Nitric oxide production by human peritoneal mesothelial cells

Photobiomodulation (450 nm) alters the infection of periodontitis bacteria via the ROS/MAPK/mTOR signaling pathway

We aimed to investigate the effects of photobiomodulation (PBM) on periodontitis. A periodontitis model was established via Porphyromonas gingivalis infection in beagles. Mandibular second and third premolars were removed, and implants were positioned immediately after tooth extraction. Left gingiva was irradiated with PBM (450 nm) as the LG group, and right side without irradiation was regarded as the CG (control) group. PBM treatment increased oxidative stress by increasing the levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS). The elevated levels of H₂O₂ (a biomarker of oxidative stress) and the free radicals (NO^• and O₂^•-) reduced the concentration of dominant pathogens and regulated ROS/RNS/AMP-activated protein kinase (AMPK)/mTOR pathway by affecting p-AMPK, Runt-related transcription factor 2 (RUNX2), p-c-Jun N-terminal kinase (JNK)/mammalian target of rapamycin (mTOR), and acetyl-CoA carboxylase 1 (ACC1). PBM therapy increased salivary levels of interleukin-1 receptor antagonist (IL-1ra), interleukin (IL)-10, total antioxidant capacity (TAC) and catalase (CAT), and reduced the levels of tumor necrosis factor (TNF)α and interleukin (IL)-1β, malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) (p < 0.05). All the results contributed to preventing periodontitis infection. PBM therapy improved bone mineral density and implant osseointegration by controlling dominant pathogens invasion via the upregulation of salivary anti-inflammatory and antioxidant defense by affecting ROS/RNS/AMPK/mTOR signaling pathway.

Diagnostic and prognostic role of peritoneal CA 125 in peritoneal dialysis patients presenting with acute peritonitis

BACKGROUND

Cancer antigen 125 (CA125) is made by peritoneal mesothelial cells and can be measured in spent dialysate effluent from peritoneal dialysis (PD) patients. It has been suggested that CA125 is a marker of peritoneal mesothelial cell mass and turnover. As PD CA125 increases during peritoneal inflammation, we wished to determine whether measuring PD CA125 during peritonitis provided additional information in determining outcome of peritonitis.

METHODS

We prospectively measured peritoneal CA125 in 127 adult PD patients presenting with 187 acute episodes of PD peritonitis, measuring peritoneal CA125 from a sample of dialysate effluent obtained from a 4 hour 2 litre 13.6 g/l dextrose peritoneal dwell.

RESULTS

Mean patient age 60.8 ± 17.1 years, 62.6% male, 33.7% diabetic and the median PD vintage was 22 (11-48) months. 127 patients (66.8%) presented with their first episode of peritonitis, 20% their second episode, 13.2% third or greater. Gram positive bacteria accounted for 64.7% of all peritonitis episodes and Gram negative bacteria 21.1%. Treatment was successful for 151 episodes of PD peritonitis (81.1%). The median PD effluent total WBC was 1240 (430-3660)/ml and serum CRP 67 (20-144) mg/l, with a PD CA125 of 38 (20.3-72.3) IU/l on presentation. There were positive correlations between PD effluent CA125 concentrations and total WBC on presentation (r = 0.41, p =  <0.001) and dialysis vintage (r =  -0.43, p < 0.001) but not with patient age, diabetic status, or serum CRP.There was no difference in PD effluent CA125 concentrations between Gram positive, and Gram negative peritonitis or between those episodes which responded to treatment, median 38 IU/ml (21-69) vs those with treatment failures 38 IU/ml (15-94).

CONCLUSION

We did not find any additional diagnostic or prognostic benefit for measuring effluent CA125 in PD patients presenting with acute peritonitis compared to standard investigations, including peritoneal WBC and serum CRP. As such our study would not support the routine measurement of peritoneal CA125 during episodes of peritonitis.

Association between nitric oxide and oxidative stress in continuous ambulatory peritoneal dialysis patients with peritonitis

BACKGROUND

Peritonitis is a major complication in continuous ambulatory peritoneal dialysis (CAPD) patients, and the mechanisms involved in the pathology are important if the success rate of treatment strategies is to increase.

MATERIAL AND METHODS

A total of 50 CAPD patients (25 with 25 episodes of peritonitis and 25 with no clinical or laboratory signs of infection) were included in the study. Malondialdehyde (MDA) and nitric oxide (NO) metabolites in serum and dialysate effluents were determined.

RESULTS

The dialysate/serum (D/S) ratio of the NO metabolites and serum NO metabolite concentrations were significantly higher in the peritonitis group. Serum and dialysate MDA concentrations were also significantly higher in the peritonitis group. The D/S ratio of MDA was significantly higher in the control group.

CONCLUSIONS

Local peritoneal NO production and oxidative stress seem to increase in CAPD patients during the peritonitis attack.

Amadori adducts activate nuclear factor-kappaB-related proinflammatory genes in cultured human peritoneal mesothelial cells

Diabetes mellitus leads to a high incidence of several so-called complications, sharing similar pathophysiological features in several territories. Previous reports points at early nonenzymatic glycosylation products (Amadori adducts) as mediators of diabetic vascular complications. In the present study, we analysed a possible role for Amadori adducts as stimulators of proinflammatory pathways in human peritoneal mesothelial cells (HPMCs). Cultured HPMCs isolated from 13 different patients (mean age 38.7+/-16 years) were exposed to different Amadori adducts, that is, highly glycated haemoglobin (10 nM) and glycated bovine serum albumin (0.25 mg ml(-1)), as well as to their respective low glycosylation controls. Amadori adducts, but not their respective controls, elicited a marked increase of NF-kappaB activation, as determined by electromobility shift assays and transient transfection experiments. Additionally, Amadori adducts significantly increased the production of NF-kappaB-related proinflammatory molecules, including cytokines, such as TNF-alpha, IL-1beta or IL-6, and enzymes, such as cyclooxygenase-2 and inducible nitric oxide (NO) synthase, this latter leading to the release of NO by HPMCs. The effects of Amadori adducts were mediated by different reactive oxygen and nitrosative species (e.g. superoxide anions, hydroxyl radicals, and peroxynitrite), as they were blunted by coincubation with the appropriate scavengers. Furthermore, NO generated upon exposure to Amadori adducts further stimulated NF-kappaB activation, either directly or after combination with superoxide anions to form peroxynitrite. We conclude that Amadori adducts can favour peritoneal inflammation by exacerbating changes in NO synthesis pathway and triggering NF-kappaB-related proinflammatory signals in human mesothelial cells.