Metformin Use in Practice: Compliance With Guidelines for Patients With Diabetes and Preserved Renal Function.

IN BRIEF Several contraindications limit the use of metformin, most notably the risk of lactic acidosis. This article reports on an examination of a population of patients with diabetes with preserved renal function to evaluate provider compliance with guidelines on metformin use and to identify factors that contributed when practice diverged from recommendations. It found that metformin was withheld from approximately one-third of these patients because of 1) an existent contraindication to metformin, 2) patient behavior or preference, or 3) provider preference or bias based on patient or personal factors. Although providers generally follow current recommendations for the use of metformin, deviations from guidelines in practice are common.

Pulse pressure in cambodian americans: relationships to weight and mental health.

UNLABELLED: Few studies have explored interrelationships among mental health and health status in refugees using objective, clinical data. Pulse pressure (PP) has recently emerged as an easily obtained, strong, independent determinant of mortality. We conducted a chart review of electronic records for 24 consecutive months to investigate PP among Cambodian refugees receiving services at a community clinic in Connecticut, USA. 301 patients charts were retrieved, 41 contained complete data for all variables. We found high rates of cardiovascular, anthropometric, and mental health problems. Among women, higher weight was related to higher PP. Among men, higher mental health symptom scores were marginally related to higher PP. Findings held after controlling for age. DISCUSSION: Adiposity and mental health symptoms, which are known to be related to trauma history, contribute to elevated PP in this resettled refugee population. Given that PP may be modifiable through lifestyle intervention, further investigation of these problems in this needy population is warranted.

The National Cambodian American Town Hall Meeting: a community dialogue on "eat, walk, sleep" for health.

BACKGROUND: The 2009 National Cambodian American Town Hall Meeting was a public-private partnership convened to address long-term health issues related the Cambodian holocaust. Goals for participants were to dispel myths about diabetes; goals for the partnership were to build research capacity and to strengthen relationships. METHODS: Partners collaborated on all aspects of the meeting which was held in Khmer by bridged videoconferencing in 10 sites and webinar at 5 sites across the United States over a 3-hour period. EAT, WALK, SLEEP for Health (EWS), the National Cambodian American Diabetes Project program, provided the framework for the meeting. RESULTS: Pre and post surveys were completed by 323 participants. Modest improvements were seen in participants' belief that they could improve their own and their community's health, although significant barriers remained. Participants and community partners evaluated the meeting positively. CONCLUSIONS: The meeting is a model for other populations, and results inform future work.

Trauma, healthcare access, and health outcomes among Southeast Asian refugees in Connecticut.

Mental health problems among Southeast Asian refugees have been documented. However, longer term health consequences of mass violence as re-settled refugees age are less well described. This study investigated relationships among trauma symptoms, self-reported health outcomes, and barriers to healthcare among Cambodian and Vietnamese persons in Connecticut. An internet phone directory was used to generate a list of names that was compared to 2000 census data to estimate the proportion of the population in each group. From these lists, 190 telephone listings were selected at random. Interviewers telephoned selected listings to screen for eligible participants and obtain an appointment for interview. Surveys were administered through face-to-face interviews during home visits conducted in Khmer or Vietnamese. The Harvard Trauma Questionnaire assessed trauma symptoms. Questions regarding the presence of physician diagnosed heart disease, hypertension, diabetes, and chronic pain were adapted as written from the Health Interview Survey. Healthcare access and occurrence were measured with questions regarding cost and access, patient-provider understanding, and interpretive services. Hierarchical modeling was used to account for respondent nesting within family. Analyses controlled for age, sex, and country of origin. Individuals who reported greater trauma symptoms were more likely to report heart disease by a factor of 1.82, hypertension by a factor of 1.41, and total count of diseases by a factor of 1.22, as well as lower levels of subjective health. Greater trauma symptoms were also associated with greater lack of understanding, cost and access problems, and the need for an interpreter. Although the majority of Southeast Asian immigrants came to the United States as refugees approximately 20-30 years ago, there continues to be high levels of trauma symptoms among this population which are associated with increased risk for disease and decreased access to healthcare services.

Aberrant crypt foci as predictors of colorectal neoplasia on repeat colonoscopy.

