Pan-tumour analysis of COX-2 expression in dogs

Cyclooxgenase-2 (COX-2) is associated with inflammatory microenvironment and tumour progression. COX-2 expression was reported in canine tumours, and anti-COX treatment showed therapeutic effects in selected tumour types. Currently, direct comparisons between different tumour types or reports were impossible due to varying evaluation protocols. Additionally, COX-2 expression in relatively uncommon tumours were yet to be evaluated. Here, we analysed COX-2 expression across various tumour types in dogs in a consistent protocol, aiming to revisit accumulated evidence in the field and report novel candidate tumours for anti-COX therapy. COX-2 expression in 32 histological types of tumours, which consisted of 347 samples in total, was investigated using immunohistochemistry followed by the Belshaw's method scoring (range: 0-12). More than the half of the samples expressed COX-2 in mast cell tumours, transitional cell carcinoma in the urinary tract, squamous cell carcinoma, liposarcoma, and melanoma, with COX-2 median scores ranging from 1-8. On the other hand, <20% tissues expressed COX-2 in the half of tumour types investigated. Overall COX-2 positive rate was 27%. In conclusion, the results confirmed COX-2 expression in the well-known COX-2-expresing tumour types and suggested novel candidate tumours for anti-COX-2 therapy. At the same time, overall COX-2 expression was low, and inter- and intra-histology heterogeneity was apparent. This study will provide a foundation reference for future research in canine tumours.

Tumor cell-derived spermidine is an oncometabolite that suppresses TCR clustering for intratumoral CD8+ T cell activation

The activation and expansion of T cells that recognize cancer cells is an essential aspect to antitumor immunity. Tumors may escape destruction by the immune system through ectopic expression of inhibitory immune ligands typically exemplified by the PD-L1/PD-1 pathway. Here, we reveal another facet of tumor evasion from T cell surveillance. By secretome profiling of necrotic tumor cells, we identified an oncometabolite spermidine as a unique inhibitor of T cell receptor (TCR) signaling. Mechanistically, spermidine causes the downregulation of the plasma membrane cholesterol levels, resulting in the suppression of TCR clustering. Using syngeneic mouse models, we show that spermidine is abundantly detected in the tumor immune microenvironment (TIME) and that administration of the polyamine synthesis inhibitor effectively enhanced CD8+ T cell-dependent antitumor responses. Further, the combination of the polyamine synthesis inhibitor with anti-PD-1 immune checkpoint antibody resulted in a much stronger antitumor immune response. This study reveals an aspect of immunosuppressive TIME, wherein spermidine functions as a metabolic T cell checkpoint that may offer a unique approach for promoting tumor immunotherapy.

Potential of HMGB-inhibitory oligodeoxynucleotide ISM ODN to neutrophil recruitment in mouse model of hepatitis

High-mobility group box 1 (HMGB1) is a nucleotide-binding chromatin protein that has also been characterized as a prototypical damage-associate molecular pattern. It triggers inflammatory responses upon release from damaged or dying cells. In fact, HMGB1 has been linked to the induction of many inflammatory diseases through immune cell activation including neutrophil recruitment. In this study, we examined the impact of HMGB1-binding inhibitory oligodeoxynucleotide (ISM ODN) on the development of hepatitis using a murine model of the disease. Our results indicate that ISM ODN effectively suppresses pathological features of hepatitis, including neutrophil accumulation. This study therefore may offer clinical insight into the treatment of hepatitis and possibly other inflammatory diseases.

Anti-CCR4 treatment depletes regulatory T cells and leads to clinical activity in a canine model of advanced prostate cancer

Background

Targeting regulatory T cell (Treg) infiltration is an emerging strategy for cancer immunotherapy. However, its efficacy in advanced prostate cancer remains unclear. Here, we showed the therapeutic efficacy of anti-Treg treatment in a canine model of advanced prostate cancer.

Methods

We used dogs with naturally occurring prostate cancer to study the molecular mechanism underlying Treg infiltration and the effect of anti-Treg treatment. Tumor-infiltrating Tregs was evaluated by immunohistochemistry, and the association with prognosis was examined in dogs with spontaneous prostate cancer. The molecular mechanism of Treg infiltration was explored by RNA sequencing and protein analyses. A non-randomized canine clinical trial was conducted to define the therapeutic potential of anti-Treg treatment for advanced prostate cancer. Human prostate cancer datasets were analyzed to compare gene expression in dogs and humans.

Results

Tumor-infiltrating Tregs were associated with poor prognosis in dogs bearing spontaneous prostate cancer. RNA sequencing and protein analyses showed a possible link between the CCL17–CCR4 pathway and the increase of tumor-infiltrating Tregs. Dogs with advanced prostate cancer responded to mogamulizumab, a monoclonal antibody targeting CCR4, with decreased circulating Tregs, improved survival, and low incidence of clinically relevant adverse events. Urinary CCL17 concentration and BRAF^V595E mutation were independently predictive of the response to mogamulizumab. Analysis of a transcriptomic dataset of human prostate cancer showed that the CCL17–CCR4 axis correlated with Foxp3. In silico survival analyses revealed that high expression of CCL17 was associated with poor prognosis. Immunohistochemistry confirmed that tumor-infiltrating Tregs expressed CCR4 in human patients with prostate cancer.

Conclusions

Anti-Treg treatment, through CCR4 blockade, may be a promising therapeutic approach for advanced prostate cancer in dogs and some population of human patients.

Expression of podoplanin in various types of feline tumor tissues

Podoplanin is expressed in various human tumors where it promotes tumor progression, epithelial-mesenchymal transition, and distant metastasis. Podoplanin is also expressed in cancer-associated fibroblasts and induces tumor malignancy. The objective of this study was to evaluate podoplanin expression in various types of feline tumor tissues. Immunohistochemical analysis revealed that podoplanin was expressed in cells of 13/15 (87%) squamous cell carcinomas and 5/19 (26%) fibrosarcomas. Moreover, cancer-associated fibroblasts expressed podoplanin in most tumor types, including 18/21 (86%) mammary adenocarcinoma tissues. Our findings demonstrate that various types of feline tumor tissues expressed podoplanin, indicating the importance of the comparative aspects of podoplanin expression, which may be used as a novel research model for podoplanin biology.

