Relative expression and correlation of tumor necrosis factor-α, interferon-γ, and interleukin-17 in the rheumatoid synovium.

Although tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin-17 (IL-17) play important roles in RA, their relative expression and possible correlation in synovial tissues are not well understood. In this study, mRNA expression levels of IFN-γ, IL-17, and TNF-α were investigated in individual patients with RA and the correlations between pairs of these three pro-inflammatory cytokines were analyzed. Synovial tissues were obtained during arthroplasties from 24 joints of 24 RA patients. After harvesting synovial tissues, total RNA was isolated then quantitative real-time polymerase chain reaction (qRT-PCR) for IFN-γ, IL-17, and TNF-α was performed. Correlation of expression levels between them was also analyzed. Expression levels of TNF-α, IFN-γ, and IL-17 in patients receiving TNF inhibitors (TNFi) and those treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) alone were also compared between groups. Based on relative expression levels of the three pro-inflammatory cytokines, patients were classified into three major types; an IFN-γ plus TNF-α-dominant type, an IL-17-dominant type, and the other type. TNF-α expression levels were correlated with IFN-γ. In addition, there was a negative correlation between TNF-α and IL-17, and IFN-γ and IL-17. Median relative expression levels of TNF-α have no significant difference between the TNFi and the csDMARDs groups. In the rheumatoid synovial tissues, expression levels of TNF-α were modulated in parallel with IFN-γ, and TNF-α and IL-17, or IFN-γ and IL-17 did not co-express at high levels. This characteristic expression pattern of the three pro-inflammatory cytokines may be clinically useful information in the current cytokine-targeted treatment with biological DMARDs for RA.

Increase of nerve growth factor levels in the human herniated intervertebral disc: can annular rupture trigger discogenic back pain?

INTRODUCTION: Nerve growth factor (NGF) has an important role in the generation of discogenic pain. We hypothesized that annular rupture is a trigger for discogenic pain through the action of NGF. In this study, the protein levels of NGF in discs from patients with disc herniation were examined and compared with those from discs of patients with other lumbar degenerative disc diseases. METHODS: Patients (n = 55) with lumbar degenerative disc disease treated by surgery were included. Nucleus pulposus tissue (or herniated disc tissue) was surgically removed and homogenized; protein levels were quantified using an enzyme-linked immunosorbent assay (ELISA) for NGF. Levels of NGF in the discs were compared between 1) patients with herniated discs (herniated group) and those with other lumbar degenerative disc diseases (non-herniated group), and 2) low-grade and high-grade degenerated discs. Patient's symptoms were assessed using a visual analog scale (VAS) and the Oswestry disability index (ODI); the influence of NGF levels on pre- and post-operative symptoms was examined. RESULTS: Mean levels of NGF in discs of patients were significantly higher in herniated discs (83.4 pg/mg total protein) than those in non-herniated discs (68.4 pg/mg). CONCLUSIONS: This study reports that NGF increased in herniated discs, and may play an important role in the generation of discogenic pain. Analysis of patient symptoms revealed that pre-operative NGF levels were related to post-operative residual lower extremity pain and LBP in motion. The results suggest that NGF in the disc is related to pain generation, however, the impact of NGF on generation of LBP varies in individual patients.

Phosphorylated neurofilament subunit NF-H becomes elevated in the cerebrospinal fluid of patients with acutely worsening symptoms of compression myelopathy.

It is known that the severity of compression myelopathy sometimes worsens rapidly and results in poor functional recovery because of limited axonal regeneration. Levels of phosphorylated neurofilament subunit NF-H (pNF-H), which indicate axonal degeneration, are elevated in other neurological disorders. To our knowledge, there has been no examination of pNF-H levels in compression myelopathy. Therefore, we conducted a pilot cross-sectional study to evaluate pNF-H levels in the cerebrospinal fluid (CSF) of patients with worsening symptoms of cervical compression myelopathy. From January 2011 to March 2013, 51 samples of CSF were collected from patients at the time of myelography before spinal surgery. The indications for surgery were acutely worsening compression myelopathy (AM) in eight, chronic compression myelopathy (CM) in six, and lumbar canal stenosis (LCS) in 37 patients. The pNF-H levels were measured using a standard enzyme-linked immunosorbent assay. The mean ± standard deviation pNF-H value was 2127.1 ± 556.8 pg/ml in AM patients, 175.8 ± 67.38 pg/ml in CM patients and 518.7 ± 665.7 pg/ml in LCS patients. A significant increase in pNF-H levels was detected in the CSF of patients with AM compared with those with either CM or LCS. The clinical outcome of surgical treatment for patients with cervical myelopathy was satisfactory in both AM and CM patients. Despite the limitations of small sample size and lack of healthy CSF control data due to ethical considerations, our results suggest that pNF-H in CSF can act as a biomarker that reflects the severity of AM.

