Glycolaldehyde‐modified β‐lactoglobulin AGEs are unable to stimulate inflammatory signaling pathways in RAGE‐expressing human cell lines

Scope: Advanced glycation endproducts (AGEs) are suspected to stimulate inflammatory signaling pathways in target tissues via activation of the receptor for AGEs. Endotoxins are generally recognized as potential contamination of AGE preparations and stimulate biological actions that are very similar as or identical to those induced by AGEs. Methods and results: In our study, we used glycolaldehyde‐modified β‐lactoglobulin preparations as model AGEs and employed two methods to remove endotoxin using either affinity columns or extraction with Triton X‐114 (TX‐114). Affinity column‐purified AGEs retained their ability to stimulate inflammatory signaling as measured by mRNA expression of inflammatory cytokines in the human lung epithelial cell line Beas2b. However, glycolaldehyde‐modified AGEs purified by extraction with TX‐114 did not show any stimulation of mRNA expression of inflammatory cytokines. The presence of a cell stimulating endotoxin‐like activity was demonstrated in the detergent phase after extraction with TX‐114, thus indicating that not AGEs but a lipophilic contamination was responsible for the stimulation of inflammatory signaling. Conclusion: Our results demonstrate that glycolaldehyde‐modified AGEs are unable to induce inflammatory signaling in receptor for AGE‐expressing cells. The observed cell‐activating activity can be ascribed to an endotoxin‐like lipophilic contamination present in AGE preparations and affinity column purification was insufficient to remove this contamination.     

Effect of colostrum on the acute-phase response in neonatal dairy calves

The core part of the mammal innate immune system is the acute-phase response (APR), during which acute-phase proteins (APP) are synthesized. Colostrum contains immunomodulating factors such as proinflammatory cytokines and APP in large quantities. We looked at proinflammatory cytokines [IL-1β, IL-6, and tumor necrosis factor-α (TNF-α)] and APP [serum amyloid A (SAA) and haptoglobin (Hp)] in colostrum and in calves' serum. The aim of this study was to evaluate the effects of colostrum on the calves' systemic APR and the associations of the calves' serum APR with short- and long-term weight gain (at the age of 1, 3, and 9 mo). A total of 143 female dairy calves were studied during their first 3 wk of life. The calves were separated from their mothers immediately after birth and bottle-fed 3 L of quality-controlled colostrum once within 2 h after birth. Serum samples were collected once a week during the first 3 wk of life (a total of 1–3 samples per calf). Mean sampling age (±standard deviation) was 4.3 (±2.0) d in the first week, 11.0 (±2.0) d in the second week, and 18.0 (±2.0) d in the third week. Linear regression models were used to study associations of colostrum APP and cytokine concentration with serum APR markers and for studying associations of colostrum and serum APR markers with calves' average daily weight gain (ADWG). Mixed linear regression models were used to compare serum concentrations of APR markers by study weeks. The colostrum IL-6 concentrations were positively associated with serum IL-6 in the first 3 wk of life. Colostrum IL-1β was positively associated with calves' serum IL-1β during the first week of life, and colostrum TNF-α was positively associated with calves' serum TNF-α during the first 2 wk of life. Serum IL-1β concentrations differed over the 3 wk, being the highest during the first week and the lowest during the second week. For IL-6, the concentration during the first week was the highest, and for TNF-α, a steady decline in the concentration was observed. Serum SAA concentrations were elevated during the first 2 wk of life and subsequently declined during the third week. Albumin concentrations were lowest in the first week, whereas Hp concentrations were highest during the second week. Serum concentrations of SAA, Hp, IL-6, and TNF-α during the second week were negatively associated with ADWG at 9 mo of age. The SAA concentrations during the third week of age had a negative association with 9-mo ADWG. Serum Hp concentrations in the third week were negatively associated with 3-mo ADWG. The results of our study suggest that colostrum cytokines influence calf serum cytokine concentrations. Thus, they influence the newborn calves' adaptation to the environment and the development of their immune system. Factors that activate an APR during the second and third week of life have a long-term influence on calves' development.     

Plasticity of Intestinal Epithelium: Stem Cell Niches and Regulatory Signals

The discovery of Lgr5+ intestinal stem cells (ISCs) triggered a breakthrough in the field of ISC research. Lgr5+ ISCs maintain the homeostasis of the intestinal epithelium in the steady state, while these cells are susceptible to epithelial damage induced by chemicals, pathogens, or irradiation. During the regeneration process of the intestinal epithelium, more quiescent +4 stem cells and short-lived transit-amplifying (TA) progenitor cells residing above Lgr5+ ISCs undergo dedifferentiation and act as stem-like cells. In addition, several recent reports have shown that a subset of terminally differentiated cells, including Paneth cells, tuft cells, or enteroendocrine cells, may also have some degree of plasticity in specific situations. The function of ISCs is maintained by the neighboring stem cell niches, which strictly regulate the key signal pathways in ISCs. In addition, various inflammatory cytokines play critical roles in intestinal regeneration and stem cell functions following epithelial injury. Here, we summarize the current understanding of ISCs and their niches, review recent findings regarding cellular plasticity and its regulatory mechanism, and discuss how inflammatory cytokines contribute to epithelial regeneration.     

