Diabetes is a complex disease characterized by hyperglycemia, dyslipidemia, and insulin resistance. Plasma advanced glycation end products (AGEs) activated the receptor for advanced glycation end products (RAGE) and the activation of RAGE is implicated to be the pathogenesis of type 2 diabetic mellitus (T2DM) patient vascular complications. Sitagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, is a new oral hypoglycemic agent for the treatment of T2DM. However, the beneficial effects on vascular calcification remain unclear. In this study, we used a high-fat diet (HFD)-fed low-density lipoprotein receptor deficiency (LDLR^−/−) mice model to investigate the potential effects of sitagliptin on HFD-induced arterial calcification. Mice were randomly divided into 3 groups: (1) normal diet group, (2) HFD group and (3) HFD + sitagliptin group. After 24 weeks treatment, we collected the blood for chemistry parameters and DPP4 activity measurement, and harvested the aorta to evaluate calcification using immunohistochemistry and calcium content. To determine the effects of sitagliptin, tumor necrosis factor (TNF)-α combined with S100A12 was used to induce oxidative stress, activation of nicotinamide adenine dinucleotide phosphate (NADPH), up-regulation of bone markers and RAGE expression, and cell calcium deposition on human aortic smooth muscle cells (HASMCs). We found that sitagliptin effectively blunted the HFD-induced artery calcification and significantly lowered the levels of fasting serum glucose, triglyceride (TG), nitrotyrosine and TNF-α, decreased the calcium deposits, and reduced arterial calcification. In an in-vitro study, both S100A12 and TNF-α stimulated RAGE expression and cellular calcium deposits in HASMCs. The potency of S100A12 on HASMCs was amplified by the presence of TNF-α. Sitagliptin and Apocynin (APO), an NADPH oxidase inhibitor, inhibited the TNF-α + S100A12-induced NADPH oxidase and nuclear factor (NF)-κB activation, cellular oxidative stress, RAGE expression, osteo transcription factors expression and calcium deposition. In addition, treatment with sitagliptin, knockdown of RAGE or TNF-α receptor blunted the TNF-α + S100A12-induced RAGE expression. Our findings suggest that sitagliptin may suppress the initiation and progression of arterial calcification by inhibiting the activation of NADPH oxidase and NF-κB, followed by decreasing the expression of RAGE.

Abdominal aortic aneurysm (AAA) is a multifactorial cardiovascular disease with a high risk of death, and it occurs in the infrarenal aorta with vascular dilatation. High blood pressure acts on the aortic wall, resulting in rupture and causing life-threatening intra-abdominal hemorrhage. Vascular smooth muscle cell (VSMC) dysregulation and extracellular matrix (ECM) degradation, especially elastin breaks, contribute to structural changes in the aortic wall. The pathogenesis of AAA includes the occurrence of oxidative stress, inflammatory cell infiltration, elastic fiber fragmentation, VSMC apoptosis, and phenotypic transformation. Tributyrin (TB) is decomposed by intestinal lipase and has a function similar to that of butyrate. Whether TB has a protective effect against AAA remains uncertain. In the present study, we established an AAA murine model by angiotensin II (AngII) induction in low-density lipoprotein receptor knockout (LDLR^-/-) mice and investigated the effects of orally administered TB on the AAA size, ratio of macrophage infiltration, levels of matrix metalloproteinase (MMP) expression, and epigenetic regulation. TB attenuates AngII-induced AAA size and decreases elastin fragmentation, macrophage infiltration, and MMP expression in the medial layer of the aorta and reduces the levels of SBP (systolic blood pressure, p < 0.001) and MMP-2 (p < 0.02) in the serum. TB reduces the AngII-stimulated expression levels of MMP2 (p < 0.05), MMP9 (p < 0.05), MMP12, and MMP14 in human aortic smooth muscle cells (HASMCs). Moreover, TB and valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, suppress AngII receptor type 1 (AT1R, p < 0.05) activation and increase the expression of acetyl histone H3 by HDAC activity inhibition (p < 0.05). Our findings suggest that TB exerts its protective effect by suppressing the activation of HDAC to attenuate the AngII-induced AT1R signaling cascade.

Currently, there are two major theories regarding the pathogenesis of sepsis: hyperimmune and hypoimmune. The hyperimmune theory suggests that a cytokine storm causes the symptoms of sepsis. On the contrary, the hypoimmune theory suggests that immunosuppression causes the manifestations of sepsis. By conducting a microarray analysis on peripheral leukocytes from patients with sepsis, this study found that hyperactivity of TH17 immunity was noted in sepsis patients. Innate immunity-related genes are significantly upregulated, including CD14, TLR1,2,4,5,8, HSP70, CEBP proteins, AP1 (JUNB and FOSL2), TGFB1, IL6, TGFA, CSF2 receptor, TNFRSF1A, S100A binding proteins, CCR2, FPR2, amyloid proteins, pentraxin, defensins, CLEC5A, whole complement machinery, CPD, NCF, MMP, neutrophil elastase, caspases, IgG and IgA Fc receptors (CD64, CD32), ALOX5, PTGS, LTB4R, LTA4H, and ICAM1. The majority of adaptive immunity genes were downregulated, including MHC-related genes, TCR genes, granzymes/perforin, CD40, CD8, CD3, TCR signaling, BCR signaling, T and B cell-specific transcription factors, NK killer receptors, and TH17 helper-specific transcription factors (STAT3, RORA, and REL), as well as Treg-related genes, including TGFB1, IL15, STAT5B, SMAD2/4, CD36, and thrombospondin. The findings of this study show that Th17 with Treg over-presentation play an important role in the pathophysiology of sepsis.

