lipid-a and Fibrosis

Obesity-induced myocardial fibrosis may lead to diastolic dysfunction and ultimately heart failure. Activation of the transforming growth factor (TGF)-βl and its downstream Smad2/3 pathways may play a pivotal role in the pathogenesis of obesity-induced myocardial fibrosis, and the antidiabetic dipeptidyl peptidase 4 inhibitors (DPP4i) might affect these pathways. We investigated whether DPP4i reduces myocardial fibrosis by inhibiting the TGF-β1 and Smad2/3 pathways in the myocardium of a diet-induced obesity (DIO) rat model. Eight-week-old male spontaneously hypertensive rats (SHRs) were fed either a normal fat diet (chow) or a high-fat diet (HFD) and then the HFD-fed SHRs were randomized to either the DPP4i (MK-0626) or control (distilled water) groups for 12weeks. At 20weeks old, all the rats underwent hemodynamic and metabolic studies and Doppler echocardiography. Compared with the normal fat diet (chow)-fed SHRs, the HFD-fed SHRs developed a more intense degree of hyperglycemia and dyslipidemia and showed a constellation of left ventricular (LV) diastolic dysfunction, and exacerbated myocardial fibrosis, as well as activation of the TGF-β1 and Smad2/3 pathways. DPP4i significantly improved the metabolic and hemodynamic parameters. The echocardiogram showed that DPP4i improved the LV diastolic dysfunction (early to late ventricular filling velocity [E/A] ratio, 1.49±0.21 vs. 1.77±0.09, p<0.05). Furthermore, DPP4i significantly reduced myocardial fibrosis and collagen production by the myocardium and suppressed TGF-β1 and phosphorylation of Smad2/3 in the heart. In addition, DPP4i decreased TGF-β1-induced collagen production and TGF-β1-mediated phosphorylation and nuclear translocation of Smad2/3 in rat cardiac fibroblasts. In conclusion, DPP4 inhibition attenuated myocardial fibrosis and improved LV diastolic dysfunction in a DIO rat model by modulating the TGF-β1 and Smad2/3 pathways.

Topics: Animals; Blood Glucose; Diet, High-Fat; Dipeptidyl-Peptidase IV Inhibitors; Fibrosis; Insulin; Lipid A; Male; Myocardium; Obesity; Rats; Rats, Inbred SHR; Signal Transduction; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta1; Triazoles

Conflicting results have been reported on vaccination against hepatitis B virus (HBV) as a prophylaxis against viral recurrence after liver transplantation. We investigated the efficacy of 1-year, monthly vaccination using an adjuvant 3-deacylated monophosphoryl-lipid-A (MPL) recombinant S vaccine initially administered together with hepatitis B immunoglobulins (HBIg) in 18 patients transplanted for HBV-related cirrhosis. All received 12 vaccine doses (HBsAg, 20 mcg plus MPL, 50 mcg): the initial six doses (phase I) were administered within 7days after intravenous HBIg (2000IU), while the last 6 (phase II) following HBIg withdrawal. All patients received lamivudine during the study. Anti-HBs titers were determined before each dose and then for 1year after vaccination. After phase I anti-HBs titers were greater than 100IU/l in all patients and in three (16.6%) were greater than 500IU/l. After phase II 10 patients (55.5%) achieved anti-HBs titers greater than 100IU/l and five (27.7%) greater than 500IU/l. One year after vaccination eight patients (44.4%) maintained anti-HBs titers greater than 100IU/l, with a median titer of 234IU/l (102-1205), and 2 (11.1%) greater than 500IU/l. One-year extended monthly vaccination with a MPL-adjuvant recombinant vaccine induces a sustained protective anti-HBs response in approximately half of transplant recipients.

Topics: Adult; Female; Fibrosis; Hepatitis B; Hepatitis B Vaccines; Hepatitis B virus; Humans; Immunoglobulins; Lipid A; Liver Transplantation; Male; Middle Aged; Time Factors; Treatment Outcome; Vaccines, Synthetic

Alginate-poly-L-lysine (PLL) microcapsules can be used for transplantation of insulin-producing cells for treatment of type I diabetes. In this work we wanted to study the inflammatory reactions against implanted microcapsules due to PLL. We have seen that by reducing the PLL layer, less overgrowth of the capsule is obtained. By incubating different cell types with PLL and afterwards measuring cell viability with MTT, we found massive cell death at concentrations of PLL higher than 10 microg/ml. Staining with annexin V and propidium iodide showed that PLL induced necrosis but not apoptosis. The proinflammatory cytokine, tumor necrosis factor (TNF), was detected in supernatants from monocytes stimulated with PLL. The TNF response was partly inhibited with antibodies against CD14, which is a well-known receptor for lipopolysaccharide (LPS). Bactericidal permeability increasing protein (BPI) and a lipid A analogue (B-975), which both inhibit LPS, did not inhibit PLL from stimulating monocytes to TNF production. This indicates that PLL and LPS bind to different sites on monocytes, but because they both are inhibited by a p38 MAP kinase inhibitor, they seem to have a common element in the signal transducing pathway. These results suggest that PLL may provoke inflammatory responses either directly or indirectly through its necrosis-inducing abilities. By combining soluble PLL and alginate both the toxic and TNF-inducing effects of PLL were reduced. The implications of these data are to use alginate microcapsules with low amounts of PLL for transplantation purposes.

Topics: Alginates; Animals; Anti-Infective Agents; Antimicrobial Cationic Peptides; Biocompatible Materials; Blood Proteins; Capsules; Cell Death; Fibrosarcoma; Fibrosis; Glucuronic Acid; Hexuronic Acids; Humans; Islets of Langerhans Transplantation; Jurkat Cells; Lipid A; Membrane Proteins; Mice; Mice, Inbred BALB C; Microscopy, Confocal; Monocytes; Necrosis; Polylysine; Tumor Necrosis Factor-alpha