Heme oxygenase‐1 protects human periodontal ligament cells against substance P‐induced RANKL expression

Lee H‐J, Jeong G‐S, Pi S‐H, Lee S‐I, Bae W‐J, Kim S‐J, Lee S‐K, Kim E‐C. Heme oxygenase‐1 protects human periodontal ligament cells against substance P‐induced RANKL expression. J Periodont Res 2010; 45: 367–374. © 2010 John Wiley & Sons A/S Background and Objective: Although substance P (SP) stimulates bone resorption activity and this is reported to be correlated with the degree of periodontal inflammation, it is unclear how human periodontal ligament cells regulate neuropeptide‐induced osteoclastogenesis or the possible involvement of heme oxygenase‐1 (HO‐1) might be. This study examines how SP affects osteoprotegerin (OPG) and RANKL expression via HO‐1. Material and Methods: Using immortalized human periodontal ligament cells, the effects of SP on the expression of HO‐1, RANKL and OPG mRNA and proteins were determined by RT‐PCR and western blotting, respectively. Various concentrations of SP (10^?7, 10^?8, 10^?9 and 10^?10 m ) were added to the medium, and the cells were treated for 0, 0.25, 0.5, 1, 2 and 3 d. Results: Substance P upregulated RANKL and HO‐1 and downregulated OPG mRNA and protein expression in periodontal ligament cells, in a concentration‐ and time‐dependent manner. A HO‐1 inducer inhibited both the upregulation of RANKL expression and downregulation of OPG expression by SP in periodontal ligament cells. By contrast, treatment with a HO‐1 inhibitor or HO‐1 small interferring RNA (siRNA) enhanced SP‐stimulated RANKL expression. Inhibitors of ERK and p38 MAP kinases, phosphoinositide 3‐kinase and nuclear factor‐κB blocked the effects of SP on RANKL expression in periodontal ligament cells. Conclusion: These results suggest that SP stimulates osteoclastic differentiation by increasing the expression of RANKL vs. OPG via the HO‐1 pathway in periodontal ligament cells. The HO‐1 pathway may be an effective therapeutic target for inhibiting chronic periodontitis involving alveolar bone resorption.     

Nicotine and lipopolysaccharide stimulate the production of MMPs and prostaglandin E(2) by hypoxia-inducible factor-1α up-regulation in human periodontal ligament cells

Kim Y‐S, Shin S‐I, Kang K‐L, Herr Y, Bae W‐J, Kim E‐C. Nicotine and lipopolysaccharide stimulate the production of MMPs and prostaglandin E₂ by hypoxia‐inducible factor‐1α up‐regulation in human periodontal ligament cells. J Periodont Res 2012; 47: 719–728. © 2012 John Wiley & Sons A/S Background and Objective: Although hypoxia‐inducible factor 1α (HIF‐1α) is up‐regulated in the periodontal pockets of periodontitis patients, the expression and precise molecular mechanisms of HIF‐1α remain unknown in human periodontal ligament cells (PDLCs). The aim of this study was to explore the effects, as well as the signaling pathway, of nicotine and lipopolysaccharide (LPS) on the expression of HIF‐1α and on the production of its target genes, including cyclooxygenase‐2 (COX‐2)‐derived prostaglandin E₂ (PGE₂), MMP‐2 and MMP‐9 in PDLCs. Material and Methods: The expression of COX‐2 and HIF‐1α proteins was evaluated using western blotting. The production of PGE₂ and MMPs was evaluated using enzyme immunoassays and zymography, respectively. Results: LPS and nicotine synergistically induced the production of PGE₂, MMP‐2 and MMP‐9, and increased the expression of MMP‐2, MMP‐9, COX‐2 and HIF‐1α proteins. Inhibition of HIF‐1α activity by chetomin or knockdown of HIF1α gene expression by small interfering RNA markedly attenuated the production of LPS‐ and nicotine‐stimulated PGE₂ and MMPs, as well as the expression of COX‐2 and HIF‐1α. Furthermore, pretreatment with inhibitors of COX‐2, p38, extracellular signal‐regulated kinase, Jun N‐terminal kinase, protein kinase C, phosphatidylinositol 3‐kinase and nuclear factor‐kappaB decreased the expression of nicotine‐ and LPS‐induced HIF‐1α and COX‐2, as well as the activity of PGE₂ and MMPs. Conclusion: These data demonstrate novel mechanisms by which nicotine and LPS promote periodontal tissue destruction, and provide further evidence that HIF‐1α is a potential target in periodontal disease associated with smoking and dental plaque.     

Neuronal nitric oxide synthase is up-regulated by angiotensin II and attenuates NADPH oxidase activity and facilitates relaxation in murine left ventricular myocytes

