Fibrosis in diabetes complications: Pathogenic mechanisms and circulating and urinary markers

Diabetes mellitus is characterized by a lack of insulin causing elevated blood glucose, often with associated insulin resistance. Over time, especially in genetically susceptible individuals, such chronic hyperglycemia can cause tissue injury. One pathological response to tissue injury is the development of fibrosis, which involves predominant extracellular matrix (ECM) accumulation. The main factors that regulate ECM in diabetes are thought to be pro-sclerotic cytokines and protease/anti-protease systems. This review will examine the key markers and regulators of tissue fibrosis in diabetes and whether their levels in biological fluids may have clinical utility

The association between cardiorespiratory fitness, liver fat and insulin resistance in adults with or without type 2 diabetes : a cross-sectional analysis

Background: Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and reductions in liver fat content. However, there are limited data concerning the relationship between CRF and liver fat content in adults with varying degrees of metabolic dysfunction. Methods: The aim of this study was to examine the association between CRF, liver fat content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional analysis. CRF was determined via a graded exercise test. Liver fat content was assessed via proton magnetic resonance spectroscopy and insulin resistance was assessed via homeostatic model of insulin resistance (HOMA-IR). A partial correlation analysis, controlling for age and gender, was performed to determine the association between CRF, demographic, cardiometabolic, and anthropometric variables. Independent t tests were performed to compare cardiometabolic outcomes between participants with T2D and participants without T2D. Results: Seventy-two adults (46% male) with a mean age of 49.28 ± 10.8 years, BMI of 34.69 ± 4.87 kg/m2 , liver fat content of 8.37 ± 6.90%, HOMA-IR of 3.07 ± 2.33 and CRF of 21.52 ± 3.77 mL/kg/min participated in this study. CRF was inversely associated with liver fat content (r = − 0.28, p = 0.019) and HOMA-IR (r = − 0.40, p < 0.001). Participants with T2D had significantly higher liver fat content (+ 3.66%, p = 0.024) and HOMA-IR (+ 2.44, p < 0.001) than participants without T2D. Participants with T2D tended to have lower CRF than participants without T2D (− 1.5 ml/kg/min, p = 0.094). Conclusion: CRF was inversely associated with liver fat content and insulin resistance. Participants with T2D had lower CRF than those without T2D, however, the difference was not statistically significant. Further longitudinal studies are required to elucidate the relationship between CRF and the progression of obesity-related diseases such as T2D. Registration: ACTRN12614001220651 (retrospectively registered on the 19th November 2014) and ACTRN12614000723684 (prospectively registered on the 8th July 2014)

Association of Patient Profile with Glycemic Control and Hypoglycemia with Insulin Glargine 300 U/mL in Type 2 Diabetes: A Post Hoc Patient-Level Meta-Analysis

ABSTRACT Aims: To examine the association of baseline patient characteristics with study outcomes in people with type 2 diabetes receiving insulin glargine 300 U/mL (Gla-300) versus glargine 100 U/mL (Gla-100), over a 6-month period. Methods: A post hoc patient-level metaanalysis using data from three multicenter, randomized, open-label, parallel-group, phase 3a studies of similar design, in people previously receiving either basal and prandial insulin, basal insulin ? oral antihyperglycemic drugs, or no prior insulin (EDITION 1, 2 and 3, respectively). The endpoints, glycated hemoglobin (HbA1c), hypoglycemia, body weight change, and insulin dose were investigated by subgroups: age (\65 and C 65 years), body mass index (BMI; \ 30 and C 30 kg/m2), age at onset (\40, 40–50, and [ 50 years), and diabetes duration (\ 10 and C 10 years). Results: Reduction in HbA1c was comparable between insulins, regardless of subgroup. The lower risk of C 1 nocturnal (00:00–05:59 h) confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemic event with Gla-300 versus Gla-100 was also unaffected by participant characteristics. While heterogeneity of treatment effect between diabetes duration subgroups was seen for the risk of C 1 confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemic event at any time (24 h), treatment effect consistently favored Gla-300; no evidence of heterogeneity was observed for the other subgroups. Annualized rates of confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemia and body weight change were not influenced by participant characteristics; a similar pattern was observed with insulin dose. Conclusions: Comparable glycemic control was observed with Gla-300 versus Gla-100, with less hypoglycemia, regardless of age, BMI, age at onset or diabetes duration. Funding: Sanofi. Plain Language Summary: Plain language summary available for this article. Keywords: Glycated Hemoglobin A; Hypoglycemia; Insulin Glargine; Type 2 Diabetes PLAIN LANGUAGE SUMMARY Treatments for patients with type 2 diabetes aim to reduce the levels of blood glucose and can include injections with insulin. However, care must be taken to prevent blood glucose levels falling too low (a state called hypoglycemia). Previous studies have shown that insulin glargine 300 units/mL (Gla-300) provides similar reductions in blood glucose levels as insulin glargine 100 units/mL (Gla-100) but is less likely to cause hypoglycemia. However, different patients may respond differently to treatments depending on their individual clinical and biological characteristics. The aim of this study was to evaluate how different profiles of patients with type 2 diabetes responded to Gla-300 and Gla-100 injections. Patients were grouped by different ages, weights, age at diabetes diagnosis, and number of years since diagnosis of diabetes. We found that Gla-300 and Gla-100 reduced glycated hemoglobin (HbA1c; a marker of blood glucose control over the previous 2–3 months) similarly, regardless of how patients were grouped. However, patients treated with Gla-300 were less likely to experience hypoglycemia than those treated with Gla-100, and this association was also true regardless of different patient characteristics. We therefore concluded that Gla-300 is an effective and safe treatment in patients with type 2 diabetes, regardless of their age, weight, age at diabetes diagnosis, and years since diagnosis

