Is the association between diabetes mellitus and pulmonary fibrosis real?

An emerging feature of type 1 diabetes mellitus and type 2 diabetes mellitus is their association with pulmonary fibrosis, which negatively affects the prognosis of patients. Here, we provide a brief update of the field and the remaining open questions

Diabetes mellitus and bone metabolism.

Diabetes mellitus and bone metabolism affect mesenchymal tissues and have numerous epidemiological and pathophysiological associations in common. Diabetes mellitus affects bone metabolism and increases fracture risk. The pathophysiological mechanims how type 1 and type 2 diabetes impair bone metabolism and bone strength may differ which is outlined in this review. Direct metabolic effects in additon to centrally controlled endocrine loops exert suppressive effects on bone formation and may also stimulate bone Resorption. Decreased bone formation in combination with increased bone resorption strongly increases fracture risk

Analysis of immune cells in single sciatic nerves and dorsal root ganglion from a single mouse using flow cytometry.

Nerve-resident immune cells in the peripheral nervous system (PNS) are essential to maintaining neuronal integrity in a healthy nerve. The immune cells of the PNS are affected by injury and disease, affecting the nerve function and the capacity for regeneration. Neuronal immune cells are commonly analyzed by immunofluorescence (IF). While IF is essential for determining the location of the immune cells in the nerve, IF is only semi-quantitative and the method is limited to the number of markers that can be analyzed simultaneously and the degree of surface expression. In this study, flow cytometry was used for quantitative analysis of leukocyte infiltration into sciatic nerves or dorsal root ganglions (DRGs) of individual mice. Single cell analysis was performed using DAPI and several proteins were analyzed simultaneously for either surface or intracellular expression. Both sciatic nerves from one mouse that were treated according to this protocol generated >= 30,000 single nucleated events. The proportion of leukocytes in the sciatic nerves, determined by expression of CD45, was approximately 5% of total cell content in the sciatic nerve and approximately 5-10% in the DRG. Although this protocol focuses primarily on the immune cell population within the PNS, the flexibility of flow cytometry to measure a number of markers simultaneously means that the other cells populations present within the nerve, such as Schwann cells, pericytes, fibroblasts, and endothelial cells, can also be analyzed using this method. This method therefore provides a new means for studying systemic effects on the PNS, such as neurotoxicology and genetic models of neuropathy or in chronic diseases, such as diabetes

STZ causes depletion of immune cells in sciatic nerve and dorsal root ganglion in experimental diabetes.

Streptozotocin (STZ) treatment, a common model for inducing diabetes in rodent models, induces thermal hyperalgesia and neuronal toxicity independently of hyperglycemia by oxidizing and activating TRPA1 and TRPV1. Following treatment with STZ, CD45+ immune cells were found to be depleted in sciatic nerve (SN) and DRG in mice, prior to hyperglycemia. Macrophages were also lost in DRG and NFκB-p65-activation was increased in SN macrophages. Immune cells were significantly reduced in both SN and DRG up to three weeks, post-treatment. Loss of PNS-resident macrophages in response to STZ-mediated toxicity may affect the regenerative capacity of the nerve in response to further injury caused by diabetes

Evidence against a role for the parkinsonism-associated protein DJ-1 in methylglyoxal detoxification.

Methylglyoxal (MG) is a reactive metabolite that forms adducts on cysteine, lysine and arginine residues of proteins, thereby affecting their function. Methylglyoxal is detoxified by the Glyoxalase system, consisting of two enzymes, Glo1 and Glo2, that act sequentially to convert MG into D-lactate. Recently, the Parkinsonism-associated protein DJ-1 was described in vitro to have glyoxalase activity, thereby detoxifying the MG metabolite, or deglycase activity, thereby removing the adduct formed by MG on proteins. Since Drosophila is an established model system to study signaling, neurodegeneration, and metabolic regulation in vivo, we asked whether DJ-1 contributes to MG detoxification in vivo. Using both DJ-1 knockdown in Drosophila cells in culture, and DJ-1 β knock-out flies, we could detect no contribution of DJ-1 to survival to MG challenge or to accumulation of MG protein adducts. Furthermore, we provide data suggesting that the previously reported deglycation activity of DJ- 1 can be ascribed to a TRIS buffer artifact

The glyoxalase system—new insights into an ancient metabolism.

The glyoxalase system was discovered over a hundred years ago and since then it has been claimed to provide the role of an indispensable enzyme system in order to protect cells from a toxic byproduct of glycolysis. This review gives a broad overview of what has been postulated in the last 30 years of glyoxalase research, but within this context it also challenges the concept that the glyoxalase system is an exclusive tool of detoxification and that its substrate, methylglyoxal, is solely a detrimental burden for every living cell due to its toxicity. An overview of consequences of a complete loss of the glyoxalase system in various model organisms is presented with an emphasis on the role of alternative detoxification pathways of methylglyoxal. Furthermore, this review focuses on the overlooked posttranslational modification of Glyoxalase 1 and its possible implications for cellular maintenance under various (patho-)physiological conditions. As a final note, an intriguing point of view for the substrate methylglyoxal is offered, the concept of methylglyoxal (MG)-mediated hormesis

Purification and Characterization of the Soluble form of the Receptor for Advanced Glycation End-Products (sRAGE): A Novel Fast, Economical and Convenient Method.

The receptor for advanced glycation end-products (RAGE) is a multi-ligand receptor which belongs to the pattern recognition receptor family and can bind to various ligands such as advanced glycation end-products (AGEs), members of the S100 protein family, glycosaminoglycans, amyloid beta peptides, high-mobility group box-1 (HMGB1) and nucleic acids through its extracellular domain. The RAGE-ligand interaction leads to the activation of MAP kinase and NF-kB signaling pathways. Further ligand-induced up-regulation of RAGE is involved in various patho-physiological situations including late diabetic complications, Alzheimer disease and several other neurodegenerative diseases. A secreted soluble isoform of RAGE (sRAGE), corresponding to the extracellular domain only, has the ability to block RAGE-associated cellular activation and signaling. Further application of recombinant sRAGE has been shown to block RAGE-mediated pathophysiological conditions in various models of cancer or multiple sclerosis. These finding demonstrates sRAGE as a therapeutic tool to block RAGE-associated inflammatory signaling. In this manuscript, we describe a two-step simple, novel and convenient method for expressing and purifying scalable quantities of biologically active murine form of sRAGE by using E. coli as an expression host. The method we propose has several advantages over the current available methods particularly in terms of yield and quality of preparation. The sRAGE produced by this expression system retains all the secondary structural properties as analyzed by the ligand binding affinities. The produced protein also retains all the DNA-RAGE binding functional properties and thus can be a valuable tool for studying dynamics of this novel RAGE ligand. Moreover this method can be utilized by researchers to generate biologically active endotoxin-free sRAGE for in vivo applications to study and treat RAGE-associated pathologies