon index and Bray-Curtis with principal coordinate analysis, respectively. False discovery rate (FDR) correction was implemented to account for potential housing effect.

RESULTS

In control mice, there was no difference in α or β diversity between male and female mice (FDR, 0.76 and 0.99, respectively). However, male mice that underwent CLP with daily chronic stress had a decrease in microbiota α diversity at 7 days post-CLP (Shannon FDR, 0.005), which was sustained at 14 days post-CLP (Shannon FDR, 0.001), compared with baseline. In addition, male mice maintained differences in β diversity even at day 14 compared with controls (FDR, <0.0001). In contrast, female mice had a decreased microbiota α diversity (Shannon FDR, 0.03) and β diversity (FDR, 0.02) 7 days post-CLP but recovered their α and β diversity by post-CLP day 14 (Shannon FDR, 0.5, and FDR, 0.02, respectively). Further analysis of females revealed that only young female mice were not different (β diversity) post-CLP day 14 to controls.

CONCLUSION

Although sepsis-induced perturbations of the intestinal microbiota occur initially in both male and female C57BL/6 mice, females demonstrate different microbiota by day 14. This may be seen primarily in younger females. This difference in recovery may play a role in outcome differences between sexes after sepsis.

A phase II, open-label, pilot study evaluating the safety and activity of liposomal irinotecan (Nal-IRI) in combination with 5-FU and oxaliplatin (NALIRIFOX) in preoperative treatment of pancreatic adenocarcinoma: NEO-Nal-IRI study

TPS4196

Background: Neoadjuvant treatment for potentially curable pancreatic cancer (PDAC) is increasing in acceptability, but a standard regimen has yet to be established. Multiple studies have demonstrated feasibility and effectiveness of the FOLFIRINOX (5-fluorouracil, leucovorin, oxaliplatin and irinotecan) regimen in the perioperative setting. However, FOLFIRINOX often requires dose modifications, delays and growth factor support due to excessive toxicity which can complicate care delivery when given pre-op. Liposomal irinotecan injection (Nal-IRI) is FDA approved in combination with 5-FU/LV with a well-tolerated safety profile in relapsed, refractory metastatic PDAC. The current study aims to substitute Nal-IRI for traditional irinotecan in the standard FOLFIRINOX regimen (NALIRIFOX) and to demonstrate safe and effective neoadjuvant delivery. Methods: This phase 2, open-label, multicenter single-arm study focuses on patients (pts) with operable PDAC without metastatic disease. Other key eligibility criteria include age ≥18 years, resectability confirmed by multiD GI tumor board (resectable vs. borderline), adequate cardiac, renal, hepatic function and ECOG performance status of 0 to 1. Pts receive NALIRIFOX regimen as per the table every 2 weeks for four months followed by disease reassessment. Pts who remain surgical candidates will undergo surgical resection within 4 to 8 weeks following last dose of therapy. The primary endpoint is to assess safety and feasibility of regimen in pre-op setting. Secondary endpoints include R0 resection rate, clinical, biochemical and radiological response rate and patient-reported quality of life during treatment as measured by the NCI validated FACT-G scale. Enrollment continues to a maximum of 28 evaluable pts to demonstrate a reduction in historical 30-day post-op complication rate. Clinical trial information: NCT03483038. [Table: see text]

When is a lipoma not a lipoma? Case report presenting a lipoblastoma-like tumor of the gluteal cleft in an older gentleman with literature review

Introduction and importance

Lipoblastoma-like tumors are rare tumors that can be confused with lipoblastomas and liposarcomas but have distinct characteristics. This tumor has previously been identified in the vulva of females, and recently in isolated cases of young males. Given its rarity, we present an instance of this tumor in an older man, demonstrating that this pathology is not limited to a specific age or sex, and surgeons and pathologists must be aware of it in their differential.

Case presentation

A 58-year-old male presented for evaluation of an enlarging mass in his right gluteal cleft. Prior to referral for surgical evaluation, the patient underwent an ultrasound-guided biopsy of the mass. Histologically, the tumor was a low-grade cellular spindle cell neoplasm in a fibrous to myxoid stroma. Immunohistochemical and molecular workup ruled out several malignant mesenchymal neoplasms, including myxoid liposarcoma, dedifferentiated liposarcoma, melanoma, low-grade fibromyxoid sarcoma, and sarcomatoid carcinoma. The patient initially declined surgery, but the mass continued to grow, and excision was chosen given the uncertain pathology. The tumor was resected with negative margins and histologically characterized as a “lipoblastoma-like lesion”, with features of a myxoid liposarcoma and spindle cell lipoma. Seven months post-resection, there were no signs of recurrence or metastasis.

Clinical discussion

Despite radiologic and pathologic similarities to malignant lipomatous tumors, lipoblastoma-like tumors are benign and have a good prognosis.

Conclusions

Clinicians should be aware of this entity despite its rarity as resection with negative margins is curative and may be needed to rule out more aggressive tumors.

•

Lipoblastoma-like tumors (LLTs) are rare soft tissue tumors.

•

LLTs can easily be confused clinically and pathologically for benign lipomas but also malignant liposarcomas.

•

Pathologic evaluation is able to distinguish these tumors from their more aggressive counterparts.

•

Because of their rare nature, clinicians may over or under-treat these tumors which require surgical excision.

•

Local recurrence is rare but is predicated on negative surgical margins.

A phase II, open-label pilot study evaluating the safety and activity of liposomal irinotecan (Nal-IRI) in combination with 5-FU and oxaliplatin (NALIRIFOX) in preoperative treatment of pancreatic adenocarcinoma: NEO-Nal-IRI study

