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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Abstract-The early and long-term effects of coronary artery ligation on the plasma and left ventricular angiotensinconverting enzyme (ACE and ACE2) activities, ACE and ACE2 mRNA levels, circulating angiotensin (Ang) levels [Ang I, Ang-(1-7), Ang-(1-9), and Ang II], and cardiac function were evaluated 1 and 8 weeks after experimental myocardial infarction in adult Sprague Dawley rats. Sham-operated rats were used as controls. Coronary artery ligation caused myocardial infarction, hypertrophy, and dysfunction 8 weeks after surgery. At week 1, circulating Ang II and Ang-(1-9) levels as well as left ventricular and plasma ACE and ACE2 activities increased in myocardial-infarcted rats as compared with controls. At 8 weeks post-myocardial infarction, circulating ACE activity, ACE mRNA levels, and Ang II levels remained higher, but plasma and left ventricular ACE2 activities and mRNA levels and circulating levels of Ang-(1-9) were lower than in controls. No changes in plasma Ang-(1-7) levels were observed at any time. Enalapril prevented cardiac hypertrophy and dysfunction as well as the changes in left ventricular ACE, left ventricular and plasmatic ACE2, and circulating levels of Ang II and Ang-(1-9) after 8 weeks postinfarction. Thus, the decrease in ACE2 expression and activity and circulating Ang-(1-9) levels in late ventricular dysfunction post-myocardial infarction were prevented with enalapril. These findings suggest that in this second arm of the renin-angiotensin system, ACE2 may act through Ang-(1-9), rather than Ang-(1-7), as a counterregulator of the first arm, where ACE catalyzes the formation of Ang II. Key Words: angiotensin-converting enzyme Ⅲ myocardial infarction Ⅲ renin-angiotensin system Ⅲ remodeling Ⅲ cardiac function T he renin-angiotensin system (RAS) is a more complex system than originally thought. A new angiotensin-converting enzyme (ACE), ACE2, has been recently identified as a homologue of ACE. 1 ACE2 is also a metalloprotease consisting of 805 amino acids with a considerable degree of homology to ACE (40% identity and 61% similarity). 2,3 ACE2 contains a single zinc-binding domain and is a carboxypeptidase, unlike somatic ACE, which contains 2 zinc-binding domains and is a dipeptidyl carboxypeptidase. 2 Both ACE2 and ACE are bound to the plasma membrane and must be cleaved to release the soluble enzyme. 2 Their cellular and tissue distributions are also different, in that ACE is expressed in the endothelium throughout the vasculature, whereas ACE2 is distributed to most tissues, including to the heart and kidney. 3 Analyses in vitro have shown that ACE2 cleaves angiotensin (Ang) I to Ang-(1-9), which is then cleaved by ACE to Ang-(1-7). However, ACE2 also cleaves Ang II to form Ang-(1-7). Because Ang-(1-7) is a potent vasodepressor peptide, its actions could counterbalance the vasopressor effect of Ang II. 4,5 ACE2 does not act on bradykinins and its activity is not inhibited by ACE inhibitors. 2 Although a significant activation of the RAS system occurs after myocardial infarction, 6 -10 ...