Endoplasmic reticulum stress-induced apoptosis contributes to articular cartilage degeneration via C/EBP homologous protein

OBJECTIVE

When endoplasmic reticulum (ER) stress, i.e., the excessive accumulation of unfolded proteins in ER, endangers homeostasis, apoptosis is induced by C/EBP homologous protein (Chop). In osteoarthritis (OA) cartilage, Chop expression and apoptosis increase as degeneration progresses. We investigated the role of Chop in murine chondrocyte apoptosis and in the progression of cartilage degeneration.

METHOD

We induced experimental OA in Chop-knockout (Chop(-/-)) mice by medial collateral ligament transection and meniscectomy and compared cartilage degeneration, apoptosis, and ER stress in Chop(-/-)- and wild-type (Chop(+/+)) mice. In our in vitro experiments we treated murine Chop(-/-) chondrocytes with the ER stress inducer tunicamycin (TM) and evaluated apoptosis, ER stress, and chondrocyte function.

RESULTS

In vivo, the degree of ER stress was similar in Chop(-/-)- and Chop(+/+) mice. However, in Chop(-/-) mice apoptosis and cartilage degeneration were lower by 26.4% and 42.4% at 4 weeks, by 26.8% and 44.9% at 8 weeks, and by 26.9% and 32.3% at 12 weeks after surgery than Chop(+/+) mice, respectively. In vitro, the degree of ER stress induction by TM was similar in Chop(-/-)- and Chop(+/+) chondrocytes. On the other hand, apoptosis was 55.3% lower and the suppression of collagen type II and aggrecan mRNA was 21.0% and 23.3% less, and the increase of matrix metalloproteinase-13 mRNA was 20.0% less in Chop(-/-)- than Chop(+/+) chondrocytes.

CONCLUSION

Our results indicate that Chop plays a direct role in chondrocyte apoptosis and that Chop-mediated apoptosis contributes to the progression of cartilage degeneration in mice.

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

TWEAK/Fn14 pathway promotes a T helper 2-type chronic colitis with fibrosis in mice

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), a TNF superfamily member, induces damage of the epithelial cells (ECs) and production of inflammatory mediaters through its receptor Fn14 in a model of acute colitis. In our current study of chronic colitis induced by repeated rectal injection of a hapten, we found that inflammation, fibrosis, and T helper 2 (Th2)-type immunity were significantly reduced in Fn14 gene knockout (KO) mice when compared with wild-type (WT) control mice. Expression of thymic stromal lymphopoietin (TSLP) was lower in Fn14 KO colon ECs than in WT ECs. TWEAK potentiates the induction of TSLP by interleukin-13 (IL-13) in colon explants from WT but not in Fn14 KO tissue. TSLP receptor KO mice exhibit milder chronic colitis, similar to that in Fn14 KO mice. TWEAK and IL-13 synergistically promote fibroblast proliferation. Thus we propose an IL-13-TWEAK/Fn14-TSLP axis as a key mechanism underlying chronic colitis with fibrosis.

Astaxanthin ameliorates heat stress-induced impairment of blastocyst development in vitro:--astaxanthin colocalization with and action on mitochondria--

PURPOSE

The effects of astaxanthin (Ax) on the in vitro development of bovine embryos cultured under heat stress were investigated in combination with the assessment of its cellular accumulation and action on mitochondrial membrane potential (ΔΨm).

METHODS

Bovine ≥8-cell embryos were collected on day 3 after in vitro fertilization and exposed to single (day 4) or repeated (day 4 and 5) heat stress (10 h/day at 40.5 °C). Ax was added into culture medium under the repeated heat stress and blastocyst development was evaluated. The cellular uptake of Ax in embryos was examined using bright-field and confocal laser-scanning microscopy, and high-performance liquid chromatography. The relationship between Ax and mitochondria localization was assessed using MitoTracker dye. The effects of Ax on ΔΨm were investigated using JC-1 dye.

RESULTS

Blastocyst development in the repeated heat stress treatment decreased significantly (P < 0.05) compared with those in single heat stress or normal thermal treatment. The addition of Ax into culture medium did lead to a significant recovery in blastocyst development in the repeated heat-treated group. Ax was detected in cytoplasm of embryos and observed to colocalize with mitochondria. Ax recovered ΔΨm in embryos that was decreased by the heat treatment.