TPS619

Background: Neoadjuvant treatment for potentially curable pancreatic cancer (PDAC) is increasing in acceptability, but a standard regimen has yet to be established. Multiple studies have demonstrated feasibility and effectiveness of the FOLFIRINOX (5-fluorouracil, leucovorin, oxaliplatin and irinotecan) regimen in the perioperative setting. However, FOLFIRINOX often requires dose modifications, delays and growth factor support due to excessive toxicity which can complicate care delivery when given pre-op. Liposomal irinotecan injection (Nal-IRI) in combination with 5FU/LV is FDA approved with a well-tolerated safety profile in relapsed, refractory metastatic PDAC. The current study aims to substitute Nal-IRI for traditional irinotecan in the standard FOLFIRINOX regimen (NALIRIFOX) and to demonstrate safe and effective neoadjuvant delivery. Methods: This phase 2, open-label, multicenter single-arm study focuses on patients (pts) with operable PDAC without metastatic disease. Other key eligibility criteria include age ≥18 years, resectability confirmed by multiD GI tumor board (resectable vs. borderline), adequate cardiac, renal, hepatic function and ECOG performance status of 0 to 1. Pts receive NALIRIFOX regimen as per the table every 2 weeks for four months followed by disease reassessment. Pts who remain surgical candidates will undergo surgical resection within 4 to 8 weeks following last dose of therapy. The primary endpoint is to assess safety and feasibility of regimen in pre-op setting. Secondary endpoints include R0 resection rate, clinical, biochemical and radiological response rate and patient-reported quality of life during treatment as measured by the NCI validated FACT-G scale. Exploratory ctDNA and stool microbiome analyses are also planned. Enrollment continues to a maximum of 28 evaluable pts to demonstrate a reduction in historical 30-day post-op complication rate. Clinical trial information: NCT03483038. [Table: see text]

Routine Radiologic Assessment for Anastomotic Leak Is Not Necessary in Asymptomatic Patients After Esophagectomy for Esophageal Cancer

BACKGROUND

Anastomotic leaks (AL) are a major source of post-esophagectomy morbidity and patients are often initially asymptomatic. Debate exists on timing and utility of imaging to detect AL post-esophagectomy. We sought to evaluate the efficacy and timing of radiographic AL evaluation in esophageal cancer patients post-esophagectomy.

METHODS

A retrospective database of esophageal cancer patients who underwent esophagectomy at a single institution from 2004 to 2020 was used to determine the utilization, timing, and sensitivity of radiologic testing for AL post-esophagectomy.

RESULTS

Seventy-six patients were identified of which 37 (49%) had a cervical anastomosis. Sixty-four (84%) underwent 71 "asymptomatic radiographic leak tests" (ARLT), 7 of which had 2 different tests, including: 41 fluoroscopic esophagrams (58%), 18 CT-esophagrams (25%), and 12 upper GI studies (17%). Seventeen patients (22%) developed clinical signs of AL (hemodynamic instability, leukocytosis) and underwent "symptomatic radiographic leak tests" (SRLT) with fluoroscopic esophagram (n = 9, 12%), CT-esophagram (n = 7, 9%), or upper GI study (n = 1, 1%). ARLT and SRLT were positive in 2/64 (3%) and 17/17 (100%) patients, respectively, for 19 total ALs (25%). Among the 17 SRLT( +) patients, 1 was also ARLT( +), 13 were initially ARLT( -), and 3 were not evaluated by ARLT. The median postoperative day for ARLT and SRLT was 4.0 (IQR 3.0-5.5) and 9.0 days (IQR 6.0-13.0), respectively, with a statistically significant difference (p < 0.005). The sensitivity and specificity of ARLT for detecting AL were 13.3% and 100.0%, respectively.

CONCLUSIONS

Based on the low ARLT sensitivity, routine use of imaging to detect asymptomatic ALs post-esophagectomy may be limited. Symptomatic ALs were often present in a delayed fashion, even after initial negative imaging.

A phase Ib/II study (IMMCO-1) of atezolizumab plus tivozanib in immunologically cold pancreatic, gallbladder, and biliary cancers

TPS491

Background: Checkpoint inhibition (CPI) represents a significant advance in cancer care however it is not effective in the treatment of several immunologically cold tumors including pancreatic, gallbladder, and biliary cancers where checkpoint inhibitors have produced objective response rates of <5%. VEGF is thought to play a key role in modulating the anti-tumor immune response. Secreted by tumors, it leads to endothelial cell proliferation, vascular permeability, and vasodilation that together leads to the development of an abnormal vasculature with excessive permeability and poor blood flow, thus limiting immune surveillance. In addition, VEGF inhibits dendritic cell differentiation, limiting the presentation of tumor antigens to CD4 and CD8 T cells. Through the inhibition of VEGF, it may be possible to potentiate the effect of immune checkpoint blockade. Combined use of a VEGF tyrosine kinase inhibitor (TKI) and checkpoint inhibitor is already standard of care in advanced kidney, cervical and endometrial cancers. There has been suggestion that such a combination may have clinical activity in some microsatellite stable (MSS) GI malignancies. This signal seeking study aims to build upon those observations by incorporating a pan-VEGF axis inhibitor (tivozanib) with CPI. Methods: This is an open-label non-randomized phase Ib/II signal seeking basket study in multiple immunologically cold tumors. The co-primary endpoints are safety and efficacy of the combination of the VEGF-TKI tivozanib and CPI atezolizumab. Key eligibility criteria includes patients with MSS pancreatic, biliary (cholangiocarcinoma and gallbladder), well-differentiated grade 2 and 3 neuroendocrine tumors, ovarian and vulvar cancer, soft tissue sarcoma, castrate resistant prostate cancer, and HER2 positive hormone receptor negative breast cancer, that is metastatic and progressed on at least one line of therapy. Key exclusion criteria will include patients with known mismatch repair deficiency, microsatellite instability, or high tumor mutational burden. The phase Ib portion will assess the safety profile of the combination of tivozanib and atezolizumab with a potential dose de-escalation of tivozanib using a 3+3 study design. Starting doses include tivozanib 1.34 mg per day for 21 days of each 28-day cycle and atezolizumab 1680 mg on day 1 of every 28-day cycle. The phase II portion will enroll up to 26 additional patients using the dose of tivozanib found to be safe in the Ib portion. Disease response assessments are every 12 weeks with CT Chest, Abdomen, and Pelvis via RECIST 1.1. Treatment will continue until progression or intolerance. This signal seeking study is looking to confirm the best objective response rate for evaluable patients increasing from <7% (null hypothesis) to 25% (one-sided alpha = 0.05; 80% power). Active enrollment continues. Clinical trial information: NCT05000294.