OBJECTIVE: To estimate the risk for colorectal neoplasia detected on repeat colonoscopy in relation to aberrant crypt foci (ACF) frequency reported during the previous baseline examination. METHODS: From July 2003 until December 2008, patients had a colonoscopy with an ACF study using a magnifying colonoscope. The distal 20 cm section of colon was sprayed with Methylene Blue to ascertain the ACF frequency, the independent variable. Patients were categorized into low and high ACF count using the median as the cut point. Data collected from consenting patients included age, gender, height, weight, ethnicity, smoking history, family history of colorectal cancer (CRC), and personal history of colorectal neoplasia. A follow-up colonoscopy was performed at an interval as dictated by clinical surveillance guidelines. The main outcome was surveillance detected advanced colorectal neoplasia (SDAN) detected on repeat colonoscopy. Logistic Regression was used to calculate risk of SDAN on repeat colonoscopy in relation to baseline ACF count. RESULTS: 74 patients had a baseline ACF exam and a repeat surveillance colonoscopy. The median ACF was six and thus a high ACF count was >6 ACF and a low ACF count was ≤6 ACF. Patients diagnosed with SDAN were more likely to have had a high ACF number at baseline compared to patients without these lesions at follow-up (adjusted odds ratio = 12.27; 95% confidence interval: 2.00-75.25) controlling for age, sex, smoking, history of prior adenoma, family history of colon cancer, obesity, and time interval to surveillance exam. A sub analysis of our results demonstrated that this relationship was observed in 48 patients who were undergoing a surveillance colonoscopy for a previous adenoma and not those receiving surveillance for a family history of neoplasia. CONCLUSIONS: Increased number of ACF in the distal colorectum was independently associated with substantial risk for future advanced neoplasia. This relationship was observed in patients undergoing surveillance for previous adenomas. Thus, ACF may serve as potential biomarkers in patients with adenomas to help identify patients who may need additional surveillance.

Peroxisome proliferator-activated receptor gamma is required for CD4+ T cell-mediated lymphopenia-associated autoimmunity.

The nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ) was shown to play an immunoregulatory role in many immune-related cell types, and activation of PPARγ was reported to be an effective therapeutic approach in murine and human autoimmune disease. However, despite an association between lymphopenia and autoimmunity, there has been no study on the role of T cell PPARγ in lymphopenia-associated autoimmunity. In the present studies, we examined the role of PPARγ in CD4(+) T cells in two murine models of lymphopenia-associated autoimmunity. Surprisingly, we found that PPARγ expression in CD4(+) CD25(-) T cells (T effector cells [Teffs]) is actually required for development of autoimmunity under lymphopenic conditions. Mechanistically, the inability of PPARγ-deficient (T-PPAR) Teffs to mediate lymphopenic autoimmunity is associated with a significant decrease in accumulation of Teffs in the spleen, lymph nodes, and tissues after adoptive transfer. This abnormal accumulation of T-PPAR Teffs was associated with defects in both in vivo proliferation and survival. Additionally, T-PPAR Teffs demonstrated decreased cytokine production in inflammatory sites and decreased expression of the homing receptor α4ß7. Finally, these abnormalities in T-PPAR Teff function were not elicited by lymphopenia alone but also required the additional activation involved in the mediation of autoimmunity. Thus, in contrast to its documented immunosuppressive role, we identified an unexpected function for PPARγ in Teffs: a role in Teff proliferation and survival in lymphopenia-associated autoimmunity. These findings highlight both the multifunctional role of PPARγ in T cells and the complexity of PPARγ as a potential therapeutic target in autoimmunity.

Natural but not inducible regulatory T cells require TNF-alpha signaling for in vivo function.