CONCLUSIONS

Ax ameliorated the heat stress-induced impairment of blastocyst development. Our results suggest that the direct action of Ax on mitochondrial activity via cellular uptake is a mechanism of the ameliorating effects.

Visualization of lenticulostriate arteries by flow-sensitive black-blood MR angiography on a 1.5 T MRI system: a comparative study between subjects with and without stroke

BACKGROUND AND PURPOSE

The branches of the LSA are the main causative arteries for lacunar infarction, though the vascular changes are largely unknown. Herein, we examined the correlation of LSA imaging findings in patients with lacunar infarction compared with controls by using FSBB-MRA.

MATERIALS AND METHODS

Fifteen patients (9 men, 6 women; mean age, 73 years) with infarction at the basal ganglia and/or its vicinity were prospectively enrolled, and 12 aged-matched control subjects (6 men, 6 women; mean age, 68 years) were examined by using FSBB-MRA on a 1.5T MR imaging system. Total number and length of visualized LSA branches were compared by a 2-tailed 2-sample t test. Stepwise multiple regression analyses were performed, including hypertension, hyperlipidemia, smoking history, and diabetes mellitus after evaluation of their colinearity. P<.05 after correction for multiple comparisons was considered significant.

RESULTS

Patients with stroke had significantly fewer LSA branches (average, 6.3; 95% CI, 5.4-7.1) than controls (8.7; 95% CI, 7.8-9.5) (P=.0003). The total LSA lengths were 117 mm (95% CI, 96-138 mm) for patients with stroke and 162 mm (95% CI, 133-91 mm) for control subjects (P=.01). In stepwise multiple regression analysis, only the LSA branch numbers were significantly related to infarction (P=.0003), while only hypertension was significantly related to total LSA length (P=.0085).

CONCLUSIONS

Using FSBB-MRA to visualize LSA branches, we found a significant reduction in the numbers of LSA branches in patients with stroke, and hypertension was inversely related to total LSA length. FSBB is a promising method to investigate the LSA by using 1.5T MR imaging.

A study on how a 6-month aerobic exercise program can modify coronary risk factors depending on their severity in middle-aged sedentary women

It is well known that physical exercise can reduce coronary risk factors. But how an aerobic exercise modifies coronary risk factors in relation to severity and physical fitness is still controversial.Fifty-four middle-aged women (mean age, 55 years) completed a 6-month on-site and home-based anaerobic threshold-level exercise program. The changes in coronary risk factor profiles were observed during the pre-intervention and intervention periods. Before the intervention (during control period), most coronary risk factors showed a rather unfavorable trend. After the program, their mean body weight decreased from 56.7 to 55.7 kg (p>0.05) and the proportion of body fat from 30.9 to 27.9% (p>0.05) without any reduction in lean body mass. Systolic blood pressure (SBP) decreased from 129.0 to 125.0 mm Hg (p>0.05) and diastolic blood pressure from 79.5 to 76.6 mm Hg (p>0.05). Fasting plasma glucose (FPG) declined from 109.6 to 103.4 mg/dl (p>0.05). Changes in SBP and FPG were most remarkable in their respective worst tertile. Serum lipids improved only modestly. Maximum oxygen uptake increased from 23.6 to 26.1 ml/kg/min (p>0.01). However, no significant correlations were found between changes in coronary risk factors and those in physical fitness. We conclude that the 6-month aerobic exercise program would modify women's coronary risk factors depending on their initial values, probably independently of the changes in physical fitness.

Interpretation of ion-exchange chromatographic retention based on an electrical double-layer model

An ion-exchange chromatographic model based on the Stern-Gouy-Chapman electrical double-layer theory is presented. We assume several equilibria occurring at the surface of an ion-exchange resin, such as the ion-pair formation of counterions with an ion-exchange site, the adsorption of ions, and the ion-pair formation of an adsorbed ions with their counterions. These equilibria are affected by the potential at the planes (the surface and the Stern layer potential) where the reactions occur. In addition, the nonselective accumulation of ions in the diffuse layer is also taken into account. Based on the developed model and derived equations, the nature of log k'-log X (X is the concentration of an eluent ion) plots is investigated for various sets of parameters and is compared with that of possible experimental results. Three extreme cases can be distinguished:  (1) ion-pair-controlled, (2) adsorption-controlled, and (3) accumulation in the diffuse layer-controlled retention. Though log k'-log X plots, when they are studied over wide eluent concentration ranges (more than 2 orders), do not necessarily show precise linearity especially in the presence of eluent adsorption and extremely high eluent ion-pair formation, the linear regression analyses give negative unit slopes (within 10% deviations) for monovalent solute-eluent combinations. Since the deviation from linearity relation is mostly found in very low k' ranges (e.g., k' < 1), it is possible only in very limited cases to confirm nonlinearity experimentally. This may have mistakenly led to the idea that selectivity coefficients can be regarded as constants and thus the log k'-log X plots should be linear with the slope equal to (charge ratios) × (-1) in ion-exchange chromatographic experiments. The efficiency of the developed model is verified by its ability to predict experimental results, e.g., nonlinear log k'-log X plots, changes in separation factors with varying ion-exchange affinity of an eluent ion, adsorption isotherms at different salt concentration, etc.

