Anti-melanoma Differentiation-associated Gene 5 Antibody-positive Dermatomyositis Presenting as Refractory Gingivitis at the First Clinical Manifestation

We herein report a case of melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis that developed in a patient with refractory gingivitis. The diagnosis of anti-MDA5 antibody-positive dermatomyositis was made based on a characteristic skin rash, weakness of proximal muscles, interstitial pneumonia, and positivity for anti-MDA5 antibody. The patient was started on triple therapy with high-dose prednisolone, tacrolimus, and intravenous cyclophosphamide. After treatment, the refractory gingivitis disappeared, and the other skin rash and interstitial lung disease also improved. In the diagnosis and treatment of anti-MDA5 antibody-positive dermatomyositis, it is necessary to pay attention to the intraoral findings, including the gingiva.

Oxidative Stress Inhibits Endotoxin Tolerance and May Affect Periodontitis

Periodontal disease is caused by dysbiosis of the dental biofilm and the host inflammatory response. Various pathogenic factors, such as proteases and lipopolysaccharides (LPSs) produced by bacteria, are involved in disease progression. Endotoxin tolerance is a function of myeloid cells, which sustain inflammation and promote tissue regeneration upon prolonged stimulation by endotoxins such as LPS. The role of endotoxin tolerance is gaining attention in various chronic inflammatory diseases, but its role in periodontal disease remains elusive. Oxidative stress, one of the major risk factors for periodontal disease, promotes disease progression through various mechanisms, of which only some are known. The effect of oxidative stress on endotoxin tolerance has not yet been studied, and we postulated that endotoxin tolerance regulation may be an additional mechanism through which oxidative stress influences periodontal disease. This study aimed to reveal the effect of oxidative stress on endotoxin tolerance and that of endotoxin tolerance on periodontitis progression. The effect of oxidative stress on endotoxin tolerance was analyzed in vitro using peritoneal macrophages of mice and hydrogen peroxide (H₂O₂). The results showed that oxidative stress inhibits endotoxin tolerance induced by Porphyromonas gingivalis LPS in macrophages, at least partially, by downregulating LPS-elicited negative regulators of Toll-like receptor (TLR) signaling. A novel oxidative stress mouse model was established using SMP30KO mice incapable of ascorbate biosynthesis. Using this model, we revealed that oxidative stress impairs endotoxin tolerance potential in macrophages in vivo. Furthermore, gingival expression of endotoxin tolerance-related genes and TLR signaling negative regulators was decreased, and symptoms of ligature-induced periodontitis were aggravated in the oxidative stress mouse model. Our findings suggest that oxidative stress may contribute to periodontitis progression through endotoxin tolerance inhibition.

Bone marrow concentrate promotes bone regeneration with a suboptimal-dose of rhBMP-2

Bone marrow concentrate (BMC), which is enriched in mononuclear cells (MNCs) and platelets, has recently attracted the attention of clinicians as a new optional means for bone engineering. We previously reported that the osteoinductive effect of bone morphogenetic protein-2 (BMP-2) could be enhanced synergistically by co-transplantation of peripheral blood (PB)-derived platelet-rich plasma (PRP). This study aims to investigate whether BMC can effectively promote bone formation induced by low-dose BMP-2, thereby reducing the undesirable side-effects of BMP-2, compared to PRP. Human BMC was obtained from bone marrow aspirates using an automated blood separator. The BMC was then seeded onto β-TCP granules pre-adsorbed with a suboptimal-dose (minimum concentration to induce bone formation at 2 weeks in mice) of recombinant human (rh) BMP-2. These specimens were transplanted subcutaneously to the dorsal skin of immunodeficient-mice and the induction of ectopic bone formation was assessed 2 and 4 weeks post-transplantation. Transplantations of five other groups [PB, PRP, platelet-poor plasma (PPP), bone marrow aspirate (BM), and BM-PPP] were employed as experimental controls. Then, to clarify the effects on vertical bone augmentation, specimens from the six groups were transplanted for on-lay placement on the craniums of mice. The results indicated that BMC, which contained an approximately 2.5-fold increase in the number of MNCs compared to PRP, could accelerate ectopic bone formation until 2 weeks post-transplantation. On the cranium, the BMC group promoted bone augmentation with a suboptimal-dose of rhBMP-2 compared to other groups. Particularly in the BMC specimens harvested at 4 weeks, we observed newly formed bone surrounding the TCP granules at sites far from the calvarial bone. In conclusion, the addition of BMC could reduce the amount of rhBMP-2 by one-half via its synergistic effect on early-phase osteoinduction. We propose here that BMC transplantation facilitates the clinical use of rhBMP-2 as an alternative strategy for bone engineering.

