Chronic treatment with a glucagon receptor antagonist lowers glucose and moderately raises circulating glucagon and glucagon-like peptide 1 without severe alpha cell hypertrophy in diet-induced obese mice

AIMS/HYPOTHESIS

Antagonism of the glucagon receptor (GCGR) represents a potential approach for treating diabetes. Cpd-A, a potent and selective GCGR antagonist (GRA) was studied in preclinical models to assess its effects on alpha cells.

METHODS

Studies were conducted with Cpd-A to examine the effects on glucose-lowering efficacy, its effects in combination with a dipeptidyl peptidase-4 (DPP-4) inhibitor, and the extent and reversibility of alpha cell hypertrophy associated with GCGR antagonism in mouse models.

RESULTS

Chronic treatment with Cpd-A resulted in effective and sustained glucose lowering in mouse models in which endogenous murine Gcgr was replaced with human GCGR (hGCGR). Treatment with Cpd-A also led to stable, moderate elevations in both glucagon and glucagon-like peptide 1 (GLP-1) levels, which were completely reversible and not associated with a hyperglycaemic overshoot following termination of treatment. When combined with a DPP-4 inhibitor, Cpd-A led to additional improvement of glycaemic control correlated with elevated active GLP-1 levels after glucose challenge. In contrast to Gcgr-knockout mice in which alpha cell hypertrophy was detected, chronic treatment with Cpd-A in obese hGCGR mice did not result in gross morphological changes in pancreatic tissue.

CONCLUSIONS/INTERPRETATION

A GRA lowered glucose effectively in diabetic models without significant alpha cell hypertrophy during or following chronic treatment. Treatment with a GRA may represent an effective approach for glycaemic control in patients with type 2 diabetes, which could be further enhanced when combined with DPP-4 inhibitors.

Expression of the T helper 17-associated cytokines IL-17A and IL-17F in asthma and COPD

Background:

Asthma and COPD are characterized by airway dysfunction and inflammation. Neutrophilic airway inflammation is a common feature of COPD and is recognized in asthma, particularly in severe disease. The T helper (Th) 17 cytokines IL-17A and IL-17F have been implicated in the development of neutrophilic airway inflammation, but their expression in asthma and COPD is uncertain.

Methods:

We assessed IL-17A and IL-17F expression in the bronchial submucosa from 30 subjects with asthma, 10 ex-smokers with mild to moderate COPD, and 27 nonsmoking and 14 smoking control subjects. Sputum IL-17 concentration was measured in 165 subjects with asthma and 27 with COPD.

Results:

The median (interquartile range) IL-17A cells/mm² submucosa was increased in mild to moderate asthma (2.1 [2.4]) compared with healthy control subjects (0.4 [2.8]) but not in severe asthma (P = .04). In COPD, IL-17A⁺ cells/mm² submucosa were increased (0.5 [3.7]) compared with nonsmoking control subjects (0 [0]) but not compared with smoking control subjects (P = .046). IL-17F⁺ cells/mm² submucosa were increased in severe asthma (2.7 [3.6]) and mild to moderate asthma (1.6 [1.0]) compared with healthy controls subjects (0.7 [1.4]) (P = .001) but was not increased in subjects with COPD. IL-17A and IL-17F were not associated with increased neutrophilic inflammation, but IL-17F was correlated with the submucosal eosinophil count (rs = 0.5, P = .005). The sputum IL-17 concentration in COPD was increased compared with asthma (2 [0-7] pg/mL vs 0 [0-2] pg/mL, P < .0001) and was correlated with post-bronchodilator FEV₁% predicted (r = −0.5, P = .008) and FEV₁/FVC (r = −0.4, P = .04).

Conclusions:

Our findings support a potential role for the Th17 cytokines IL-17A and IL-17F in asthma and COPD, but do not demonstrate a relationship with neutrophilic inflammation.

Clinical evidence of herb-drug interactions: a systematic review by the natural standard research collaboration

To evaluate the pharmacokinetics and adverse effects of medicinal herbs, as well as clinical evidence of herb-drug interactions.

