The time is now for new, lower diabetes diagnostic thresholds

Current thresholds for diagnosing diabetes are outdated and do not represent advancements in disease understanding or ability to impact course. Today, evidence supports intervening earlier along the disease continuum to mitigate transition to frank disease and delay/reduce adverse clinical outcomes. We believe it is time for lower diabetes diagnostic criteria.

The Diabetes Syndrome - A Collection of Conditions with Common, Interrelated Pathophysiologic Mechanisms

The four basic pathophysiologic mechanisms which damage the β-cell within diabetes (ie, genetic and epigenetic changes, inflammation, an abnormal environment, and insulin resistance [IR]) also contribute to cell and tissue damage and elevate the risk of developing all typical diabetes-related complications. Genetic susceptibility to damage from abnormal external and internal environmental factors has been described including inflammation and IR. All these mechanisms can promote epigenetic changes, and in total, these pathophysiologic mechanisms interact and react with each other to cause damage to cells and tissues ultimately leading to disease. Importantly, these pathophysiologic mechanisms also serve to link other common conditions including cancer, dementia, psoriasis, atherosclerotic cardiovascular disease (ASCVD), nonalcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH). The “Diabetes Syndrome”, an overarching group of interrelated conditions linked by these overlapping mechanisms, can be viewed as a conceptual framework that can facilitate understanding of the inter-relationships of superficially disparate conditions. Recognizing the association of the conditions within the Diabetes Syndrome due to common pathophysiologies has the potential to provide both benefit to the patient (eg, prevention, early detection, precision medicine) and to the advancement of medicine (eg, driving education, research, and dynamic decision-based medical practice).

Diabetes and Psoriasis: Different Sides of the Same Prism

Diabetes and psoriasis are prevalent conditions with a spectrum of serious adverse outcomes. Both diseases are common comorbidities for each other, and diabetes is considered as a risk factor for psoriasis and vice versa. However, it is our contention that these diseases are not merely comorbidities of each other but rather share common underlying pathophysiologies (ie, genes and epigenetic changes, inflammation, abnormal environment, and insulin resistance) that drive disease. As such, they can be viewed as facets of the same prism. Genes can cause or permit susceptibility to damage from abnormal external and internal environmental factors, inflammation, and insulin resistance which can also drive epigenetic changes. These co-existing mechanisms act in a vicious cycle over time to potentiate cell and tissue damage to ultimately drive disease. Viewing diabetes and psoriasis through the same prism suggests potential for therapies that could be used to treat both conditions. Although additional controlled trials and research are warranted, we believe that our understanding of the overlapping pathophysiologies continues to grow, so too will our therapeutic options.

Structural and functional properties of CCN proteins

The CCN family currently comprises six members (CCN1-6) that regulate diverse cell functions, including mitogenesis, adhesion, apoptosis, extracellular matrix (ECM) production, growth arrest, and migration. These properties can result in a multiplicity of effects during development, differentiation, wound healing, and disease states, such as tumorigenesis and fibrosis. CCN proteins have emerged as major regulators of chondrogenesis, angiogenesis, and fibrogenesis. CCN proteins are mosaic in nature and consist of up to four structurally conserved modules, at least two of which are involved in binding to cell surfaces via molecules that include integrins, heparan sulfate proteoglycans, and low-density lipoprotein receptor-related protein. CCN proteins use integrins as signal transducing receptors to regulate context-dependent responses in individual cell types. The involvement of integrins in mediating CCN signaling allows for considerable plasticity in response because some effects are specific for certain integrin subtypes and integrin signaling is coordinated with other signaling pathways in the cell. In addition to their own biological properties, CCN proteins regulate the functions of other bioactive molecules (e.g., growth factors) via direct binding interactions. CCN molecules demonstrate complex multifaceted modes of action and regulation and have emerged as important matricellular regulators of cell function.

Expression of connective tissue growth factor (CCN2) in desmoplastic small round cell tumour

BACKGROUND

Desmoplastic small round cell tumour (DSRCT) is a rare and often fatal abdominal tumour that is distinguished by well defined islands of cells, surrounded by prominent desmoplastic stroma. As in certain other tumours, the function of the Wilms's tumour protein (WT1) in repressing gene transcription is lost in DSRCT.

AIMS

To assess the expression and localisation of connective tissue growth factor (CCN2) in DSRCT because this protein is transcriptionally repressed by WT1 and is associated with the production of abundant extracellular matrix.

METHODS

CCN2 was assessed by in situ hybridisation and immunohistochemistry.