Atorvastatin and pitavastatin enhance lipoprotein lipase production in L6 skeletal muscle cells through activation of adenosine monophosphate-activated protein kinase.

Pravastatin and atorvastatin increase the serum level of lipoprotein lipase (LPL) mass in vivo but do not increase LPL activity in 3T3-L1 preadipocytes in vitro. LPL is mainly produced by adipose tissue and skeletal muscle cells. Metformin enhances LPL in skeletal muscle through adenosine monophosphate-activated protein kinase (AMPK) activation but not in adipocytes. This study aimed to examine the effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) on LPL production and to investigate the mechanism by which statins enhance skeletal muscle cell LPL production. L6 skeletal muscle cells were incubated with pravastatin, simvastatin, atorvastatin or pitavastatin. LPL activity, protein levels and mRNA expression were measured. Atorvastatin and pitavastatin significantly increased LPL activity, protein levels and mRNA expression in L6 skeletal muscle cells at 1 µmol/L, but neither statin had an effect at 10 µmol/L. We measured AMPK to clarify the mechanism by which statins increase LPL production in skeletal muscle cells. At 1 µmol/L, both atorvastatin and pitavastatin enhanced AMPK activity, but this enhancement was abolished when AMPK signaling was blocked by compound C. The increased expressions of LPL protein and mRNA by atorvastatin and pitavastatin were reduced by compound C. In addition, mevalonic acid abolished atorvastatin- and pitavastatin-induced AMPK activation and LPL expression. These results suggest that atorvastatin and pitavastatin increase LPL activity, protein levels and LPL mRNA expression by activating AMPK in skeletal muscle cells.

Formula diet is effective for the reduction and differentiation of visceral adipose tissue in Zucker fatty rats.

AIM: Formula diet (FD), which is used as a tool for calorie restriction, has beneficial effects on metabolic disorders in obese patients; however, the molecular mechanism is not fully understood. METHODS: Sixteen-week-old male Zucker Diabetic Fatty (ZDF) rats were divided into 3 groups (n= 10 each): calorie-controlled low-fat diet [Control; 75 kcal/day, protein : fat : carbohydrate (P:F:C)=25:15: 60], calorie-restricted low-fat diet (CR-LFD; 56 kcal/day, P:F:C=25:15:60), and calorie-restricted FD (CR-FD; 56 kcal/day, P:F:C=50:14:36) group, and fed each diet for 4 weeks. Before the study, baseline data were obtained in 10 rats. After 4 weeks, body weight and epididymal fat weight were measured, and blood samples, mesenteric and subcutaneous adipose tissues were collected for analyses. Messenger RNA expression was evaluated by real-time PCR, and protein expression by Western blotting. RESULTS: The decrease in epididymal fat weight was significantly greater in the CR-FD group than in control and CR-LFD groups, although changes in body weight were not different among groups. The decrease in fasting plasma glucose and increase in plasma adiponectin were greater in the CR-FD group than in the control group, but not in the CR-LFD group. The decrease in triglyceride and increase in HDL-cholesterol were greatest in the CR-FD group. Both mRNA and protein of peroxisome proliferator-activated receptor γ coactivator (PGC)-1α, adiponectin, lipoprotein lipase and PPARγ were overexpressed in the CR-FD group, especially in mesenteric adipose tissue. CONCLUSIONS: FD may have beneficial effects on abdominal obesity and metabolic disorders by reducing visceral fat and improving glucose and lipid profiles, possibly through modulating adipose tissue function.

Metformin promotes induction of lipoprotein lipase in skeletal muscle through activation of adenosine monophosphate-activated protein kinase.

Metformin is known to increase lipoprotein lipase (LPL) mass level in serum. Lipoprotein lipase is produced by adipose tissue and skeletal muscles. This study aimed to examine the effect of metformin on LPL production in adipocytes and skeletal muscle cells and to investigate the mechanism by which metformin enhances LPL production. 3T3-L1 preadipocytes and L6 skeletal muscle cells were incubated with metformin or 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR). Lipoprotein lipase activity, LPL protein expression, and LPL messenger RNA (mRNA) expression were measured. Metformin increased LPL activity only in skeletal muscle cells. To clarify the mechanism of this phenomenon, AICAR, which is well known as an activator of adenosine monophosphate-activated protein kinase (AMPK), was used. Metformin and AICAR enhanced phosphorylated AMPK in skeletal muscle cells by Western blot analysis. Like metformin, AICAR increased LPL activity only in skeletal muscle cells. Both metformin and AICAR also enhanced LPL protein and LPL mRNA expressions in skeletal muscle cells but not in adipocytes. Phosphorylated AMPK protein expression was decreased when AMPK signaling was interfered by AMPKalpha small interfering RNA. Lipoprotein lipase activity and LPL expression, which were enhanced by 1 mumol/L metformin, were reduced by AMPKalpha small interfering RNA. These results suggest that metformin increases LPL activity, LPL protein expression, and LPL mRNA expression through activation of AMPK in skeletal muscle cells but not in adipocytes.