Background: Plasma advanced glycation end products (AGEs) activates the receptor for advanced glycation end products (RAGE) and the activation of RAGE is implicated to be the pathogenesis of type 2 diabetic mellitus patient vascular complications. Attenuating the activation of RAGE may exert a protective effect against the development of cardiovascular disease. Dipeptidyl peptidase-4 (DPP4) inhibitors are a new class of oral hypoglycemic agents for the treatment of type 2 diabetes mellitus. Whether sitagliptin, a DPP-4 inhibitor, has a beneficial effect on vascular calcification remains undetermined. Methods: In the present study, we fed low-density lipoprotein receptor knockout (LDLR^-/-) mice a high fat diet to induce diabetic mellitus and studied the effect of orally administered sitagliptin on the high fat diet fed LDLR^-/- mice aorta medial calcification, RAGE expression, oxidative stress, aorta calcium content. Tumor necrosis factor (TNF)-α combined with S100A12 was used to induce HASMC oxidative stress, activation of NADPH, up-regulation of the bone markers and RAGE expression, and cell calcium deposition. Effect of sitagliptin, siRNA for RAGE and apocynin on blunting TNF-α and S100A12 induced HASMC oxidative stress, calcification and NADPH activation were also investigated. Results: Sitagliptin attenuated the HFD-induced LDLR^-/- mice hyperlipidemia, hyperglycemia, increase in serum TNF-α, aorta calcium deposition and the expression of RAGE in the medial layer of the aorta. TNF-α combined with S100A12 stimulated HASMC RAGE expression, calcium deposition, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) activation, and up-regulation of bone marker (bone morphogenetic protein-2, Msh homeobox 2, and runt‑related transcription factor 2) expression. Sitagliptin and apocynin (APO), an NADPH oxidase inhibitor, suppressed the TNF-α+S100A12 treatment effects on the activation of NADPH oxidase and Nuclear factor (NF)-κB and the resultant oxidative stress, up-regulation of RAGE and bone markers expression and calcium deposition. Our findings suggest that sitagliptin imparts its protective effect by suppressing NADPH oxidase and NF-κB activation to blunt the up-regulation of RAGE expression.Conclusion: Our findings suggest that sitagliptin may suppress the initiation and progression of artery calcification by inhibiting the activation of NADPH oxidase and NF-κB and the resultant up-regulation of expression of RAGE.

Background/Objectives: Staphylococcus argenteus is a recently recognized member of the Staphylococcus aureus complex that is almost identical to S. aureus phenotypically and by 16S rRNA gene sequences. Although genomic analyses demonstrate that S. argenteus is phylogenetically distinct from S. aureus, the two species exhibit more than 90% nucleotide identity and routine identification methods—including routine biochemical assays and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)—cannot reliably distinguish between the two. We develop and validate a MALDI-TOF MS-based model for accurate identification of S. argenteus. Methods: A multiplex PCR assay targeting crtM and NRPS genes served as the reference standard. MALDI-TOF MS spectra from 25 S. argenteus and 25 methicillin-susceptible S. aureus (MSSA) isolates were analyzed using ClinProTools to identify characteristic peaks and develop the identification model. The model was validated using 40 S. argenteus and 80 MSSA isolates, then applied to 130 randomly selected clinical isolates. Results: Five characteristic peaks—m/z values 5005, 5285, 5323, 6440, and 6526—were identified. Isolates exhibiting at least 4 of these 5 peaks were classified as S. argenteus; those exhibiting fewer than 4 were classified as S. aureus. The model achieved 100% specificity and 100% sensitivity in both the development and validation phases. In the clinical application phase, the model correctly classified all isolates, whereas conventional MALDI-TOF MS yielded several misidentifications. Conclusions: The identification model, and the simple peak-based rule it is based on, can accurately distinguish S. argenteus from MSSA, offering a practical diagnostic tool for clinical microbiology laboratories.

Background: Staphylococcus argenteus is a recently recognized member of the Staphylococcus aureus complex that is almost identical to S. aureus phenotypically and by 16S rRNA gene sequences. Although genomic analyses demonstrate that S. argenteus is phylogenetically distinct from S. aureus, the two species exhibit more than 90% nucleotide identity and routine identification methods—including routine biochemical assays and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)—cannot reliably distinguish between the two. Objectives: We develop and validate a MALDI-TOF MS–based model for accurate identification of S. argenteus. Methods: A multiplex PCR assay targeting crtM and NRPS genes served as the reference standard. MALDI-TOF MS spectra from 25 S. argenteus and 25 methicillin-susceptible S. aureus (MSSA) isolates were analyzed using ClinProTools to identify characteristic peaks and develop the identification model. The model was validated using 40 S. argenteus and 80 MSSA isolates, then applied to 130 randomly selected clinical isolates. Results: Five characteristic peaks—m/z values 5005, 5285, 5323, 6440, and 6526—were identified. Isolates exhibiting at least 4 of these 5 peaks were classified as S. argenteus; those exhibiting fewer than 4 were classified as S. aureus. The model achieved 100% specificity and 100% sensitivity in both the development and validation phases. In the clinical application phase, the model correctly classified all isolates, whereas conventional MALDI-TOF MS yielded several misidentifications. Conclusions: The identification model, and the simple peak-based rule it is based on, can accurately distinguish S. argenteus from MSSA, offering a practical diagnostic tool for clinical microbiology laboratories.