Selective autophagy associated with iron overload aggravates non-alcoholic steatohepatitis via ferroptosis.

Non-alcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease (NAFLD) that causes cirrhosis and hepatocellular carcinoma. Iron is an essential trace element in the body; however, excess iron can cause tissue damage and dysfunction. Iron overload is often observed in patients with NASH, and the amount of iron accumulated in the liver positively correlates with the histological severity of NASH. Ferroptosis, a novel form of iron-dependent cell death, is caused by the accumulation of lipid peroxidation and oxidative stress and is related to NASH. In addition, ferroptosis is closely related to autophagy, an intracellular self-degradation process. Although autophagy has many beneficial effects, it may also be harmful to the organism, for example, inducing ferroptosis. It is unclear whether iron overload aggravates NASH via autophagy. The aim of this research is to determine the mechanism by which iron overload induces ferroptosis via autophagy and aggravates NASH. Stroke-prone spontaneously hypertensive rats (SHRSP5/Dmcr) were divided into two groups and fed a high-fat and high-cholesterol (HFC) diet for eight weeks. Iron dextran was administered to the Fe group in addition to the HFC diet. Blood analysis, histological staining, calcineurin activity assay, quantitative reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence staining, and electron microscopy were performed. The results showed that iron overload promoted autophagy via nuclear translocation of transcription factor EB (TFEB) and induced ferritinophagy, which is the autophagic degradation of ferritin. In addition, the HFC diet induced lipophagy, the autophagic degradation of lipid droplets. The Fe group also exhibited promoted ferroptosis and aggravated hepatic inflammation and fibrosis. In conclusion, iron overload accelerates ferritinophagy and lipophagy, aggravating NASH pathology via ferroptosis. These findings indicate the therapeutic potential of inhibiting autophagy and ferroptosis for treating NASH.

Antioxidant action of xanthine oxidase inhibitor febuxostat protects the liver and blood vasculature in SHRSP5/Dmcr rats.

BACKGROUND: Xanthine oxidase (XO) generates reactive oxygen species during uric acid production. Therefore, XO inhibitors, which suppress oxidative stress, may effectively treat non-alcoholic steatohepatitis (NASH) and atherosclerosis via uric acid reduction. In this study, we examined the antioxidant effect of the XO inhibitor febuxostat on NASH and atherosclerosis in stroke-prone spontaneously hypertensive 5 (SHRSP5/Dmcr) rats. METHODS: SHRSP5/Dmcr rats were divided into three groups: SHRSP5/Dmcr + high-fat and high-cholesterol (HFC) diet [control group, n = 5], SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) [fructose group, n = 5], and SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) + febuxostat (1.0 mg/kg/day) [febuxostat group, n = 5]. Glucose and insulin resistance, blood biochemistry, histopathological staining, endothelial function, and oxidative stress markers were evaluated. RESULTS: Febuxostat reduced the plasma uric acid levels. Oxidative stress-related genes were downregulated, whereas antioxidant factor-related genes were upregulated in the febuxostat group compared with those in the fructose group. Febuxostat also ameliorated inflammation, fibrosis, and lipid accumulation in the liver. Mesenteric lipid deposition decreased in the arteries, and aortic endothelial function improved in the febuxostat group. CONCLUSIONS: Overall, the XO inhibitor febuxostat exerted protective effects against NASH and atherosclerosis in SHRSP5/Dmcr rats.

Suppression of nitric oxide synthase aggravates non-alcoholic steatohepatitis and atherosclerosis in SHRSP5/Dmcr rat via acceleration of abnormal lipid metabolism.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is a progressive subtype of non-alcoholic fatty liver disease (NAFLD) that is closely related to cardiovascular disease (CVD). Nitric oxide (NO) plays a critical role in the control of various biological processes. Dysfunction of the NO signaling pathway is associated with various diseases such as atherosclerosis, vascular inflammatory disease, and diabetes. Recently, it has been reported that NO is related to lipid and cholesterol metabolism. Chronic NO synthase (NOS) inhibition accelerates NAFLD by increasing hepatic lipid deposition. However, the detailed relationship between NO and abnormal lipid and cholesterol metabolism in NAFLD/NASH has not been completely explained. We aimed to determine the effects of NOS inhibition by N omega-nitro-L-arginine methyl ester hydrochloride (L-NAME), a NOS inhibitor, on NASH and CVD via lipid and cholesterol metabolism. METHODS: Stroke-prone spontaneously hypertensive rats were fed a high-fat and high-cholesterol diet for 8 weeks and administered L-NAME for the last 2 weeks. Following blood and tissue sampling, biochemical analysis, histopathological staining, quantitative RT-PCR analysis, and western blotting were performed. RESULTS: L-NAME markedly increased hepatic triglyceride (TG) and cholesterol levels by promoting TG synthesis and cholesterol absorption from the diet. L-NAME increased the mRNA levels of inflammatory markers and fibrotic areas in the liver. Cholesterol secretion from the liver was promoted in rats administered L-NAME, which increased serum cholesterol. L-NAME significantly increased the level of oxidative stress marker and lipid deposition in the arteries. CONCLUSIONS: NOS inhibition simultaneously aggravates NASH and atherosclerosis via hepatic lipid and cholesterol metabolism.

