Exocrine pancreas in type 1 and type 2 diabetes: different patterns of fibrosis, metaplasia, angiopathy, and adiposity.

The endocrine and exocrine compartments of the pancreas are spatially related but functionally distinct. Multiple diseases affect both compartments, including type 1 diabetes (T1D), pancreatitis, cystic fibrosis, and pancreatic cancer. To better understand how the exocrine pancreas changes with age, obesity, and diabetes, we performed systematic analysis of wellpreserved tissue sections from the pancreatic head, body, and tail of organ donors with T1D (n = 20), type 2 diabetes (T2D, n = 25), and donors with no diabetes (ND, n = 74). Among ND donors, we found that acinar-to-ductal metaplasia (ADM), angiopathy, and pancreatic adiposity increased with age, while ADM and adiposity also increased with BMI. Compared to age- and sex-matched ND organs, T1D pancreata had greater acinar atrophy and angiopathy with fewer intralobular adipocytes. T2D pancreata had greater ADM, angiopathy, and total T lymphocytes, but no difference in adipocyte number, compared to ND organs. While total pancreatic fibrosis was increased in both T1D and T2D, the pattern was different with T1D pancreata having greater periductal and perivascular fibrosis, whereas T2D pancreata had greater lobular and parenchymal fibrosis. Thus, the exocrine pancreas undergoes distinct changes as individuals age or develop T1D or T2D.

Human pancreatic capillaries and nerve fibers persist in type 1 diabetes despite beta cell loss.

The autonomic nervous system regulates pancreatic function. Islet capillaries are essential for the extension of axonal projections into islets, and both of these structures are important for appropriate islet hormone secretion. Because beta cells provide important paracrine cues for islet glucagon secretion and neurovascular development, we postulated that beta cell loss in type 1 diabetes (T1D) would lead to a decline in intraislet capillaries and reduction of islet innervation, possibly contributing to abnormal glucagon secretion. To define morphological characteristics of capillaries and nerve fibers in islets and acinar tissue compartments, we analyzed neurovascular assembly across the largest cohort of T1D and normal individuals studied thus far. Because innervation has been studied extensively in rodent models of T1D, we also compared the neurovascular architecture between mouse and human pancreas and assembled transcriptomic profiles of molecules guiding islet angiogenesis and neuronal development. We found striking interspecies differences in islet neurovascular assembly but relatively modest differences at transcriptome level, suggesting that posttranscriptional regulation may be involved in this process. To determine whether islet neurovascular arrangement is altered after beta cell loss in T1D, we compared pancreatic tissues from non-diabetic, recent-onset T1D (<10-yr duration), and longstanding T1D (>10-yr duration) donors. Recent-onset T1D showed greater islet and acinar capillary density compared to non-diabetic and longstanding T1D donors. Both recent-onset and longstanding T1D had greater islet nerve fiber density compared to non-diabetic donors. We did not detect changes in sympathetic axons in either T1D cohort. Additionally, nerve fibers overlapped with extracellular matrix (ECM), supporting its role in the formation and function of axonal processes. These results indicate that pancreatic capillaries and nerve fibers persist in T1D despite beta cell loss, suggesting that alpha cell secretory changes may be decoupled from neurovascular components.NEW & NOTEWORTHY Defining the neurovascular architecture in the pancreas of individuals with type 1 diabetes (T1D) is crucial to understanding the mechanisms of dysregulated glucagon secretion. In the largest T1D cohort of biobanked tissues analyzed to date, we found that pancreatic capillaries and nerve fibers persist in human T1D despite beta cell loss, suggesting that alpha cell secretory changes may be decoupled from neurovascular components. Because innervation has been studied extensively in rodent T1D models, our studies also provide the first rigorous direct comparisons of neurovascular assembly in mouse and human, indicating dramatic interspecies differences.

Synthesis and evaluation of etoposide and podophyllotoxin analogs against topoisomerase IIα and HCT-116 cells.

