Gallic acid induced apoptotic events in HCT-15 colon cancer cells

AIM: To investigate the inhibitory action of diet-derived phenolic compound gallic acid(GA) against HCT-15 colon cancer cells.METHODS: The antiproliferative effect of GA against colon cancer cells was determined by performing thiazolyl blue tetrazolium bromide(MTT) assay. The colony forming ability of GA treated colon cancer cells was evaluated using the colony forming assay. The cell cycle changes induced by GA in HCT-15 cells were analyzed by propidium iodide staining. Levels of reactive oxygen species(ROS) and mitochondrial membrane potential of HCT-15 exposed to GA was assessed using 2',7'-dichlorfluorescein-diacetate and rhodamine-123 respectively, with the help of flow cytometry. Morphological changes caused by GA treatment in the colon cancer cells were identified by scanning electron microscope and photomicrograph examination. Apoptosis was confirmed using flow cytometric analysis of GA treated HCT-15 cells after staining with Yo-Pro-1.RESULTS: MTT assay results illustrated that GA has an inhibitory effect on HCT-15 cells with IC50 value of 740 μmol/L. A time-dependent inhibition of colony formation was evident with GA treatment. Cell cycle arrest was evident from the accumulation of GA treated HCT-15 cells at sub-G1 phase(0.98 ± 1.03 vs 58.01 ± 2.05)with increasing exposure time. Flow cytometric analysis of GA treated HCT-15 cells depicted early events associated with apoptosis like lipid layer breakage and fall in mitochondrial membrane potential apart from an increase in the generation of ROS which were in a time dependent manner. SEM and photomicrograph images of the GA-treated cells displayed membrane blebbing and cell shrinking characteristics of apoptosis. Further apoptosis confirmation by Yo-Pro-1 staining also showed the time-dependent increase of apoptotic cells after treatment.CONCLUSION: These results show that GA induced ROS dependent apoptosis and inhibited the growth of colon cancer cells.     

Incretin agents in type 2 diabetes

OBJECTIVE

To evaluate the emerging classes of antihyperglycemic agents that target the incretin pathway, including their therapeutic efficacy and side effect profiles, in order to help identify their place among the treatment options for patients with type 2 diabetes.

QUALITY OF EVIDENCE

MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched. Most evidence is level I and II.

MAIN MESSAGE

Two classes of incretin agents are currently available: glucagonlike peptide 1 (GLP1) receptor agonists and dipeptidyl peptidase 4 (DPP4) inhibitors, both of which lower hyperglycemia considerably without increasing the risk of hypoglycemia. The GLP1 receptor agonists have a greater effect on patients’ glycated hemoglobin A_1c levels and cause sustained weight loss, whereas the DPP4 inhibitors are weight-neutral.

CONCLUSION

The GLP1 and DPP4 incretin agents, promising and versatile antihyperglycemic agents, are finding their way into the therapeutic algorithm for treating type 2 diabetes. They can be used in patients not adequately controlled by metformin monotherapy or as initial therapy in those for whom metformin is contraindicated.     

Fructose-1,6-bisphosphate reduces inflammatory pain-like behaviour in mice: role of adenosine acting on A1 receptors

Background and purpose:

D-Fructose-1,6-bisphosphate (FBP) is an intermediate in the glycolytic pathway, exerting pharmacological actions on inflammation by inhibiting cytokine production or interfering with adenosine production. Here, the possible antinociceptive effect of FBP and its mechanism of action in the carrageenin paw inflammation model in mice were addressed, focusing on the two mechanisms described above.

Experimental approach:

Mechanical hyperalgesia (decrease in the nociceptive threshold) was evaluated by the electronic pressure-metre test; cytokine levels were measured by elisa and adenosine was determined by high performance liquid chromatography.

Key results:

Pretreatment of mice with FBP reduced hyperalgesia induced by intraplantar injection of carrageenin (up to 54%), tumour necrosis factor α (40%), interleukin-1 β (46%), CXCL1 (33%), prostaglandin E₂ (41%) or dopamine (55%). However, FBP treatment did not alter carrageenin-induced cytokine (tumour necrosis factor α and interleukin-1 β) or chemokine (CXCL1) production. On the other hand, the antinociceptive effect of FBP was prevented by systemic and intraplantar treatment with an adenosine A₁ receptor antagonist (8-cyclopentyl-1,3-dipropylxanthine), suggesting that the FBP effect is mediated by peripheral adenosine acting on A₁ receptors. Giving FBP to mice increased adenosine levels in plasma, and adenosine treatment of paw inflammation presented a similar antinociceptive mechanism to that of FBP.

Conclusions and implications:

In addition to anti-inflammatory action, FBP also presents an antinociceptive effect upon inflammatory hyperalgesia. Its mechanism of action seems dependent on adenosine production but not on modulation of hyperalgesic cytokine/chemokine production. In turn, adenosine acts peripherally on its A₁ receptor inhibiting hyperalgesia. FBP may have possible therapeutic applications in reducing inflammatory pain.     

