Myocardial fat accumulation is associated with cardiac dysfunction in patients with type 2 diabetes, especially in elderly or female patients: a retrospective observational study

BACKGROUND

Ectopic fat is fat that accumulates in or around specific organs or compartments of the body including myocardium. The clinical features of type 2 diabetes patients with high fat accumulation in the myocardium remain unknown. Moreover, little is known about the influence of myocardial fat accumulation in type 2 diabetes on coronary artery disease and cardiac dysfunction. We aimed to clarify the clinical features, including cardiac functions, of type 2 diabetes patients with myocardial fat accumulation.

METHODS

We retrospectively enrolled type 2 diabetes patients who underwent ECG-gated coronary computed tomography angiography (CCTA) and abdominal computed tomography (CT) scan examinations within 1 year of CCTA from January 2000 to March 2021. High fat accumulation in the myocardium was defined as the low mean myocardial CT value of three regions of interest, and the associations between CT values and clinical characteristics or cardiac functions were assessed.

RESULTS

In total, 124 patients were enrolled (72 males and 52 females). The mean age was 66.6 years, the mean BMI was 26.2 kg/m², the mean ejection fraction (EF) was 67.6%, and the mean myocardial CT value was 47.7 Hounsfield unit. A significant positive correlation was found between myocardial CT value and EF (r = 0.3644, p = 0.0004). The multiple regression analyses also showed that myocardial CT value was independently associated with EF (estimate, 0.304; 95% confidence interval (CI) 0.092 to 0.517; p = 0.0056). Myocardial CT value showed significant negative correlations with BMI, visceral fat area and subcutaneous fat area (r = - 0.1923, - 0.2654, and -0.3569, respectively, p < 0.05). In patients who were ≥ 65 years or female, myocardial CT value showed significant positive correlations with not only EF (r = 0.3542 and 0.4085, respectively, p < 0.01) but also early lateral annular tissue Doppler velocity (Lat e') (r = 0.5148 and 0.5361, respectively, p < 0.05). The multiple regression analyses showed that myocardial CT value was independently associated with EF and Lat e' in these subgroups (p < 0.05).

CONCLUSIONS

Patients with type 2 diabetes, especially in elderly or female patients, who had more myocardial fat had more severe left ventricular systolic and diastolic dysfunctions. Reducing myocardial fat accumulation may be a therapeutic target for type 2 diabetes patients.

Increase in Adiponectin Level Prevents the Development of Type 2 Diabetes in Japanese Men With Low Adiponectin Levels

Context

Low serum adiponectin (Ad) level is an important risk factor for the development of type 2 diabetes mellitus (T2DM).

Objective

To determine whether the changes in Ad in subjects with low baseline serum Ad levels can reduce the rate of development of T2DM.

Design/Setting/Participants

We performed a large-scale longitudinal study of 7052 healthy Japanese men who underwent general health checkups more than twice between April 2007 and May 2015 at the Physical Check up Center, Sumitomo Hospital. The participants were divided into quartile groups according to baseline Ad level. Subjects of the lowest baseline Ad group (≤5.2 μg/mL) were subdivided into quartile subgroups according to the percent change in Ad (%ΔAd) and into two subgroups according to endpoint Ad (>5.2 and ≤5.2 μg/mL).

Main Outcome Measures

The cumulative incidence rate of T2DM.

Results

The cumulative incidence rate of T2DM of the lowest baseline Ad group (≤5.2 μg/mL) was significantly higher than the other quartile groups. The cumulative incidence rates of T2DM were significantly lower in the largest (≥21.5%) and the second largest (9.3% to 21.4%) %ΔAd-increased subgroups compared with the %ΔAd-decreased subgroup (P < 0.001 and P = 0.005, respectively). The cumulative incidence rates of T2DM were significantly lower in the endpoint Ad >5.2 μg/mL subgroup than in the ≤5.2 μg/mL subgroup (P < 0.001).