Angiotensin II (Ang II) is critical in myocardial pathogenesis, mostly via stimulating NADPH oxidase. Neuronal nitric oxide synthase (nNOS) has recently been shown to play important roles in modulating myocardial oxidative stress and contractility. Here, we examine whether nNOS is regulated by Ang II and affects NADPH oxidase production of intracellular reactive oxygen species (ROS(i)) and contractile function in left ventricular (LV) myocytes. Our results showed that Ang II induced biphasic effects on ROS(i) and LV myocyte relaxation (TR(50)) without affecting the amplitude of sarcomere shortening and L-type Ca(2+) current density: TR(50) was prolonged at 30 min but was shortened after 3h (or after Ang II treatment in vivo). Correspondingly, ROS(i) was increased, followed by a reduction to control level. Quantitative RT-PCR and immunoblotting experiments showed that Ang II (3h) increased the mRNA and protein expression of nNOS and increased NO production (nitrite assay) in LV myocyte homogenates, suggesting that nNOS activity may be enhanced and involved in mediating the effects of Ang II. Indeed, n(omega)-nitro-l-arginine methyl ester (l-NAME) or a selective nNOS inhibitor, S-methyl-l-thiocitrulline (SMTC) increased NADPH oxidase production of superoxide/ROS(i) and abolished faster myocyte relaxation induced by Ang II. The positive lusitropic effect of Ang II was not mediated by PKA-, CaMKII-dependent signaling or peroxynitrite. Conversely, inhibition of cGMP/PKG pathway abolished the Ang II-induced faster relaxation by reducing phospholamban (PLN) Ser(16) phosphorylation. Taken together, these results clearly demonstrate that myocardial nNOS is up-regulated by Ang II and functions as an early adaptive mechanism to attenuate NADPH oxidase activity and facilitate myocardial relaxation.     

Living donor liver transplantation in hepatocellular carcinoma beyond the Milan criteria

Background/Aims: In patients with hepatocellular carcinoma (HCC) exceeding the Milan criteria, the recurrence rate after liver transplantation is over 50%. We investigated pretransplant factor(s) that could predict recurrence after living donor liver transplantation (LDLT) in patients with HCC exceeding the Milan criteria. Methods: Pre‐operative imaging showed that, of the 111 HCC patients who underwent LDLT between June 1995 and January 2006, 37 exceeded the Milan criteria. Clinical factors before LDLT were evaluated. Results: The 1‐ and 3‐year cumulative recurrence rates were 35 and 55% respectively. Pretransplant risk factors for HCC recurrence were large tumour size (>6 cm, P=0.001), tumour exposed to the liver surface (P=0.014) and progressive disease after pretransplant treatment (P=0.038). The 2‐year HCC recurrence rates in patients with 0, 1, 2 and 3 factors were 0% (0/4), 9% (1/16), 80% (8/10) and 100% (7/7) respectively (P<0.001). The 2‐year survival rate was significantly higher in patients with 0 or 1 factor than in patients with two or more factors (P=0.022). Conclusions: In patients with HCC exceeding the Milan criteria, the three pretransplant factors that may be useful for identifying those with high HCC recurrence potential after LDLT are tumour size >6 cm, progressive disease after pretransplant treatment and tumour exposed to the liver surface.     

Adipose-derived stem cells on the healing of ischemic colitis: a therapeutic effect by angiogenesis

Background

There has been no specific treatment for ischemic colitis. We verified the effects of adipose-derived stem cells (ASCs) on ischemia-induced colitis in a rat model.

Methods

Forty male Sprague–Dawley rats (10?weeks old; weight, 350?±?20?g) were divided into two groups: a control group (only fibrinogen and thrombin injected, n?=?20) and an ASC group (local implantation of ASCs mixed with thrombin and fibrinogen, n?=?20). An ischemic colitis model was established by modifying Nagahata's methods with double-blind randomization. ASCs (1?×?10⁶ cells) were implanted intramurally into the ischemic area using a fibrin glue mixture. The severity of adhesion, degree of ileus, the number and size of the ulcers, Wallace macroscopic and microscopic scores, and microvascular density were measured.

Results

The degree of ileus was significantly lower, and significantly fewer and smaller ulcerations were found in the ASC group than those in the control group. Wallace macroscopic and microscopic scores were lower in the ASC group than in the control group (1.90?±?1.22 versus 3.25?±?1.83, p?<?0.01 and 1.55?±?1.88 versus 2.84?±?1.89, p?<?0.05, respectively). Microvascular density was higher in the ASC group than in the control (54.45?±?19.45 versus 26.54?±?13.14, p?<?0.01, respectively).

Conclusions

Local implantation of ASCs into an ischemic-injured colonic wall reduced the grade of ischemic injury and enhanced tissue healing by promoting angiogenesis.     

Small-sized acute subdural hematoma: operate or not.

A retrospective study of 90 cases of small-sized (less than 3 mm on the printed CT film) acute (within 24 hours) subdural hematoma (SASDH) is presented. From March 1985 to December 1986, the SASDH were immediately operated on (operation rate: 86.0%). From January 1988 to December 1989, we attempted to treat them conservatively (operation rate: 49.1%). The patient population for this study consisted of 38 surgically-treated patients in the first period (Group I), 26 surgically-treated patients in the second period (Group IIs), and 26 conservatively-treated patients in the second period (Group IIc). We compared the clinical features, radiologic findings, and outcome of these 3 groups. The clinical features of Group I, including age, sex, Glasgow Coma Scale (GCS) score on admission, pupillary status on arrival, and interval from injury to the CT, did not differ significantly from those of Group II (P greater than 0.01). The only difference was the timing of the operation. In Group I, 20 patients (52.6%) received an operation within 4 hours, while in Group IIs, only 7 patients (26.9%) underwent surgery within 4 hours (P less than 0.05). The radiologic findings of Group I, including the thickness and volume of the hematoma, the degree of midline shift, and the frequency of skull fracture, also did not differ from those of Group II (P greater than 0.1). However, the outcome of Group II strikingly differed from that of Group I. The mortality rate was 76.3% in Group I, while it was 44.2% in Group II (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)