TNF-α has a multifunctional role in autoimmune diseases as reflected in the variable responses of different human diseases to anti-TNF-α therapy. Recent studies have suggested that TNF-α modulates autoimmunity partially via effects on regulatory T cells (Tregs) and that these effects are mediated through the type II TNFR (TNFR2). We have investigated the requirement for TNFR2-expression on murine natural Tregs (nTregs) and induced Tregs (iTregs) in mediating suppression of colitis. Surprisingly, we find that TNFR2-expression is required for both spleen- and thymus-derived nTreg-mediated suppression, but is not required for iTreg-mediated suppression. Abnormal TNFR2(-/-) nTreg function was not associated with an in vivo decrease in accumulation, stability, or expression of markers known to be relevant in Treg function. Because iTregs are generated in the presence of TGF-ß, we investigated whether activation in the presence of TGF-ß could overcome the functional defect in TNFR2(-/-) nTregs. Although preactivation alone did not restore suppressive function of nTregs, preactivation in the presence of TGF-ß did. These results identify potentially critical differences in activation requirements for nTregs versus iTregs. Furthermore, our findings are consistent with reports suggesting that nTregs are activated in sites of inflammation while iTregs are activated in lymph nodes. Finally, by demonstrating that nTregs require TNF-α for optimal function whereas iTregs do not, our results suggest that the enigma of variable responses of different human diseases to anti-TNF-α therapy may relate to whether nTregs or iTregs have the predominant regulatory role in a given disease.

Cbl-b(-/-) T cells demonstrate in vivo resistance to regulatory T cells but a context-dependent resistance to TGF-beta.

Cbl-b is an E3 ubiquitin ligase that negatively regulates T cell activation. Cbl-b(-/-) mice develop spontaneous autoimmunity, and Cbl-b dysregulation has been described in both murine and human autoimmune diseases. Although the mechanisms underlying the development of autoimmunity in Cbl-b(-/-) mice are not yet clear, we have reported that Cbl-b(-/-) CD4(+)CD25(-) effector T cells (Teffs) are resistant to CD4(+)CD25(+) regulatory T cell (Treg)-mediated suppression in vitro and have suggested that this may be an important mechanism in the development of autoimmunity. To confirm the relevance of this resistance to autoimmune disease, we now show that Cbl-b(-/-) Teffs are resistant to suppression by Tregs in vivo and that this involves a resistance of truly naive Cbl-b(-/-) Teffs. Additionally, we show that Cbl-b(-/-) Tregs are fully functional in vivo, further suggesting that the regulatory abnormalities in Cbl-b(-/-) mice are related to defects in Teff, not Treg, function. To characterize the relevance of TGF-beta sensitivity in Treg resistance, we examined in vivo Th17 generation and report that Cbl-b(-/-) mice are able to mount a normal Th17 response in vivo. As Cbl-b(-/-) Teffs have been shown to be insensitive to the suppressive effects of TGF-beta in other in vivo models, the present results suggest that Cbl-b(-/-) Teffs demonstrate a context-dependent sensitivity to TGF-beta in vivo. Overall, our results suggest that resistance to Tregs may be a bona fide mechanism underlying autoimmunity and that Cbl-b(-/-) mice offer unique approaches for studying the interrelationships between Treg function, TGF-beta-mediated responses, and the development of autoimmunity.

Increased frequency of serrated aberrant crypt foci among smokers.

OBJECTIVES: The American College of Gastroenterology has published guidelines recently that suggest that smokers with a history of >20 pack years may need screening for colorectal cancer (CRC) at an earlier age than non-smokers. Aberrant crypt foci (ACF) may represent important precursors for colorectal neoplasms and potential surrogate biomarkers. Clarifying the role of ACF in relation to known CRC risk factors such as smoking may have important implications for screening as well as our understanding of tobacco use and colorectal carcinogenesis. Our goal was to examine whether smoking at least 20 pack years was associated with an increased frequency of ACF. METHODS: We gathered detailed smoking history, personal and family history of CRC, and other epidemiologic data (age, gender, height, weight, ethnicity, and medication use) from 125 patients undergoing routine screening or surveillance colonoscopy. We used a magnifying colonoscope (Olympus Close Focus Colonoscope XCF-Q160ALE, Olympus Corporation, Tokyo, Japan) and examined the distal 20 cm section of colon after staining with 0.5% methylene blue. ACF were counted and characterized histologically. Hyperplastic ACF were further characterized as either serrated or non-serrated. RESULTS: Smoking at least 20 pack years was associated with an increased likelihood (adjusted odds ratio (OR)=3.45; 95% confidence interval (CI)=1.93-6.18) of having more than the median number of ACF (> or = 15) compared with non-smokers. Similarly, patients with a personal history of advanced neoplasia were more likely (adjusted OR=3.42; 95% CI=1.01-11.67) to have a greater than median number of ACF compared with patients without this diagnosis. Smokers were more likely than non-smokers to have serrated ACF (P=0.002). CONCLUSIONS: Smoking at least 20 pack years seems to be associated with increased number of ACF in the rectum and distal sigmoid, especially those with serrated histology. Our data support ACG guidelines for earlier screening for CRC among smokers and add to our understanding of how colorectal carcinogenesis is related to tobacco use.