Conclusions

Increases in serum Ad levels of at least ~10% or >5.2 μg/mL can potentially reduce the risk of development of T2DM in Japanese men with low baseline Ad levels who are at a high risk of developing T2DM.

Effective waist circumference reduction rate necessary to avoid the development of type 2 diabetes in Japanese men with abdominal obesity

The aim of this study was to determine the effective waist circumference (WC) reduction rate in avoiding the development of type 2 diabetes mellitus (T2DM) in <55 years and ≥55 years Japanese men with abdominal obesity. The study subjects were 795 men with WC ≥85 cm, fasting plasma glucose <126 mg/dL, 2-hr plasma glucose on 75 g of oral glucose tolerance test <200 mg/dL, and HbA1c 5.6-6.4 % (38-40 mmol/mol) at baseline who underwent general health checkups more than twice between April 2007 and May 2015. They were divided into 5 groups based on the change in WC during the observation period (WC gain group, and four groups stratified according the rate of WC loss). The subjects were also divided into the <55 years and ≥55 years (at baseline) subgroups. The cumulative incidence rate of T2DM was analyzed and compared among the groups. The cumulative incidence rates of the largest WC loss quartile (≥5.45 %) in all age, of the largest WC loss quartile (≥5.60 %) and second largest WC loss quartile (3.44-5.59 %) in the <55 years subgroup, and of the largest WC loss quartile (≥5.37 %) in the ≥55 years subgroup were significantly lower than that of the gain group (p<0.001, p=0.009, 0.012, and 0.012, respectively). WC reduction rate of at least about 3 % in the younger (<55 years) and at least about 5 % in the older (≥55 years) non-diabetic Japanese men with abdominal obesity can effectively reduce the chance of development of T2DM.

A Novel Mutation in the type Iα Regulatory Subunit of Protein Kinase A (PRKAR1A) in a Cushing's Syndrome Patient with Primary Pigmented Nodular Adrenocortical Disease

A 40-year-old man presented with Cushing's syndrome due to bilateral adrenal hyperplasia with multiple nodules. Computed tomography scan results were atypical demonstrating an enlargement of the bilateral adrenal glands harboring multiple small nodules, but the lesion was clinically diagnosed to be primary pigmented nodular adrenocortical disease (PPNAD) based on both endocrinological test results and his family history. We performed bilateral adrenalectomy and confirmed the diagnosis histologically. An analysis of the patient and his mother's genomic DNA identified a novel mutation in the type Iα regulatory subunit of protein kinase A (PRKAR1A) gene; p.E17X (c.49G>T). This confirmed the diagnosis of PPNAD which is associated with Carney Complex.

Serum adiponectin levels predict the risk of coronary heart disease in Japanese patients with type 2 diabetes

AIMS/INTRODUCTION

An inverse association between adiponectin and coronary heart disease (CHD) has been found in Caucasians, but it is uncertain whether this association can be extrapolated to the East Asian population. The present study aimed to investigate whether serum adiponectin levels can predict CHD in Japanese patients with type 2 diabetes as observed in Caucasians.

MATERIALS AND METHODS

This longitudinal study included 504 patients with type 2 diabetes (342 men and 162 women) who were admitted to Sumitomo Hospital between July 2005 and December 2006. We used Cox proportional hazard analysis to estimate the hazard ratio (HR) of CHD associated with serum adiponectin levels at baseline.

RESULTS

During a median follow up of 5.7 years (2177 person-years), 40 participants had new CHD and 10 had recurrent CHD. After multivariate adjustment, the highest compared with the lowest quartile of serum adiponectin levels had a significantly reduced risk of CHD (hazard ratio [HR] 0.35; 95% confidence interval [CI] 0.13-0.94; P = 0.017). The multivariate adjusted HR for the risk of CHD according to a doubling of adiponectin at baseline was 0.61 (95% CI 0.39-0.97; P = 0.037).

CONCLUSIONS

High serum adiponectin levels are significantly associated with a lower risk of CHD in Japanese patients with type 2 diabetes. This association is independent of other well-known CHD risk factors.