Case report: A third variant in the 5′ UTR of TWIST1 creates a novel upstream translation initiation site in a child with Saethre-Chotzen syndrome

Introduction: Saethre-Chotzen syndrome, a craniosynostosis syndrome characterized by the premature closure of the coronal sutures, dysmorphic facial features and limb anomalies, is caused by haploinsufficiency of TWIST1. Although the majority of variants localize in the coding region of the gene, two variants in the 5′ UTR have been recently reported to generate novel upstream initiation codons. Methods: Skeletal dysplasia Next-generation sequencing (NGS) panel was used for genetic analysis in a patient with bicoronal synostosis, facial dysmorphisms and limb anomalies. The variant pathogenicity was assessed by a luciferase reporter promoter assay. Results: Here, we describe the identification of a third ATG-creating de novo variant, c.-18C>T, in the 5′ UTR of TWIST1 in the patient with a clinical diagnosis of Saethre-Chotzen syndrome. It was predicted to create an out-of-frame new upstream translation initiation codon resulting in a 40 amino acid larger functionally inactive protein. We performed luciferase reporter promoter assays to demonstrate that the variant does indeed reduce translation from the main open reading frame. Conclusion: This is the third variant identified in this region and confirms the introduction of upstream ATGs in the 5′ UTR of TWIST1 as a pathogenic mechanism in Saethre-Chotzen syndrome. This case report shows the necessity for performing functional characterization of variants of unknown significance within national health services

SGLT2 inhibitors for patients with type 2 diabetes and CKD: a narrative review

Sodium‐glucose co-transporter 2 (SGLT2) inhibitors have recently emerg ed as an effective means to protect kidney function in people with type 2 diabetes and chronic kidney disease (CKD). In this review, we explore the role of SGLT2 inhibition in these individuals. SGLT2 inhibitors specifically act to inhibit sodium and glucose reabsorption in the early proximal tubule of the renal nephron. Although originally developed as glucose-lowering agents through their ability to induce glycosuria, it became apparent in cardiovascular outcome trials that the trajectory of kidney function decline w as significantly slowed and the incidence of serious falls in kidney function was reduced in participants receiving an SGLT2 inhibitor. These observations have recently led to spe cific outcome trials in participants with CKD, including DAPA-CKD, CREDENCE and EMPA-KIDNEY, and real-world studies, like CVD-REAL-3, that have confirmed the observation of kidney benefits in this setting. In response, recent KDIGO Guidelines have recommended the use of SGLT2 inhibitors as first-line therapy in patients with CKD, alongside statins, renin–angiotensin– aldosterone system inhibitors and multifactorial risk factor management as indicated. However, SGLT2 inhibitors remain significantly underutilized in the setting of CKD. Indeed, an inertia paradox exists, with patients with more severe disease less likely to receive an SGLT2 inhibitor. Concerns regarding safety appear unfounded, as acute kidney injury, hyperkalaemia, major acute cardiovascular events and cardiac death in patients with CKD appear to be lower following SGLT2 inhibition. The first-in-clas s indication of dapagliflozin for CKD may begin a new approach to managing kidney disease in type 2 diabetes

Regulation of pro-inflammatory and pro-fibrotic factors by CCN2/CTGF in H9c2 cardiomyocytes