Subcutaneous late phase responses are augmented during local inhalational tolerance in a murine asthma model.

Acute exposure of sensitized mice to antigen elicits allergic airway disease (AAD) characterized by Th2 cytokine-dependent pulmonary eosinophilia, methacholine hyperresponsiveness and antigen-specific IgE elevation. However, chronic exposure induces a local inhalational tolerance (LIT), with resolution of the airway responses but persistent systemic IgE production. To further determine if systemic immunologic responses were maintained during LIT, we assessed subcutaneous late phase responses to ovalbumin in this model. Sensitized and AAD mice developed small subcutaneous responses to ovalbumin, with footpad thickness increasing to 113.7 and 113.6% of baseline, respectively. In comparison, LIT mice developed marked foot swelling (141.6%). Histologic examination confirmed increased inflammation in the chronic animals, with a significant contribution by eosinophils. Thus, the resolution of airway inflammatory responses with chronic antigen inhalation is a localized response, not associated with loss of systemic responses to antigen.

Effects of the physico-chemical nature of two biomimetic crystals on the innate immune response.

The influence of the physico-chemical features of particulates made of calcium phosphate (hydroxyapatite, HAP) crystals, or monosodium urate monohydrate (MSUM) crystals, on the innate immune response was investigated in mice after intraperitoneal injections. The phenotype and activation status of harvested peritoneal cells from C57BL/6 mice was determined by flow cytometry analysis at 24, 48 and 72 h after particulate injections and compared to a known adjuvant, aluminum phosphate (ALP). A rigorous characterization of the chemistry, structure, morphology and particle size of the particulates was completed. Mid-sized (10 mum mean size) particulates of both crystal types recruited the most cells, as compared to fine (1 mum) or large (100 mum) particulates. Analysis of sub-populations of the peritoneal cells revealed that MSUM induced fewer PMNs and eosinophils than HAP or ALP. MSUM also had the greatest effect on the expression of CD11b, MHC-Class II and CD86 on peritoneal macrophages indicating MSUM provides a robust antigen presenting and co-stimulatory bridge between the innate and adaptive immune systems. This study indicates that manipulation of the physico-chemical features of particulates is a means of controlling the innate immune response and that knife-like morphologies are more stimulatory than spherical or plate-like shapes. Proper utilization of the physico-chemical features of particulates offers a new direction for the development of more effective vaccine adjuvants.

Mutations in BRAF and KRAS differentially distinguish serrated versus non-serrated hyperplastic aberrant crypt foci in humans.

We previously reported that colon carcinomas, adenomas, and hyperplastic polyps exhibiting a serrated histology were very likely to possess BRAF mutations, whereas when these same advanced colonic lesions exhibited non-serrated histology, they were wild type for BRAF; among hyperplastic polyps, KRAS mutations were found mainly in a non-serrated variant. On this basis, we predicted that hyperplastic aberrant crypt foci (ACF), a putative precancerous lesion found in the colon, exhibiting a serrated phenotype would also harbor BRAF mutations and that non-serrated ACF would not. In contrast, KRAS mutations would be found more often in the non-serrated ACF. We examined 55 ACF collected during screening colonoscopy from a total of 28 patients. Following laser capture microdissection, DNA was isolated, and mutations in BRAF and KRAS were determined by direct PCR sequencing. When hyperplastic lesions were further classified into serrated and non-serrated histologies, there was a strong inverse relationship between BRAF and KRAS mutations: a BRAF(V600E) mutation was identified in 10 of 16 serrated compared with 1 of 33 non-serrated lesions (P = 0.001); conversely, KRAS mutations were present in 3 of 16 serrated compared with 14 of 33 non-serrated lesions. Our finding of a strong association between BRAF mutations and serrated histology in hyperplastic ACF supports the idea that these lesions are an early, sentinel, or a potentially initiating step on the serrated pathway to colorectal carcinoma.