Relationship between serum adiponectin levels and age in healthy subjects and patients with type 2 diabetes

OBJECTIVE

Serum adiponectin levels are affected by gender, body fat mass, several pathological factors or therapeutic interventions and it might be also affected by age. This study aimed to investigate the relationship between serum adiponectin levels and age in several physiological states.

DESIGN, PATIENTS AND MEASUREMENTS

The study was carried out in 21 100 healthy subjects (12 363 men and 8737 women) and 1833 patients with type 2 diabetes (1233 men and 600 women). Physical and demographic characteristics were recorded, and blood samples were collected to measure serum adiponectin levels. Using these data, we determined the relationships between serum adiponectin levels and various parameters, including age.

RESULTS

Serum adiponectin levels increased with increasing age of healthy subjects and in patients with diabetes, in both men and women. Serum adiponectin levels were positively correlated with age in healthy subjects and patients with diabetes, in both men and women. In stepwise multiple regression analysis with serum adiponectin levels as the dependent variable and physiological characteristics as explanatory variables, age was significantly and independently associated with serum adiponectin levels in each of these groups of subjects.

CONCLUSIONS

Serum adiponectin levels are significantly and positively associated with age in healthy subjects and in patients with diabetes. This association is independent of renal function, body fat status, glucose metabolism and lipid profiles.

Association of adiponectin with blood pressure in healthy people

OBJECTIVE

With the increasing prevalence of diseases related to obesity, metabolic syndrome and its key player adiponectin are now attracting considerable attention. Hypoadiponectinaemia is reported to be a risk factor for hypertension and associated with endothelial dysfunction, which is closely related to complications of obesity such as hypertension. As there is limited information regarding serum adiponectin levels in normotensive people, we undertook the large-scale study to determine the association of adiponectin with blood pressure (BP) in mainly normotensive people.

DESIGN, PATIENTS AND MEASUREMENTS

In 21 100 Japanese adults (12 363 men and 8737 women) who had no apparent diseases, we examined the relationship between the serum adiponectin concentration and BP by performing a questionnaire survey, physical measurements and measurement of laboratory parameters including the serum adiponectin level.

RESULTS

Subjects with hypoadiponectinaemia had higher systolic and diastolic BPs as already reported. And interestingly, subjects with higher adiponectin had lower systolic and diastolic BP. According to linear regression analysis, adiponectin showed a significant negative correlation with systolic and diastolic BP independently of the other variables. Analysis of covariance according to adiponectin quintiles showed that systolic and diastolic BP in highest adiponectin quintile was significantly lower than in other quintiles.

CONCLUSIONS

This study revealed that there were significant trends toward lower systolic and diastolic BP with higher adiponectin not only in hypertensive people but also in normotensive people.

Resolution of gelatinous bone marrow transformation following hormone replacement therapy in a patient with primary insufficiency of the adrenal and thyroid glands

A 59-year-old man with recurrent oral cancer presented with severe pancytopenia, hyponatremia and hypoglycemia. Endocrine testing showed a partial primary adrenal insufficiency and primary hypothyroidism. The bone marrow biopsy showed a gelatinous transformation with hypocellularity and fat atrophy. His pancytopenia, hyponatremia and hypoglycemia resolved following treatment with corticosteroids and thyroid hormone replacement therapy. The follow-up bone marrow biopsy demonstrated a resolution of the gelatinous transformation. This case is a rare example of a patient with a primary insufficiency of the adrenal and thyroid glands that is associated with gelatinous bone marrow transformation (GMT). The GMT was resolved through the administration of corticosteroids and thyroid hormone replacement therapy.

Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities

Objective:

Along with the increasing prevalence of obesity and related diseases, particularly atherosclerotic diseases, metabolic syndrome (MetS) is now a common and major public health issue in many countries around the world. Adiponectin, a protein secreted by the adipose tissue, has become recognized as a key player in the development of MetS. These days, not only MetS but also borderline metabolic/physiological abnormalities, such as impaired fasting glucose, high normal blood pressure and high normal plasma cholesterol, have been reported to be risk factors for atherosclerotic disease. Therefore, we undertook this study to determine the relationship between adiponectin and borderline metabolic/physiological abnormalities, as well as MetS.

Design:

A cross-sectional study performed from April 2007 to November 2009.

Subjects:

In 16 892 Japanese adults (10 008 men and 6884 women), we examined the relationship between the serum adiponectin concentration and borderline metabolic/physiological abnormalities or MetS by a questionnaire survey about medical treatment, body size measurement and measurement of laboratory parameters including the serum adiponectin concentration.

Results:

Adiponectin showed a significant negative correlation with the number of MetS components. In subjects without overt diabetes mellitus, hypertension or dyslipidemia, the adiponectin concentration also showed a significant negative correlation with the number of borderline metabolic abnormalities.

Conclusion:

The decrease of circulating adiponectin may start before the development of diabetes mellitus, hypertension, dyslipidemia or MetS. Adiponectin is an important biomarker for reflecting the adverse influence of visceral fat in persons with MetS, and also in these subclinical states.

Long-term efficacy of trilostane for Cushing's syndrome due to adrenocorticotropin-independent bilateral macronodular adrenocortical hyperplasia

A 66-year-old man with Cushing's syndrome due to adrenocorticotropin-independent bilateral macronodular adrenocortical hyperplasia (AIMAH) was treated for 7 years with trilostane, a 3β-hydroxysteroid dehydrogenase inhibitor. Administration of trilostane reduced the serum cortisol level to around the upper limit of normal for 7 years, and symptoms of excessive glucocorticoid production (such as moon face and obesity) were gradually improved. On the other hand, the size of both adrenal glands gradually increased despite treatment with trilostane. Though trilostane therapy could not prevent adrenal growth, it did suppress cortisol secretion over the long term, so it might be a reasonable option for AIMAH in addition to adrenalectomy.

Expression of chemokines, CXC chemokine ligand 10 (CXCL10) and CXCR3 in the inflamed islets of patients with recent-onset autoimmune type 1 diabetes

The aim of this study is to present direct evidence for the involvement of CXC chemokine ligand 10 (CXCL10) and CXCR3 in human autoimmune type 1 diabetes. We examined five patients with recent-onset type 1 diabetes and five control subjects without diabetes. Islet cell antibodies or GAD antibodies or both were detected in all five patients. We used double-immunofluorescence to detect the expression of CXCL10 and CXCR3 (the receptor of CXCL10). CXCL10 was detected in the islets of all five patients. Almost all (84.2 ± 10.3 %, mean ± SD) CXCL10-positive cells were insulin-positive in the islet area. CXCL10-positive cells with glucagons, somatostatins or pancreatic polypeptides were not detected at all. CXCL10 expression was not seen in any islet without beta cells. CXCR3 was detected in the islet areas of all five patients. Almost all (80.3 ± 13.4 %, mean ± SD) CXCR3-positive cells were CD3-positive T cells. Our study showed that CXCL10 was expressed in the remaining beta cells, and the infiltrating T cells expressed CXCR3, in pancreatic islets of patients with recent-onset type 1 diabetes. The interaction of CXCL10 and CXCR3 would contribute to the selective destruction of beta cells in the development of type 1 diabetes.

The HNF-1alpha-SNARE connection

Maturity-onset diabetes of the young (MODY) is a monogenic form of type 2 diabetes mellitus that is characterized by impairment of glucose-stimulated insulin secretion from pancreatic beta-cells. We previously reported that heterozygous mutations of the hepatocyte nuclear factor (HNF)-1alpha gene cause a form of MODY (MODY3). We have subsequently found that collectrin, a recently cloned kidney-specific gene of unknown function, is a novel target of HNF-1alpha in pancreatic beta-cells. In addition, we have demonstrated that collectrin forms a complex with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex by direct interaction with snapin, a protein that is thought to be involved in neurotransmission by binding to synaptosomal-associated protein, 25 KD (SNAP25). Collectrin favours the formation of SNARE complexes and controls insulin exocytosis.