METHODS

Electronic searches were conducted in multiple databases, including MEDLINE, EMBASE, the Cochrane Library, CINAHL, NAPRALERT, International Pharmaceutical Abstracts, CANCERLIT, CISCOM, and HerbMed. Search terms used included common names, scientific names, and synonyms for the herbs and their primary active constituents. Bibliographies of relevant articles were also searched by hand to obtain additional references. No restrictions were placed on language or quality of publications. All literature collected pertained to adverse effects, pharmacokinetics, and suspected or confirmed cases of herb-drug interactions.

RESULTS

Over 80 herbs or botanicals (including plants, fungi, algae, and common constituents) were identified that had clinically significant interactions with prescription and over-the-counter drugs. Interestingly, herbs beginning with the letter "g" (garlic, ginger, ginkgo, and grapefruit) were among the herbs most commonly involved in herb-drug interactions. Drugs with anticoagulant/antiplatelet activity (e.g. warfarin, aspirin) were frequently implicated in herb-drug interactions, with documented interactions with over 30 herbs and herbal products. Because many herbs have demonstrated adverse effects on the liver, the potential for interaction with hepatotoxic agents (such as acetaminophen) is also significant. Clinical outcomes of reported herb-drug interactions ranged from mild to severe. Of note, fatalities (though rare) have occurred with concomitant ephedra and caffeine use.

CONCLUSION

As herbal products (and dietary supplements in general) continue to grow in popularity, patients and health care providers should be vigilant of potential herb-drug interactions.

Exacerbated fatigue and motor deficits in interleukin-10-deficient mice after peripheral immune stimulation

The anti-inflammatory cytokine interleukin (IL)-10 is important for regulating inflammation in the periphery and brain, but whether it protects against infection- or age-related psychomotor disturbances and fatigue is unknown. Therefore, the present study evaluated motor coordination, time to fatigue, and several central and peripheral proinflammatory cytokines in male young adult (3-mo-old) and middle-aged (12-mo-old) wild-type (IL-10(+/+)) and IL-10-deficient (IL-10(-/-)) mice after intraperitoneal injection of lipopolysaccharide (LPS) or saline. No age-related differences were observed; therefore, data from the two ages were pooled and analyzed to determine effects of genotype and treatment. LPS treatment increased IL-1beta, IL-6, and TNFalpha mRNA in all brain areas examined in IL-10(+/+) and IL-10(-/-) mice, but to a greater extent and for a longer time in IL-10(-/-) mice. Plasma IL-1beta and IL-6 were increased similarly in IL-10(+/+) and IL-10(-/-) mice 4 h after LPS but remained elevated longer in IL-10(-/-) mice, whereas TNFalpha was higher in IL-10(-/-) mice throughout after LPS treatment. Motor performance and motor learning in IL-10(+/+) mice were not affected by LPS treatment; however, both were reduced in IL-10(-/-) mice treated with LPS compared with those treated with saline. Furthermore, although LPS reduced the time to fatigue in IL-10(+/+) and IL-10(-/-) mice, the effects were exacerbated in IL-10(-/-) mice. Thus the increased brain and peripheral inflammation induced by LPS in IL-10(-/-) mice was associated with increased coordination deficits and fatigue. These data suggest that IL-10 may inhibit motor deficits and fatigue associated with peripheral infections via its anti-inflammatory effects.

Successful ageing in adversity: the LASER-AD longitudinal study

BACKGROUND

Most models of successful ageing do not allow for the possibility of living "successfully," despite some degree of cognitive or physical impairment. We reviewed the successful ageing and related quality of life literature to identify their potential predictors. We then tested our hypotheses that wellbeing in adversity would be predicted by mental health (anxiety and depression) and social factors rather than physical health and that it would be stable over time.

METHOD

We interviewed 224 people with Alzheimer's disease (AD) and their family carers, recruited to be representative of those living with AD in the community. We re-interviewed 122 (73.1% of eligible) participants 18 months later. Our main outcome measure was the perception of the person with AD on their life as a whole.

RESULTS

Mean "wellbeing in adversity" scores did not change significantly over time (t = 0.23). Social relationships, subjective mental health, health perception, activities of daily living and baseline wellbeing in adversity were the significant correlates of wellbeing in adversity on univariate analysis. Only baseline wellbeing in adversity and mental health score were significant predictors in our regression analysis. In a well fitting structural equation model, less severe dementia and better health perception predicted fewer mental health problems and social relationships, but were not direct predictors of wellbeing in adversity at 18 months.