RESULTS

CCN2 mRNA and protein were colocalised to the tumour cells themselves, in addition to stromal fibroblasts and vascular endothelial cells.

CONCLUSIONS

These data show that CCN2 is produced in high amounts by several cell types in DSRCT, and highlight a potential role for this factor in the autocrine and paracrine regulation of tumour cell growth, matrigenesis, and angiogenesis.

Connective tissue growth factor (CTGF/CCN2) in hepatic fibrosis

Connective tissue growth factor (CTGF/CCN2) is a highly profibrogenic molecule which is overexpressed in many fibrotic lesions, including those of the liver. CTGF/CCN2 is transcriptionally activated by transforming growth factor-beta (TGF-beta) and appears to mediate some of the extracellular matrix (ECM)-inducing properties that have been previously attributed to TGF-beta. CTGF/CCN2 and TGF-beta stimulate connective tissue cell proliferation and ECM synthesis in vitro and exhibit shared fibrogenic and angiogenic properties in vivo. In fibrotic liver, CTGF/CCN2 mRNA and protein are produced by fibroblasts, myofibroblasts, hepatic stellate cells (HSCs), endothelial cells, and bile duct epithelial cells. CTGF/CCN2 is also produced at high levels in hepatocytes during cytochrome P-4502E1-mediated ethanol oxidation. CTGF/CCN2 expression in cultured HSCs is enhanced following their activation or stimulation by TGF-beta while exogenous CTGF/CCN2 is able to promote HSC adhesion, proliferation, locomotion, and collagen production. Collectively, these data suggest that during initiating or downstream fibrogenic events in the liver, production of CTGF/CCN2 is regulated primarily by TGF-beta in one or more cell types and that CTGF/CCN2 plays important roles in HSC activation and progression of fibrosis. This article reviews the data that support the importance of CTGF/CCN2 in hepatic fibrosis and highlights the concept that CTGF/CCN2 may represent a new therapeutic target in this disease.

Upregulation of endogenous heparin-binding EGF-like growth factor (HB-EGF) expression after intestinal ischemia/reperfusion injury

Expression of endogenous heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), a proven intestinal cytoprotective molecule, was examined in intestinal epithelial cells (IEC) in vitro, and in intestine undergoing ischemia/reperfusion (I/R) injury in vivo. In vitro, cells were exposed to anoxia for 90 min followed by reoxygenation for 1-3 h (A/R). In vivo, total midgut I/R injury was produced in rats by occlusion of the superior mesenteric artery for 30 or 90 min followed by reperfusion for 4 h. In situ hybridization and immunohistochemistry were used to study HB-EGF mRNA expression and protein production. In vitro, normal IEC had no detectable HB-EGF mRNA or protein expression. After anoxia, cells expressed HB-EGF mRNA and protein, with expression reaching a peak 2-3 h after reoxygenation. In vivo, only very low levels of HB-EGF mRNA and no detectable protein were found in normal intestine. Four hours after I/R, HB-EGF protein was detected in villous epithelia subjected to 30 min but not 90 min of ischemia, whereas HB-EGF mRNA was highly expressed after both ischemic intervals. Endogenous HB-EGF is immediately upregulated in IEC after A/R injury and in intestine after I/R injury. Thus, HB-EGF acts as an immediate early gene under these conditions.

The heparin-binding 10 kDa fragment of connective tissue growth factor (CTGF) containing module 4 alone stimulates cell adhesion

Connective tissue growth factor (CTGF) is a 349-residue mosaic protein that contains four structural modules implicated in protein-protein interactions. To address the functionality of residues 247-349 (containing module 4 alone), this region of CTGF was produced as a maltose binding protein (MBP) fusion protein in E. coli. After removal of MBP, recombinant CTGF commenced at Glu(247), was of M(r) 10 000, was immunoreactive with anti-CTGF[247-260], bound strongly to heparin, and promoted dose-dependent adhesion of fibroblasts, myofibroblasts, endothelial cells, and epithelial cells. An 8 kDa presumptive C-terminally truncated form of CTGF commencing at Glu(247) also promoted cell adhesion. CTGF-mediated cell adhesion was abolished by heparin or EDTA. These data demonstrate the presence of heparin-binding and cell-adhesion motifs within the C-terminal 103 residues of CTGF and show that CTGF-mediated cell adhesion is heparin-and divalent cation-dependent. Thus, CTGF isoforms comprising essentially module 4 are intrinsically functional in the absence of the other constituent modules of CTGF.