DC-STAMP Is an Osteoclast Fusogen Engaged in Periodontal Bone Resorption

Dendritic cell-specific transmembrane protein (DC-STAMP) plays a key role in the induction of osteoclast (OC) cell fusion, as well as DC-mediated immune regulation. While DC-STAMP gene expression is upregulated in the gingival tissue with periodontitis, its pathophysiological roles in periodontitis remain unclear. To evaluate the effects of DC-STAMP in periodontitis, anti-DC-STAMP-monoclonal antibody (mAb) was tested in a mouse model of ligature-induced periodontitis ( n = 6-7/group) where Pasteurella pneumotropica ( Pp)-reactive immune response activated T cells to produce receptor activator of nuclear factor kappa-B ligand (RANKL), which, in turn, promotes the periodontal bone loss via upregulation of osteoclastogenesis. DC-STAMP was expressed on the cell surface of mature multinuclear OCs, as well as immature mononuclear OCs, in primary cultures of RANKL-stimulated bone marrow cells. Anti-DC-STAMP-mAb suppressed the emergence of large, but not small, multinuclear OCs, suggesting that DC-STAMP is engaged in the late stage of cell fusion. Anti-DC-STAMP-mAb also inhibited pit formation caused by RANKL-stimulated bone marrow cells. Attachment of ligature to a second maxillary molar induced DC-STAMP messenger RNA and protein, along with elevated tartrate-resistant acid phosphatase-positive (TRAP+) OCs and alveolar bone loss. As we expected, systemic administration of anti-DC-STAMP-mAb downregulated the ligature-induced alveolar bone loss. Importantly, local injection of anti-DC-STAMP-mAb also suppressed alveolar bone loss and reduced the total number of multinucleated TRAP+ cells in mice that received ligature attachment. Attachment of ligature induced significantly elevated tumor necrosis factor-α, interleukin-1β, and RANKL in the gingival tissue compared with the control site without ligature ( P < 0.05), which was unaffected by local injection with either anti-DC-STAMP-mAb or control-mAb. Neither in vivo anti- Pp IgG antibody nor in vitro anti- Pp T-cell response and resultant production of RANKL was affected by anti-DC-STAMP-mAb. This study illustrated the roles of DC-STAMP in promoting local OC cell fusion without affecting adaptive immune responses to oral bacteria. Therefore, it is plausible that a novel therapeutic regimen targeting DC-STAMP could suppress periodontal bone loss.

MR Imaging of Adult Glomerulocystic Kidney Disease

A 59-year-old man with hypertension and severe renal dysfunction was diagnosed as having adult glomerulocystic kidney disease. MR imaging of the kidney showed a diffuse reduction of the intensity of the renal cortex with a loss of normal cortico-medullary differentiation on T1-weighted images. Numerous small cortical cysts were also demonstrated. These MR findings complemented the results of the biopsy and were useful for making a definitive diagnosis.

Ferromagnetic spin coupling in the chromium dimer cation: measurements by photodissociation spectroscopy combined with coupled-cluster calculations

The magnetic coupling of the chromium dimer cation, Cr2 (+), has been an outstanding problem for decades. An optical absorption spectrum of Cr2 (+) has been obtained by photodissociation spectroscopy in the photon-energy range from 2.0 to 5.0 eV. Besides, calculations have been performed by the equation-of-motion coupled-cluster singles and doubles method for vertical excitation of the species. Their coincidence supports our assignment that the ground electronic state exhibits a ferromagnetic spin coupling, which is contrary to those of neutral and negatively charged dimers, Cr2 and Cr2 (-), in their lowest spin states.

Transient Exposure to Hypoxic and Anoxic Oxygen Concentrations Promotes Either Osteogenic or Ligamentogenic Characteristics of PDL Cells

The periodontal ligament (PDL) has a reservoir of mesenchymal stem cells (MSCs) and this tissue is easily available following teeth removal procedures. However, PDL-derived cells (PDLCs) availability for tissue engineering is limited because they are heterogeneous cells at various differentiation and lineage commitments. Therefore, efficient culture conditions to increase MSCs number are needed to use PDLCs in tissue engineering. Recent reports indicate that low-oxygen conditions amplified stem/progenitor cell numbers and inhibited cell differentiation. Our aim was to establish which low-oxygen culture conditions favored bone or tendon/ligament regeneration in cultured PDLCs. Human PDLCs were cultured and exposed to either hypoxic (O₂≤5%) or anoxic (O₂<0.1%) oxygen conditions in low-glucose/serum-free media for 24 hours. After 24 h, as expected, cell survival was significantly less in PDLCs exposed to anoxic conditions as compared with cells under normal or hypoxic conditions. PDLCs exposed to hypoxic conditions had the highest percentages for MSC markers (CD105, CD166, Stro-1). For both hypoxic and anoxic conditions, stem cell marker genes (oct4, sox2, p75) were upregulated after 6 h. At 24 h, these stem cell markers were maintained in PDLCs under hypoxic condition. Interestingly under anoxic conditions, expression of scleraxis gene (a key transcription factor for tendo/ligamentogenesis) was upregulated markedly. When hypoxic PDLCs were subcultured into osteogenic medium, in vitro calcification and prominent in vivo bone formation in mice calvaria were observed. When anoxic PDLCs were subcultured into tendo/ligamentogenic medium, expression of aggrecan (a mature tenogenic gene) increased remarkably. No obvious differences were detectable on chondrogenic and adipogenic inducibilities. We propose that transient exposure to low-oxygen during the culture enhanced MSC population in PDL. In addition, different low-oxygen concentrations favored osteogenic or tendo/ligamentogenic inducibilities of cultured PDLCs.

Novel biological strategies for treatment of wear particle-induced periprosthetic osteolysis of orthopaedic implants for joint replacement

Wear particles and by-products from joint replacements and other orthopaedic implants may result in a local chronic inflammatory and foreign body reaction. This may lead to persistent synovitis resulting in joint pain and swelling, periprosthetic osteolysis, implant loosening and pathologic fracture. Strategies to modulate the adverse effects of wear debris may improve the function and longevity of joint replacements and other orthopaedic implants, potentially delaying or avoiding complex revision surgical procedures. Three novel biological strategies to mitigate the chronic inflammatory reaction to orthopaedic wear particles are reported. These include (i) interference with systemic macrophage trafficking to the local implant site, (ii) modulation of macrophages from an M1 (pro-inflammatory) to an M2 (anti-inflammatory, pro-tissue healing) phenotype in the periprosthetic tissues, and (iii) local inhibition of the transcription factor nuclear factor kappa B (NF-κB) by delivery of an NF-κB decoy oligodeoxynucleotide, thereby interfering with the production of pro-inflammatory mediators. These three approaches have been shown to be viable strategies for mitigating the undesirable effects of wear particles in preclinical studies. Targeted local delivery of specific biologics may potentially extend the lifetime of orthopaedic implants.