Etoposide is a widely-used anticancer agent that targets human type II topoisomerases. Evidence suggests that metabolism of etoposide in myeloid progenitor cells is associated with translocations involved in leukemia development. Previous studies suggest halogenation at the C-2' position of etoposide reduces metabolism. Halogens were introduced into the C-2' position by electrophilic aromatic halogenation onto etoposide (ETOP, 1), podophyllotoxin (PPT, 2), and 4-dimethylepipodophyllotoxin (DMEP, 3), and to bridge the gap of knowledge regarding the activity of these metabolically stable analogs. Five halogenated analogs (6-10) were synthesized. Analogs 8-10 displayed variable ability to inhibit DNA relaxation. Analog 9 was the only analog to show concentration-dependent enhancement of Top2-mediated DNA cleavage. Dose response assay results indicated that 8 and 10 were most effective at decreasing the viability of HCT-116 and A549 cancer cell lines in culture. Flow cytometry with 8 and 10 in HCT-116 cells provide evidence of sub-G1 cell populations indicative of apoptosis. Taken together, these results indicate C-2' halogenation of etoposide and its precursors, although metabolically stable, decreases overall activity relative to etoposide.

MTG16 is a tumor suppressor in colitis-associated carcinoma.

MTG16 is a member of the myeloid translocation gene (MTG) family of transcriptional corepressors. While MTGs were originally identified in chromosomal translocations in acute myeloid leukemia, recent studies have uncovered a role in intestinal biology. For example, Mtg16-/- mice have increased intestinal proliferation and are more sensitive to intestinal injury in colitis models. MTG16 is also underexpressed in patients with moderate/severe ulcerative colitis. Based on these findings, we postulated that MTG16 might protect against colitis-associated carcinogenesis. MTG16 was downregulated at the protein and RNA levels in patients with inflammatory bowel disease and in those with colitis-associated carcinoma. Mtg16-/- mice subjected to inflammatory carcinogenesis modeling exhibited worse colitis and increased tumor multiplicity and size. Loss of MTG16 also increased severity of dysplasia, apoptosis, proliferation, DNA damage, and WNT signaling. Moreover, transplantation of WT marrow into Mtg16-/- mice failed to rescue the Mtg16-/- protumorigenic phenotypes, indicating an epithelium-specific role for MTG16. While MTG dysfunction is widely appreciated in hematopoietic malignancies, the role of this gene family in epithelial homeostasis, and in colon cancer, was unrealized. This report identifies MTG16 as an important modulator of colitis and tumor development in inflammatory carcinogenesis.

Selenoprotein P influences colitis-induced tumorigenesis by mediating stemness and oxidative damage.

Patients with inflammatory bowel disease are at increased risk for colon cancer due to augmented oxidative stress. These patients also have compromised antioxidant defenses as the result of nutritional deficiencies. The micronutrient selenium is essential for selenoprotein production and is transported from the liver to target tissues via selenoprotein P (SEPP1). Target tissues also produce SEPP1, which is thought to possess an endogenous antioxidant function. Here, we have shown that mice with Sepp1 haploinsufficiency or mutations that disrupt either the selenium transport or the enzymatic domain of SEPP1 exhibit increased colitis-associated carcinogenesis as the result of increased genomic instability and promotion of a protumorigenic microenvironment. Reduced SEPP1 function markedly increased M2-polarized macrophages, indicating a role for SEPP1 in macrophage polarization and immune function. Furthermore, compared with partial loss, complete loss of SEPP1 substantially reduced tumor burden, in part due to increased apoptosis. Using intestinal organoid cultures, we found that, compared with those from WT animals, Sepp1-null cultures display increased stem cell characteristics that are coupled with increased ROS production, DNA damage, proliferation, decreased cell survival, and modulation of WNT signaling in response to H2O2-mediated oxidative stress. Together, these data demonstrate that SEPP1 influences inflammatory tumorigenesis by affecting genomic stability, the inflammatory microenvironment, and epithelial stem cell functions.