Simultaneous determination of nineteen hallucinogenic tryptamines/β-calbolines and phenethylamines using gas chromatography–mass spectrometry and liquid chromatography–electrospray ionisation-mass spectrometry

To investigate the trend of non-controlled drugs of abuse, simultaneous analytical methods were developed using GC-MS and LC-ESI-MS for 8 tryptamines/beta-carbolines, 6 phenethylamines of typically non-controlled substances in Japan, and, additionally, five legally controlled tryptamines and phenethylamines originally found in fungi or plants. Moreover, the proposed methods were applied to analyses of these drugs in 99 kinds of products (a total number of 123 products purchased at adult shops or via the Internet over the past 2 years in Japan), which potentially advertised psychotropic/psychoactive effects. The samples were extracted with methanol under ultrasonication. After centrifugation, the extracts were filtered prior to injections. GC-MS analysis was performed using a DB-5MS capillary column. Regarding the LC-ESI-MS analysis; the separation of the target drugs was optimized on an ODS column in acetonitrile/MeOH (7:3)-10 mM ammonium formate buffer (pH 3.5)/acetonitrile (95:5) by a linear gradient program and a quantitative analysis was carried out by the monitoring of each [M+H]+ in the positive ion mode of ESI-MS. As a result of the analyses using GC-MS and LC-ESI-MS, 5-MeO-DIPT (the synthetic substance known by the street name "Foxy") was found in 8 out of the 99 kinds of products. Additionally, AMT (from brown powder), DMT (from dried plant), harmine and harmaline (from dried plant) were also found in some of the 99 products. These analytical methods could be useful for the investigation of the distribution of the non-controlled psychotropic tryptamines/beta-carbolines and phenethylamines in the market.

Hair analysis for pharmaceutical drugs. II. Effective extraction and determination of sildenafil (Viagra) and its N-desmethyl metabolite in rat and human hair by GC-MS

In order to study the incorporation of sildenafil (SDF) and its N-demethylated metabolite (norSDF) into hair, animal model experiments were carried out. After shaving the back hair, SDF was dosed to two sets of three male dark-agouti pigmented rats (5 weeks old) per each group at 25 mg/kg once a day for 5 successive days with intraperitoneal (i.p.) (set1) and oral administration (set2). The regrown back hair was collected 14 d after the first administration. Three typical extraction methods, using methanol-5 M hydrochloric acid, methanol-trifluoroacetic acid and 1 M sodium hydroxide, were evaluated using the rat hair samples containing SDF and norSDF. Methanol-5 M hydrochloric acid was the best extraction method in terms of high efficiency and reproducibility. The extract was purified using Bond Elut Certify columns and was derivatized with trimethylsilylimidazole: N,O-bis(trimethylsilyltrifluoroacetamide): trimethylchlorosilane (3: 3: 2) at 90 degrees C for 30 min. The trimethylsilylated products were analyzed by GC-MS using selected ion monitoring. SDF and norSDF were simultaneously detected in the rat hair. The hair concentrations were 4.9-6.3 (av. 5.8) ng/mg and 15.6-20.3 (av. 17.6) ng/mg for SDF and norSDF, respectively, with i.p. administration, and 2.6-4.1 (av. 3.6) ng/mg and 8.1-10.4 (av. 9.1) ng/mg with oral administration. The hair concentrations of norSDF were about three times higher than those of SDF, and the ratios of both compounds showed no significant difference between i.p. and oral administrations. This method was applied to the scalp hair of two patients who orally took SDF at regular intervals for the treatment of penile erectile dysfunction. The hair concentrations of SDF and norSDF in the two patients were 19.8 and 55.9 ng/mg, and 1.7 and 5.6 ng/mg, respectively.