Suppression of lipoprotein lipase expression in 3T3-L1 cells by inhibition of adipogenic differentiation through activation of the renin-angiotensin system.

The renin-angiotensin system (RAS) may inhibit adipogenic differentiation by down-regulating peroxisome proliferator-activated receptor gamma gene expression in adipocytes, and adipocytes express all components of the RAS, including angiotensinogen. Expression of lipoprotein lipase (LPL), which is expressed mainly in adipocytes, is considered to be affected by adipogenic differentiation. We studied whether LPL expression in mouse 3T3-L1 cells is suppressed by inhibition of adipogenic differentiation through activation of RAS by the cells. The mean 3T3-L1 cell size increased and peroxisome proliferator-activated receptor gamma messenger RNA (mRNA) expression in the cells measured by reverse transcriptase polymerase chain reaction (RT-PCR) was enhanced with increase in incubation time. The LPL activity, LPL protein expression (Western blot), and mRNA expression (RT-PCR) in 3T3-L1 cells increased transiently followed by a decline during long-term incubation. Angiotensin II suppressed adipogenic differentiation, LPL activity, protein expression, and mRNA expression in 3T3-L1 cells. On the other hand, the selective angiotensin type 1 receptor blocker valsartan enhanced adipogenic differentiation and LPL activity in 3T3-L1 cells. Angiotensinogen mRNA expression in 3T3-L1 cells measured by RT-PCR was enhanced with increase in incubation time. These results suggest that LPL expression may be suppressed by inhibition of adipogenic differentiation through activation of endogenous RAS in 3T3-L1 cells angiotensin type 1 receptor.

Vascular smooth muscle cell apoptosis induced by 7-ketocholesterol was mediated via Ca2+ and inhibited by the calcium channel blocker nifedipine.

Previous reports indicate that 7-ketocholesterol (7KCHO) induces apoptosis of cultured human vascular smooth muscle cells (SMCs). We hypothesized that calcium channel blockers will inhibit SMC apoptosis induced by 7KCHO because caspase-3 activity is Ca2+ dependent and 7KCHO stimulates caspase-3 and SMC apoptosis. So, the protective effect of the calcium channel blocker nifedipine on SMC apoptosis induced by 7KCHO was investigated. When 7KCHO (50 micromol/L) was added to SMCs, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling was positive. DNA extracted from SMCs exposed to 7KCHO showed a ladder pattern on agarose electrophoresis. In the presence of extracellular Ca2+, the Ca2+ influx, caspase-3 activity, and fragmented DNA also increased in SMCs incubated with 7KCHO dose-dependently. However, in the absence of extracellular Ca2+, no effects of 7KCHO on caspase-3 activity and fragmented DNA were observed. In the presence of nifedipine, the 7KCHO-induced increases in Ca2+ influx, caspase-3 activity, and the amount of fragmented DNA decreased significantly. These results suggest that 7KCHO-induced apoptosis of SMCs is inhibited by calcium channel blockade, and that Ca2+ influx into cells mediated by 7KCHO plays an important role in 7KCHO-induced apoptosis.

Pitavastatin enhanced lipoprotein lipase expression in 3T3-L1 preadipocytes.

It is known that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) enhance the expression- of the low-density lipoprotein (LDL) receptor and lower the level of LDL cholesterol in the blood. But, a triglyceride (TG)-lowering effect is also observed during their administration. To clarify the possibility that statins enhance LPL activity and its mechanism, the effects of statins on the expression of LPL in adipocytes were studied. When statins (pravastatin, simvastatin, atorvastatin and pitavastatin) were added to the culture medium of mouse 3T3-L1 preadipocytes at final concentrations of 1 microM for 3 days, LPL activity increased. Pitavastatin increased the activity the most. Western and Northern blotting showed that LPL protein and m-RNA were strongly expressed on the addition of pitavastatin. With the addition of mevalonate (10 microM, 3 days), LPL activity weakened significantly. Statins, especially pitavastatin, increased the expression of LPL in 3T3-L1 preadipocytes. The TG-lowering effect of pitavastatin might be mediated by enhancement of LPL production in adipocytes.