Spin coupling and orbital angular momentum quenching in free iron clusters

Magnetic spin and orbital moments of size-selected free iron cluster ions Fe{n}{+} (n=3-20) have been determined via x-ray magnetic circular dichroism spectroscopy. Iron atoms within the clusters exhibit ferromagnetic coupling except for Fe{13}{+}, where the central atom is coupled antiferromagnetically to the atoms in the surrounding shell. Even in very small clusters, the orbital magnetic moment is strongly quenched and reduced to 5%-25% of its atomic value while the spin magnetic moment remains at 60%-90%. This demonstrates that the formation of bonds quenches orbital angular momenta in homonuclear iron clusters already for coordination numbers much smaller than those of the bulk.

Probing structures of small gold cluster cations with dinitrogen

Small gold cluster cations, Au(n)(+), adsorb N(2) molecules effectively under multiple collision conditions. The saturation number for N(2) adsorption on a gold cluster cation depends on the number of dangling gold atoms and the triangular apexes. The saturation numbers were interpreted to arrive at the geometrical structures of gold cluster cations. The gold cluster cations of sizes 3 and 6 have single isomers, whilst cluster cations with 4, 5, and 7 atoms have two isomers. For the gold cluster cation with six atoms, a higher-energy and lower-symmetry structure was observed. The gold cluster cations with eight or more atoms do not adsorb N(2), which can be attributed to a two-dimensional to three-dimensional structural transition at n = 8.

Photon-trap spectroscopy applied to molecules adsorbed on a solid surface: probing with a standing wave versus a propagating wave

We apply photon-trap spectroscopy, a generalized scheme of cavity ringdown spectroscopy, to infrared spectroscopy of molecular adsorbates on a solid substrate. The storage lifetime of light in a high-finesse Fabry-Perot cavity provides a high absorbance sensitivity for the substrate sample, which is placed exactly normal to the light beam in the cavity to minimize optical losses. Infrared spectra of the C-H stretching vibration of alkylsiloxane monolayer films on a silicon substrate are measured in three ways, namely by employing pulsed and continuous-wave lasers as well as by conventional Fourier transform infrared spectroscopy. The magnitude of optical absorption is shown to vary by the character of the interacting light used in the measurement, i.e., a standing wave versus a propagating wave.

Infrared spectra of organic monolayer films in a standing wave measured by photon-trap spectroscopy

Photon-trap spectroscopy, a generalized scheme of cavity ringdown spectroscopy, is applied to measure an infrared spectrum of the C-H stretching vibration of alkylsiloxane monolayer films grafted on a silicon substrate. A continuous-wave laser beam is introduced into a high-finesse Fabry-Pérot cavity containing the substrate placed exactly normal to the light beam to minimize optical losses. The lifetime of the light trapped in the cavity is measured to detect optical absorption sensitively. The results show clear dependence of the absorbance on the location of the monolayers with respect to a standing wave formed in the cavity; the absorbance is practically zero when the monolayers on both the surfaces are adjusted at nodes, whereas it is maximized at antinodes. The present experiment is materialized on the basis of the principles established by our previous study [Terasaki et al., J. Opt. Soc. Am. B 22, 675 (2005)].

Blockade of VEGF accelerates proteinuria, via decrease in nephrin expression in rat crescentic glomerulonephritis

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that maintains the glomerular and peritubular capillary (PTC) network in the kidney. The soluble form of the VEGF receptor-1 (soluble fms-like tyrosine kinase 1 (sFlt-1)) is known to regulate VEGF activity by binding VEGF in the circulation. We hypothesized that VEGF may be beneficial for maintaining glomerular filtration barrier and vascular network in rats with progressive glomerulonephritis (GN). For blockade of VEGF activity in vivo, rats were transfected twice with plasmid DNA encoding the murine sFlt-1 gene into femoral muscle 3 days before and 2 weeks after the induction of antiglomerular basement membrane antibody-induced GN. Inhibition of VEGF with sFlt-1 resulted in massive urinary protein excretion, concomitantly with downregulated expression of nephrin in nephritic rats. Further, blockade of VEGF induced mild proteinuria in normal rats. Administration of sFlt-1 affected neither the infiltration of macrophages nor crescentic formation. In contrast, treatment of sFlt-1 accelerated the progression of glomerulosclerosis and interstitial fibrosis accompanied with renal dysfunction and PTC loss at day 56. VEGF may play a role in maintaining the podocyte function as well as renal vasculature, thereby protecting glomeruli and interstitium from progressive renal insults.

Anti-MCP-1 gene therapy inhibits vascular smooth muscle cells proliferation and attenuates vein graft thickening both in vitro and in vivo

OBJECTIVE

Because late vein graft failure is caused by intimal hyperplasia (IH) and accelerated atherosclerosis, and these processes are thought to be inflammation driven, influx of monocytes is one of the first phenomena seen in IH, we would like to provide direct evidence for a role of the MCP-1 pathway in the development of vein graft disease.