Detection of indoleamine 2,3-dioxygenase 1-expressing cells in canine normal and tumor tissues

Cancer immunotherapy is a novel cancer treatment for canine tumors. Indoleamine 2,3-dioxygenase 1 (IDO1) is overexpressed in some human tumors and inhibits antitumor immunity. In this study, we comprehensively evaluated expression pattern of IDO1 and the nature of IDO1-expressing cells in canine normal and tumor tissues. In normal tissue samples, IDO1 expression was detected only in the lymph nodes, spleen, tonsil tissues, and colon tissues. In contrast, IDO1-positive tumor cells were observed in several tumor tissue types. This is the first study to evaluate IDO1 expression in canine normal and tumor tissues, and the results suggest that IDO1 is a promising target for novel cancer immunotherapy in dogs with tumors.

The impact of damage-associated molecules released from canine tumor cells on gene expression in macrophages

Dying or damaged cells that are not completely eradicated by the immune system release their intracellular components in the extracellular space. Aberrant exposure of the damage-associated molecules to the immune system is often associated with inflammation and cancer pathogenesis. Thus, elucidating the role of damage-associated molecules in inducing sterile immune responses is crucial. In this study, we show that prostaglandin E2 (PGE2) is produced in the supernatants from several types of canine necrotic tumor cell lines. Inhibition of PGE2 production by indomethacin, a potent inhibitor of cyclooxygenase (COX) enzymes, induces the expression of tumor necrosis factor (Tnf) mRNA in the necrotic tumor cell supernatants. These results comply with the previous observations reported in mouse cell lines. Furthermore, comprehensive ribonucleic acid-sequencing (RNA-seq) analysis revealed that three categories of genes were induced by the damage-associated molecules: (i) a group of PGE2-inducible genes, (ii) genes that promote inflammation and are suppressed by PGE2, and (iii) a group of genes not suppressed by PGE2. Collectively, our findings reveal the hitherto unknown immune regulatory system by PGE2 and damage-associated molecules, which may have clinical implications in inflammation and cancer.

Phase I/II Clinical Trial of the Anti-Podoplanin Monoclonal Antibody Therapy in Dogs with Malignant Melanoma

Podoplanin (PDPN), a small transmembrane mucin-like glycoprotein, is ectopically expressed on tumor cells. PDPN is known to be linked with several aspects of tumor malignancies in certain types of human and canine tumors. Therefore, it is considered to be a novel therapeutic target. Monoclonal antibodies targeting PDPN expressed in human tumor cells showed obvious anti-tumor effects in preclinical studies using mouse models. Previously, we generated a cancer-specific mouse-dog chimeric anti-PDPN antibody, P38Bf, which specifically recognizes PDPN expressed in canine tumor cells. In this study, we investigated the safety and anti-tumor effects of P38Bf in preclinical and clinical trials. P38Bf showed dose-dependent antibody-dependent cellular cytotoxicity against canine malignant melanoma cells. In a preclinical trial with one healthy dog, P38Bf administration did not induce adverse effects over approximately 2 months. In phase I/II clinical trials of three dogs with malignant melanoma, one dog vomited, and all dogs had increased serum levels of C-reactive protein, although all adverse effects were grade 1 or 2. Severe adverse effects leading to withdrawal of the clinical trial were not observed. Furthermore, one dog had stable disease with P38Bf injections. This is the first reported clinical trial of anti-PDPN antibody therapy using spontaneously occurring canine tumor models.

BRAFV595E Mutation Associates CCL17 Expression and Regulatory T Cell Recruitment in Urothelial Carcinoma of Dogs

Regulatory T cells may serve as targets in cancer immunotherapy. A previous study showed that the chemokine CCL17 and the receptor CCR4 play roles in regulatory T cell recruitment in canine urothelial carcinoma. In this article, we show that the BRAF^V595E mutation is associated with tumor-produced CCL17 and regulatory T cell infiltration in dogs with urothelial carcinoma. In comparison with healthy dogs, dogs with urothelial carcinoma showed increased CCL17 mRNA expression in the bladder and elevated CCL17 protein concentration in urine. Immunohistochemistry showed increased levels of Foxp3⁺ regulatory T cells in the tumor tissues of urothelial carcinoma. The density of Foxp3⁺ regulatory T cells was positively correlated with CCL17 concentration in urine, indicating that CCL17 is involved in regulatory T cell recruitment. Moreover, tumor-infiltrating regulatory T cells and urine CCL17 concentration were associated with poor prognosis in dogs with urothelial carcinoma. The number of tumor-infiltrating regulatory T cells, CCL17 mRNA expression, and urine CCL17 concentration in cases with BRAF^V595E mutation were higher than those in cases with wild-type BRAF. In vitro, high CCL17 production was detected in a canine urothelial carcinoma cell line with BRAF^V595E mutation but not in an urothelial carcinoma cell line with wild-type BRAF. Dabrafenib, a BRAF inhibitor, decreased CCL17 production in the cell line with BRAF^V595E mutation. These results suggest that BRAF^V595E mutation induced CCL17 production and contributed to regulatory T cell recruitment in canine urothelial carcinoma.

Evaluation of epithelial and mesenchymal cell markers in canine urinary bladder transitional cell carcinoma

Canine transitional cell carcinoma (cTCC) is the most common malignant tumour in the urinary bladder: it is highly invasive and exhibits metastatic characteristics. Inflammation is also strongly related to cTCC. Epithelial tumours often exhibit a mesenchymal cell phenotype during tumour invasion and metastasis owing to epithelial-mesenchymal transition (EMT), which is often induced in chronic inflammation. The aim of this retrospective study was to investigate the expression of epithelial and mesenchymal cell markers in tumour cells and to evaluate its relationship with prognosis of cTCC. In this study, 29 dogs with cTCC who underwent surgical treatment were enrolled. Clinical parameters were reviewed using medical records. Tissue expression of epithelial and mesenchymal markers was evaluated by immunohistochemical analysis. The association between the expression of mesenchymal cell markers and clinical parameters, including prognosis, was statistically examined. In five normal bladder tissues used as controls, no expression of mesenchymal markers was observed, except for one tissue that expressed fibronectin. Conversely, epithelial tumour cells expressed vimentin and fibronectin in 23/29 and 19/28 cTCC tissues, respectively. Regarding clinical parameters, vimentin score in Miniature Dachshunds was significantly higher than those in other dog breeds (P < 0.001). Multivariate survival analyses revealed that age>12 years was related to shorter progression-free survival (P = 0.02). Higher vimentin score, lower fibronectin score, and advanced clinical T stage were significantly correlated with shorter median survival time (P < 0.05). The results of this study indicate that vimentin expression was associated with cTCC progression. Further studies are needed to examine the incidence and relevance of EMT in cTCC.

