| Background and objective :Psoriasis is a disease that occurs under the background of polygenic inheritance.It is a chronic inflammatory immune disease,which is mainly involved in malpighian cell and T cells.The main manifestation of patients with psoriasis is squamous erythema.Clinical studies have found that patients with psoriasis are prone to insulin resistance and metabolic disorder.However,abnormal levels of some metabolites may promote the body's inflammatory response.In recent years,metabonomics studies have shown that the level of galactose in patients with psoriasis significantly increased.Galactose is a kind of low sugar molecules produced in the glucose metabolism process.Galactosidase can resolve milk,carrageenan and other substances to galactose and finally into the glucose metabolism pathway under the action of related enzymes.Under normal circumstances,it can be metabolized.When the body with insulin resistant,glucose metabolism disorder,abnormal glucose metabolism enzymes,or when we eating too much food containing galactose,it may cause galactose accumulation in the body.When the concentration is too high,it will promote the secretion of IL-6,IL-1?,TNF-? and other inflammatory factors,then stimulate the inflammation in the body.IL-6,IL-1?,TNF-? and other inflammatory factors play an important role in the inflammatory reaction in patients with psoriasis,they are involved in the keratinocyte proliferation of patients with psoriasis.Whether the abnormal metabolism of galactose in psoriatic patients is related to the occurrence and development of psoriasis through the activation of inflammatory response is lack of relevant research.The objective of this study is to determine whether the level of galactose in psoriatic patients is higher than in normal subjects,and analyze the correlation between the levels of galactose and inflammatory factors,metabolic indexes in patients with psoriasis.Then investigat the effect of galactose onkeratinocyte proliferation,keratinocyte inflammatory factor expression and insulin signaling pathway by in vitro experiments.Finally,to investigat the level of alpha galactosidase mRNA expression in PBMC of patients with psoriasis vulgaris.Methods:(1)Investigat the levels of galactose in patients with psoriasis vulgaris and their correlation with metabolic markers and inflammatory factors: We collected the laboratory indicators and clinical data of 57 psoriasis vulgaris patients with psoriasis hospitalized in Guangdong Provincial Dermatology Hospital from Jan 2015 to Feb2017 and sex and age matched 28 controls.1.We tested the level of serum galactose of the two groups by colorimetry,and nalysed the difference of galactose levels between the two groups and the the correlation between galactose and PASI score,blood glucose,blood lipid and uric acid.2.A total of 38 patients with psoriasis vulgaris and16 normal subjects were randomly selected to detecte the serum levels of fasting insulin levels in the two groups by chemiluminescence method.The insulin resistance index was calculated by the steady state model method.Then analyzed the correlation between galactose and insulin resistance.3.A total of 25 patients with psoriasis vulgaris and 25 normal subjects were randomly selected to detecte the serum levels of IL-6,IL-1?,TNF-?,IL-17,IL-22 and IL-23 by ELISA,and then analyzed the relationship between serum galactose levels and inflammatory factors in patients with psoriasis vulgaris.(2)Effects of galactose on the proliferation of HaCaT cells,expression of inflammatory factors and PI3K/Akt pathway: 1.Cell proliferation assay: HaCaT cells were inoculated in 96-well plates for 24 h,and then different concentrations of galactose(0?mol/L,200 ?mol/L,500?mol/L,1000?mol/L,2000?mol/L,5000?mol/L)were added and cultured for another 24 h.The optical density of plates was then detected by a microplate reader at 450 nm.Three parallel holes were established foreach dose,and the experiment was thrice repeated.2.Text on inflammatory cytokine expression: HaCaT cells were inoculated in 12-well plates for 24 h,and then different concentrations of galactose(0?mol/L,200?mol/L,2000?mol/L)were added and cultured for another 24 h.Extracte the total RNA and test the expression of IL-6,IL-1?and TNF-? by RT-PCR method.3.Text on Insulin signaling pathway effect: Western Blot was used to test the expression of p-Akt and Akt in HaCa T cells which was interfered by different concentrations of galactose(0?mol/L,200?mol/L,2000?mol/L)for 24 h and then interfered by insulin for 10 mins.