Reduced-distortion diffusion MRI of the craniovertebral junction

BACKGROUND AND PURPOSE

CVJ lesion suffers from a high sensitivity to susceptibility and distortion artifacts, which sometimes makes diffusion image difficult to interpret. Our purpose was to evaluate the potential for diffusion MR imaging using RS-EPI compared with SS-EPI in the assessment of the CVJ.

MATERIALS AND METHODS

RS-EPI and SS-EPI DTI images were acquired from 10 healthy volunteers using 3T MRI with a 32-channel head coil. For both sequences, the following parameters were used: 1-mm(2) in-plane resolution; 3-mm section thickness; TR = 5200 ms; 1 acquisition at b = 0 and 12 different encoding directions at b = 1000 seconds/mm(2). The RS-EPI sequence scan time was 9.44 minutes (1 average). The SS-EPI sequence was 9.37 minutes (8 averages). Diffusion tensor calculation and image analysis were performed using DTIStudio software. Diffusion trace images and color-coded fiber orientation maps were evaluated by 2 independent readers for distortion and delineation of fine structure using a semiquantitative scale in selected landmark locations. The absolute distances between the temporal base and the cerebellar contour between the T2-weighted images and the diffusion trace images obtained with RS-EPI and SS-EPI were also compared.

RESULTS

The contours of the temporal lobe and cerebellum were better delineated and distortion artifacts were clearly reduced with the RS-EPI sequence. More fine structures were also visible in the brain stem and cerebellum with the RS-EPI sequence. The amount of distortion was significantly reduced with RS-EPI compared with SS-EPI (P < .01).

CONCLUSIONS

The RS-EPI DTI sequence was less prone to geometric distortion than the SS-EPI sequence and allowed a better delineation of CVJ internal structure. Although the acquisition time is still relatively long, the RS-EPI appears as a promising approach to perform DTI studies in CVJ lesions, such as brain stem ischemia, neurodegenerative diseases, brain and skull base tumors, or inflammation.

Evaluation of CT angiography for visualisation of the lenticulostriate artery: difference between normotensive and hypertensive patients

OBJECTIVE

High-resolution CT angiography (CTA) is currently available using multidetector row CT (MDCT); however, its use for small artery visualisation has been limited. To evaluate its capability, we investigated CTA visualisation for difference in number of the lenticulostriate artery (LSA) branches between normotensive and hypertensive patients, because hypertension is a major cause of LSA damage.

METHODS

This was a retrospective study evaluating cerebrovascular CTA at our hospital conducted from February 2008 to June 2009 under approval of the institutional review board. 117 patients (39 males and 78 females, 19-88 years old) were included. CTA was conducted using a 64 channel MDCT. Total numbers of LSA branches were examined for differences by age with regression analysis and the presence or absence of hypertension and/or aneurysm using two-sample t-tests. A p-value <0.016 was considered statistically significant after correction for multiple comparisons. A multiple variable analysis of three factors was also conducted.

RESULTS

The average number of LSA branches was 3.6 [95% confidence interval (CI) 3.0-4.1] and 4.4 (95% CI 4.1-4.7), respectively, for a patient with and without history of hypertension, and the difference was statistically significant (p=0.013). The difference was approximately one branch in the multiple variable analysis. No significant correlation was observed for age and no significant difference was observed for the presence or absence of aneurysms.

CONCLUSIONS

Contrast-enhanced CTA can visualise significant differences in the number of LSA branches among patients with and without hypertension. Advances in knowledge Current high-resolution CTA can visualise LSA well, which enables finding a difference in the LSA between normotensive subjects and hypertensive patients.