METHODS AND RESULTS

MCP-1 expression is demonstrated in various stages of vein graft disease in a murine model in which venous interpositions are placed in the carotid arteries of hypercholesterolemic ApoE3Leiden mice and in cultured human saphenous vein (HSV) segments in which IH occurs. The functional involvement of MCP-1 in vein graft remodeling is demonstrated by blocking the MCP-1 receptor CCR-2 using 7ND-MCP-1. 7ND-MCP1 gene transfer resulted in 51% reduction in IH in the mouse model, when compared with controls. In HSV cultures neointima formation was inhibited by 53%. In addition, we demonstrate a direct inhibitory effect of 7ND-MCP-1 on the proliferation of smooth muscle cell (SMC) in HSV cultures and in SMC cell cultures.

CONCLUSIONS

These data, for the first time, prove that MCP-1 has a pivotal role in vein graft thickening due to intimal hyperplasia and accelerated atherosclerosis.

Analysis of corneal inflammation induced by cauterisation in CCR2 and MCP-1 knockout mice

AIM

To elucidate the role of CCR2/MCP-1 in corneal inflammation.

METHODS

A cauterisation induced corneal inflammation model was used. The corneas were cauterised with silver nitrate in CCR2 knockout (KO) mice, MCP-1 KO mice, and control mice. Clinical signs such as corneal oedema and opacity were examined 96 hours after cauterisation and the phenotypes of the cells infiltrating the cornea were analysed by flow cytometry. Corneal inflammation in neutrophil depleted mice was also analysed.

RESULTS

After cauterisation both CCR2 KO and MCP-1 KO mice showed the same levels of corneal oedema and opacity as control mice. Flow cytometry revealed that in control mice most of the infiltrating cells were neutrophils and macrophages, whereas in both CCR2 KO mice and MCP-1 KO mice, the number of macrophages infiltrating the cornea were markedly reduced. However, prominent infiltrates of neutrophils were still observed in the cornea in CCR2 KO mice and MCP-1 KO mice. The depletion of neutrophils significantly reduced the oedema and opacity induced in the cornea by cauterisation.

CONCLUSION

The CCR2 and MCP-1 molecules are not essential for cauterisation induced corneal inflammation. Neutrophils, rather than migrated macrophages, are the final effector cells involved in inducing inflammation in this model.

Anti-monocyte chemoattractant protein 1 gene therapy attenuates experimental chronic pancreatitis induced by dibutyltin dichloride in rats

BACKGROUND

Monocyte chemoattractant protein 1 (MCP-1) is a member of the C-C chemokine family and exerts strong chemoattractant activity in monocytes, macrophages, and lymphocytes. Rat pancreatic fibrosis induced by dibutyltin dichloride (DBTC) is considered to be an appropriate chronic pancreatitis model histologically and enzymatically, as has demonstrated in a previous study.

AIM

We examined the effect of human dominant negative inhibitor of MCP-1 (mutant MCP-1) on progression of chronic pancreatitis induced by DBTC in a rat model.

METHODS

We used the experimental model of chronic pancreatitis induced by DBTC in rats. Mutant MCP-1 or empty plasmid at a dose of 50 microg/body weight was administrated into rat thigh muscles on days 4, 11, and 18 after administration of DBTC. On days 14 and 28, we evaluated the effect of mutant MCP-1 morphologically and biochemically.

RESULTS

The mutant MCP-1 treated group inhibited early pancreatic inflammation and later pancreatic fibrosis histologically, and showed a decrease in serum MCP-1 concentration, intrapancreatic hydroxyproline, alpha-smooth muscle actin, and an increase in intrapancreatic amylase and protein content compared with the empty plasmid treated group. The mutant MCP-1 group also inhibited intrapancreatic mRNA expression of cytokines and chemokines.

CONCLUSIONS

: Our findings suggest that monocyte/macrophage recruitment and the systemic MCP-1 signal pathway contribute to progression of chronic pancreatitis, and that blockade of MCP-1 may suppress the development of pancreatic fibrosis.

Monocyte chemoattractant protein-1 activates a regional Th1 immunoresponse in nephritis of MRL/lpr mice

OBJECTIVE

Monocyte chemoattractant protein-1 (MCP-1) is upregulated and recruits and activates inflammatory cells in nephritis of MRL lpr mice. It has been shown that anti-MCP-1 gene therapy is specifically effective in nephritis, while it was apparent that an imbalance towards Th1 predominance accelerates nephritis in MRL/lpr mice. The aim of this study was to clarify whether blockade of the MCP-1 signal by anti-MCP-1 gene therapy influences the Th1/Th2 balance in MRL/lpr mice.

METHOD

An NH2-terminal deletion mutant of the MCP-1 gene (7ND) was injected into the skeletal muscles of MRL/Ipr mice with advanced stage nephritis to suppress MCP-1 and its receptor (CCR2) signaling pathway. We evaluated the local tissue production of cytokines in splenocytes and microdissected infiltrating cells within the glomeruli or interstitium.

RESULT

Although the production of cytokines in splenocytes was not influenced by anti-MCP-1 gene therapy, kidney glomeruli IL-12 mRNA production and interstitium-infiltrating cell production of IL-12 and IFN-gamma mRNA were significantly reduced.

CONCLUSION

The blockade of MCP-1 gene therapy does not influence helper T cell polarization, but acts directly on the regional Th1 immunoreaction in MRL/lpr mice.