Basic characteristics between mechanomyogram and muscle force during twitch and tetanic contractions in rat skeletal muscles.

The mechanomyogram (MMG) is a signal measured by various vibration sensors for slight vibrations induced by muscle contraction, and it reflects the muscle force during electrically induced-contraction or until 60%-70% maximum voluntary contraction, so the MMG is considered an alternative and novel measurement tool for muscle strength. We simultaneously measured the MMG and muscle force in the gastrocnemius (GC), vastus intermedius (VI), and soleus (SOL) muscles of rats. The muscle force was measured by attaching a hook to the tendon using a load cell, and the MMG was measured using a charged-coupled device-type displacement sensor at the middle of the target muscle. The MMG-twitch waveform was very similar to that of the muscle force; however, the half relaxation time and relaxation time (10%), which are relaxation parameters, were prolonged compared to those of the muscle force. The MMG amplitude correlated with the muscle force. Since stimulation frequencies that are necessary to evoke tetanic progression have a significant correlation with the twitch parameter, there is a close relationship between twitch and tetanus in the MMG signal. Therefore, we suggest that the MMG, which is electrically induced and detected by a laser displacement sensor, may be an alternative tool for measuring muscle strength.

Bile acids aggravate nonalcoholic steatohepatitis and cardiovascular disease in SHRSP5/Dmcr rat model.

BACKGROUND AND AIMS: Nonalcoholic steatohepatitis (NASH) is linked to an increased risk of cardiovascular disease, regardless of the risk factors in metabolic syndrome. However, the intermediary factors between NASH and cardiovascular disease are still unknown. A previous study revealed that serum and hepatic bile acid (BA) levels are increased in some NASH patients. We aimed to examine whether NASH and cardiovascular disease were aggravated by BA using an animal model. METHOD AND RESULTS: From 10 to 18 weeks of age, SHRSP5/Dmcr rats divided into 3 groups were fed 3 types of high-fat and high-cholesterol (HFC) diets which were changed in the cholic acid (CA) concentration (0%, 2%, or 4%). The nitro oxide synthase inhibition (L-NAME) was administered intraperitoneally from 16 to 18 weeks of age. The 4% CA groups showed the worst LV dysfunction and myocardial fibrosis, and demonstrated severe hepatic fibrosis and lipid depositions. In addition, a large amount of lipid accumulation was observed in the aortas of the 4% CA group, and NFκB and VCAM-1 gene expression levels were increased. These findings were not seen in the 0% CA group. CONCLUSION: In the SHRSP5/Dmcr rat model, NASH and cardiovascular disease were aggravated with increasing BAs concentrations in an HFC diet.

Influence of different mixing pads on physical and mechanical properties of glass ionomer cement / 北京大学学报(医学版)

OBJECTIVE@#To analyze the influence of different mixing pads on the physical and mechanical properties of glass ionomer cement.@*METHODS@#Three different glass ionomer base cements were mixed with a plastic spatula on three different mixing pads including paper pad, glass pad and silicon pad whose HS were 40, 60 and 80. The GIC was packed into stainless steel molds to get specimens. Surface roughness, surface hardness and compressive strength were evaluated.@*RESULTS@#As for compressive strength, CF: There was the highest mean compressive strength that was significantly higher than those of silicon pad 60 group, paper 60 group and paper 20 group in silicon pad 40 group, the differences P values were 0.002, 0.027, and 0.036, statistically significant difference between the above groups (P<0.05). IX: there was the highest mean compressive strength that was significantly higher than those of silicon pad 60 group in paper pad 20 group,the differences P value was 0.008, statistically significant (P<0.05). FX: there was the highest mean compressive strength that was no significantly higher than those of paper pad 20 group in silicon pad 40 group, but was significantly higher than those of the other groups. As for surface hardness, CF: there was the highest mean surface hardness that was significantly higher than those of silicon pad 60 and 80 group, paper 60 group in silicon pad 40 group, the differences P value was 0.021, 0.001, 0.032, 0.008 and 0.016, statistically significant difference between the above groups (P<0.05). IX and FX: there was no statistical significance between any two groups in surface hardness. As for surface roughness, CF: there was no statistical significance between any two groups in surface roughness. IX: there was the lowest mean surface roughness that was significantly lower than those of paper pad 40 and 60 group in glass pad group, the differences P values were 0.003 and 0.027, statistically significant difference between the above groups (P<0.05). FX: there was the lowest mean surface roughness that was significantly lower than those of paper pad 60 group in glass pad group, the differences P value was 0.018, showing a statistical difference (P<0.05).@*CONCLUSION@#Mixing glass ionomer cement on silicon pad 40 results in higher compressive strength and lower surface roughness, worthy of clinical popularization.