Structure of pyrazole derivatives impact their affinity, stoichiometry, and cooperative interactions for CYP2E1 complexes.

CYP2E1 plays a critical role in detoxification and carcinogenic activation of drugs, pollutants, and dietary compounds; however, these metabolic processes can involve poorly characterized cooperative interactions that compromise the ability to understand and predict CYP2E1 metabolism. Herein, we employed an array of ten azoles with an emphasis on pyrazoles to establish the selectivity of catalytic and cooperative CYP2E1 sites through binding and catalytic studies. Spectral binding studies for monocyclic azoles suggested two binding events, while bicyclic azoles suggested one. Pyrazole had moderate affinity toward the CYP2E1 catalytic site that improved when a methyl group was introduced at either position 3 or 4. The presence of methyl groups simultaneously at positions 3 and 5 blocked binding, and a phenyl group at position 3 did not improve binding affinity. In contrast, pyrazole fusion to a benzene or cyclohexane ring greatly increased affinity. The consequences of these binding events on CYP2E1 catalysis were studied through inhibition studies with 4-nitrophenol, a substrate known to bind both sites. Most pyrazoles shared a common mixed cooperative inhibition mechanism in which pyrazole binding rescued CYP2E1 from substrate inhibition. Overall, inhibitor affinities toward the CYP2E1 catalytic site were similar to those reported in binding studies, and the same trend was observed for binding at the cooperative site. Taken together, these studies identified key structural determinants in the affinity and stoichiometry of azole interactions with CYP2E1 and consequences on catalysis that further advance an understanding of the relationship between structure and function for this enzyme.

Dietary selenium deficiency exacerbates DSS-induced epithelial injury and AOM/DSS-induced tumorigenesis.

Selenium (Se) is an essential micronutrient that exerts its functions via selenoproteins. Little is known about the role of Se in inflammatory bowel disease (IBD). Epidemiological studies have inversely correlated nutritional Se status with IBD severity and colon cancer risk. Moreover, molecular studies have revealed that Se deficiency activates WNT signaling, a pathway essential to intestinal stem cell programs and pivotal to injury recovery processes in IBD that is also activated in inflammatory neoplastic transformation. In order to better understand the role of Se in epithelial injury and tumorigenesis resulting from inflammatory stimuli, we examined colonic phenotypes in Se-deficient or -sufficient mice in response to dextran sodium sulfate (DSS)-induced colitis, and azoxymethane (AOM) followed by cyclical administration of DSS, respectively. In response to DSS alone, Se-deficient mice demonstrated increased morbidity, weight loss, stool scores, and colonic injury with a concomitant increase in DNA damage and increases in inflammation-related cytokines. As there was an increase in DNA damage as well as expression of several EGF and TGF-ß pathway genes in response to inflammatory injury, we sought to determine if tumorigenesis was altered in the setting of inflammatory carcinogenesis. Se-deficient mice subjected to AOM/DSS treatment to model colitis-associated cancer (CAC) had increased tumor number, though not size, as well as increased incidence of high grade dysplasia. This increase in tumor initiation was likely due to a general increase in colonic DNA damage, as increased 8-OHdG staining was seen in Se-deficient tumors and adjacent, non-tumor mucosa. Taken together, our results indicate that Se deficiency worsens experimental colitis and promotes tumor development and progression in inflammatory carcinogenesis.

Converting to transdermal fentanyl: avoidance of underdosing.