Effect of aluminium ion on bioavailability of levofloxacin following oral administration of cilexetil ester of levofloxacin as prodrug in rats

A prodrug of levofloxacin (LVFX), cilexetil ester of LVFX (LVFX-CLX), was synthesized to examine whether the prodrug can avoid chelate formation with metal cations in the gastrointestinal tract. LVFX-CLX exhibited a 10-times higher partition coefficient than LVFX. In vitro, LVFX was precipitated by 76.1% in the presence of a 10-times higher concentration of aluminium chloride (Al³⁺), but LVFX-CLX was not. LVFX-CLX was rapidly hydrolyzed enzymatically by rat plasma, intestinal mucosal and liver homogenates at 37 °C, but not by pancreatic enzymes and luminal fluid. The minimum inhibitory concentration values of LVFX-CLX against S. aureus, E. coli and P. aeruginosa were far higher than that of LVFX. In rats, area under the plasma concentration-time curve from zero to 4 h (AUC_0-4h) of LVFX after oral administration of LVFX-CLX was 1.34-fold higher than that after LVFX, though it did not reach significance level. Co-administration of Al³⁺ with LVFX and LVFX-CLX in rats decreased AUC_0-4h of plasma LVFX by 75% and 60%, respectively, however, the AUC_0-4h of plasma LVFX after co-administration of LVFX-CLX and Al³⁺ was 2.2-times higher than that after co-administration of LVFX and Al³⁺. These results suggested that the use of LVFX-CLX may reduce the modulation of intestinal microflora caused by LVFX and the suppressive effect of Al³⁺ on intestinal absorption of LVFX.

Acute Deterioration of Kidney Function after Total Hip Arthroplasty

Introduction:

Post-operative acute kidney injury is a serious complication and identifying modifiable factors could assist in peri-operative management. This study aimed to identify the pre-operative and intra-operative factors associated with the incidence of post-operative acute kidney injury and acute deterioration of kidney function after total hip arthroplasty.

Materials and methods: This single-center, retrospective, observational study included 203 patients who underwent unilateral primary total hip arthroplasty. Acute kidney injury was determined using biochemical markers according to the risk, injury, failure, loss of kidney function, and end-stage kidney disease (RIFLE) criteria. Acute deterioration of kidney function was defined as the reduction of estimated glomerular filtration rate by ≥10ml/min/1.73m².

Results:

Prior to total hip arthroplasty, 20% of all patients met the chronic renal dysfunction criterion of glomerular filtration rates <60ml/min/1.73m² (glomerular filtration rate categories G3a-G5). Incidence rates of acute kidney injury and acute deterioration of kidney function after total hip arthroplasty were 0.49% and 6.9%, respectively. Multivariate regression analysis showed that diabetes mellitus and use of nonsteroidal anti-inflammatory drugs before total hip arthroplasty were significant risk factors for acute deterioration of kidney function. Advanced age, preoperative renal dysfunction, antihypertensive, diuretics, or statin use, operation time, total blood loss, type of anesthetic, and body mass index were not significant risk factors.

Conclusion:

Diabetes mellitus and use of nonsteroidal anti-inflammatory drugs were controllable risks, and multidisciplinary approaches are a reasonable means of minimising peri-operative acute kidney injury or acute deterioration of kidney function.

Aberrant expression of the COX2/PGE2 axis is induced by activation of the RAF/MEK/ERK pathway in BRAFV595E canine urothelial carcinoma

Cancer-promoting inflammation is an important event in cancer development. Canine urothelial carcinoma (cUC) overexpresses prostaglandin E2 (PGE2) and has a unique sensitivity to cyclooxygenase 2 (COX2)-inhibiting therapy. In addition, majority of cUC harbour BRAFV595E mutation. However, mechanisms underlying aberrant PGE2 production in BRAFV595E cUC patients remain unclear. Drug screening revealed that inhibition of RAF/MEK/ERK pathway, p38 and JNK pathway reduced PGE2 production in cUC cells. By pharmacological inhibition of the multiple components in the pathway, activation of the ERK MAPK pathway was shown to mediate overexpression of COX2 and production of PGE2 in BRAFV595E cUC cells. In silico gain-of-function analysis of the BRAF mutation also implicated involvement of mutation in the process. The positive association between ERK activation and COX2 expression was further validated in the clinical patients. Moreover, it was also suggested that p38 and JNK regulates PGE2 production independently of ERK pathway, possibly through COX2-dependent and COX1-/COX2- independent manner, respectively. In conclusion, this study demonstrated that activation of ERK induces production of PGE2 in BRAFV595E cUC cells, which is also independently regulated by p38 and JNK. With its unique vulnerability to COX-targeted therapy, BRAFV595E cUC may serve as a valuable model to study the tumour-promoting inflammation.

Overexpression of human epidermal growth factor receptor 2 in canine primary lung cancer

Human epidermal growth factor receptor 2 (HER2) overexpression has been reported in various human cancers. HER2-targeted therapies showed clinical responses in humans with HER2-positive tumors. The incidence of canine primary lung cancer (cPLC) is increasing, but there are no effective systemic therapies for dogs with late-stage cPLC. HER2-targeted therapy could be an option for cPLC, but HER2 expression in cPLC remains unknown. We evaluated HER2 expression in cPLC. Immunohistochemical analysis revealed that 3 samples (19%) scored 3+; 8 (50%), 2+; 5 (31%); and 1+ and 0 (0%), 0. Of the cPLC tissues, 69% were HER2 positive (scored ≥2+). These data would lead to further evaluation of the role of HER2 in cPLC as a mechanism of malignancy and therapeutic target.

Immunohistochemical evaluation of HER2 expression in canine thyroid carcinoma

The human epidermal growth factor receptor 2 (HER2) is expressed in various human cancers including thyroid cancers (TC) and is used as a diagnostic marker and therapeutic target. Canine TC (cTC), the most common endocrine malignancy in dogs, shows a high metastasis rate, and HER2-targeted therapy could be a candidate for treatment. Here, we immunohistochemically evaluated HER2 expression in 21 paraffin-embedded cTC tissues and scored the degree of expression based on intensity and positivity (score: 0–3+). Four samples (19%) scored 3+; 6 (29%), 2+; 7 (33%), 1+; and 4 (19%), 0. Therefore, 48% of the cTC tissues were HER2 positive (scored ≥2+). These data may lead to further evaluation of the role of HER2 in cTC as a mechanism of malignancy and a therapeutic target.