The gene transfer of soluble VEGF type I receptor (Flt-1) attenuates peritoneal fibrosis formation in mice but not soluble TGF-beta type II receptor gene transfer

Peritoneal fibrosis formation is a consequence of inflammation/injury and a significant medical problem to be solved. The effects of soluble VEGF receptor type I (sFlt-1) gene transfer on experimental peritoneal fibrosis were examined and compared with soluble transforming growth factor-beta (TGF-beta) receptor type II (sTGF beta RII) gene transfer. Male C57BL/6 mice were injected with 1.5 x 10(8) plaque-forming unit of adenovirus encoding active TGF-beta (AdTGF beta) intraperitoneally. Some mice had been treated with sTGF betaRII or sFlt-1 plasmid injection into skeletal muscle with electroporation 4 days before virus administration. Mice were euthanized at day 14 after virus administration. AdTGF beta induced significant elevation of serum active TGF-beta, caused significant inflammatory response [weight loss, elevation of serum amyloid-P (SAP) and IL-12, increased expression of monocyte chemoattractant protein-1 (MCP-1) mRNA], and induced marked thickening of the peritoneum and collagen deposition. Gene transfer of sFlt-1 reduced the collagen deposition approximately 81% in mesenteric tissue. Treatment with sFlt-1 decreased ICAM-1 and MCP-1 mRNA expression significantly. Significant negative correlation between serum sFlt-1 and placental growth factor level was observed, whereas there was no significant negative correlation between sFlt-1 and VEGF. On the other hand, sTGF beta RII treatment enhanced the AdTGF beta-induced inflammation (significant elevation of SAP, TNF-alpha, and IL-12 levels and upregulation of ICAM-1 and MCP-1 mRNA expressions) and failed to prevent collagen deposition. These observations indicate that sFlt-1 gene transfer might be of therapeutic benefit in peritoneal fibrosis.

The relative contributions of each subset of ocular infiltrated cells in experimental choroidal neovascularisation

AIM

Choroidal neovascularisation (CNV) is a major cause of blindness in adults. The aim of this study was to investigate the role of infiltrating cells in the development of experimental CNV.

METHODS

CNV was induced in C57BL/6 (B6) mice by laser photocoagulation (PC). After PC, the numbers of each subset of infiltrated cells were analysed by flow cytometry at multiple time points. Each subset (except for macrophages) was depleted by the specific antibodies in vivo. Thereafter, the area of CNV was compared between the control B6 mice and the specific antibody treated mice 7 days after PC. The CNV formation in neutrophil depleted CC chemokine receptor-2 (CCR2) knockout mice was also examined to minimise the effects of macrophages.

RESULTS

In the early phase of CNV formation, a large number of neutrophils and macrophages infiltrated to the eyes. Natural killer (NK) cells and T lymphocytes were barely detected while no B lymphocytes were detected. The CNV areas did not significantly change compared between the control B6 mice and the specific antibody treated mice. However, the neutrophil depleted CCR2KO mice resulted in a reduction of CNV.

CONCLUSION

Although lymphocytes and NK cells had little effect on CNV formation, neutrophils partially contributed to CNV in the absence of macrophages.

Antimonocyte chemoattractant protein-1 gene therapy reduces experimental in-stent restenosis in hypercholesterolemic rabbits and monkeys

In-stent restenosis results exclusively from neointimal hyperplasia due to mechanical injury and a foreign body response to the prosthesis. Inflammation mediated by monocyte chemoattractant protein-1 (MCP-1) might therefore underlie in-stent restenosis. We recently devised a new strategy for anti-MCP-1 gene therapy by transfecting an N-terminal deletion mutant of the MCP-1 gene into skeletal muscles. We used this strategy to investigate the role of MCP-1 in experimental in-stent restenosis in hypercholesterolemic rabbits and monkeys. Transfection of the mutant MCP-1 gene suppressed monocyte infiltration/activation in the stented arterial wall and markedly reduced the development of neointimal hyperplasia. This strategy also suppressed local expression of MCP-1 and inflammatory cytokines. Therefore, inhibition of MCP-1-mediated inflammation is effective in reducing experimental in-stent restenosis. This strategy might be a useful form of gene therapy against human in-stent restenosis.

Anti-monocyte chemoattractant protein-1 gene therapy attenuates nephritis in MRL/lpr mice

OBJECTIVE

Monocyte chemoattractant protein-1 (MCP-1) is up-regulated and recruits and activates inflammatory cells in human diffuse proliferative lupus nephritis (DPLN) and in nephritis of lupus model MRL/lpr mice. The aim of this study was to examine whether anti-MCP-1 gene therapy inhibits the progression of nephritis in MRL/lpr mice.

METHOD

An NH(2)-terminal deletion mutant of the MCP-1 gene, 7ND, was injected into skeletal muscles of MRL/lpr mice with advanced stage nephritis to blockade MCP-1 and its receptor (CCR2) signalling pathway.

RESULT

Histological findings of kidneys in treated mice, which received more than four injections of 7ND, showed that protection against renal injury resulted from reduced infiltration of leucocytes. Therefore, this therapy has been shown to prolong the life span of MRL/lpr mice.

CONCLUSION

Anti-MCP-1 gene therapy is specifically effective in the localized inflammatory region. The data presented here indicate that this anti-MCP-1 gene therapy may be effective adjunct in the management of DPLN.

Inhibition of neointimal hyperplasia after balloon injury by cis-element 'decoy' of early growth response gene-1 in hypercholesterolemic rabbits

Early growth response factor-1 (Egr-1) is a transcription factor that is rapidly activated after vascular injury and thus might contribute to vascular proliferation and inflammation. We hypothesized that Egr-1 might therefore be a therapeutic target against restenosis. Hypercholesterolemic rabbits were intraluminally administered synthetic DNA as a 'decoy' against Egr-1 immediately after carotid artery balloon injury. Efficient transfection was confirmed by the delivery of a fluorescence-labeled decoy. Gel mobility-shift assay showed increased Egr-1 activity after balloon injury and its prevention by Egr-1 decoy transfection in vivo. Egr-1 decoy transfection attenuated early inflammation and proliferation and later neointimal hyperplasia. In addition, Egr-1 decoy transfection reduced gene expression and protein production of Egr-1-dependent genes such as platelet-derived growth factor-B, transforming growth factor-beta1, and monocyte chemoattractant protein-1. The Egr-1 pathway has an essential role in the pathogenesis of neointimal hyperplasia after balloon injury in hypercholesterolemic rabbits. This decoy strategy is a potential practical form of therapy for human restenosis.

