Publications

OPINION STATEMENT

Patients with long-standing ulcerative colitis (UC) and extensive Crohn's disease (CD) colitis have a high risk of colorectal cancer (CRC) and are recommended to undergo surveillance with colonoscopy. Recent data highlights their increased risk of CRC compared to the general population despite colonoscopy surveillance. The proportion of IBD patients diagnosed with interval CRC within 6 to 36 months following a clearing colonoscopy was 15 %. Optimizing colonoscopy surveillance methods is important. Studies have demonstrated that the best endoscopic surveillance strategy to detect dysplasia is chromoendoscopy with surface application of dyes to enhance the mucosal visualization and that visible dysplasia should be endoscopically resected. In this chapter we will summarize the optimal surveillance and management techniques for colorectal dysplasia in IBD patients.

The rapid rise in childhood allergies (atopy) in Westernized nations has implicated associated environmental exposures and lifestyles as primary drivers of disease development. Culture-based microbiological studies indicate that atopy has demonstrable ties to altered gut microbial colonization in very early life. Infants who exhibit more severe multisensitization to food- or aero-allergens have a significantly higher risk of subsequently developing asthma in childhood. Hence an emerging hypothesis posits that environment- or lifestyle-driven aberrancies in the early-life gut microbiome composition and by extension, microbial function, represent a key mediator of childhood allergic asthma. Animal studies support this hypothesis. Environmental microbial exposures epidemiologically associated with allergy protection in humans confer protection against airway allergy in mice. In addition, gut microbiome-derived short-chain fatty acids produced from a high-fiber diet have been shown to protect against allergy via modulation of both local and remote mucosal immunity as well as hematopoietic antigen-presenting cell populations. Here we review key data supporting the concept of a gut-airway axis and its critical role in childhood atopy.

Carbapenemases are enzymes that are capable of inactivating all or almost all beta-lactam antimicrobial agents. These enzymes are frequently coexpressed with other resistance mechanisms to non-beta-lactams, leading to extremely drug-resistant pathogens. Once a curiosity, these enzymes have spread into organisms that are among the most common causes of infection, such as Klebsiella pneumoniae and Escherichia coli. Identification of these organisms has proved challenging for clinical microbiology laboratories, leading to revisions in susceptibility standards for carbapenems. Although currently a rare cause of infection in children, these carbapenem-resistant Enterobacteriaceae (CRE) are becoming endemic in a variety of healthcare settings. Management of infections due to CRE is complicated by a lack of effective treatment options and clinical data on their effectiveness. Treatment of CRE infections in children is particularly challenging because therapeutic options for CRE lack adequate data on dosing and safety in children. Use of unconventional combination treatment regimens, including agents to which the organism is resistant in vitro, may provide some benefit in the treatment of severe CRE infection. Fortunately, several agents with the potential for treatment of CRE infections have been recently approved or are in late clinical development, although few data will be available in the short term to inform use in children.

AIMS

Recommendations for metformin use are dependent on eGFR category: eGFR >45 ml/min/1.73 m - "first-line agent"; eGFR 30-44 - "use with caution"; eGFR<30 - "do not use". Misclassification of metformin eligibility by creatinine-based MDRD GFR estimates (eGFRcr) may contribute to its misuse. We investigated the impact of cystatin c estimates of GFR (eGFRcys) on metformin eligibility.

METHODS

In a consecutive cohort of 550 Veterans with diabetes, metformin use and eligibility were assessed by eGFR category, using eGFRcr and eGFRcys. Discrepancy in eligibility was defined as cases where eGFRcr and eGFRcys categories (<30, 30-44, 45-60, and >60 ml/min/1.73 m) differed with an absolute difference in eGFR of >5 ml/min/1.73 m. We modeled predictors of metformin use and eGFR category discrepancy with multivariable relative risk regression and multinomial logistic regression.

RESULTS

Subjects were 95% male, median age 68, and racially diverse (45% White, 22% Black, 11% Asian, 22% unknown). Metformin use decreased with severity of eGFRcr category, from 63% in eGFRcr >60 to 3% in eGFRcr <30. eGFRcys reclassified 20% of Veterans into different eGFR categories. Factors associated with a more severe eGFRcys category compared to eGFRcr were older age (aOR = 2.21 per decade, 1.44-1.82), higher BMI (aOR = 1.04 per kg/m, 1.01-1.08) and albuminuria >30 mg/g (aOR = 1.81, 1.20-2.73).