Detection of human epidermal growth factor receptor 2 overexpression in canine anal sac gland carcinoma

Canine anal sac gland carcinoma (ASGC) frequently occurs in the apocrine glands of the canine anal sac and shows aggressive biological behavior. The expression of human epidermal growth factor receptor 2 (HER2) has been reported in various human and canine tumors. HER2 is a promising therapeutic target of these tumors, and HER2-targeted drugs, such as trastuzumab and lapatinib, have improved the outcome of these patients. In this study, HER2 expression in ASGC was evaluated to investigate its potential as a therapeutic target for canine ASGC. HER2 mRNA expression in surgically resected ASGC tissues was significantly higher than that in normal anal sac tissue. To evaluate the expression of HER2 protein, paraffin-embedded ASGC tissues were immunohistochemically evaluated. Strong and broad staining of HER2 was detected in ASGC tissues, while HER2 was weakly to moderately stained in normal anal sac apocrine glands and squamous epithelia. The degree of HER2 expression in ASGC tissues was scored based on its intensity and positivity (score: 0-3+). Scoring of HER2 expression revealed 6 samples (24%) scored 3+, 14 (56%) scored 2+, and 5 (20%) scored 1+, with no samples scoring 0. In all, 80% of canine ASGC tissues were positive for HER2 (scored ≥2+). Furthermore, putative HER2-overexpressed cells in ASGC were detected with trastuzumab by flow cytometry. These preliminary data may lead to further evaluation of the role of HER2 in canine ASGC as a mechanism of malignancy and as a therapeutic target for HER2-targeted therapy.

Aldehyde dehydrogenase activity helps identify a subpopulation of murine adipose-derived stem cells with enhanced adipogenic and osteogenic differentiation potential

AIM

To identify and characterize functionally distinct subpopulation of adipose-derived stem cells (ADSCs).

METHODS

ADSCs cultured from mouse subcutaneous adipose tissue were sorted fluorescence-activated cell sorter based on aldehyde dehydrogenase (ALDH) activity, a widely used stem cell marker. Differentiation potentials were analyzed by utilizing immunocytofluorescece and its quantitative analysis.

RESULTS

Approximately 15% of bulk ADSCs showed high ALDH activity in flow cytometric analysis. Although significant difference was not seen in proliferation capacity, the adipogenic and osteogenic differentiation capacity was higher in ALDH^Hi subpopulations than in ALDH^Lo. Gene set enrichment analysis revealed that ribosome-related gene sets were enriched in the ALDH^Hi subpopulation.

CONCLUSION

High ALDH activity is a useful marker for identifying functionally different subpopulations in murine ADSCs. Additionally, we suggested the importance of ribosome for differentiation of ADSCs by gene set enrichment analysis.

Aldehyde dehydrogenase activity identifies a subpopulation of canine adipose-derived stem cells with higher differentiation potential

Adipose-derived stem cells (ADSCs) are abundant and readily obtained, and have been studied for their clinical applicability in regenerative medicine. Some surface antigens have been identified as markers of different ADSC subpopulations in mice and humans. However, it is unclear whether functionally distinct subpopulations exist in dogs. To address this issue, we evaluated aldehyde dehydrogenase (ALDH) activity—a widely used stem cell marker in mice and humans—by flow cytometry. Approximately 20% of bulk ADSCs showed high ALDH activity. Compared to cells with low activity (ALDH^Lo), the high-activity (ALDH^Hi) subpopulation exhibited a higher capacity for adipogenic and osteogenic differentiation. This is the first report of distinct ADSC subpopulations in dogs that differ in terms of adipogenic and osteogenic differentiation potential.

Craniocervical junction abnormalities with atlantoaxial subluxation caused by ventral subluxation of C2 in a dog

Craniocervical junction abnormalities with atlantoaxial subluxation caused by ventral subluxation of C2 were diagnosed in a 6-month-old female Pomeranian with tetraplegia as a clinical sign. Lateral survey radiography of the neck with flexion revealed atlantoaxial subluxation with ventral subluxation of C2. Computed tomography revealed absence of dens and atlanto-occipital overlapping. Magnetic resonance imaging showed compression of the spinal cord and indentation of caudal cerebellum. The diagnosis was Chiari-like malformation, atlantoaxial subluxation with ventral displacement of C2, atlanto-occipital overlapping, and syringomyelia. The dog underwent foramen magnum decompression, dorsal laminectomy of C1, and ventral fixation of the atlantoaxial joint. Soon after the operation, voluntary movements of the legs were recovered. Finally, the dog could stand and walk without assistance. The dog had complicated malformations at the craniocervical junction but foramen magnum decompression and dorsal laminectomy for Chiari-like malformation, and ventral fixation for atlantoaxial subluxation resulted in an excellent clinical outcome.

Additive combination of actarit and methotrexate in the treatment of refractory rheumatoid arthritis

Abstract The objective of this study was to evaluate the efficacy and safety of an additive combination of a disease-modifying antirheumatic drug (DMARD) actarit and low-dose methotrexate (MTX) in patients with active rheumatoid arthritis (RA) unresponsive to MTX. Thirty-four patients with active RA, who had been unsuccessfully treated with MTX for at least 3 months were enrolled on a 24-week course of actarit (300 mg/day) and MTX (2.5-10 mg/week). Disease activity was evaluated by physical global assessments using conventional measures (Japan Rheumatism Association), and the American College of Rheumatology (ACR) criteria of improvements in RA. Thirty-two patients completed this study. No severe adverse drug reactions were seen. Patients whose RA did not respond to MTX alone responded to the combination therapy, with a significant improvement in the duration of morning stiffness, grip strength, swollen joint counts, patient's articular pain score, modified health assessment questionnaire (M-HAQ) score, score of both patient's and physician's global assessments, and C-reactive proteins (CRP). Sixteen patients (50.0%) and 9 patients (31.0%) showed a significant improvement in overall conventional measures, and ACR response criteria, respectively, and 60.0% of RA patients who received MTX for more than 1 year showed improvement in ACR definition. Patients who responded to the combination treatment within the first 12 weeks showed persistent improvement for the remaining part of the 24 week period. Our results indicate that the additive combination of actarit and MTX is safe, and without serious adverse effects, and has an excellent efficacy in patients with active and refractory RA.

Quenching electron runaway in positive high-voltage-impulse discharges in air by laser filaments

Strong hard (ε>100 keV) x rays being observed from impulse atmospheric discharges with maximal voltages from U=0.5 to 0.9 MV just before the breakdown were completely stopped with the use of femtosecond-laser-filament plasma. Runaway electrons generating such x rays and being estimated to achieve their maximal energy, ε~U, near the positive electrode disappear if a laser filament plasma is ignited perpendicularly to the runaway near the positive electrode. A preheating mechanism for formation of the electron runaway in air is proposed.

