RESULTS: We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic β-cells. By culturing rat pancreatic β-cells (INS-1) cells in high-glucose media, we identified a source of increased miR-15a in the blood as exosomes secreted by pancreatic β-cells. We postulate that miR-15a, produced in pancreatic β-cells, can enter the bloodstream and contribute to retinal injury. miR-15a overexpression in Müller cells can be induced by exposing Müller cells to exosomes derived from INS-1 cells under high-glucose conditions and results in oxidative stress by targeting Akt3, which leads to apoptotic cell death. The in vivo relevance of these findings is supported by results from high-fat diet and pancreatic β-cell-specific miR-15a-/- mice.
INNOVATION: This study highlights an important and underappreciated mechanism of remote cell-cell communication (exosomal transfer of miRNA) and its influence on the development of T2D complications.
CONCLUSION: Our findings suggest that circulating miR-15a contributes to the pathogenesis of diabetes and supports the concept that miRNAs released by one cell type can travel through the circulation and play a role in disease progression via their transfer to different cell types, inducing oxidative stress and cell injury. Antioxid. Redox Signal. 27, 913-930.
METHODS: This study adopted a comparative case study design with a qualitative focus to identify similarities and differences of the potential barriers and facilitators to implementing the insulin PDA across different sites. Focus groups and individual interviews were conducted with 28 healthcare providers and 15 patients from five public health clinics under the Ministry of Health in Malaysia. The interviews were transcribed verbatim and analysed using the thematic approach.
RESULTS: Five themes emerged which were: 1) time constraint; 2) PDA costs; 3) tailoring PDA use to patient profile; 4) patient decisional role; and 5) leadership and staff motivation. Based on the interviews and drawing on observations and interview reflection notes, time constraint emerged as the common prominent factor that cut across all the clinics, however, tailoring PDA use to patient profile; patient decisional role; leadership and staff motivation varied due to the distinct challenges faced by specific clinics. Among clinics from semi-urban areas with more patients from limited education and lower socio-economic status, patients' ability to comprehend the insulin PDA and their tendency to rely on their doctors and family to make health decisions were felt to be a prominent barrier to the insulin PDA implementation. Staff motivation appeared to be stronger in most of the clinics where specific time was allocated to diabetes team to attend to diabetes patients and this was felt could be a potential facilitator, however, a lack of leadership might affect the insulin PDA implementation even though a diabetes team is present.
CONCLUSIONS: This study found time constraint as a major potential barrier for PDA implementation and effective implementation of the insulin PDA across different public health clinics would depend on leadership and staff motivation and, the need to tailor PDA use to patient profile. To ensure successful implementation, implementers should avoid a 'one size fits all' approach when implementing health innovations.
METHODS: One hundred and one formalin-fixed and paraffin-processed triple-negative breast cancer cases from the University of Malaya Medical Centre were tested immunohistochemically for cytokeratins 5/6 and 14, PTEN, and IGFBP2. The resulting slides were scored for proportion and intensity of staining.
RESULTS: Loss of tumor nuclear and cytoplasmic staining for PTEN occurred in 48.3% of cases and was significantly associated with younger age at diagnosis (47 years compared with 57 years in those without PTEN loss; P = .005). Independent predictors of PTEN loss were late stage at presentation (P = .026), cytokeratin 5/6 positivity (P = .028), and IGFBP2 expression (P = .042). High levels of IGFBP2 expression were seen in 32% of cases; an independent predictor of high levels was cytokeratin 14 negativity (P = .005). PTEN loss and high levels of IGFBP2 expression were associated with poorer survival, but neither of these trends was significant.
CONCLUSIONS: PTEN loss is a frequent event in triple-negative breast cancers and is significantly associated with younger age at onset of breast cancer, late stage, and IGFBP2 expression.
DESIGN: Immunohistochemical expression of IGFBP-2 protein was semi-quantitatively assessed in tissue microarrays containing 9 normal cervix, 10 low grade cervical intraepithelial neoplasia (LGCIN), 10 high grade cervical intraepithelial neoplasia (HGCIN) and 42 squamous cell carcinoma (SCC) cases. The gene expression profiles of IGFBP-2, IGF-1, IGF-1R, PTEN, MDM2, AKT1 and TP53 were determined in three cervical tissue samples each from normal cervix, human papillomavirus (HPV)-infected LGCIN, HGCIN and SCC, using Human Transcriptome Array 2.0.
RESULTS: IGFBP-2 protein was highly expressed in the cytoplasm of SCC cells compared to normal cervix (p = .013). The expression was not significantly associated with CIN grade or SCC stage. Transcriptomics profiling demonstrated upregulation of IGFBP-2 and TP53 in HGCIN and SCC compared to normal cervix. IGF-1, IGF-1R and PTEN genes were downregulated in all histological groups. IGF-1 gene was significantly downregulated in SCC (p = .031), while PTEN gene was significantly downregulated in HGCIN (p = .012), compared to normal cervix. MDM2 and AKT1 genes were downregulated in LGCIN and HGCIN, while upregulated in SCC.
CONCLUSION: In cervical carcinogenesis, IGFBP-2 appears to play an oncogenic role, probably through an IGF-independent mechanism.