Sepsis-Induced Myopathy and Gut Microbiome Dysbiosis: Mechanistic Links and Therapeutic Targets

ABSTRACT

Sepsis is currently defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. The skeletal muscle system is among the host organ systems compromised by sepsis. The resulting neuromuscular dysfunction and impaired regenerative capacity defines sepsis-induced myopathy and manifests as atrophy, loss of strength, and hindered regeneration after injury. These outcomes delay recovery from critical illness and confer increased vulnerability to morbidity and mortality. The mechanisms underlying sepsis-induced myopathy, including the potential contribution of peripheral organs, remain largely unexplored. The gut microbiome is an immunological and homeostatic entity that interacts with and controls end-organ function, including the skeletal muscle system. Sepsis induces alterations in the gut microbiota composition, which is globally termed a state of "dysbiosis" for the host compared to baseline microbiota composition. In this review, we critically evaluate existing evidence and potential mechanisms linking sepsis-induced myopathy with gut microbiota dysbiosis.

Bacteria and Sepsis: Microbiome to the Rescue?

The microbiome is the metagenome of all microbes that live on and within every individual, and evidence for its role in the pathogenesis of a variety of diseases has been increasing over the past several decades. While there are various causes of sepsis, defined as the abnormal host response to infection, the host microbiome may provide a unifying explanation for discrepancies that are seen in septic patient survival based on age, sex, and other confounding factors. As has been the case for other human diseases, evidence exists for the microbiome to control patient outcomes after sepsis. In this review, associative data for the microbiome and sepsis survival are presented with causative mechanisms that may be at play. Finally, clinical trials to manipulate the microbiome in order to improve patient outcomes after sepsis are presented as well as areas of potential future research in order to aid in the clinical treatment of these patients.

SSAT State-of-the-Art Conference: Advancements in the Microbiome

The microbiome plays a major role in human physiology by influencing obesity, inducing inflammation, and impacting cancer therapies. During the 60th Annual Meeting of the Society of the Alimentary Tract (SSAT) at the State-of-the-Art Conference, experts in the field discussed the influence of the microbiome. This paper is a summary of the influence of the microbiome on obesity, inflammatory bowel disease, pancreatic cancer, cancer therapies, and gastrointestinal optimization. This review shows how the microbiome plays an important role in the development of diseases and surgical complications. Future studies are needed in targeting the gut microbiome to develop individualized therapies.

Stress-related changes in the gut microbiome after trauma

BACKGROUND

The gut microbiome protects the host from infection by promoting epithelial integrity and providing basal immunologic stimulation. Disruption of this delicate ecosystem is linked to morbidity and mortality among critically ill patients, but the impact of traumatic injury on the gut microbiome is poorly understood. This study sought to identify alterations in gut microbiota following trauma and persistent stress in rodents without confounding antibiotics.

METHODS

Male Sprague-Dawley rats aged 9 weeks to 11 weeks were randomized to naive, lung contusion with hemorrhagic shock (LCHS), and LCHS plus either 7 (LCHS/CS 7/7) or 14 days (LCHS/CS 14) of restraint cylinder stress for 2 hours daily. Stool was collected on Days 0, 3, 7, and 14 for bacterial whole genome DNA isolation. Alpha diversity, or the number and relative abundance of unique bacterial species within each cohort, was assessed using Chao1 indices. Beta diversity, or the measure of differences in biodiversity across cohorts, was assessed by principle coordinate analysis. False discovery rate correction was applied to all statistical analyses and corrected for cohousing effects.

RESULTS

Rodent groups subject to restraint stress demonstrated a progressive increase in alpha diversity over time. These microbiota changes resolved after cessation of stress (LCHS/CS 7/7) but continued to increase among rats subjected to ongoing stress (LCHS/CS 14). The LCHS/CS 7/7 also demonstrated reductions in class Actinobacteria and increased abundance of the genus Bacteroides by Day 7, which resolved by Day 14. Increased abundance of Bacteroides was also noted in the LCHS/CS 14 cohort, suggesting the role of chronic stress in its destabilization.

CONCLUSION

This study points to persistent stress as a potential source of the destabilization of microbial diversity seen after trauma. This lack of microbiota stability could be associated with worse long-term outcomes in critically ill trauma patients. Further studies are warranted to elucidate mechanistic pathways and potential therapeutic modalities.

Septic Stability? Gut Microbiota in Young Adult Mice Maintains Overall Stability After Sepsis Compared to Old Adult Mice

BACKGROUND

Older adults have worse outcomes after sepsis than young adults. Additionally, alterations of the gut microbiota have been demonstrated to contribute to sepsis-related mortality. We sought to determine if there were alterations in the gut microbiota with a novel sepsis model in old adult mice, which enter a state of persistent inflammation, immunosuppression, and catabolism (PICS), as compared with young adult mice, which recover with the sepsis model.

METHODS

Mixed sex old (∼20 mo) and young (∼4 mo) C57Bl/6J mice underwent cecal ligation and puncture with daily chronic stress (CLP+DCS) and were compared with naive age-matched controls. Mice were sacrificed at CLP+DCS day 7 and feces collected for bacterial DNA isolation. The V3-V4 hypervariable region was amplified, 16S rRNA gene sequencing performed, and cohorts compared. α-Diversity was assessed using Chao1 and Shannon indices using rarefied counts, and β-diversity was assessed using Bray-Curtis dissimilarity.

RESULTS

Naive old adult mice had significantly different α and β-diversity compared with naive adult young adult mice. After CLP+DCS, there was a significant shift in the α and β-diversity (FDR = 0.03 for both) of old adult mice (naive vs. CLP+DCS). However, no significant shift was displayed in the microbiota of young mice that underwent CLP+DCS in regards to α-diversity (FDR = 0.052) and β-diversity (FDR = 0.12), demonstrating a greater overall stability of their microbiota at 7 days despite the septic insult. The taxonomic changes in old mice undergoing CLP+DCS were dominated by decreased abundance of the order Clostridiales and genera Oscillospira.

CONCLUSION

Young adult mice maintain an overall microbiome stability 7 days after CLP+DCS after compared with old adult mice. The lack of microbiome stability could contribute to PICS and worse long-term outcomes in older adult sepsis survivors. Further studies are warranted to elucidate mechanistic pathways and potential therapeutics.

Implications of the microbiome in the development and treatment of pancreatic cancer: Thinking outside of the box by looking inside the gut

Pancreatic ductal adenocarcinoma is the third leading cause of cancer-related death in the United States. As one of the most lethal cancer types, the prognosis for patients diagnosed with pancreatic cancer remains dismal and novel investigations are urgently needed. Evidence for an association of microbes with pancreatic cancer risk, development, treatment response, and post-treatment survivorship is rapidly developing. Herein, we provide an overview on the role of the microbiome as it relates to the natural history of pancreatic cancer, including host immune interactions, alterations in metabolism, direct carcinogenic effect, and its role in treatment response.