Paraoxonase (Pon1) Q192R polymorphism and serum Pon1 activity in diabetic patients on maintenance hemodialysis

Patients with diabetic nephropathy have an increased risk of coronary heart disease (CHD). Paraoxonase (Pon1) is a high-density lipoprotein- (HDL) associated enzyme that protects low-density lipoprotein from oxidation and also protects against atherosclerosis. We investigated the relationship of serum Pon1 activity, Pon1 Q192R polymorphism and HDL-C level to type 2 diabetes mellitus (DM) in patients on maintenance hemodialysis (HD). DM patients (n = 56, F/M = 17/39, aged 64.5 +/- 7.5 years) and non-DM patients (n = 89, F/M = 28/61, aged 62.7 +/- 8.3 years) under HD were included in this study. Salt-stimulated serum Pon1 activities were measured using paraoxon as a substrate. Pon1 Q192R polymorphism was detected by the mutagenically separated polymerase chain reaction. DM patients on HD had significantly lower HDL-C levels and serum Pon1 activities than non-DM patients on HD (657 +/- 277 vs. 763 +/- 257 IU/l, p < 0.01). The distribution of Pon1 Q 192R genotypes in all subjects did not differ from that predicted from the Hardy-Weinberg equilibrium. Serum Pon1 activities in both DM and non-DM patients on HD were regulated by Pon1 Q192R polymorphism: RR > QR > QQ. However, the reduced Pon1 activities in DM patients on HD were related to DM independent of the Pon1 genotype: reduced Pon1 activity was related to DM in RR carriers. Serum Pon1 activities were positively correlated with HDL-C levels. The association between HDL-C and DM in hemodialyzed patients was independent of Pon1 activity as assessed by an analysis of variance. But the relation between Pon1 activity and DM was modified by HDL-C levels: significantly when HDL-C was below 50 mg/dl, but not significantly when HDL-C was above 50 mg/dl. The results of a logistic regression analysis show that reduced serum Pon1 activities and low HDL-C levels were additively associated with DM. In conclusion, Pon1 status and HDL levels are independently associated with DM in patients on hemodialysis and may contribute to the increased risk of CHD in diabetic nephropathy.

Regulation of glucose transporter 1 expression by gliclazide in rat L6 myoblasts

Sulphonylureas are known to enhance insulin secretion from the pancreas and its sensitivity of the extrapancreatic target organs. In this study, we clarified a direct extrapancreatic effect of the sulphonylureas and of gliclazide, on the glucose transport system in cultured rat L6 myoblasts, which predominantly expressed glucose transporter 1 (GLUT 1). Our results show that gliclazide stimulated 2-deoxy-[3H]-D-glucose (2DG) uptake, 24 h after treatment, in a dose-dependent manner, and it also increased GLUT 1 protein synthesis and mRNA expression; 2DG uptake and GLUT 1 protein synthesis induced by gliclazide were completely blocked by protein kinase A (PKA) inhibitors (H89 and rp-cAMP), and gliclazide increased the intracellular cAMP levels 3 to 24 hr after the treatment. These results show that in rat L6 myoblasts, gliclazide stimulates glucose transport activity by the induction of GLUT 1 gene expression through PKA.

Inhibition of neuronal nitric oxide synthase ameliorates renal hyperfiltration in streptozotocin-induced diabetic rat

Systemic inhibition of nitric oxide synthase (NOS) in streptozotocin-induced (STZ-induced) diabetic rats results in decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) and an increase in renal vascular resistance (RVR). However, the exact isoform of NOS involved in diabetic renal hyperfiltration has not been determined. This study was conducted to clarify whether NO derived from neuronal NOS is involved in diabetic renal hyperfiltration when using a selective inhibitor of neuronal NOS, 7-nitro indazole (7-NI). Continuous infusion of NG-nitro-L -arginine methyl ester (L-NAME) at 5 microg/kg/min ameliorated renal hyperfiltration, decreased RPF, and increased RVR in diabetic rats without affecting the mean arterial pressure (MAP). 7-NI administered intraperitoneally in diabetic rats significantly reduced GFR without affecting MAP, but the renal hyperfiltration was still observed after the administration of 7-NI. The combined administration of L-NAME after 7-NI caused a further decrease in GFR in diabetic rats and ultimately resulted in normalization of GFR. 7-NI did not change any parameters of renal hemodynamics in control rats. Urinary excretion of nitrite/nitrate and cyclic guanosine monophosphate was significantly increased in diabetic rats over values found in control rats. Our results suggested that a local inhibition of NO in the kidney was involved in the amelioration of diabetic renal hyperfiltration and that NO derived from neuronal NOS is involved, at least in part, in renal hyperfiltration in STZ-induced diabetic rats.

Enantioselective metabolism of propanolol in isolated hepatocytes prepared from untreated, PB- or 3-MC-pretreated rats

The present paper describes the metabolism of a chiral drug propranolol (PL) using isolated hepatocytes freshly prepared from untreated, PB- or 3-MC-pretreated rats. In order to examine not only the existence of enantioselectivity but also the effect of enzyme inducer (PB or 3-MC) on PL metabolism, 500 microM PL (RS-PL, R(+)-PL or S(-)-PL) was incubated at 37 degrees C using 8 x 10(6) cells/ml isolated rat hepatocytes. Then, the elimination amount of PL and the formation amounts of eight kinds of the metabolites including ring hydroxylated metabolites (4-OH-, 5-OH- and 7-OH-PL) and side chain metabolites (NDP, AcNDP, PGL, NLA and NAA) were simultaneously determined by HPLC. By 3-MC- and PB-pretreatment, a significant increase was noticed in PL elimination and also in the formation of PL metabolites, NDP, NLA and NAA. Furthermore, the presence of enantioselectivity was observed, i.e. the substrate R(+)-PL was always eliminated faster than the substrate S(-)-PL. Regarding the metabolite formation, NDP, AcNDP and NAA were dominantly produced from R(+)-PL, and NLA, PGL and the ring hydroxylated metabolites from S(-)-PL. In all cases of PL elimination and the metabolite formation, the amounts of the metabolites derived from RS-PL indicated the mean values of the respective amounts derived from R(+)-PL and S (-)-PL. Using the three kinds of isolated rat hepatocytes mentioned above, the kinetic parameters of NDP-formation at 37 degrees C for 10 min were calculated using RS-PL, R(+)-PL or S(-)-PL as a substrate. From the pseudo values of V'max/K'm (microliter/min.8 x 10(6) cells), the easiest formation of NDP from R(+)-PL was observed in the rat hepatocyte system pretreated with 3-MC.