CONCLUSIONS

Metformin use is low among Veterans with CKD. eGFRcys may serve as a confirmatory estimate of kidney function to allow safe use of metformin among patients with CKD, particularly among older individuals and those with albuminuria.

PURPOSE OF REVIEW

The review will provide an update on the pathophysiology and studies of inflammation associated with the asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) and the mechanism(s) responsible for persistent expiratory airflow limitation in never-smoked asthma patients who develop loss of lung elastic recoil consistent with an asthma-COPD clinical phenotype (ACOS in nonsmokers).

RECENT FINDINGS

Patients with a clinical diagnosis of ACOS have more frequent respiratory exacerbations and hospitalizations than COPD patients without ACOS. ACOS patients should be treated with inhaled corticosteroids, short and long-acting β2-agonist, and long-acting muscarinic receptor antagonist. Biomarker work suggests that a molecular phenotype of ACOS (e.g., elevated markers of eosinophilic or type 2 inflammation) incompletely corresponds to clinical phenotypes. Recently, we reported sentinel observation of unsuspected mild diffuse centrilobular emphysema in never-smoked asthma patients at autopsy, despite mild changes in lung computed tomography and normal diffusing capacity.

SUMMARY

Recent studies have shown that subgroups of COPD and asthma patients may have overlapping immune responses. Never-smoked asthma patients may have persistent expiratory airflow limitation because of loss of lung elastic recoil. This may be because of unsuspected centrilobular emphysema detected at autopsy, and not easily diagnosed on lung computed tomography and diffusing capacity.

We have recently shown that repeated exposure of the peripheral terminal of the primary afferent nociceptor to the mu-opioid receptor (MOR) agonist DAMGO ([D-Ala, N-Me-Phe, Gly-ol]-enkephalin acetate salt) induces a model of transition to chronic pain that we have termed type II hyperalgesic priming. Similar to type I hyperalgesic priming, there is a markedly prolonged response to subsequent administration of proalgesic cytokines, prototypically prostaglandin E2 (PGE2). However, type II hyperalgesic priming differs from type I in being rapidly induced, protein kinase A (PKA), rather than PKCε dependent, not reversed by a protein translation inhibitor, occurring in female as well as in male rats, and isolectin B4-negative neuron dependent. We report that, as with the repeated injection of a MOR agonist, the repeated administration of an agonist at the A1-adenosine receptor, also a Gi-protein coupled receptor, N-cyclopentyladenosine (CPA), also produces priming similar to DAMGO-induced type II hyperalgesic priming. In this study, we demonstrate that priming induced by repeated exposure to this A1-adenosine receptor agonist shares the same mechanisms, as MOR-agonist induced priming. However, the prolongation of PGE2 hyperalgesia induced by repeated administration of CPA depends on G-protein αi subunit activation, differently from DAMGO-induced type II priming, in which it depends on the β/γ subunit. These data implicate a novel form of Gi-protein signaling pathway in the type II hyperalgesic priming induced by repeated administration of an agonist at A1-adenosine receptor to the peripheral terminal of the nociceptor.

PURPOSE OF REVIEW

The purpose is to review recent insights into the impact of HIV-associated immune activation on AIDS and non-AIDS morbidity and mortality.

RECENT FINDINGS

Immune activation has long been recognized as an important consequence of untreated HIV infection and predictor of AIDS progression, which declines but fails to normalize during suppressive antiretroviral therapy, and continues to predict disease in this setting. Thus, a major research agenda is to develop novel therapies to reduce persistent immune activation in treated HIV infection. Yet, the optimal targets for interventions remain unclear. Both the specific root causes of immune activation and the many interconnected pathways of immune activation that are most likely to drive disease risk in HIV-infected individuals remain incompletely characterized, but recent studies have shed new light on these topics.

SUMMARY

In the context of this review, we will summarize recent evidence helping to elucidate the immunologic pathways that appear most strongly predictive of infectious and noninfectious morbidity. We will also highlight the likelihood that not all root drivers of immune activation - and the discrete immunologic pathways to which they give rise - are likely to produce the same disease manifestations and/or be equally attenuated by early antiretroviral therapy initiation.