Proton Pump Inhibitor Use After Hiatal Hernia Repair: Inhibitor of Recurrent Symptoms and Potential Revisional Surgery

BACKGROUND

Hiatal hernia recurrence after hiatal hernia repair (HHR) is often underdiagnosed and underreported but may present with recurrent gastroesophageal reflux disease (GERD) symptoms. Because of their availability, proton pump inhibitor (PPI) use is common and may mask patients who would benefit from revisional surgery, which has been shown to improve symptoms and quality of life.

METHODS

A retrospective analysis was performed to evaluate recurrence patterns of patients who underwent HHR, specifically for the indication of GERD, from 2007 to 2015 at a single Veterans Administration Medical Center. Clinicopathologic parameters were reviewed for association with hiatal hernia recurrence, including postoperative PPI use.

RESULTS

Sixty-four patients were identified with a median follow-up time of 57.8 mo. Thirty-eight patients developed an anatomic recurrence, which did not demonstrate any associated factors on univariate analysis. Seventy percent of patients remained or were restarted on PPI after their initial surgery. For patients with a documented recurrence, the median time to start a PPI was 224 d, but the time to identify recurrence on imaging or endoscopy was 712.5 d. Eleven (39.3%) patients had a reintervention for anatomic recurrence, of which all had developed recurrent symptoms of GERD.

CONCLUSIONS

Most patients who developed recurrent hiatal hernia were restarted on PPI without workup for their symptoms. The time of initiation of PPI was much earlier than the time of identification of a recurrent hiatal hernia. The use of PPIs in patients whom have undergone HHR may delay proper workup to identify recurrent hiatal hernia amenable to surgical repair and should be reserved until patients develop recurrent symptoms and have at least begun a diagnostic workup to rule out an anatomic cause for the recurrent symptoms.

Minimally Invasive Ivor Lewis Esophagectomy with Linear Stapled Anastomosis Associated with Low Leak and Stricture Rates

BACKGROUND

Minimally invasive foregut surgery is increasingly performed for both benign and malignant diseases. We present a retrospective series of patients who underwent minimally invasive Ivor Lewis esophagectomy (MIE) with linear stapled anastomosis performed at two centers in the USA, with a focus on evaluating leak and stricture rates.

METHODS

Patients treated from 2007 to 2018 were included, and data on demographics, oncologic treatment, pathology, and outcomes were analyzed. The surgical technique utilized laparoscopic and thoracoscopic access, with an intrathoracic esophagogastric anastomosis using a 6-cm linear stapled side-to-side technique.

RESULTS

A total of 124 patients were included and 114 resections (91.9%) were completed in a minimally invasive fashion with a 6-cm linear stapled side-to-side anastomosis. Patients were predominantly male (90.7%) with a median age of 66.0 years and body mass index of 28.8 kg/m². Of 121 patients with malignancy, negative margins were obtained in 94.3% and median lymph node yield was 15 (IQR 12-22). In the intention to treat analysis, median operative time was 463 min (IQR 403-515), blood loss was 150 mL (IQR 100-200), and length of stay was 8 days (IQR 7-11). Postoperative complications were experienced by 64 patients (51.6%) including respiratory failure in 14 (11.3%) and pneumonia in 12 (9.7%). In patients who successfully underwent a 6-cm stapled side-to-side anastomosis, anastomotic leaks occurred in 6 patients (5.1%) without need for operative intervention, and anastomotic strictures occurred in 6 patients (5.1%) requiring endoscopic management.

CONCLUSIONS

Ivor Lewis MIE with a 6-cm linear stapled anastomosis can be completed with a high technical success rate, and low rates of anastomotic leak and stricture.

Microbiota in pancreatic health and disease: the next frontier in microbiome research

Diseases intrinsic to the pancreas such as pancreatitis, pancreatic cancer and type 1 diabetes mellitus impart substantial health and financial burdens on society but identification of novel mechanisms contributing to these pathologies are slow to emerge. A novel area of research suggests that pancreatic-specific disorders might be modulated by the gut microbiota, either through a local (direct pancreatic influence) or in a remote (nonpancreatic) fashion. In this Perspectives, we examine literature implicating microorganisms in diseases of the pancreas, specifically pancreatitis, type 1 diabetes mellitus and pancreatic ductal adenocarcinoma. We also discuss evidence of an inherent pancreatic microbiota and the influence of the intestinal microbiota as it relates to disease association and development. In doing so, we address pitfalls in the current literature and areas of investigation that are needed to advance a developing field of research that has clinical potential to reduce the societal burden of pancreatic diseases.

Protein Signatures and Tissue Diagnosis of Pancreatic Cancer

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration fails to diagnose up to 25% of patients with pancreatic ductal adenocarcinoma (PDAC). Proteomics can help to overcome this clinical dilemma. We hypothesized that soluble protein signatures can differentiate PDAC from benign tissues.

STUDY DESIGN

Tissues were obtained from resected surgical specimens, lysed, and homogenates collected for analysis with a 41-protein multiplex assay. Analyte concentrations were normalized to total protein. Statistical analysis was performed to evaluate for differences in PDAC vs benign tissue.

RESULTS

Tissues were obtained from 159 patients, 82 patients with PDAC naïve to therapy and 77 with benign pancreatic pathology. Fourteen analytes had a receiver operating characteristic curve area of >0.75 for predicting PDAC vs benign tissue. A recursive partitioning model using only 2 analytes, interleukin 1 receptor antagonist and transforming growth factor-α, provided an accuracy, sensitivity, and specificity of 91.2%, 90.2%, and 92.2%, respectively. A penalized logistic regression model found 12 analytes that provide diagnostic value to a protein signature. The mean area under the receiver operating characteristic after 50 tenfold cross-validations was 0.951. Accuracy, sensitivity, and specificity of this model were 91.2%, 87.8%, and 94.8%, respectively. Applying the scenario of 80% disease prevalence in patients undergoing endoscopic ultrasound with fine-needle aspiration for a pancreatic head mass, positive predictive value is 98.5% (95% CI 93.0% to 99.7%) and negative predictive value is 66.0% (95% CI 54.9% to 75.6%).