A unique issue in the standardization of Chinese materia medica: processing

Processing of Chinese Materia Medica (CMM) is a pharmaceutical technique to fulfill the different requirements of therapy, dispensing and making preparations according to traditional Chinese medicine theory. The aims of processing are to enhance the efficacy and/or reduce the toxicity of crude drugs. Those processed products are named as decoction pieces, which are used in clinics. Therefore, there is a close relationship between processing, safety, and efficacy of Chinese medicines. Some toxicity or side effects are caused by improper processing methods and some are due to improper combination of herbal mixtures. Standardization of processing methods for Chinese herbs is as important as authentication to maintain their quality and ensure their safe use. The objective of this paper is to review the literature covering the current situation and problems of CMM processing as well as recent progress in research in this area. A summary of the most urgent work needed is proposed.     

Comparison of pro B-natriuretic peptide in hypertensive patients with and without diastolic dysfunction

Aim: to evaluate whether pro BNP can be used for detection of diastolic dysfunction. Methods: thirty nine hypertensive patients with normal systolic function, consecutively referred for echocardiography examination between October and December 2004 were recruited in the study. Diastolic dysfunction was diagnosed when echocardiographic mitral flow pattern demonstrated impaired relaxation, pseudonormalization or restrictive like patterns. NT-pro BNP levels were assessed using electro chemiluminescence Immunoassay (ECLIA) method. Unpaired t test was used to analyze the results. Results: twelve out of thirty nine subjects had normal diastolic function. All base line characteristics, except for uric acid, were equally distributed between normal and abnormal diastolic function group. NT-pro BNP levels were nearly significantly higher in the diastolic dysfunction group (P=0.053). Conclusion: NT-pro BNP levels trends to be higher in hypertensive subjects with diastolic dysfunction.     

Contemporary approaches to designing and evaluating vaccines against Chlamydia

The clinically relevant pathologic consequences of primary ocular, genital, or respiratory human infection by members of the genus Chlamydia are conjunctivitis, cervicitis, urethritis and sinusitis. The major complications and sometimes debilitating evolutionary outcomes of these infections include: trichiasis and cicatrizing trachoma, endometritis or pelvic inflammatory disease and involuntary tubal factor infertility and bronchopulmonary pneumonia. These diseases, in addition to other chlamydia-associated chronic syndromes (e.g., artherosclerosis, multiple sclerosis and Alzheimer's disease), pose serious public healthcare and huge budgetary concerns. The current medical opinion is that an efficacious prophylactic vaccine is a sine qua non--to control the morbidity of chiamydial infection in the human population. The research goal for an efficacious human chlamydial vaccine has faced key challenges to define the elements of protective immunity to facilitate vaccine evaluation, the judicious selection of appropriate vaccine candidates that possess stable antigenic and immunologic properties and the development of effective delivery vehicles and adjuvants to boost immune effectors to achieve long-term protective immunity. Progress in the functional immunobiology of Chlamydia has established the essential immunologic paradigms for vaccine selection and evaluation, including the obligatory requirement for a vaccine to induce T-helper Type 1 immune response that controls chlamydiae. Recent advances in chlamydial genomics and proteomics should enhance the identification of likely chlamydial gene products that fulfill the antigenic requirements of putative vaccine candidates. Major inroads are however needed in the construction and development of novel and effective delivery systems, such as vectors and adjuvants. This review summarizes the status of contemporary chlamydial vaccine research and promising trends fueling the growing optimism for an efficacious vaccine. The unified approach to vaccines for the genus Chlamydia is validated by the several conserved genes and common immunogenic proteins among member species and the similarity of immune effectors controlling Chlamydia species in animals and humans.     

Fc receptor-mediated antibody regulation of T cell immunity against intracellular pathogens

Immunity to intracellular microbial pathogens, including Chlamydia species, is controlled primarily by cell-mediated effector mechanisms, yet, the absence of antibodies results in inefficient microbial clearance. We investigated the hypothesis that certain Fc receptor functions promote the rapid induction of elevated T helper type 1 (Th1) response, which effectively clears chlamydiae. FcR(-/-) mice exhibited a delayed and reduced frequency of Chlamydia-specific Th1 cells, compared to FcR(+/+) mice. In vitro, antichlamydial antibodies increased the rate of Th1 activation by FcR(+/+) but not FcR(-/-) antigen-presenting cells. FcR(-/-) dendritic cells and the T cell-associated IgG2A and IgA mediate enhanced Th1 activation by antibodies. Immunization with chlamydia-antibody complexes induced elevated and protective Th1 response. These results provide a mechanistic basis for requiring both T cell and humoral immune responses in protective immunity and vaccine evaluation. Findings offer a paradigm in host defense wherein different effector components function indirectly to maximize the principal effector mechanism.