Increased inactivation of nitric oxide is involved in impaired coronary flow reserve in heart failure

Recent evidence suggests that increased inactivation of endothelium-derived nitric oxide (NO) by oxygen free radical (OFR) formation is involved in the pathogenesis of endothelial dysfunction in heart failure (HF). However, it is unclear whether increased OFR limits coronary flow reserve in HF. To test this hypothesis, we examined the effects of antioxidant therapy on coronary flow reserve in a canine model of tachycardia-induced HF. The flow reserve (percent increase in coronary blood flow) to adenosine or to 20-s ischemia was less and OFR formation (electron-spin resonance spectroscopy) in myocardial tissues was greater in HF dogs than in controls. Immunohistochemical staining of 4-hydroxy-2-nonenal, an OFR-induced lipid peroxide, was detected in coronary microvessels of HF dogs. Intracoronary infusion of a cell-permeable OFR scavenger, tiron, suppressed OFR formation and improved the vasodilating capacity to adenosine or brief ischemia in HF dogs but not in controls. A NO synthesis inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), diminished the beneficial effects of tiron in HF dogs. Vasodilation to sodium nitroprusside was similar between control and HF dogs, and no change in its response was noted with tiron or tiron + L-NMMA in either group. In summary, antioxidant treatment with tiron improved coronary flow reserve by increasing NO bioactivity in HF dogs. Thus increased OFR formation may impair coronary flow reserve in HF by reducing NO bioactivity.

Downregulation of angiotensin II type 1 receptor by hydrophobic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in vascular smooth muscle cells

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, so-called statins, reduce the relative risk of a major coronary event by lowering the serum cholesterol level. In addition, statins may confer beneficial effects by cholesterol-lowering independent mechanisms, which are incompletely characterized. Because angiotensin II (Ang II) plays crucial roles in the pathogenesis of cardiovascular diseases, we examined the effect of statins on the expression of the Ang II type 1 receptor (AT(1)-R) in cultured vascular smooth muscle cells (VSMCs). Cerivastatin and fluvastatin reduced the AT(1)-R mRNA and the AT(1)-R protein levels; however, pravastatin lacked this effect. Cerivastatin and fluvastatin suppressed the AT(1)-R promoter activity measured by luciferase assay but did not affect AT(1)-R mRNA stability, suggesting that the suppression occurs at the transcriptional level. Coincubation of VSMCs with mevalonate or geranylgeranyl pyrophosphate but not with farnesyl pyrophosphate reversed the cerivastatin-induced AT(1)-R downregulation. Overexpression of dominant-negative Rho A also suppressed AT(1)-R mRNA expression. Treatment with cerivastatin for 24 hours reduced the calcium response of VSMCs to Ang II. Taken together, statins downregulate AT(1)-R expression through a mevalonate-dependent, geranylgeranyl pyrophosphate-dependent, and Rho A-dependent manner and attenuate the biological function of Ang II. Downregulation of AT(1)-R may contribute to the cholesterol-independent beneficial effect of statins on the cardiovascular system.

Thrombin induces interleukin-6 expression through the cAMP response element in vascular smooth muscle cells

The plasma level of interleukin-6 (IL-6) is elevated in patients with acute coronary syndromes and has prognostic value. Thrombin is a potent mitogen for vascular smooth muscle cells (VSMCs) and plays an important role in the progression of atherosclerosis. We examined the mechanism of thrombin-induced IL-6 expression in VSMCs. Thrombin induced IL-6 mRNA and protein expression in a dose-dependent manner. Pharmacological inhibition of extracellular signal-regulated protein kinase (ERK), p38 mitogen-activated protein kinase (MAPK), or epidermal growth factor receptor (EGF-R) suppressed the thrombin-induced IL-6 expression. Deletion and mutation analysis of the promoter region of the IL-6 gene by using luciferase as a reporter showed that the DNA segment between -228 and -150 bp containing the cAMP response element (CRE) site played a critical role. Thrombin also induced phosphorylation of CRE binding protein (CREB) in an ERK- and a p38 MAPK-dependent manner. Overexpression of the dominant-negative form of CREB inhibited thrombin-induced IL-6 mRNA expression. These results suggest that the CRE site and CREB play an important role in thrombin-induced IL-6 gene expression in VSMCs. Transactivation of EGF-R and activation of ERK and p38 MAPK are involved in this process. CREB may be a novel transcription factor that regulates thrombin-induced gene expression.