CONCLUSIONS

Protein signatures from pancreatic specimens can differentiate PDAC from benign tissue. Additional work to validate these findings in a unique sample set is warranted.

Where and how our brain represents the temporal structure of observed action

Reacting faster to the behaviour of others provides evolutionary advantages. Reacting to unpredictable events takes hundreds of milliseconds. Understanding where and how the brain represents what actions are likely to follow one another is, therefore, important. Everyday actions occur in predictable sequences, yet neuroscientists focus on how brains respond to unexpected, individual motor acts. Using fMRI, we show the brain encodes sequence-related information in the motor system. Using EEG, we show visual responses are faster and smaller for predictable sequences. We hope this paradigm encourages the field to shift its focus from single acts to motor sequences. It sheds light on how we adapt to the actions of others and suggests that the motor system may implement perceptual predictive coding.

Packed red blood cell donor age affects overall survival in transfused patients undergoing hepatectomy for non-hepatocellular malignancy

BACKGROUND

Patients undergoing hepatectomy often require packed red blood cell (PRBC) transfusion, which has been associated with worse oncologic outcomes. However, limited data exist regarding the impact of PRBC donor factors. We hypothesized that PRBC donor age impacts survival after hepatectomy for non-hepatocellular malignancies.

METHODS

Patients who underwent hepatectomy for non-hepatocellular malignancy from 2005 to 2014 were retrospectively evaluated. Impact of clinicopathologic and PRBC factors on oncologic outcomes were assessed.

RESULTS

Of 149 identified patients, 76 received a perioperative PRBC transfusion (median 2 units). Transfusion was associated with increased median length of stay (8 vs. 6 days; p < 0.01) and median operative blood loss (700 vs. 350 mL; p < 0.01) versus non-transfused, respectively. In transfused patients, receipt of PRBC from older donors compared to younger resulted in decreased RFS (0.94 vs. 2.63 years, respectively; p = 0.02) and OS (1.94 vs. 3.44 years, respectively; p = 0.6). The PRBC donor age was an independent predictor of decreased recurrence free survival on multivariate analysis (HR 2.5, p = 0.04).

CONCLUSIONS

In patients undergoing hepatectomy for non-hepatocellular malignancies and receiving perioperative transfusion, PRBC donor age may impact survival and warrants further investigation.

Intestinal microbiota enhances pancreatic carcinogenesis in preclinical models

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States yet data are scant regarding host factors influencing pancreatic carcinogenesis. Increasing evidence support the role of the host microbiota in carcinogenesis but its role in PDAC is not well established. Herein, we report that antibiotic-mediated microbial depletion of KrasG12D/PTENlox/+ mice showed a decreased proportion of poorly differentiated tumors compared to microbiota-intact KrasG12D/PTENlox/+ mice. Subsequent 16S rRNA PCR showed that ~50% of KrasG12D/PTENlox/+ mice with PDAC harbored intrapancreatic bacteria. To determine if a similar observation in humans correlates with presence of PDAC, benign and malignant human pancreatic surgical specimens demonstrated a microbiota by 16S bacterial sequencing and culture confirmation. However, the microbial composition did not differentiate PDAC from non-PDAC tissue. Furthermore, murine pancreas did not naturally acquire a pancreatic microbiota, as germ-free mice transferred to specific pathogen-free housing failed to acquire intrapancreatic bacteria over time, which was not augmented by a murine model of colitis. Finally, antibiotic-mediated microbial depletion of Nod-SCID mice, compared to microbiota-intact, showed increased time to PDAC xenograft formation, smaller tumors, and attenuated growth. Interestingly, both xenograft cohorts were devoid of intratumoral bacteria by 16S rRNA PCR, suggesting that intrapancreatic/intratumoral microbiota is not the sole driver of PDAC acceleration. Xenografts from microbiota-intact mice demonstrated innate immune suppression by immunohistochemistry and differential regulation of oncogenic pathways as determined by RNA sequencing. Our work supports a long-distance role of the intestinal microbiota on PDAC progression and opens new research avenues regarding pancreatic carcinogenesis.

Viscoelastic properties of human pancreatic tumors and in vitro constructs to mimic mechanical properties

Pancreatic ductal adenocarcinoma (PDAC) is almost universally fatal, in large part due to a protective fibrotic barrier generated by tumor-associated stromal (TAS) cells. This barrier is thought to promote cancer cell survival and confounds attempts to develop effective therapies. We present a 3D in vitro system that replicates the mechanical properties of the PDAC microenvironment, representing an invaluable tool for understanding the biology of the disease. Mesoscale indentation quantified viscoelastic metrics of resected malignant tumors, inflamed chronic pancreatitis regions, and histologically normal tissue. Both pancreatitis (2.15 ± 0.41 kPa, Mean ± SD) and tumors (5.46 ± 3.18 kPa) exhibit higher Steady-State Modulus (SSM) than normal tissue (1.06 ± 0.25 kPa; p < .005). The average viscosity of pancreatitis samples (63.2 ± 26.7 kPa·s) is significantly lower than that of both normal tissue (252 ± 134 kPa·s) and tumors (349 ± 222 kPa·s; p < .005). To mimic this remodeling behavior, PDAC and TAS cells were isolated from human PDAC tumors. Conditioned medium from PDAC cells was used to culture TAS-embedded collagen hydrogels. After 7 days, TAS-embedded gels in control medium reached SSM (1.45 ± 0.12 kPa) near normal pancreas, while gels maintained with conditioned medium achieved higher SSM (3.38 ± 0.146 kPa) consistent with tumors. Taken together, we have demonstrated an in vitro system that recapitulates in vivo stiffening of PDAC tumors. In addition, our quantification of viscoelastic properties suggests that elastography algorithms incorporating viscosity may be able to more accurately distinguish between pancreatic cancer and pancreatitis.

STATEMENT OF SIGNIFICANCE

Understanding tumor-stroma crosstalk in pancreatic ductal adenocarcinoma (PDAC) is challenged by a lack of stroma-mimicking model systems. To design appropriate models, pancreatic tissue must be characterized with a method capable of evaluating in vitro models as well. Our indentation-based characterization tool quantified the distinct viscoelastic signatures of inflamed resections from pancreatitis, tumors from PDAC, and otherwise normal tissue to inform development of mechanically appropriate engineered tissues and scaffolds. We also made progress toward a 3D in vitro system that recapitulates mechanical properties of tumors. Our in vitro model of stromal cells in collagen and complementary characterization system can be used to investigate mechanisms of cancer-stroma crosstalk in PDAC and to propose and test innovative therapies.