Change of the host immune response during the early phase of interferon therapy correlates with its long-term efficacy for chronic hepatitis C

Host immunomodulation through T cell action may play a pivotal role in determining the response to interferon (IFN) therapy for chronic hepatitis C. We examined whether the early changes in the host immune response were helpful in predicting the final effect in 31 patients with chronic hepatitis C receiving IFN. IFN treatment significantly reduced the serum levels of intercellular adhesion molecule-1 (ICAM-1) and E-selectin, and significantly increased those of vascular cell adhesion molecule-1 (VCAM-1) and interleukin-2 receptor alpha (IL-2Ralpha) in the first 7-10 days. Serum levels of these immunological parameters did not correlate with serum alanine aminotransferase (ALT) when evaluated with either absolute values or relative values (over pre-treatment value), implying that our results are not just secondary to improvement in hepatic inflammation. The relative changes (Delta) in these parameters reflected the long-term response to IFN therapy, i.e. the lower the change, the more effective the therapy was. Among these serum parameters, DeltaIL-2Ralpha within the first 7-10 days of IFN treatment was the most useful parameter in predicting the response to therapy. In conclusion, a dynamic immunomodulation during the early phase of IFN therapy may determine the subsequent long-term response to IFN therapy.

Parathyroid hormone-related peptide producing cholangiocellular carcinoma with a marked psammoma formation

Humoral hypercalcemia caused by parathyroid hormone-related peptide (PTHrP), associated with cholangiocellular carcinoma (CCC), has rarely been documented. There have been no reports of CCC associated with extensive calcification of the tumor with psammoma body formation. A 66-year-old man was admitted with a large calcified tumor in the liver detected on an abdominal X-ray. An ultrasound-guided fine needle biopsy specimen of the liver tumor showed evidence of adenocarcinoma. He had hypercalcemia with an elevated PTHrP level. The patient died because of disseminated intravascular coagulation and progressive hepatic failure. A postmortem examination revealed a large poorly differentiated CCC in the liver. Immunohistochemical examination showed the presence of PTHrP-positive tumor cells. The calcified lesion consisted of a number of accumulated psammoma bodies. We present a case of PTHrP producing CCC with a marked psammoma formation.

Long-term oral intake of low-dose cadmium exacerbates age-related impairment of renal functional reserve in rats

Our study was designed to clarify whether renal functional reserve (RFR) was impaired in rats chronically treated with oral low-dose cadmium (Cd). Rats (n = 15) were treated with 1 ppm of cadmium chloride added to drinking water. We measured RFR (representing the ability to increase glomerular filtration rate [GFR] and renal plasma flow [RPF] in response to infusion of glycine) at 2 and 10 months after initiation of exposure to Cd. Urinary excretion of Cd was significantly higher in 10-month Cd-treated rats than in age-matched control rats (provided with distilled water only). Weight gain was noted in Cd-treated rats, which was identical to that in age-matched control rats. Urinary volume and urinary excretions of sodium, protein, and glucose were similar in the two groups. There were no differences in the basal mean arterial pressure (MAP) and renal hemodynamics between 2-month Cd-treated and age-matched control rats. Infusion of glycine resulted in significant increases in GFR and RPF and a significant reduction in renal vascular resistance (RVR) in both 2-month Cd-treated and age-matched control rats (control, GFR: 133 +/- 10%, RPF: 148 +/- 8%; 2-month Cd-treated rats, GFR: 152 +/- 12% and RPF: 154 +/- 7%). The basal MAP and renal hemodynamics in 10-month Cd-treated rats were also identical to those in age-matched control rats. Infusion of glycine significantly increased GFR in 10-month control rats (132 +/- 15%), but not in 10-month Cd-treated rats (98 +/- 11%), but did not change MAP, RPF, and RVR in both groups. In addition to age-related pathological changes, mild renal interstitial edema and degenerative mitochondria with diminished matrix density and loss of the cristae in the proximal tubular cells were more frequent in 10-month Cd-treated rats. Our results suggest that long-term oral intake of low-dose Cd in rats exacerbate age-related impairment of renal functional reserve and degeneration of the proximal tubular epithelial cells.

Delirious episodes induced by intravenous administration of clomipramine associated with an acute increase in its plasma concentrations

The aim of this paper is to describe two cases of clomipramine-induced delirium. One 61-year-old and one 67-year-old female depressive patients became delirious after beginning intravenous clomipramine injections in addition to their oral clomipramine administrations. Their plasma levels of both clomipramine and its metabolite, desmethylclomipramine, were acutely increased about twofold during delirium. The intravenous clomipramine administrations were discontinued. Their delirious state was gradually improved after stopping the intravenous clomipramine administrations. These findings suggest that acute increases of plasma levels of clomipramine and desmethylclomipramine after intravenous clomipramine injections might be related to the appearance of the delirious episodes.

Intercellular adhesion molecule 1 underlies the functional heterogeneity of synovial cells in patients with rheumatoid arthritis: involvement of cell cycle machinery

OBJECTIVE

To investigate whether synovial cells from rheumatoid arthritis (RA) synovium can be divided into 2 functionally different subpopulations: active or proliferative cells and apoptotic cells.

METHODS

Expression of cell surface and cytoplasmic molecules on synovial cells was assessed by immunohistochemistry, flow cytometry, or Western blotting. Cells were categorized as intercellular adhesion molecule 1 (ICAM-1) positive or negative based on positive and negative selection of antibody-coated beads. Cell cycle and apoptosis were assessed using propidium iodide staining, TUNEL method, and DNA fragmentation.

RESULTS

Expression of ICAM-1 and Fas was noted mainly in the synovial lining to sublining layer in vivo, and synovial cells could be clearly distinguished as ICAM-1 positive or negative. The expression of Fas was higher on ICAM-1-positive cells than on ICAM-1-negative cells in vitro. The functional and phenotypic heterogeneity between ICAM-1-positive and -negative cells was further emphasized by cell cycle machinery. The majority of ICAM-1-positive cells were arrested at the G0/G1 phase, whereas many of the ICAM-1-negative cells were at the S to G2/M proliferating phase. In ICAM-1-positive cells, p53 and p21 expression was up-regulated and cyclin-dependent protein kinase 6 activity was inhibited. Most ICAM-1-positive cells were apoptotic (as evidenced by TUNEL positivity and DNA fragmentation). ICAM-1-positive cells were induced not only by interleukin-1beta, but also by Fas crosslinking.

CONCLUSION

ICAM-1-positive synovial cells represent growth arrest and subsequent apoptosis, whereas ICAM-1-negative cells are proliferative. Such differences in regulation of the cell cycle based on ICAM-1 status are important determinants of the lifespan, proliferation, and growth arrest of RA synoviocytes.