Renin-angiotensin system is involved in the mechanism of increased serum asymmetric dimethylarginine in essential hypertension

Endothelium-dependent/nitric oxide (NO)-mediated vasodilation is impaired in hypertensive individuals. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, is synthesized by many types of cells including vascular endothelial cells. The serum level of ADMA is elevated in patients with essential hypertension, but the mechanism for this increase is unknown. Therefore, the present study examined whether the renin-angiotensin system (RAS) is involved. Patients with essential hypertension [systolic blood pressure (BP) > 160 mmHg and/or diastolic BP > 95 mmHg] were randomized to an angiotensin-converting enzyme (ACE) inhibitor treatment group (perindopril, 4mg/day for 4 weeks, n = 7), an angiotensin II type 1 (AT1) receptor antagonist treatment group (losartan, 50 mg/day for 4 weeks, n = 7) or a beta-blocker treatment group (bisoprolol, 5 mg/day for 4 weeks, n = 7). Before and after the treatment, BP, serum concentration of ADMA and plasma concentration of von Willebrand factor (vWF, a biological marker of endothelial injury) were measured. Perindopril, losartan and bisoprolol decreased BP to a similar extent, and either perindopril or losartan, but not bisoprolol, significantly decreased serum ADMA and plasma vWF. These findings suggest that the RAS may contribute to the mechanism of increased serum ADMA as well as to the endothelial injury observed in hypertensive patients. The vasculoprotective actions of ACE inhibitors or AT1 receptor antagonists may be explained at least in part by amelioration of the endothelial injury through a decrease in the serum ADMA concentration.

Role of nitric oxide in regulation of coronary blood flow in response to increased metabolic demand in dogs with pacing-induced heart failure

The role of endothelium-derived nitric oxide (NO) in the metabolic control of coronary blood flow (CBF) in heart failure (HF) is poorly understood, so the present study investigated the effects of inhibitors of NO synthesis on the response of CBF to changes in myocardial oxygen consumption (MVO2) in dogs with HF produced by rapid ventricular pacing and in control dogs. The CBF, MVO2, and other hemodynamic parameters were measured in anesthetized animals. Before infusion of Nomega-nitro-L-arginine methyl ester (L-NAME), the increases in CBF and MVO2 during pacing tachycardia were not significantly different between the control and HF dogs. Intracoronary infusion of L-NAME did not alter the responses of CBF or MVO2 to pacing tachycardia in the control dogs, but in the HF dogs, it reduced the CBF response to pacing tachycardia without altering the tachycardia-induced changes in MVO2. Intracoronary infusion of L-arginine reversed the effect of L-NAME. These results suggest that in HF dogs NO contributes to the regulation of CBF in response to an increased metabolic demand.

Antiinflammatory and antiarteriosclerotic actions of HMG-CoA reductase inhibitors in a rat model of chronic inhibition of nitric oxide synthesis

Recent studies suggest that some of the beneficial effects of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may be due to their cholesterol-lowering independent effects on the blood vessels. Chronic inhibition of endothelial nitric oxide (NO) synthesis by oral administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) to rats induces early vascular inflammation as well as subsequent arteriosclerosis. The aim of the study is to test whether treatment with statins attenuates such arteriosclerotic changes through their cholesterol-lowering independent effects. We investigated the effect of statins (pravastatin and cerivastatin) on the arteriosclerotic changes in the rat model. We found that treatment with statins did not affect serum lipid levels but markedly inhibited the L-NAME-induced vascular inflammation and arteriosclerosis. Treatment with statins augmented endothelial NO synthase activity in L-NAME-treated rats. We also found the L-NAME induced increase in Rho membrane translocation in hearts and its prevention by statins. Such vasculoprotective effects of statins were suppressed by the higher dose of L-NAME. In summary, in this study, we found that statins such as pravastatin and cerivastatin inhibited vascular inflammation and arteriosclerosis through their lipid-lowering independent actions in this model. Such antiarteriosclerotic effects may involve the increase in endothelial NO synthase activity and the inhibition of Rho activity.

Alpha1-adrenoceptor-Gq-RhoA signaling is upregulated to increase myofibrillar Ca2+ sensitivity in failing hearts

Alpha1-adrenergic stimulation, coupled to Gq, has been shown to promote heart failure. However, the role of alpha1-adrenergic signaling in the regulation of myocardial contractility in failing myocardium is still poorly understood. To investigate this, we observed 1) the effect of phenylephrine on myofibrillar Ca2+ sensitivity in alpha-toxin-skinned cardiomyocytes, and 2) protein expression of Gq, RhoA, and myosin light chain phosphorylation using tachypacing-induced canine failing hearts. Phenylephrine significantly increased myofibrillar Ca2+ sensitivity in failing but not in normal cardiomyocytes. Whereas Y-27632 (Rho kinase inhibitor) blocked the phenylephrine-induced Ca2+ sensitization in the failing myocytes, calphostin C (protein kinase C inhibitor) had no effect on Ca2+ sensitization. The protein expression of Galpha(q) and RhoA and the phosphorylation level of regulatory myosin light chain significantly increased in the failing myocardium. Our results suggest that alpha1-adrenoceptor-Gq signaling is upregulated in the failing myocardium to increase the myofibrillar Ca2+ sensitivity mainly through the RhoA-Rho kinase pathway rather than through the protein kinase C pathway.

Cerivastatin, a hydroxymethylglutaryl coenzyme a reductase inhibitor, improves endothelial function in elderly diabetic patients within 3 days

BACKGROUND

The short-term effects of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) on endothelial function at doses that do not affect plasma lipid levels are not known.

METHODS AND RESULTS

We investigated the short-term effects of cerivastatin, a hydroxymethylglutaryl coenzyme A reductase inhibitor, on endothelial function and endothelium-related products in elderly diabetic patients. Twenty-seven elderly diabetic patients (aged 69.3+/-3.4 years), with or without mild hypercholesterolemia, were enrolled in this study, which tested cerivastatin treatment (0.15 mg/d) for 3 days. Endothelium-dependent flow-mediated dilatation, endothelium-independent dilatation by nitroglycerin in the brachial artery, nitric oxide-related products (nitrite/nitrate and cGMP), endothelium-related products (von Willebrand Factor, soluble vascular cell adhesion molecule-1, and soluble intercellular adhesion molecule-1), and a marker of oxidant stress (8-isoprostane) were assessed. Levels of plasma lipids were not changed before and after treatment with cerivastatin. Flow-mediated dilatation was significantly increased by cerivastatin treatment, as were plasma nitrite/nitrate levels (from 16.9+/-3.4 to 22.0+/-3.7 micromol/L, P<0.05) and cGMP values. The percent of nitroglycerin-induced dilatation was not changed. Plasma concentrations of 8-isoprostane decreased, and levels of soluble vascular cell adhesion molecule also tended to decrease with cerivastatin.