Impact of Palliative Chemotherapy and Travel Distance on Hospice Referral in Patients With Stage IV Pancreatic Cancer: A Retrospective Analysis Within a Veterans Administration Medical Center

BACKGROUND

Metastatic pancreatic ductal adenocarcinoma (mPDAC) has a poor prognosis despite chemotherapy advancements. Although hospice utilization has increased, timing of referral is not always optimal.

AIM

To investigate whether palliative chemotherapy and travel distance to the treatment center impact hospice referral patterns in veterans of the US military in order to identify potential areas for improving referral timing.

DESIGN

Demographic and clinical data were collected retrospectively according to the timing of hospice referral. Settings/Participants: Patients with mPDAC within a Veterans Administration Medical Center from 2005 to 2014.

RESULTS

Of 58 patients identified, 52 were referred to hospice. The median time from diagnosis to referral and referral to death was 2.4 and 3.1 weeks, respectively. Palliative chemotherapy was administered to 22 (42.3%) patients, with 30 (57.7%) patients not treated due to poor functional status (n = 16, 53.3%) or patient refusal (n = 14, 46.7%). Subset analysis for those travelling >60 miles versus <60 miles to the treatment center showed the median time to hospice referral was 1.7 versus 4.7 weeks. With no significant differences between groups, univariate analysis demonstrated that those referred to hospice >2.4 weeks from diagnosis more often received chemotherapy ( P < .001) and lived <60 miles from the treatment center ( P = .05).

CONCLUSION

Receipt of palliative chemotherapy and proximity to the treatment center appear to delay referral to hospice in patients with mPDAC. Increasing physician awareness of such factors that may impact the decision to involve hospice is necessary for delivering optimal oncology care.

Gastric neuromuscular histology in patients with refractory gastroparesis: Relationships to etiology, gastric emptying, and response to gastric electric stimulation

BACKGROUND

The aims of this study were to describe the histology in gastroparesis, specifically to relate histopathology to etiology of gastroparesis (idiopathic and diabetic gastroparesis), gastric emptying, and clinical response to gastric electric stimulation.

METHODS

Full thickness gastric body sections obtained during insertion of gastric stimulator in gastroparetics were stained with Hematoxylin & Eosin, Masson Trichrome and immunohistochemical stains for Neuron-Specific Enolase and c-Kit.

KEY RESULTS

In all, 145 gastroparetics (71 diabetics, 71 idiopathic, 2 post-surgical, and 1 chronic intestinal pseudo-obstruction) had full thickness gastric body biopsies. A lymphocytic infiltrate was seen in the intermyenteric plexus in 22 diabetic and 23 idiopathic gastroparesis patients. Fibrosis was present in the inner circular layer in 13 diabetic and 15 idiopathics and in the outer longitudinal layer in 46 diabetic and 51 idiopathics. Diabetic gastroparesis had less ganglion cells (3.27±1.82 vs 4.81±2.81/hpf; P<.01) and less ganglia (0.90±0.44 vs 1.10±0.50/hpf; P=.01) than idiopathic gastroparesis. Interstitial cells of Cajal (ICC) count was slightly lower in the inner circular layer in diabetic than idiopathics (2.77±1.47 vs 3.18±1.34/hpf; P=.08). Delayed gastric emptying was associated with reduced ICCs in the myenteric plexus. Global therapeutic response to gastric electric stimulation was inversely related to ganglia/hpf (R=-.22; P=.008). In diabetics, improvements in nausea, vomiting, and abdominal pain were inversely related to fibrosis.

CONCLUSION AND INFERENCES

Histologic assessment of full thickness gastric biopsy specimens allows correlation of histopathology to the gastroparesis disease process, its etiology, gastric emptying, and response to gastric electric stimulation treatment.

The effects of red cell transfusion donor age on nosocomial infection among trauma patients

BACKGROUND

We hypothesized that packed red blood cell (PRBC) transfusions from older donors would be associated with fewer nosocomial infections among trauma patients.

METHODS

We performed a four-year retrospective analysis of 264 consecutive adult trauma patients who received ≥1 PRBC transfusion during admission. The capacity of donor age to predict nosocomial infection was assessed by logistic regression.

RESULTS

Thirty-three percent of all patients developed a nosocomial infection. Donor age was significantly higher among patients with nosocomial infection (40.3 vs. 37.6 years, p = 0.035), and the incidence of infection was directly proportional to donor age. The association between donor age and infection was strongest among recipients age ≥60 years, and was significant on multivariate regression for this cohort (OR 1.07 (95% CI 1.01-1.13), p = 0.024).

CONCLUSIONS

Among trauma patients receiving PRBC transfusions, blood from older donors may be associated with increased risk for nosocomial infection.

Palliative chemotherapy and travel distance impacts hospice referral in patients with stage IV pancreatic cancer

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Background: Despite advances in chemotherapy (CTx), the prognosis for metastatic pancreatic ductal adenocarcinoma (mPDAC) is poor and while hospice is known to improve end-of-life care, referrals are often placed close to death. This may be due to accessibility issues or misconceptions that referral implies abandonment. We hypothesized that utilization of palliative CTx and travel distance to the treatment center impacts hospice referral patterns. Methods: Patients with histologically confirmed or radiographically presumed mPDAC as their initial diagnosis were retrospectively identified in a Veterans Administration Medical Center (VAMC) from 2005-2014. Demographic and clinical data were collected according to timing of hospice referral. Results: Fifty-eight mPDAC patients were identified with a median age of 63yr of which 57 (98.3%) were male. Palliative CTx was used in 26 (44.8%) patients with 32 (55.2%) not treated due to poor performance status (n = 18; 56.3%) or patient refusal (n = 14; 43.8%). Of the 52 (89.7%) patients referred to hospice, the median time from diagnosis to referral and referral to death was 2.4wk (Interquartile Range [IQR] 14.9) and 3.1wk (IQR 6.5), respectively. The median time to hospice referral was 18.7wk for patients treated with CTx vs 1.4wk for those who did not undergo therapy (p < 0.001). The median distance from residence to the VAMC was 58.5mi (IQR 77). Subset analysis for those living > 60mi vs < 60mi to the VAMC, the median time to hospice referral was 1.7wk vs 4.7wk, respectively (p = 0.1). With no significant differences between groups in age, sex, race, or disease burden, univariate analysis demonstrated that those referred to hospice > 2.4wk from diagnosis more often received CTx (p < 0.001) and lived > 60mi from the treatment center (p = 0.05). Conclusions: The majority of patients with mPDAC were enrolled in hospice and while travel distance trended to shorter time to referral, this was not significant. However, receipt of palliative chemotherapy did delay referral and those with this delay lived farther from the hospital. These data suggest that physicians delay hospice care in patients who are able to tolerate treatment and travel long distance to receive it.

