Quality of the Australian National Health and Medical Research Council's clinical practice guidelines for the management of diabetic retinopathy

Clinical relevance: Understanding the quality of the commonly used clinical practice guidelines can help busy clinicians in selecting appropriate guidelines for evidence-based eye care for people with diabetes.Background: The National Health and Medical Research Council's (NHMRC) clinical practice guideline on diabetic retinopathy management has been widely used locally and internationally for over 10 years. However, the quality of this guideline has never been formally assessed. This study aimed to systematically evaluate the quality of the NHMRC guideline and compare it against other international guidelines.Methods: The 2008 NHMRC and another five established diabetic retinopathy management international guidelines (Scottish Intercollegiate Guidelines Network, 2017; American Academy of Ophthalmology, 2019; American Optometric Association, 2019; Royal College of Ophthalmologists, UK, 2013, and Canadian Ophthalmologic Society, 2012) were examined using the Appraisal of Guidelines, Research and Evaluation (AGREE II) instrument. Scoring by four independent reviewers was aggregated into six domain and overall rating scores. Consistency among the reviewers was assessed using intraclass correlation coefficient (ICC).Results: The AGREE II domain scores for the NHMRC guideline were: scope and purpose 72%, stakeholder involvement 64%, rigour of development 77%, clarity of presentation 96%, applicability 35%, and editorial independence 15%. The NHMRC guideline's overall score (5.3 of 7) was lower than that of most other guidelines. Compared to others, the NHMRC guideline scored well in clarity of presentation and rigour of development, but less well for editorial independence. The NHMRC guideline was the least current and a need to update it was recognised by all reviewers who identified key areas for improvement.Conclusion: The quality of the NHMRC guideline was comparable to most other established international guidelines. Several areas of strengths and weaknesses in this guideline were identified. Future updates should aim to improve transparency in development and applicability in clinical practice.

Guidelines rarely used GRADE and applied methods inconsistently: A methodological study of Australian guidelines

OBJECTIVES

The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach is accepted methodology to assess the certainty of the evidence included in systematic reviews and clinical practice guidelines. The GRADE approach is endorsed globally, in Australia, the National Health and Medical Research Council advocated for the use of the GRADE approach in 2011. The purpose of this methodological review was to assess how GRADE has been adopted for Australian practice guidelines.

STUDY DESIGN AND SETTING

This methodological review searched of the National Health and Medical Research Council Clinical Practice Guidelines Portal from 2011 to 2018, in an effort to retrieve all practice guidelines available via this medium.

RESULTS

240 guidelines were retrieved authored by 51 different organizations. 15 guidelines followed GRADE methodology. Application of GRADE methods varied between guidelines, some misreported and altered aspects of the GRADE process. Guidelines that closely adhered to the guidance from the GRADE Working Group scored higher in domain 3 (rigor of development) of the Appraisal of Guidelines for Research and Evaluation II tool, indicating a positive linear relationship between GRADE adherence and rigor of development scores.

CONCLUSION

The results of our project suggest that the use of GRADE in Australian guidelines is increasing, however, strategies to increase uptake and reporting within the guideline community need to be explored.

Structural studies of Streptococcus pyogenes streptolysin O provide insights into the early steps of membrane penetration

Cholesterol-dependent cytolysins (CDCs) are a large family of bacterial toxins that exhibit a dependence on the presence of membrane cholesterol in forming large pores in cell membranes. Significant changes in the three-dimensional structure of these toxins are necessary to convert the soluble monomeric protein into a membrane pore. We have determined the crystal structure of the archetypical member of the CDC family, streptolysin O (SLO), a virulence factor from Streptococcus pyogenes. The overall fold is similar to previously reported CDC structures, although the C-terminal domain is in a different orientation with respect to the rest of the molecule. Surprisingly, a signature stretch of CDC sequence called the undecapeptide motif, a key region involved in membrane recognition, adopts a very different structure in SLO to that of the well-characterized CDC perfringolysin O (PFO), although the sequences in this region are identical. An analysis reveals that, in PFO, there are complementary interactions between the motif and the rest of domain 4 that are lost in SLO. Molecular dynamics simulations suggest that the loss of a salt bridge in SLO and a cation-pi interaction are determining factors in the extended conformation of the motif, which in turn appears to result in a greater flexibility of the neighboring L1 loop that houses a cholesterol-sensing motif. These differences may explain the differing abilities of SLO and PFO to efficiently penetrate target cell membranes in the first step of toxin insertion into the membrane.

Diabetes impairs mobilization of mouse bone marrow-derived Lin(-)/VEGF-R2(+) progenitor cells

Endothelial progenitor cells circulating in the peripheral blood (PB) contribute to vascular repair. This study aimed to evaluate the potential of a 'cocktail' consisting of erythropoietin, granulocyte colony-stimulating factor and tetrahydrobiopterin to mobilize hematopoietic lineage negative/vascular endothelial growth factor receptor 2 positive (Lin(-)/VEGF-R2(+)) cells from the bone marrow (BM) to PB in non-diabetic and diabetic mice. Diabetes was induced in mice by intraperitoneal injection of streptozotocin. Diabetic mice were studied after 16weeks of hyperglycemia. Half the mice in each group (non-diabetic and diabetic) received daily intraperitoneal injections of the cocktail for 6 consecutive days while the other half received vehicle buffer. Mobilization of Lin(-)/VEGF-R2(+) cells, which were expanded in MCP301 medium, was evaluated after isolating them from BM and PB and their phenotypic and morphological properties were studied. We found that 16weeks of diabetes affected neither the total number of BM mononucleated cells nor the number of Lin(-)/VEGF-R2(+) cells in BM compared with non-diabetic controls. In non-diabetic mice, cocktail treatment resulted in a significant decrease in BM Lin(-)/VEGF-R2(+) cells, paralleled by a significant increase of these cells in PB. Such changes in the number of Lin(-)/VEGF-R2(+) cells in BM and PB after the cocktail treatment were less marked in diabetic mice. In vitro studies of BM Lin(-)/VEGF-R2(+) cells from diabetic and non-diabetic mice did not reveal any differences in either phenotypes or colony forming potential. These findings indicate that diabetes impairs the mobilization of Lin(-)/VEGF-R2(+) cells from BM to PB. Impaired mobilization of BM Lin(-)/VEGF-R2(+) cells soon after the onset of diabetes may contribute to complications such as diabetic retinopathy.