CONCLUSIONS

Improvement of endothelial function was in line with antiatherosclerotic effects. Cerivastatin improved impaired endothelial function in the short-term without affecting lipid profiles in elderly diabetic patients. This effect may be partly due to upregulation of endothelial nitric oxide synthase.

Rho-kinase mediates angiotensin II-induced monocyte chemoattractant protein-1 expression in rat vascular smooth muscle cells

Recently, it was shown that Rho-kinase plays an important role in blood pressure regulation. However, it is not known whether Rho-kinase is involved in atherogenesis. Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine that regulates monocyte recruitment and atherogenesis. Therefore, we examined the role of Rho and Rho-kinase in the angiotensin (Ang) II-induced expression of MCP-1. Ang II dose- and time-dependently enhanced the expression of MCP-1 mRNA and the protein production in vascular smooth muscle cells. CV11974, an Ang II type 1 receptor (AT(1)-R) specific antagonist inhibited the enhancement of MCP-1 expression by Ang II, suggesting that the effect of Ang II is mediated by the AT(1)-R. Botulinum C3 exotoxin, a specific inhibitor of Rho, suppressed Ang II-induced MCP-1 production. To examine the role of Rho-kinase in Ang II-induced MCP-1 expression, we used adenovirus-mediated overexpression of the dominant negative mutant of Rho-kinase (AdDNRhoK) or Y-27632, a specific inhibitor of Rho-kinase. Both AdDNRhoK and Y-27632 strongly inhibited Ang II-induced MCP-1 expression. Although inhibition of extracellular signal-regulated protein kinase (ERK) by PD 098,059 also inhibited Ang II-induced MCP-1 expression, Y-27632 did not affect Ang II-induced activation of ERK. These results indicate that Rho-kinase plays a critical role in Ang II-induced MCP-1 production independent of ERK. The Rho-Rho-kinase pathway may be a novel target for the inhibition of Ang II signaling and the treatment of atherosclerosis.

Regression by ACE inhibition of arteriosclerotic changes induced by chronic blockade of NO synthesis in rats

We previously reported that chronic inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME) induces vascular inflammation at week 1 and produces subsequent arteriosclerosis at week 4 and that cotreatment with an angiotensin-converting enzyme (ACE) inhibitor prevents such changes. In the present study, we tested the hypothesis that treatment with an ACE inhibitor after development of vascular inflammation could inhibit arteriosclerosis in rats. Wistar-Kyoto rats were randomized to four groups: the control group received no drugs, the 4wL-NAME group received L-NAME (100 mg x kg(-1) x day(-1)) for 4 wk, the 1wL + 3wNT group received L-NAME for 1 wk and no treatment for the subsequent 3 wk, and the 1wL + 3wACEI group received L-NAME for 1 wk and the ACE inhibitor imidapril (20 mg x kg(-1) x day(-1)) for the subsequent 3 wk. After 4 wk, we observed significant arteriosclerosis of the coronary artery (medial thickening and fibrosis) and increased cardiac ACE activity in the 1wL + 3wNT group as well as in the 4wL-NAME group, but not in the 1wL + 3wACEI group. In a separate study, we examined apoptosis formation and found that posttreatment with imidapril (20 mg x kg(-1) x day(-1)) or an ANG II AT1-receptor antagonist, CS-866 (5 mg x kg(-1) x day(-1)), induced apoptosis (TdT-mediated nick end-labeling) in monocytes and myofibroblasts appearing in the inflammatory lesions associated with a clear degradation in the heart (DNA electrophoresis). In conclusion, treatment with the ACE inhibitor after 1 wk of L-NAME administration inhibited arteriosclerosis by inducing apoptosis in the cells with inflammatory lesions in this study, suggesting that increased ANG II activity inhibited apoptosis of the cells with inflammatory lesions and thus contributed to the development of arteriosclerosis.

New anti-monocyte chemoattractant protein-1 gene therapy attenuates atherosclerosis in apolipoprotein E-knockout mice

BACKGROUND

Monocyte recruitment into the arterial wall and its activation may be the central event in atherogenesis. Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine for monocyte recruitment, and its receptor (CCR2) may mediate such in vivo response. Although the importance of the MCP-1/CCR2 pathway in atherogenesis has been clarified, it remains unanswered whether postnatal blockade of the MCP-1 signals could be a unique site-specific gene therapy.

METHODS AND RESULTS

We devised a new strategy for anti-MCP-1 gene therapy to treat atherosclerosis by transfecting an N-terminal deletion mutant of the human MCP-1 gene into a remote organ (skeletal muscle) in apolipoprotein E-knockout mice. This strategy effectively blocked MCP-1 activity and inhibited the formation of atherosclerotic lesions but had no effect on serum lipid concentrations. Furthermore, this strategy increased the lesional extracellular matrix content.

CONCLUSIONS

We conclude that this anti-MCP-1 gene therapy may serve not only to reduce atherogenesis but also to stabilize vulnerable atheromatous plaques. This strategy may be a useful and feasible form of gene therapy against atherosclerosis in humans.