Aberrant crypt foci in patients with a positive family history of sporadic colorectal cancer.

Early detection is crucial in the prevention of colorectal cancer (CRC) deaths. The earliest detectable neoplastic lesion in the colon is the aberrant crypt foci (ACF). A major question is whether ACF are precursors of CRC, and thus, early biomarkers for CRC risk. If so, we hypothesized that the number of ACF would be higher in patients who had a family history of CRC compared to patients without. We counted ACF in the distal 20cm of colon/rectum during 103 colonoscopic examinations using a prototype Close Focus Colonoscope (Olympus Corp.) with methylene blue chromendoscopy. Each patient was asked whether they had a family history of CRC in a first degree relative, or a personal history of CRC or adenoma. Patients answering 'no' to these questions (n=17) had a mean number of ACF of 4.4; the mean was significantly higher in the patients with a positive family history of CRC (9.0, p<0.01; n=43) or a personal history of advanced adenoma (7.5, p<0.05; n=34).

Expression of secretory phospholipase A2 in colon tumor cells potentiates tumor growth.

Secretory phospholipase A2 (sPLA2-IIA) has been shown to attenuate intestinal tumorigenesis in Apc(Min) mice, demonstrating that it is a tumor modifier. To further explore the actions of sPLA2-IIA in tumorigenesis, sPLA2-IIA was overexpressed in two cell lines where it is normally absent, the murine colon tumor cell line AJ02nm0, and human colon carcinoma cell line HCT-116. Two allelic variants of sPLA2-IIA were tested in this study; sPLA2-IIA(AKR) and sPLA2-IIA(SWR), which are derived from AKR/J and SWR/J mice, respectively, and differ by a single amino acid at position 63 in the calcium- and receptor-binding domain. There was no change in cell-doubling time for either allele when compared to vector controls. Furthermore, sodium butyrate and arachidonic acid (AA)-induced cell death were unchanged in control and transfected cells. Addition of the sPLA2 substrate, palmitoyl-arachidonoyl-phosphatidic acid (PAPA), to AJ02nm0 cells resulted in a modest (12%-24%), but significant (P < 0.01), inhibition of growth that was dependent on sPLA2-IIA expression. However, when AJ02nm0 and HCT-116 cells were injected subcutaneously (sc) into nude mice, Pla2g2a expression resulted in a 2.5-fold increase in tumor size. In addition, sPLA2-IIA expressing HCT-116 tumors were found to be more infiltrative than controls. We conclude that the ability of sPLA2-IIA to slow tumor cell growth is dependent upon the availability of substrate, and that in some instances sPLA2-IIA may actually enhance tumor growth. Mechanisms that may account for differences between the tumor explant model versus the Apc(Min) model of intestinal cancer are discussed.

Microsatellite instability in aberrant crypt foci from patients without concurrent colon cancer.

Aberrant crypt foci (ACF) are microscopic surface abnormalities that are putative precursors to colorectal cancer (CRC). ACF exhibit similar histological and molecular abnormalities to adenomas and CRC and potentially represent useful biomarkers of cancer risk. Microsatellite instability (MSI) is one molecular abnormality identified in concurrent ACF from CRC patients that may indicate a risk for progression. To determine if MSI can be detected in ACF from cancer-free subjects, we examined 45 ACF from 20 subjects undergoing colonoscopies. The group included 12 patients at elevated risk for CRC based on family history of CRC or personal history of CRC or advanced adenoma and 8 patients with no known risk factors. ACF were identified using close-focus magnifying chromendoscopy and collected by biopsy in situ. Genomic DNA was prepared from ACF and adjacent normal colonic epithelium isolated by laser capture microdissection and analyzed for MSI. MSI was identified in at least one marker from 9 of 30 (30%) lesions from patients at elevated risk for CRC and in 2 of 15 (13%) lesions from average risk patients. Using methylation-specific PCR analysis, we also examined the ACF for promoter hypermethylation of the DNA repair genes hMLH1 and MGMT and found moderate changes (8/39 and 3/32, respectively). Although we found only a limited relationship between hMLH1 hypermethylation and MSI, all the lesions with MGMT hypermethylation displayed an MSI-low phenotype. These lesions may be precursors to MSI-low CRC, providing a potential early biomarker to assess the effects of cancer prevention strategies.