BACKGROUND: Converting between the various opioid agents continues to be challenge for many practitioners. Specifically, variable recommendations for converting to the transdermal fentanyl patch may lead to confusion among clinicians and errors in dosing. OBJECTIVE: Our aim was to describe the inconsistencies among available opioid conversions with regard to transdermal fentanyl and to provide recommendations for safe and effective utilization of this product in patients with chronic pain. RESULTS: Available reports support the use of the morphine intravenous to oral ratio of 1:3 during the conversion to transdermal fentanyl product. CONCLUSIONS: Underdosing is an often overlooked complication of switching to transdermal fentanyl. Current recommendations for converting to transdermal fentanyl do not reflect contemporary clinical practice and should be reevaluated.

Brentuximab vedotin: an anti-CD30 antibody-drug conjugate.

PURPOSE: The pharmacology, pharmacokinetics, clinical efficacy, and safety and tolerability of brentuximab vedotin are reviewed. SUMMARY: Brentuximab vedotin is a potent antibody-drug conjugate composed of the monoclonal antibody cAC10, which targets the CD30 antigen on Hodgkin lymphoma and systemic anaplastic large-cell lymphoma (sALCL) cells; a highly stable valine-citrulline linker; and a potent chemotherapeutic agent monomethyl auristatin E, which inhibits microtubule polymerization. Brentuximab is indicated for patients with relapsed Hodgkin lymphoma after autologous stem-cell transplantation (ASCT), for patients who are not candidates for ASCT who have not responded to at least two multiagent chemotherapy regimens, and for patients with ALCL who have not responded to at least one multiagent chemotherapy regimen. In a Phase II, single-group, multicenter study, brentuximab produced an overall response rate of 75% in relapsed or refractory Hodgkin lymphoma. In another Phase II study, brentuximab demonstrated clinical benefit in sALCL, with 86% of patients achieving a response and 57% of patients achieving complete remission. Adverse events most commonly reported included nausea, fatigue, diarrhea, neutropenia, and peripheral sensory neuropathy. A Phase III study is currently ongoing in patients at high risk for residual Hodgkin lymphoma after ASCT. CONCLUSION: Brentuximab vedotin, a novel antibody-drug conjugate combining a cytotoxic agent with a selective monoclonal antibody, is a therapeutic option for patients with relapsed or refractory Hodgkin lymphoma and sALCL. Phase I and II studies have shown brentuximab to have a manageable toxicity profile.

MTG16 contributes to colonic epithelial integrity in experimental colitis.

OBJECTIVE: The myeloid translocation genes (MTGs) are transcriptional corepressors with both Mtg8(-/-) and Mtgr1(-/-) mice showing developmental and/or differentiation defects in the intestine. We sought to determine the role of MTG16 in intestinal integrity. METHODS: Baseline and stress induced colonic phenotypes were examined in Mtg16(-/-) mice. To unmask phenotypes, we treated Mtg16(-/-) mice with dextran sodium sulphate (DSS) or infected them with Citrobacter rodentium and the colons were examined for ulceration and for changes in proliferation, apoptosis and inflammation. RESULTS: Mtg16(-/-) mice have altered immune subsets, suggesting priming towards Th1 responses. Mtg16(-/-) mice developed increased weight loss, diarrhoea, mortality and histological colitis and there were increased innate (Gr1(+), F4/80(+), CD11c(+) and MHCII(+); CD11c(+)) and Th1 adaptive (CD4) immune cells in Mtg16(-/-) colons after DSS treatment. Additionally, there was increased apoptosis and a compensatory increased proliferation in Mtg16(-/-) colons. Compared with wild-type mice, Mtg16(-/-) mice exhibited increased colonic CD4;IFN-γ cells in vehicle-treated and DSS-treated mice. Adoptive transfer of wild-type marrow into Mtg16(-/-) recipients did not rescue the Mtg16(-/-) injury phenotype. Isolated colonic epithelial cells from DSS-treated Mtg16(-/-) mice exhibited increased KC (Cxcl1) mRNA expression when compared with wild-type mice. Mtg16(-/-) mice infected with C rodentium had more severe colitis and greater bacterial colonisation. Last, MTG16 mRNA levels were reduced in human ulcerative colitis versus normal colon tissues. CONCLUSIONS: These observations indicate that MTG16 is critical for colonocyte survival and regeneration in response to intestinal injury and provide evidence that this transcriptional corepressor regulates inflammatory recruitment in response to injury.