(3)Detection of alpha galactosidase m RNA expression in PBMC of patients with psoriasis vulgaris: mRNA was used to detect ?-galactosidase in patients with psoriasis vulgaris and healthy subjects by RT-PCR,then compare the mRNA expression levels of ?-galactosidase in these two groups.Results:(1)The levels of galactose in patients with psoriasis vulgaris and their correlation with metabolic markers and inflammatory factors: The level of serum galactose in patients with psoriasis vulgaris was significantly higher than that in normal controls(P<0.001).There was a positive correlation between galactose and triglyceride,insulin resistance index and negatively correlated with apolipoprotein A in patients with psoriasis vulgaris(P<0.05),and no significant association between galactose and the PASI score,glucose,uric acid,and other blood lipids.The levels of serum IL-6,IL-1?,TNF-?,IL-22 and IL-23 in patients with psoriasis vulgaris were significantly higher than those in normal subjects(P<0.05),but no significant difference in the levels of IL-17(P>0.05).Serum galactose levels were positively correlated with IL-22 levels in patients with psoriasis vulgaris(P<0.05),but no correlation between the levels of other inflammatory factors.(2)Effects of galactose on the proliferation of HaCaT cells,expression ofinflammatory factors and PI3K/Akt pathway: 1.Cell proliferation test: After 24-hour treatment by galactose(0?mol/L,200?mol/L,500?mol/L,1000?mol/L,2000?mol/L,5000?mol/L),the cell proliferation rate of 500?mol/L above concentration group was significantly higher than that of negative control group(P<0.05).2.Text on inflammatory cytokine expression: After 24-hour galactose treatment,the expression level of IL-6 in the 200 ?mol/L concentration galactose treatment group was significantly higher than that in the negative control group(P<0.05).The expression of IL-1? in HaCaT cells of doses at 200?mol/L,2000?mol/L were significantly higher than that in the negative control group(P<0.05).The expression of TNF-? in HaCaT cells of doses at 200?mol/L,2000 ?mol/L were no significant difference between the control group(P>0.05).3.Text on Insulin signaling pathway effect: Galactose could decrease the ratio of p-Akt/Akt in Insulin treated HaCaT cells when the concentration of galactose was 200?mol/L and 2000?mol/L(P<0.05,P<0.01).And the 2000?m concentration of galactose intervention group had a more significant influence on p-akt/akt ratio(P<0.05).(3)Detection of alpha galactosidase m RNA expression in PBMC of patients with psoriasis vulgaris: The expression of ?-galactosidase mRNA in psoriatic psoriasis vulgaris was significantly higher than that in healthy subjects(P<0.05)Conclusion:(1)The level of galactose in patients with psoriasis vulgaris was significantly higher than that in normal controls.The level of galactose was positively correlated with the levels of triglyceride,insulin resistance index and IL-22,and negatively correlated with the level of apolipoprotein A.It shows that galactose has some relation with metabolic disorder and inflammatory reaction in patients with psoriasis vulgaris.(2)Galactose in a certain concentration range can promote human keratinocyte proliferation in a certain concentration range,and promote the expression of IL-6 andIL-1? and inhibit the insulin signaling pathway in human keratinocyte cells.High levels of galactose in patients with psoriasis vulgaris may promote the proliferation of keratinocytes,the occurrence of insulin resistance and the inflammatory response in patients with psoriasis vulgaris by promoting the release of related inflammatory factors.(3)The mRNA expression levels of ?-galactosidase in patients with psoriasis vulgaris were significantly higher than those in healthy subjects,which might be one of the reasons for the increase of galactose levels in patients with psoriasis vulgaris.There was a significant positive correlation of galactose levels and insulin resistance in patients with psoriasis vulgaris,but the specific causal relationship is not clear.We can not exclude the probability than abnormal glucose metabolism caused by insulin resistance may lead to galactose accumulate in the body. |
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