Epigenetic alterations in RASSF1A in human aberrant crypt foci.

CpG island methylation (CIM) is an epigenetic mechanism for transcriptional silencing that occurs at various stages of colon tumorigenesis. CIM has been found in serrated adenomas and hyperplastic polyps. There is also evidence for hypermethylation in aberrant crypt foci (ACF) that are found in resected colons from cancer patients. Our study addresses promoter methylation of a tumor suppressor gene, RASSF1A, within the colonic epithelium of subjects undergoing screening colonoscopies in the absence of synchronous tumors. Patients included in this study were at elevated risk for colorectal cancer (CRC) based on family history, but without a previously occurring or synchronous colon carcinoma. ACF were identified using close-focus magnifying chromendoscopy and collected by biopsy in situ. We isolated ACF and adjacent normal colonic epithelium by laser capture microdissection (LCM) and studied methylation of the RASSF1A promoter region in ACF and in adjacent normal mucosa. Expression of RASSF1A was verified using quantitative real-time polymerase chain reaction (QRT-PCR). We found that 8.6% (3 out of 35) of ACF had K-ras mutations and 24% (6 out of 25) had RASSF1A hypermethylation. Our results demonstrate that RASSF1A hypermethylation and K-ras mutations are not mutually exclusive and are present in patients at elevated risk of CRC. Importantly, CIM of RASSF1A is an early epigenetic aberration, occurring in the absence of synchronous colon tumors and is not accompanied by field effects into the surrounding epithelium.

Critical role for IgM in host protection in experimental filarial infection.

We have previously shown that B cells (in particular B1 cells) are important in host protection against brugian infections in a murine i.p. model. In this study, we show that mice deficient in circulating IgM (secIgM-/-), but otherwise normal in their humoral responses, manifest a significant impairment in worm elimination, suggesting that one critical B cell function is the production of Ag-specific IgM. Efficient elimination of larvae is IgM dependent for both primary and challenge infections. The ability to eliminate worms is restored in secIgM-/- mice by administering sera from primed mice. We corroborated these in vivo studies with in vitro observations which show that IgM is the only isotype that reacts strongly with the surface of Brugia L3. Furthermore, activated peritoneal exudate cells adhere to L3 only in the presence of filaria-specific sera or IgM purified from them. This attachment is not reduced by heat inactivation of the serum, suggesting complement independent activity. Peritoneal exudate cells from primed mice, especially activated macrophages, carry high levels of IgM on their surfaces. Our observations suggest that an IgM-mediated reaction initiates the formation of host-protective granulomas.

The eye does not see what the mind does not know: the bacterium in the worm.

Symbiotic relationships underlie the evolutionary success of many different life forms. The filarial worms are long, slender nematode parasites that cause considerable pathology in large segments of the world's population. About 25 years ago, investigators first reported the presence of bacterial organisms living inside these parasitic worms. Recent molecular biological studies have indicated that these bacteria belong to the genus Wolbachia, members of which have been known to be associated with numerous species of insects. Elimination of the Wolbachia from the nematodes (by, for instance, treatment with broad spectrum antibiotics) results in profound disturbances in the physiology of the latter, including a complete block in reproduction. This observation, taken together with the fact that every individual worm examined to date contains Wolbachia, validates the classification of the latter as "endosymbionts." Many studies indicate that the Wolbachia may also play an important role in the pathology caused by the nematode worms, and that it might be possible to target therapy against the Wolbachia to treat the filarial disease. Intriguingly, the intense recent interest in Wolbachia is in complete contrast with the virtually complete indifference evoked by the original discovery of these organisms.