Hair analysis for pharmaceutical drugs. I. Effective extraction and determination of phenobarbital, phenytoin and their major metabolites in rat and human hair

In order to establish an analytical method for the determination of phenobarbital (PB), phenytoin (PPH) and their hydroxylated metabolites in hair, animal model experiments were performed. Five male dark-agouti pigmented rats, aged 5 weeks, were intraperitoneally and orally administered PB or PPH independently at 25 mg/kg once a day for 5 successive days. The growing back hair was collected 15d after the first administration. Four typical extraction methods, using NH4OH-methanol-acetone, TFA-methanol-acetone, 1M sodium hydroxide and proteinase K, were evaluated using the rat hair samples containing PB or PPH. Methanol-acetone-NH4OH (10: 10: 1) was the best extraction method from all aspects, such as high extraction efficiency and low noise. The analytes in the extract were methylated in acetonitrile with 20% tetramethylammonium hydroxide and methyliodide at 70 degrees C for 10 min. After purification with Bond Elut Certify, the methylated products were analyzed by GC-MS. From rat hair, PB, p-hydroxy PB, PPH and p-hydroxy PPH were detected at average concentrations of 26.9, trace, 4.2 and 0.4 ng/mg with an intraperitoneal (i.p.) injection, and at 30.9, trace, 4.0 and 0.4 ng/mg with oral administration, respectively. There was little difference in hair concentrations between i.p. injection and oral administration. This method was applied to the head hair of two patients who orally took toxic amounts of PB and two volunteers who orally took 100 mg of PPH daily for 5 d. The hair concentrations of PB in the two patients were 16.2 and 14.7 ng/mg, and those of PPH in the two volunteers were 3.3 and 0.1 ng/mg.

Evaluation of left ventricular wall motion and function in patients with previous myocardial infarction by three-dimensional 99mTc-HSAD multigated cardiac pool imaging

To evaluate left ventricular (LV) wall motion stereoscopically from all directions and to calculate the LV volume by three-dimensional (3D) imaging. 99mTc-DTPA human serum albumin-multigated cardiac pool-single photon emission computed tomography (99mTc-MUGA-SPECT) was performed. A new data processing program was developed with the Application Visualization System-Medical Viewer (AVS-MV) based on images obtained from 99mTc-MUGA-SPECT. In patients with previous myocardial infarction, LV function and LV wall motion were evaluated by 3D-99mTc-MUGA imaging. The LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were obtained from 3D-99mTc-MUGA images by the surface rendering method, and the left ventricular ejection fraction (LVEF) was calculated at thresholds of 35% (T1), 40% (T2), 45% (T3), and 50% (T4). There was a strong correlation between the LV volume calculated by 3D-99mTc-MUGA imaging at a threshold of 40% and that determined by contrast left ventriculography (LVEDV: 194.7 +/- 36.0 ml vs. 198.7 +/- 39.1 ml, r = 0.791, p < 0.001; LVESV: 91.6 +/- 44.5 ml vs. 93.3 +/- 41.3 ml, r = 0.953, p < 0.001), respectively. When compared with the LVEF data obtained by left ventriculography, significant correlations were found for 3D images reconstructed at each threshold (T1: r = 0.966; T2: r = 0.962; T3: r = 0.958; and T4: r = 0.955). In addition, when LV wall motion obtained by 3D-99mTc-MUGA imaging (LAT and LAO views) was compared with the results obtained by left ventriculography (RAO and LAO views), there was good agreement. 3D-99mTc-MUGA imaging was superior in allowing evaluation of LV wall motion in all directions and in assessment of LV function, since data acquisition and image reconstruction could be done within a short time with the three-detector imaging system and AVS-MV. This method appears to be very useful for the observation of both LV wall motion and LV function in patients with ischemic heart disease, because it is a noninvasive examination.