Involvement of Cytokines in the Pathogenesis of Diabetic Macular Edema

Diabetic macular edema (DME) is a critical complication of diabetic retinopathy, a condition that arises from the breakdown of the blood–retinal barrier and the consequent increase in vascular permeability. Over the years, attempts have been made to treat DME by various approaches, including laser photocoagulation, steroid triamcinolone acetonide, and vitrectomy. However, treatment was unsatisfactory until research identified vascular endothelial growth factor (VEGF) as a factor in the pathogenesis of DME. Intraocular anti-VEGF agents show good efficacy in DME. Nevertheless, in some patients the condition recurs or becomes resistant to treatment, suggesting that other factors may be involved. Because inflammation and retinal hypoxia are seen in DME, research has examined the potential role of cytokines and other inflammatory mediators. In this review, we provide an overview of this research and describe feedback mechanisms that may represent a target for novel treatments.     

Cell-free Stem Cell-Derived Extract Formulation for Regenerative Medicine Applications

Stem cells for regenerative medicine purposes offer therapeutic benefits, but disadvantages are still ill defined. The benefit of stem cells may be attributed to their secretion of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs), including exosomes. We present a novel cell-free stem cell-derived extract (CCM), formulated from human progenitor endothelial stem cells (hPESCs), characterized for biologically active factors using ELISA, nanoparticle tracking analysis and single particle interferometric reflectance imaging sensing. The effect on fibroblast proliferation and ability to induce stem cell migration was analyzed using Alamar Blue proliferation and Transwell migration assays, respectively. GFs including IGFBP 1, 2, 3, and 6, insulin, growth hormone, PDGF-AA, TGF-α, TGF-β1, VEGF, and the anti-inflammatory cytokine, IL-1RA were detected. Membrane enclosed particles within exosome size range and expressing exosome tetraspanins CD81 and CD9 were identified. CCM significantly increased cell proliferation and induced stem cell migration. Analysis of CCM revealed presence of GFs, CKs, and EVs, including exosomes. The presence of multiple factors including exosomes within one formulation, the ability to promote cell proliferation and induce stem cell migration may reduce inflammation and pain, and augment tissue repair.     

Cytokines and MicroRNAs as Candidate Biomarkers for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, with varied course and symptoms. Its etiology is very complex and not clearly understood. There is growing evidence of the important role of cytokines in SLE pathogenesis, as well as their utility as biomarkers and targets in new therapies. Other potential new SLE biomarkers are microRNAs. Recently, over one hundred different microRNAs have been demonstrated to have a significant impact on the immune system. Various alterations in these microRNAs, associated with disease pathogenesis, have been described. They influence the signaling pathways and functions of immune response cells. Here, we aim to review the emerging new data on SLE etiology and pathogenesis.     

Benzo[d]isothiazol-3-yl-benzamidines: a class of protective agents on culture of human cartilage and chondrocytes stimulated by IL-1beta

New derivatives of N-benzo[d]isothiazol-3-yl-benzamidine 6 a were synthesized as nonacidic anti-inflammatory/antidegenerative agents. We investigated the influence of the amidines 6 a-j on the production of NO, PGE(2), MMP-3, COX-2, ROS, and GAGs, key molecules involved in cartilage destruction in osteoarthritic diseases. The antidegenerative properties of the novel designed derivatives 6 b-j were improved with respect to N-benzo[d]isothiazol-3-yl-benzamidine 6 a. All of the compounds 6 a-j promoted the reduction of most of the IL-1beta-induced harmful effects. Derivatives 6 d, 6 h, and 6 j were the most potent of all the tested compounds, particularly in the human chondrocyte culture model.     

Inflammation and Oxidative Stress in Diabetic Kidney Disease: The Targets for SGLT2 Inhibitors and GLP-1 Receptor Agonists

The incidence of type 2 diabetes (T2D) has been increasing worldwide, and diabetic kidney disease (DKD) remains one of the leading long-term complications of T2D. Several lines of evidence indicate that glucose-lowering agents prevent the onset and progression of DKD in its early stages but are of limited efficacy in later stages of DKD. However, sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor (GLP-1R) agonists were shown to exert nephroprotective effects in patients with established DKD, i.e., those who had a reduced glomerular filtration rate. These effects cannot be solely attributed to the improved metabolic control of diabetes. In our review, we attempted to discuss the interactions of both groups of agents with inflammation and oxidative stress—the key pathways contributing to organ damage in the course of diabetes. SGLT2i and GLP-1R agonists attenuate inflammation and oxidative stress in experimental in vitro and in vivo models of DKD in several ways. In addition, we have described experiments showing the same protective mechanisms as found in DKD in non-diabetic kidney injury models as well as in some tissues and organs other than the kidney. The interaction between both drug groups, inflammation and oxidative stress appears to have a universal mechanism of organ protection in diabetes and other diseases.