Delayed Imaging Presentation of a Symptomatic Insulinoma After Bariatric Surgery

Many reports exist on hyperinsulinemic hypoglycemia after bariatric surgery, which can result in persistence of the metabolic syndrome in patients who have undergone these procedures. While the noninsulinoma pancreatogenous hypoglycemia syndrome, or nesidioblastosis, has garnered increased attention in these patients, its presentation is similar to patients with an insulinoma and this entity must therefore be evaluated and ruled out. Herein, we present a patient who developed symptoms of hypoglycemia 7 years after Roux-en-Y gastric bypass surgery. While a diagnosis of insulinoma was entertained, his laboratory values were indeterminate and imaging localization was inconclusive. Because of significant medical comorbidities, he was managed symptomatically until imaging ultimately localized a lesion in the pancreatic uncinate process consistent with an insulinoma. He subsequently underwent resection and remains disease and symptom free 1 year after surgery. This case demonstrates the diagnostic and imaging dilemma in patients with hypoglycemia after bariatric surgery and should be of interest to anyone who cares for these patients.

A clinically applicable muscular index predicts long-term survival in resectable pancreatic cancer

BACKGROUND

The relationship between myopenia, nutritional status, and long-term oncologic outcomes remains poorly characterized in patients with clinically resectable pancreatic cancer. We sought to reliably quantify prognostic indicators of preoperative cachexia in a manner applicable to any clinical setting.

METHODS

Preoperative computed tomographies were available electronically and suitable for analysis in 73 of 82 consecutive patients with pancreatic cancer undergoing pancreatoduodenectomy between November 2010 and February 2014. The psoas index was computed from the cross-sectional area of the psoas muscles normalized to vertebral body area at the third lumbar vertebra. Correlation and proportional hazards analyses were performed to identify relationships between muscularity, preoperative nutritional markers, clinicopathologic parameters, and long-term survival.

RESULTS

The psoas index correlated strongly with preoperative hemoglobin and albumin levels (P = .001 and .014, respectively) identifying a pattern of preoperative frailty. High psoas index and the albumin and hemoglobin levels were associated with improved long-term survival (hazard ratio 0.014, P < .001; hazard ratio 0.43, P < .001; and hazard ratio = 0.80, P = .014); however, on multivariate analysis, the psoas index proved to be the only independent predictor of survival (hazard ratio 0.021; P = .003). Rapid decreases in the psoas index during neoadjuvant chemotherapy were associated with poor postoperative outcomes, as were decreases in the psoas index during the postoperative period.

CONCLUSION

The data indicate that the psoas index, a calculation derived from a clinically mandated, preoperative computed tomography, is a statistically powerful and easily calculated predictor of survival in pancreatic cancer when compared to tumor grade and stage as well as previously validated nutritional parameters.

Human Pancreatic Cancer Cells Induce a MyD88-Dependent Stromal Response to Promote a Tumor-Tolerant Immune Microenvironment

Cancer cells exert mastery over the local tumor-associated stroma (TAS) to configure protective immunity within the tumor microenvironment. The immunomodulatory character of pancreatic lysates of patients with cancer differs from those with pancreatitis. In this study, we evaluated the cross-talk between pancreatic cancer and its TAS in primary human cell culture models. Upon exposure of TAS to pancreatic cancer cell-conditioned media, we documented robust secretion of IL6 and IL8. This TAS response was MyD88-dependent and sufficient to directly suppress both CD4⁺ and CD8⁺ T-cell proliferation, inducing Th17 polarization at the expense of Th1. We found that patients possessed a similar shift in circulating effector memory Th17:Th1 ratios compared with healthy controls. The TAS response also directly suppressed CD8⁺ T-cell-mediated cytotoxicity. Overall, our results demonstrate how TAS contributes to the production of an immunosuppressive tumor microenvironment in pancreatic cancer. Cancer Res; 77(3); 672-83. ©2016 AACR.

Influence of a CYP1A2 polymorphism on post-exercise heart rate variability in response to caffeine intake: a double-blind, placebo-controlled trial

BACKGROUND

Proposed differences in caffeine metabolism due to the CYP1A2*1F polymorphism have been linked to variations in cardiovascular disease risk.

AIMS

We examined the influence of a CYP1A2*1F polymorphism on post-exercise heart rate variability (HRV) in response to caffeine intake.

METHODS

Volunteers were identified as A/A homozygotes (A/A; 4 females and 7 males; age: 25.3 ± 4.1 years; BMI: 25.9 ± 4.4 kg/m²) or C allele carriers (C allele; 3 females and 6 males; age: 25.5 ± 2.8 years; BMI: 26.6 ± 5.0 kg/m²) for participation in a repeated measures, counterbalanced, double-blind, placebo-controlled trial. Participants chewed three pieces of gum containing either caffeine (CAF) (100 mg/piece) or placebo for 5 min. Thereafter, participants cycled for 15 min at 75 % of their peak oxygen consumption. Eight HRV indices computed during 5 min at baseline (BASE), 0-5 min after exercise (POST1), and 5-10 min after exercise (POST2) were used for analysis.

RESULTS

No significant group differences were detected in HRV indices at BASE, POST1, or POST2 during both trials (p > 0.05). Rate of recovery (POST2-POST1) for the square root of the mean of squared differences between successive RR intervals (RMSSD) was significantly different between A/A (6.0 ± 2.5 ms) and C allele (3.6 ± 2.5 ms) groups during the CAF trial (p = 0.048).

CONCLUSIONS

Rate of RMSSD recovery was the only variable influenced by the CYP1A2*IF polymorphism during post-exercise in response to caffeine intake. Thus, the CYP1A2*1F polymorphism did not overtly influence the effects of caffeine intake on post-exercise HRV.