Neutropenia-associated outcomes in adults with acute myeloid leukemia receiving cytarabine consolidation chemotherapy with or without granulocyte colony-stimulating factor.

STUDY OBJECTIVE: To determine whether granulocyte colony-stimulating factor (G-CSF) prophylaxis after consolidation with high- or intermediate-dose cytarabine (H/IDAC) for treatment of acute myeloid leukemia (AML) reduces the frequency of neutropenia-associated complications. DESIGN: Retrospective medical record review. SETTING: Academic medical center. PATIENTS: Seventy-eight patients aged 18 years or older in whom H/IDAC consolidation chemotherapy was initiated for consolidation of AML between November 2004 and November 2010. MEASUREMENTS AND MAIN RESULTS: Patient demographic data, information on the hospitalization for consolidation, data on G-CSF use after H/IDAC chemotherapy, and details on any readmissions were collected. Patients were deemed to have received G-CSF prophylaxis if there was documentation of the intent for use of either filgrastim or pegfilgrastim. Outcome data also were collected, including dates of relapse or second induction treatment course, and death or last follow-up visit. We compared data based on patient receipt of G-CSF (G-CSF vs no G-CSF) after each chemotherapy cycle. We assessed differences in the duration of hospitalization, fever, intravenous antibiotic use, and neutropenia, as well as rate of documented infections, time to disease recurrence, and overall survival. Compared with no G-CSF, use of G-CSF after cycle 1 of H/IDAC significantly reduced the rate of hospitalization for febrile neutropenia (p=0.039); however, no significant differences were noted for subsequent cycles. No significant differences were seen in duration of hospitalization, rate of documented infections, or time to treatment failure between groups. Overall survival was longer for patients who received G-CSF during their first cycle (p=0.018) and for those who received G-CSF during any of their cycles (p=0.04). CONCLUSION: Use of G-CSF prophylaxis after cycle 1 of H/IDAC consolidation for AML appears to reduce the frequency of hospitalization for febrile neutropenia and to increase overall survival compared with no G-CSF use. Prospective, controlled studies are needed to support our findings.

Survey of learning opportunities in academia for pharmacy residents.

PURPOSE: The types of teaching experiences offered in academia in pharmacy residency programs affiliated with or offered through colleges of pharmacy throughout the United States were evaluated. METHODS: Two 15-item questionnaires were developed, one for programs that offer a concentrated rotation in academia and one for programs that offer longitudinal opportunities in academia. These questionnaires were developed to assess the activities incorporated into the different learning experiences, the number of residents completing concentrated rotations, the residency director's perception of the benefit to the residents, and barriers that exist for institutions that do not offer concentrated rotations. The questionnaires were distributed electronically to pharmacy residency directors at academic medical centers and colleges of pharmacy in the University HealthSystem Consortium listserver. The responses were analyzed with descriptive statistics. RESULTS: Of the 154 institutions identified for survey distribution, 86 were academic medical centers and 68 were colleges of pharmacy and affiliated programs. Program directors from 99 institutions completed a questionnaire (response rate, 64.3%), representing 434 postgraduate year 1 (PGY1) and 290 postgraduate year 2 (PGY2) residency positions. Thirty-six percent (n = 36) of respondents offered a concentrated rotation in academia, and 64% (n = 63) offered longitudinal opportunities in academia. Sixty-six institutions offered a teaching certificate program; however, it was mandatory in only 42% of programs. CONCLUSION: The majority of PGY1 and PGY2 residency programs surveyed did not offer concentrated rotations in academia but did offer longitudinal opportunities for residents to gain teaching experience. The majority of programs that did not offer these experiences did want formal training on how to provide these opportunities.