Effects of different beverages on plaque pH of different caries-sensitive children / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the impacts of different beverages on plaque pH of caries-sensitive and caries-free children and to evaluate the applicability of in situ pH measurements in human dental plaque using Beetrode microelectrode.</p><p><b>METHODS</b>The subjective population consisted of 20 children (aged 3-5 years). Ten of them were caries-free(dmft = 0); the other were caries-active (dmft > 4). The dental plaque pH were measured in situ with a pH microelectrode within 1 h after drinking three different beverages respectively. Then the resting pH value (pHrest), minimum pH value (pHmin), the range of the pH (deltapH) was analyzed by ANOVA. Results There was a significant difference in pHrest between caries-free and caries-sensitive children. All the pH responses in the plaque following drinking three different beverages showed a classic Stephan-type response. The differences of the pHmin, deltapH in sound sites were no statistic significance (P > 0.05) after drinking beverages in caries-free children. However the changes in the caries-sensitive group were more pronounced than the non-caries group. There were significant differences on the pHmin, deltapH among different beverages (P < 0.05).</p><p><b>CONCLUSION</b>The cariogenicity of plaque in caries-active children was stronger than that of the caries-free group. Different beverages have different potential cariogenicity.</p>

Study on the horizontal transmission of oral Streptococcus mutans in day-nursery children / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To analyze genotypic diversity of oral Streptococcus mutans (S. mutans) and find out horizontal transmission possibility of the microbe in day-nursery children.</p><p><b>METHODS</b>The plaque samples were scratched with sterilized toothpicks from teeth of 32 day-nursery children aged between 3 and 4, then cultured on MSB plates. Clones with representative S. mutans-like were subcultured and identified to species level biochemically. AP-PCR fingerprinting was performed to distinguish genotypic diversity of those isolates. Then S. mutans isolated from different children with very similar amplicon profiles were examined by chromosomal DNA fingerprinting analysis.</p><p><b>RESULTS</b>S. mutans were isolated in oral cavities of 78.1% children, 100% in caries and 69.6% in caries-free children. A total of 57 genotypes were identified by AP-PCR. More than one amplitypes were identified in 88% of the 25 children with S. mutans colonization. Two pair of children shared common genotypic S. mutans.</p><p><b>CONCLUSION</b>There is no evident relation between number of genotype detected and caries. The presence of matching genotypes of S. mutans among day-nursery children suggests the horizontal transmission may exist.</p>

Transmission way of oral Streptococcus mutans in children / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To find out different transmission ways of oral mutans Streptococci (MS) in nursery children.</p><p><b>METHODS</b>The study group included 44 nursery children between 3 and 4 years of age and 20 mothers. Dental plaque samples were collected with sterile toothpick and cultured on MSB plates for 48 h. Individual MS colonies representative of the colonial morphologies were subcultured on TPY plates. These strains were biochemically identified to species level. AP-PCR fingerprinting analysis was preformed after identification.</p><p><b>RESULTS</b>MS was isolated in oral cavities of 65.9% children in 44 babies and 50% pairs in 20 mother-child pairs. A total of 98 MS isolates from 44 children and 20 mothers were isolated. Thirty-two different amplitype were identified in 10 mother-child pairs colonized by MS and there were similar genotypes in 7 pairs of mother-child. Twenty-nine different amplitype were identified in 24 nursery children, and there were 2 genotypes of MS isolated repeatedly among 13 nursery children.</p><p><b>CONCLUSIONS</b>The presence of matching genotypes of MS among nursery children and their mothers suggests horizontal and vertical transmission.</p>

Study on the horizontal transmission of oral Streptococcus mutans in children / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To find out horizontal transmission of oral Streptococcus mutas (S. mutans) in nursery children through analyzing the similarity of S. mutans genotypes.</p><p><b>METHODS</b>The study group included 24 nursery children between 3 and 4 years of age. Dental plaque samples were collected with sterile toothpick and cultured on MSB plates for 48 h. Individual Streptococcus mutans group colonies representative of the colonial morphologies were subcultured on TPY plates. These strains were identified to species level biochemically. AP-PCR fingerprinting was preformed after identification. S. mutans isolates from different children with very similar fingerprinting profiles were examined by chromosomal DNA fingerprinting analysis.</p><p><b>RESULTS</b>Streptococcus mutans group were isolated in oral cavities of 66.7% children, 58.3% in caries-free and 75.0% in caries children. A total of 4' S. mutans isolates from 24 subjects were analyzed by AP-PCR, and 29 different amplitypes were identifyied, 45.8% carried tw. genotypes. There were 2 genotypes of S. mutans isolated repeatedly among 12 nursery children.</p><p><b>CONCLUSION</b>The presence of matching genotypes of S. mutans among nursery children suggests horizontal transmission.</p>