Oncologic and Perioperative Outcomes Following Selective Application of Laparoscopic Pancreaticoduodenectomy for Periampullary Malignancies

BACKGROUND

Data are sparse regarding patient selection criteria or evaluating oncologic outcomes following laparoscopic pancreaticoduodenectomy (LPD). Having prospectively limited LPD to patients with resectable disease defined by National Comprehensive Cancer Network (NCCN) criteria, we evaluated perioperative and long-term oncologic outcomes of LPD compared to a similar cohort of open pancreaticoduodenectomy (OPD).

METHODS

Consecutive patients (November 2010-February 2014) undergoing pancreaticoduodenectomy (PD) for periampullary adenocarcinoma were reviewed. Patients were excluded from further analysis for benign pathology, conversion to OPD for portal vein resection, and contraindications for LPD not related to their malignancy. Outcomes of patients undergoing LPD were analyzed in an intention-to-treat manner against a cohort of patients undergoing OPD.

RESULTS

These selection criteria resulted in offering LPD to 77 % of all cancer patients. Compared to the OPD cohort, LPD was associated with significant reductions in wound infections (16 vs. 34 %; P = 0.038), pancreatic fistula (17 vs. 36 %; P = 0.032), and median hospital stay (9 vs. 12 days; P = 0.025). Overall survival (OS) was not statistically different between patients undergoing LPD vs. OPD for periampullary adenocarcinoma (median OS 27.9 vs. 23.5 months; P = 0.955) or pancreatic adenocarcinoma (N = 28 vs. 22 patients; median OS 20.7 vs. 21.1 months; P = 0.703).

CONCLUSIONS

The selective application of LPD for periampullary malignancies results in a high degree of eligibility as well as significant reductions in length of stay, wound infections, and pancreatic fistula. Overall survival after LPD is similar to OPD.

Standardization of surgical care in a high-volume center improves survival in resected pancreatic head cancer

BACKGROUND

Durable clinical gains in surgical care are frequently reliant on well-developed standardization of practices. We hypothesized that the standardization of surgical management would result in improved long-term survival in pancreatic cancer.

METHODS

Seventy-seven consecutive, eligible patients representing all patients who underwent pancreaticoduodenectomy and received comprehensive, long-term postoperative care at the University of Florida were analyzed. Patients were divided into prestandardization and poststandardization groups based on the implementation of a pancreatic surgery partnership, or standardization program.

RESULTS

Standardization resulted in a reduction in median length of stay (10 vs 12 days; P = .032), as well as significant gains in disease-free survival (17 vs 11 months; P = .017) and overall survival (OS; 26 vs 16 months; P = .004). The improvement in overall survival remained significant on multivariate analysis (hazard ratio = .46, P = .005).

CONCLUSIONS

Standardization of surgical management of pancreatic cancer was associated with significant gains in long-term survival. These results suggest strongly that management of pancreatic head adenocarcinoma be standardized likely by regionalization of care at high performing oncologic surgery programs.

Transforming Growth Factor-β Limits Secretion of Lumican by Activated Stellate Cells within Primary Pancreatic Adenocarcinoma Tumors

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is lethal cancer whose primary tumor is characterized by dense composition of cancer cells, stromal cells, and extracellular matrix (ECM) composed largely of collagen. Within the PDAC tumor microenvironment, activated pancreatic stellate cells (PSC) are the dominant stromal cell type and responsible for collagen deposition. Lumican is a secreted proteoglycan that regulates collagen fibril assembly. We have previously identified that the presence of lumican in the ECM surrounding PDAC cells is associated with improved patient outcome after multimodal therapy and surgical removal of localized PDAC.

EXPERIMENTAL DESIGN

Lumican expression in PDAC from 27 patients was determined by IHC and quantitatively analyzed for colocalization with PSCs. In vitro studies examined the molecular mechanisms of lumican transcription and secretion from PSCs (HPSCs and HPaSteC), and cell adhesion and migration assays examined the effect of lumican on PSCs in a collagen-rich environment.

RESULTS

Here we identify PSCs as a significant source of extracellular lumican production through quantitative IHC analysis. We demonstrate that the cytokine, TGF-β, negatively regulates lumican gene transcription within HPSCs through its canonical signaling pathway and binding of SMAD4 to novel SBEs identified within the promoter region. In addition, we found that the ability of HPSCs to produce and secrete extracellular lumican significantly enhances HPSCs adhesion and mobility on collagen.

CONCLUSIONS

Our results demonstrate that activated pancreatic stellate cells within PDAC secrete lumican under the negative control of TGF-β; once secreted, the extracellular lumican enhances stellate cell adhesion and mobility in a collagen-rich environment. Clin Cancer Res; 22(19); 4934-46. ©2016 AACR.

Isolation of Pancreatic Cancer Cells from a Patient-Derived Xenograft Model Allows for Practical Expansion and Preserved Heterogeneity in Culture

Commercially available, highly passaged pancreatic cancer (PC) cell lines are of limited translational value. Attempts to overcome this limitation have primarily consisted of cancer cell isolation and culture directly from human PC specimens. However, these techniques are associated with exceedingly low success rates. Here, we demonstrate a highly reproducible culture of primary PC cell lines (PPCLs) from patient-derived xenografts, which preserve, in part, the intratumoral heterogeneity known to exist in PC. PPCL expansion from patient-derived xenografts was successful in 100% of attempts (5 of 5). Phenotypic analysis was evaluated with flow cytometry, immunofluorescence microscopy, and short tandem repeat profiling. Importantly, tumorigenicity of PPCLs expanded from patient-derived xenografts was assessed by subcutaneous injection into nonobese diabeteic.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ mice. Morphologically, subcutaneous injection of all PPCLs into mice yielded tumors with similar characteristics to the parent xenograft. PPCLs uniformly expressed class I human leukocyte antigen, epithelial cell adhesion molecule, and cytokeratin-19. Heterogeneity within each PPCL persisted in culture for the frequency of cells expressing the cancer stem cell markers CD44, CD133, and c-Met and the immunologic markers human leukocyte antigen class II and programmed death ligand 1. This work therefore presents a reliable method for the rapid expansion of primary human PC cells and, thereby, provides a platform for translational investigation and, importantly, potential personalized therapeutic approaches.