CONCLUSION

Successful ageing was common among a cohort of people with dementia. The most important predictors of this were mental health and social relationships, which fully mediated the relationship we found between health perception and wellbeing 18 months later.

Prognostic analysis of tumour angiogenesis, determined by microvessel density and expression of vascular endothelial growth factor, in high-risk primary breast cancer patients treated with high-dose chemotherapy

In contrast to early breast cancer, the prognostic effect of tumour angiogenesis in tumours with advanced axillary spread has been less studied. We retrospectively analysed the effect of microvessel density (MVD) and vascular endothelial growth factor (VEGF) by immunohistochemistry on the outcome of 215 patients treated uniformly within prospective trials of high-dose chemotherapy for 4-9 and >/=10 positive nodes, and followed for a median of 9 (range 3-13) years. Microvessel density was associated with epidermal growth factor receptor (EGFR) expression (P<0.001) and tumour size (P=0.001). Vascular endothelial growth factor overexpression (51% of patients) was associated with overexpression of EGFR (P=0.01) and HER2 (P<0.05), but not with MVD (P=0.3). High MVD was associated with worse relapse-free survival (74 vs 44%, P<0.001) and overall survival (76 vs 44%, P<0.001). Vascular endothelial growth factor overexpression had no effect on outcome. Multivariate analyses showed a prognostic effect of MVD independently of other known prognostic factors in this patient population. In conclusion, tumour angiogenesis, expressed as MVD, is a major independent prognostic factor in breast cancer patients with extensive axillary involvement.

Glucagon receptor knockout mice are resistant to diet-induced obesity and streptozotocin-mediated beta cell loss and hyperglycaemia

AIMS/HYPOTHESIS

Under normal physiological conditions, glucagon signalling is important in glucose homeostasis. Hyperglucagonaemia or altered insulin:glucagon ratio plays a role in maintaining hyperglycaemia in subjects with type 2 diabetes. It has been reported that glucagon receptor knockout (Gcgr (-/-)) mice develop normally and have lower plasma glucose on a normal diet. The goal of the current research was to further investigate the role of glucagon signalling in metabolic control and glucose homeostasis.

METHODS

Gcgr (-/-) mice were challenged with a high-fat diet (HFD) and with streptozotocin, which induces beta cell damage. They were then analysed for whole-body and serum metabolic phenotypes as well as pancreatic islet morphology.

RESULTS

In comparison with wild-type mice, Gcgr (-/-) mice exhibited decreased body weight and food intake, reduced plasma glucose levels, and improved oral and intraperitoneal glucose tolerance. Elevated glucagon-like peptide-1 levels and reduced gastric emptying were also observed in Gcgr (-/-) mice, which also had reduced HFD-induced hyperinsulinaemia and hyperleptinaemia, and were resistant to the development of hepatic steatosis. In addition, Gcgr (-/-) mice were resistant to STZ-induced hyperglycaemia and pancreatic beta cell destruction.

CONCLUSIONS/INTERPRETATION

This study demonstrates that blocking glucagon signalling by targeted Gcgr gene deletion leads to an improvement in metabolic control in this mouse model.

Clinical and research applications of photodynamic therapy in dermatology: Experience of the scottish PDT centre

BACKGROUND AND OBJECTIVES

The Scottish PDT Centre has carried out 3,442 treatments on 762 patients with superficial skin lesions, especially superficial basal cell carcinoma (sBCC), Bowen's disease (BD) and actinic keratosis (AK). STUDY DESIGN MATERIALS AND METHODS: The article reviews our experience of various light sources and associated dosimetry; thereafter we discuss clinical outcome followed by some of our research studies in clinically important areas.

RESULTS

We show that improved dosimetry is required to ensure an optimal light dose is delivered to the tumour. We have shown that photosensitizers and proteins interact in such a way that their photophysical and photochemical properties are modified. We have also demonstrated the presence of DNA strand breaks with two different photosensitizers, but there is no evidence that PDT is significantly mutagenic in clinical practice.

CONCLUSIONS

In our experience, topical PDT is generally well tolerated and is an effective treatment of sBCC, BD, AK, field change and lesions at sites of poor healing.