Connective tissue growth factor (CTGF), also known as CCN2, is implicated in fibrosis through both extracellular matrix (ECM) induction and inhibition of ECM degradation. The role of CTGF in inflammation in cardiomyocytes is unknown. In some mesenchymal cell systems, CTGF mediates effects through TGF-β or tyrosine kinase cell surface receptor, TrkA, signalling. In this study, cellular mechanisms by which CTGF regulates pathways involved in fibrosis and inflammation were explored. Murine H9c2 cardiomyocytes were treated with recombinant human (rh)CTGF and ECM formation gene expression: fibronectin, collagen type -I and -III and ECM degradation genes: TIMP-1, TIMP-2 and PAI-1 were found to be induced. CTGF treatment also increased pro-inflammatory cytokines TNF-α, IL-6, MCP-1 and IL-8. CTGF upregulated TGF-β1 mRNA and rapidly induced phosphorylation of TrkA. The CTGF-induced pro-fibrotic and pro-inflammatory effects were blocked by anti-TGF-β neutralizing antibody and Alk 5 inhibitor (SB431542). A specific blocker of TrkA activation, k252a, also abrogated CTGF-induced effects on fibrosis and gene expresison of MCP-1 and IL-8, but not TNF-α or IL-6. Collectively, this data implicates CTGF in effects on pro-fibrotic genes and pro-inflammatory genes via TGF-β pathway signalling and partly through TrkA

Does in-shoe pressure analysis to assess and modify medical grade footwear improve patient adherence and understanding? A mixed methods study

Background: Medical grade footwear (MGF) with demonstrated plantar-pressure reducing effect is recommended to reduce the risk of diabetes-related foot ulceration (DFU). Efficacy of MGF relies on high adherence (≥ 80%). In-shoe pressure analysis (IPA) is used to assess and modify MGF, however, there is limited evidence for the impact on patient adherence and understanding of MGF. The primary aim of this study was to determine if self-reported adherence to MGF usage in patients with previous DFU improved following IPA compared to adherence measured prior. The secondary aim was to determine if patient understanding of MGF improved following in-shoe pressure analysis. Methods: Patients with previous DFU fitted with MGF in the last 12 months were recruited. The first three participants were included in a pilot study to test procedures and questionnaires. MGF was assessed and modified at Week 0 based on findings from IPA using the Pedar system (Novel). Patients completed two questionnaires, one assessing patient adherence to MGF at Week 0 and Week 4, the other assessing patient understanding of MGF before and after IPA at week 0. Patient understanding was measured using a 5-point Likert scale (strongly disagree 1 to strongly agree 5). Patient experience was assessed via a telephone questionnaire administered between Weeks 0–1. Results: Fifteen participants were recruited, and all completed the study. Adherence of ≥ 80% to MGF usage inside the home was 13.3% (n = 2) pre-IPA and 20.0% (n = 3) at Week 4. Outside the home, ≥ 80% adherence to MGF was 53.3% (n = 8) pre-IPA, and 80.0% (n = 12) at Week 4. Change in scores for understanding of MGF were small, however, all participants reported that undergoing the intervention was worthwhile and beneficial. Conclusions: Self-reported adherence inside the home demonstrated minimal improvement after 4 weeks, however, adherence of ≥ 80% outside the home increased by 27%, with 80% of all participants reporting high adherence at Week 4. Participants rated their learnings from the experience of IPA as beneficial

The efficacy of exercise training for cutaneous microvascular reactivity in the foot in people with diabetes and obesity : secondary analyses from a randomized controlled trial

It is unclear if cutaneous microvascular dysfunction associated with diabetes and obesity can be ameliorated with exercise. We investigated the effect of 12-weeks of exercise training on cutaneous microvascular reactivity in the foot. Thirty-three inactive adults with type 2 diabetes and obesity (55% male, 56.1 +/- 7.9 years, BMI: 35.8 +/- 5, diabetes duration: 7.9 +/- 6.3 years) were randomly allocated to 12-weeks of either (i) moderate-intensity continuous training [50-60% peak oxygen consumption (VO2peak), 30-45 min, 3 d/week], (ii) low-volume high-intensity interval training (90% VO2peak, 1-4 min, 3 d/week) or (iii) sham exercise placebo. Post-occlusive reactive hyperaemia at the hallux was determined by laser-Doppler fluxmetry. Though time to peak flux post-occlusion almost halved following moderate intensity exercise, no outcome measure reached statistical significance (p > 0.05). These secondary findings from a randomised controlled trial are the first data reporting the effect of exercise interventions on cutaneous microvascular reactivity in the foot in people with diabetes. A period of 12 weeks of moderate-intensity or low-volume high-intensity exercise may not be enough to elicit functional improvements in foot microvascular reactivity in adults with type 2 diabetes and obesity. Larger, sufficiently powered, prospective studies are necessary to determine if additional weight loss and/or higher exercise volume is required