Intercellular adhesion molecule 1 discriminates functionally different populations of human osteoblasts: characteristic involvement of cell cycle regulators

The concept of differential regulation of certain adhesion molecules on different cell subsets and their relevance to cell functions has emerged in recent years. The initial event in bone remodeling is an increase in osteoclastic bone resorption and cell adhesion between osteoclastic precursors and bone marrow stromal cells or osteoblasts is known to commit the osteoclast development. Here, we show that human osteoblasts can be divided into two subsets based on the expression of the intercellular adhesion molecule (ICAM)-1; ICAM-1+ osteoblasts highly adhered to monocytes, including osteoclast precursors, produced osteoclast differentiation factor (ODF), and induced multinuclear osteoclast-like cell formation. Anti-ODF monoclonal antibody (mAb) did not inhibit the adhesion of monocytes to osteoblastic cells, whereas anti-leukocyte function-associated antigen (LFA)-1, a receptor for ICAM-1, mAb blocked the adhesion. We thereby propose that the higher affinity adhesion via LFA-1/ICAM-1 is prerequisite for efficient function of membrane-bound ODF during osteoclast maturation. The functional characteristics of ICAM-1+ osteoblasts were emphasized further by cell cycle regulation, as manifested by (i) up-regulation of p53 and p21, (ii) reduction of activity of cyclin-dependent kinase (cdk) 6, (iii) underphosphorylation of retinoblastoma protein, (iv) increased Fas but reduced bcl-2 expression, and (v) majority of cells remained at G0/G1 phase. Furthermore, ICAM-1+ osteoblasts were induced by interleukin-1beta (IL-1beta). Taken together, we propose that the differentiation of osteoblasts to ICAM-1+ subpopulation by inflammatory cytokines plays an important role in osteoporosis, which is observed in patients with chronic inflammation, because ICAM-1+ osteoblasts can bias bone turnover to bone resorption, committing osteoclast maturation through cell adhesion with its precursor, and the majority of ICAM-1+ osteoblasts arrested at G0/G1 phase. Such regulation of cell cycle arrest also is an important determinant of the life span of cells in bone in which continuous bone remodeling maintains its homeostasis.

A case report of bilateral hydroureteronephrosis associated with systemic sclerosis

Abstract This report describes a case of atrophic bladder and bilateral hydroureteronephrosis that occurred in a patient with systemic sclerosis (SSc). A 49-year-old woman who had a 12-year history of SSc was admitted to our hospital because of bilateral hydroureteronephrosis indicated by uroflowmetric and radiological studies. Histological examination of the patient's bladder after biopsy revealed fibrotic replacement of submucosa and infiltration of mononuclear cells, but no deposition of immunoglobulins and complement components were observed. Nephrostomy to relieve the urinary retention was required. There have been few reports regarding SSc complications in hydronephrosis. The association between hydronephrosis and the pathological disorder of SSc is discussed.

An elevation of serum immunoglobulin E provides a new aspect of hyperthyroid Graves' disease

In hyperthyroid Graves' disease, short-term methimazole is sufficient to induce lasting remission in some patients, but even long-term treatment fails to do so in others. We have evaluated the role of autoimmune abnormalities in the helper T cell type 2 (TH2)-interleukin-13 (IL-13)-TSH receptor system in maintaining hyperthyroidism by comparing IgE levels in patients with various thyroid diseases. One hundred and ninety-three patients with hyperthyroid Graves' disease were treated with methimazole, and blood samples were obtained to measure serum levels of T4, T3, TSH, thyroglobulin, antimicrosomal antibody, TSH binding inhibitory Ig (TBII), thyroid-stimulating antibody, thyroid stimulation-blocking antibody, IgE, interferon-gamma, IL-4, and IL-13. Elevation of serum IgE (> or = 170 U/mL) was found in 35.5% of patients with hyperthyroid Graves' disease, and serum levels of T4, T:1, antimicrosomal antibody, and TBII were significantly greater in patients with IgE elevation than in those with normal serum IgE. During methimazole treatment, there was a parallel decrease in the serum T4 concentration in the presence or absence of an IgE elevation. However, there was a significantly smaller decrease in TBII in patients with elevated IgE than in those with normal IgE. As a result, the remission rate was significantly greater in patients with normal IgE than in those with IgE elevation. Serum levels of IL-13 were elevated in 64.7% of patients with IgE elevation in the absence of detectable TH1 marker, interferon-gamma. These findings suggest that in one third of patients with hyperthyroid Graves' disease, TH2 cells are stimulated and secrete excess amounts of IL-13, which subsequently stimulates B cells to synthesize more TSH receptor antibody and IgE, so that during methimazole treatment TBII decreases less in patients with IgE elevation, producing a lower remission rate.

Alcoholic fatty liver differentially induces a neutrophil-chemokine and hepatic necrosis after ischemia-reperfusion in rat

Primary graft nonfunction of steatotic liver allograft is one of the factors causing shortage of donor livers. Ischemia/reperfusion (I/R) injury is an important contributory factor to primary graft nonfunction. In this study, we investigated the complex chain of events from transcription factor activation to necrosis through cytokine induction and apoptosis in steatotic rat liver after warm I/R. Rats with alcoholic or nonalcoholic fatty liver were subjected to hepatic warm I/R and compared with control rats. Rats fed an ethanol diet for 6 to 8 weeks developed severe hepatic necrosis accompanied by increased neutrophil recruitment after I/R, compared with rats with nonalcoholic fatty liver or control. Hepatic apoptosis as assessed by DNA fragmentation at 4 hours after I/R, however, increased to a similar degree in each of the 2 fatty liver models compared with the control. Alcoholic fatty liver exposed to I/R showed a rapid increase in nuclear factor-kappaB (NF-kappaB) binding activity at 1 hour after I/R, which preceded an increased expression of tumor necrosis factor alpha (TNF-alpha) and cytokine-induced neutrophil chemoattractant-1 (CINC-1). In contrast, nonalcoholic fatty liver did not show such potentiation of either NF-kappaB activation or cytokine induction after I/R. Our results have indicated that alcoholic fatty liver may differentially induce CINC-1 production and hepatic necrosis after I/R. Furthermore, our results suggest that apoptosis per se does not always lead to necrosis in the liver following I/R.

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances es of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients.