Experimental study of reflectance spectrophotometric analysis of the dog's dural sac--in the open decompressed state and after the application of external dural pressure

Haemoperfusion and oxygen saturation were studied by tissue reflection spectra on the dural sac of dogs, Experimentally, decompression laminectomy and external pressure on the dural sac were carried out. Haemoperfusion and oxygen saturation were investigated in the open state, and after an external pressure was applied. After the application of external pressure, paraplegia occurred. The tissue Spectrum Analyser 'TS-200' (Sumitomo Electric Industries Co. Ltd, Japan) was used for the measurement of haemoperfusion and oxygen saturation. With this apparatus, an optical fibre probe is applied to irradiate tissue with white light, and the absorption spectrum of the reflected light from tissue is analysed. It has been confirmed that oxygen saturation was not changed in either state, however, haemoperfusion was decreased when external pressure was applied.

Muramyl dipeptide induces acute joint inflammation in the mouse

Acute joint inflammation was produced in BALB/c mice by a single intravenous injection of synthetic muramyl dipeptide (MDP), its stereoisomers and 6-O-acyl derivatives of MDP. Four adjuvant-active, but not five adjuvant-inactive MDP analogs induced acute swelling and erythema of the ankles and wrists which were detected around 6-10 hr, reached the maximum severity by 18-24 hr and subsided by days 3 to 4 after injection. Introduction of the stearoyl group, but not the alpha-branched long chain fatty acid group into the C-9 hydroxyl group of MDP enhanced and prolonged the joint lesions compared with MDP.

Recurrent myocardial infarction and unexpected sudden death in a case of d-loop d-transposition of the great arteries associated with single coronary artery

A 40-year-old man with d-loop d-transposition of the great arteries associated with single coronary artery type 3 by Hvass died unexpectedly. Postmortem study demonstrated myocardial infarction in the posterior portion of the right ventricle and interventricular septum, and complete obstruction of the proximal right coronary artery. The etiology of the unexpected death is discussed.

Characterization of monoclonal antibody specific for human type II collagen: possible implication in collagen-induced arthritis

We obtained monoclonal antibodies specific for human type II collagen and characterized them using human collagen type I, II, III and V and tropocollagen A (3/4) (TCA) and tropocollagen B (1/4) (TCB) fragments of type II collagen which were obtained by digestion with tadpole collagenase. These antibodies were of the IgG2a class and specific for the conformational determinant of TCA fragment of type II collagen. When injected intravenously into DBA/1J mice, one of the monoclonal antibodies induced arthritis, which was characterized by early onset, mildness in severity and preferential localization mainly in the peripheral joints of the lower extremities. These results suggest that, at least, one of the arthritogenic determinants of type II collagen for collagen-induced arthritis of mice exists in the three quarter region from the N-terminus of type II collagen.

Acute joint inflammation in mice after systemic injection of the cell wall, its peptidoglycan, and chemically defined peptidoglycan subunits from various bacteria

The systemic injection of an aqueous suspension of cell wall or its peptidoglycan (PG)-rich sonicate derived from group A streptococcus and Lactobacillus casei induced acute joint lesions in BALB/c, DBA/1J, (BALB/c X DBA/1J)F1, and C3H/He mouse strains, but not in C57BL/6, DBA/2, and AKR strains. Cell walls and their enzymatically degraded PG fragments from other bacteria as well as the synthetic disaccharide dipeptide and Lactobacillus plantarum cell wall-derived disaccharide tripeptide produced similar acute inflammation in susceptible BALB/c mice. Acute swelling and erythema of the ankles and wrists were observed as early as 3 h, reached maximum severity by day 2, and generally subsided by days 4 to 6 after injection. Histological studies showed synovial proliferation, marked infiltration of many mononuclear cells and a few polymorphonuclear leukocytes in the soft tissues, and extensive deposition of fibrinous exudate in the joint space. Antibody response was detectable against the PG fraction. However, anti-PG antibody does not seem to be responsible for the pathogenesis of this disease. On the other hand, experiments on decomplementation by cobra venom factor suggest that complement components are involved in the early phase of this arthritic model.