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- Klionsky, Daniel J., et al.
(author)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Bray, George A., et al.
(author)
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Long-Term Safety, Tolerability, and Weight Loss Associated With Metformin in the Diabetes Prevention Program Outcomes Study
- 2012
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In: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 35:4, s. 731-737
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Journal article (peer-reviewed)abstract
- OBJECTIVE-Metformin produced weight loss and delayed or prevented diabetes in the Diabetes Prevention Program (DPP). We examined its long-term safety and tolerability along with weight loss, and change in waist circumference during the DPP and its long-term follow-up. RESEARCH DESIGN AND METHODS-The randomized double-blind clinical trial of metformin or placebo followed by a 7-8-year open-label extension and analysis of adverse events, tolerability, and the effect of adherence on change in weight and waist circumference. RESULTS-No significant safety issues were identified. Gastrointestinal symptoms were more common in metformin than placebo participants and declined over time. During the DPP, average hemoglobin and hematocrit levels were slightly lower in the metformin group than in the placebo group. Decreases in hemoglobin and hematocrit in the metformin group occurred during the first year following randomization, with no further changes observed over time. During the DPP, metformin participants had reduced body weight and waist circumference compared with placebo (weight by 2.06 +/- 5.65% vs. 0.02 +/- 5.52%, P < 0.001, and waist circumference by 2.13 +/- 7.06 cm vs. 0.79 +/- 6.54 cm, P < 0.001 in metformin vs. placebo, respectively). The magnitude of weight loss during the 2-year double-blind period was directly related to adherence (P < 0.001). Throughout the unblinded follow-up, weight loss remained significantly greater in the metformin group than in the placebo group (2.0 vs. 0.2%, P < 0.001), and this was related to the degree of continuing metformin adherence (P < 0.001). CONCLUSIONS-Metformin used for diabetes prevention is safe and well tolerated. Weight loss is related to adherence to metformin and is durable for at least 10 years of treatment.
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