Interleukin (IL)-4 and IL-13 inhibit the differentiation of murine osteoblastic MC3T3-E1 cells

Interleukin-4 (IL-4) inhibits the spontaneous and stimulated bone resorption resulting from the inhibition of osteoclast formation, as well as osteoclastic activity. Since IL-13 shares some biological properties with IL-4, it was recently reported that IL-13 inhibits bone resorption. The present study was designed to determine the effects of murine IL-4 (IL-4) and murine IL-13 (IL-13) on the murine osteoblastic cell line MC3T3-E1. IL-4 and IL-13 stimulated 3H-thymidine incorporation in the MC3T3-E1 cells and its proliferation in dose dependent manners. A spontaneous increase in alkaline phosphatase (ALP) activity in the cells after plating was inhibited by IL-4 or IL-13, and both cytokines blunted an increase in ALP activity by human parathyroid hormone (PTH) (1-34). PTH-stimulated cyclic AMP (cAMP) production was inhibited by pretreatment with IL-4 and IL-13 for 48 hr in dose dependent manners. Pretreatment with IL-4 and IL-13 for 48 hr caused a decrease in PTH-induced cAMP production at any stimulatory concentration. However, the effective dose (ED50) was unchanged by the pretreatment with these cytokines. Pretreatment with IL-4 and IL-13 did not modulate cAMP generation by forskolin. In contrast, cAMP generation by PGE2 is greater in the cells treated with the cytokines compared to those without the cytokines. These results indicate that IL-4 and IL-13 act on MC3T3-E1 cells in the same manner, stimulating cell proliferation, but inhibiting cell differentiation. The inhibition of osteoblast differentiation by IL-4 and IL-13 may be associated with a decrease in PTH actions on osteoblasts.

Centrally administered murine-leptin stimulates the hypothalamus-pituitary- adrenal axis through arginine-vasopressin

Starvation induces a decrease in circulating leptin levels and activation of the hypothalamus-pituitary-adrenal (HPA) axis. Leptin inhibits the HPA axis in unfed rodents or genetically leptin-deficient ob/ob mice, whereas it stimulates corticotropin-releasing hormone (CRH) gene expression in the paraventricular nucleus (PVN). However, the interactions between leptin, CRH and the HPA axis are poorly understood and are likely to be complex. We recently demonstrated that central leptin administration caused increases in plasma arginine-vasopressin (AVP) and AVP gene expression of the PVN in nonstressful rats. AVP stimulates the release of adrenocorticotropic hormone (ACTH), but it also potentiates the action of CRH on ACTH release. In this study, we investigated the effects of leptin on plasma ACTH and corticosterone levels, CRH mRNA of the PVN and proopiomelanocortin (POMC) mRNA of the pituitary in nonstrained rats. Intracerebroventricularly administered leptin caused increases in plasma ACTH and corticosterone levels in dose-dependent manners. In Northern blot analyses, the leptin injection induced significant increases in the expression of CRH mRNA in the PVN and POMC mRNA in the pituitary. The increased plasma ACTH and corticosterone levels by leptin were attenuated with intracerebroventricular pretreatment of a V(1a) receptor antagonist (OPC-21268) or a V(1a)/V(1b) receptor antagonist (dP[Tyr(Me)(2)]AVP), but not with that of a V(2) receptor antagonist (OPC-31260). The leptin-induced CRH mRNA expression in the PVN and POMC mRNA expression in the pituitary were also reduced by the pretreatment with OPC-21268 and dP[Tyr(Me)(2)]AVP. These results suggest that intracerebroventricular leptin administration activates the HPA axis by AVP receptor activation through V(1a) receptors in the PVN which in turn activates CRH neurons to drive ACTH and corticosterone secretion in concert with AVP in nonstrained rats.

Comprehensive cloning and expression analysis of glycolytic genes from the filamentous fungus, Aspergillus oryzae

We cloned all the glycolytic genes from Aspergillus oryzae and analyzed their transcriptional regulation by the carbon source in the medium. The deduced amino-acid sequences of the glycolytic genes showed high identity (approximately 41-93%) to those from other lower eukaryotes. Genomic Southern hybridization indicated that all the genes existed as a single copy in the genome. Comparison of mRNA levels between mycelia grown on glucose and on pyruvate showed that most of the A. oryzae glycolytic genes were induced by glucose in the medium. The overall expression profiles of the A. oryzae glycolytic genes resembled those of Saccharomyces cerevisiae. The expression of one of the phosphofructokinase genes (pfkB), however, was repressed by glucose while both PFK1 and PFK2 were induced in S. cerevisiae. These findings indicate that further analysis of the transcriptional regulation of the A. oryzae glycolytic genes will be useful for investigating the evolutionary change of transcription regulation in lower eukaryotes and to construct promoters for industrial applications.

Uncoupling between bone formation and resorption in ovariectomized rats with chronic cadmium exposure

Osteoporosis, osteomalacia, and pathological fractures are characteristic features of Itai-Itai disease. The mechanisms of bone damage caused by cadmium (Cd) exposure have not been fully clarified. We investigated skeletal changes in ovariectomized rats with chronic Cd exposure, using bone histomorphometry and mechanical tests. Female Sprague-Dawley rats at the age of 8 weeks were ovariectomized. Eight weeks after ovariectomy, the rats were divided into two groups: Cd-OVX group (n = 15), ovariectomized rats given cadmium chloride (CdCl(2), 0.18 mg/rat) ip three times a week for 28 weeks; Cont-OVX group (n = 10), ovariectomized rats given distilled water alone for 28 weeks. Cd-OVX rats had a significant increase in serum concentration of intact osteocalcine and showed numerical but not significant increase in urinary excretion of deoxypyridinoline despite a significant decrease in glomerular filtration rate to 40% of the value in Cont-OVX rats. Bone mineral content (BMC) and density were significantly decreased in both the lumbar vertebral body and femur of Cd-OVX rats. Ultimate compressive load in the lumbar body and bending load in the midfemur were significantly lower in Cd-OVX rats than in Cont-OVX rats but the differences were not demonstrated when the values were corrected for BMC. Structural moduli in the lumbar vertebral body and the midfemur were not different between the two groups. Cd-OVX rats showed significant decreases in the trabecular bone volume and trabecular number with increased values in the indices of bone formation and resorption in the lumbar vertebral body cancellous bone in comparison with Cont-OVX rats. In the midfemur, Cd-OVX rats had significantly smaller cortical bone area than Cont-OVX rats but the moment of inertia was identical between the two groups. The indices of bone formation and resorption at endocortical surface of the midfemur were significantly increased in Cd-OVX rats over those in Cont-OVX rats, whereas the indices of bone formation at the periosteal surface were not different between the two groups. These data suggested that chronic Cd exposure exacerbated the uncoupling between bone formation and resorption in ovariectomized rats, which resulted in the osteopenia, structural changes of the bone, and decreased mechanical strength in ovariectomized rats with chronic Cd exposure.