Objective To investigate the effect of leptin on fibroblast proliferation and collagen synthesis as to elucidate that fibroblasts play a role in leptin’s effect on wound healing. Methods Purified dermal fibroblasts were derived from sucking wistar rat skin and exposedto leptin at concentration of 0, 10, 50, 100, 200, and 400 ng/ml. The survived fibroblasts were assessed by the colorimetric thiazolyl blue (MTT) assay. Replication of fibroblast was quantified by the incorporation of 3H-thymidine. Collagen synthesis of fibroblast cell was measured by the incorporation of 3H-proline into collagenasesensitive protein. Results The absorption of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 0.082±0.013, 0.091±0.018 was higher than that of control group 0.063±0.010, P＜0.05. The incorporations of 3H-thymidine of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 379±101 cpm,326±33 cpm were significantly higher than those of control group 219±56 cpm, P＜0.05. The incorporations of 3H-proline of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 911±55 cpm, 1 072±259 cpm were significantly higher than that of control group 679±176 cpm, P＜0.05. Conclusion Leptin can promote rat cutaneous fibroblast proliferation and collagen synthesis in vitro. This suggests that cutaneous fibroblast plays a role in leptin’s promoting skin wound healing and it may be one of the main mechanisms by which leptin enhances skin wound healing.
ObjectiveTo investigate the role of leptin receptor gene Gln223Arg polymorphism in pathogenesis of asthma. MethodsOne hundred and eighty-five asthmatic outpatients and inpatients in the Qingdao Municipal Hospital between June 2009 and May 2012 were recruited in the study.Two hundred and seven healthy volunteers were recruited as control.Peripheral blood was sampled from all subjects for measuring serum leptin level by ELISA,and analyzing leptin receptor gene Gln223Arg genotypes by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) in white blood cells. ResultsThere was significant difference in frequency distribution of leptin receptor gene Gln223Arg genotype between the asthma group and the health group (χ2=6.173,P=0.013,OR=1.697,95%CI 1.115-2.585).The GG genotype was associated with a 1.895-fold increased risk for asthma than the GA+AA genotype (χ2=7.283,P=0.007,OR=1.895,95%CI 1.187-3.024).The serum leptin level of the GG genotype group was significantly higher than that in the GA+AA genotype group[(2.56±1.47) ng/mL vs.(2.16±1.66) ng/mL]. ConclusionLeptin receptor gene Gln223Arg polymorphism is correlated with asthma, and the G allele might be the genetic factor that contributes to individual susceptibility for asthma by causing high serum leptin level.
ObjectiveTo explore the relationship between the -2548 G/A functional polymorphism in the 5′ promoter region of the leptin gene and gallstones. Methods The -2548 G/A polymorphisms of leptin gene were determined by polymerase chain reactionrestriction fragment length polymorphism technology (PCRRFLP) in 118 patients with cholesterol gallstones and 53 normal control subjects. Then the allele and genotype distribution were studied. Results The distribution of leptin2458 G/A in two groups was statistically significantly different: the genotype frequency of AA+GA of patients in gallstone group was higher than that in control group (χ2=4.251, P=0.039). AA+AG genotype had 2.813 times greater risk for gallstone disease compared with GG genotype (OR=2.813, 95% CI=1.020-7.757). Allele frequency distribution in the two groups was different: the allele frequency of A of patients in gallstone group was higher than that in control group (χ2=5.791, P=0.016). The risk of gallstone disease in the A alleles carriers was 1.777 times as higher as the carriers of G alleles (OR=1.777, 95% CI=1.110-2.844). ConclusionThe -2548 G/A polymorphism in the 5′ promoter region of leptin gene is significantly correlated with the gallstones. The A alleles of leptin may be a genetic factor which contributes to individual susceptibility for gallstone, while the G alleles of leptin may be a genetic factor that prevents people from gallstone.
ObjectiveTo investigate the effects of leptin on the oxidative damage in human retinal pigment epithelial (RPE) cells. MethodsHuman RPE cells (ARPE-19) were cultured in vitro, and randomly divided into control group and insulin resistance group. RPE cells were treated with 0, 10, 100 ng/mL leptin for 24, 48, 72 hours respectively. Then the levels of reactive oxygen species (ROS) expression in RPE cells were detected by 2', 7'-dichlorofluorescin-diacetate (DCFH-DA), and the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) expression in RPE cells were observed by immunocytochemistry (ICC), and the levels of human 8-oxoguanine DNA glycosylase l (hOGG1) expression in lysate were measured by Western blot. ResultsAfter 24, 48, 72 hours, the level of ROS (Control group:F=37.136, 37.178, 49.634; P < 0.05. Insulin resistance group:F=9.822, 28.881, 71.150;P < 0.05), 8-OHdG (Control group:F=88.643, 390.920, 1039.276;P < 0.05.Insulin resistance group:F=273.311, 299.155, 82.237;P < 0.05) and hOGGl (Control group:F=470.062, 1073.113, 295.456;P < 0.05. Insulin resistance group:F=240.032, 592.389, 527.760;P < 0.05) expression increased significantly with the increase of leptin concentration in control group and insulin resistance group. Under the same leptin concentration, the level of 8-OHdG has a trend that it was higher in the insulin resistance group than the control group. After 24 hours, the difference of hOGGl expression between control group and insulin resistance group was not significant (F=23.392, P > 0.05). After 72 hours, the level of hOGGl expression was significantly higher in the insulin resistance group than the control group (F=129.394, P < 0.05). The level of hOGGl expression was significantly higher at 48 hours than that at 24 hours and 72 hours (P < 0.05). ConclusionLeptin could induce the oxidative damage of RPE cells in normal and insulin resistance status. With the increase of leptin concentration and time extended, the degree of oxidative damage and its repair were both increased. The degree of oxidative repair increased with the increase of leptin concentration, but decreased with time extended.
ObjectiveTo explore the levels of serum leptin,TNF-α,IL-8 and hypersensitivity C-reactive protein (hs-CRP) in stable COPD patients with different body mass index (BMI). Methods30 healthy controls with BMI 18.5 to 23.9 kg/m2 and 105 patients with stable COPD were recruited in the study. The serum levels of leptin,TNF-α,and IL-8 were determined by radioimmunoassay and hs-CRP level was determined by versatile biochemical automatic analyzer. The COPD patients were divided into a low BMI group (BMI<18.5 kg/m2,n=32),a normal BMI group (BMI 18.5-23.9 kg/m2,n=48),and a high BMI group (BMI≥23.9 kg/m2,n=25). ResultsSerum leptin level in the COPD patients was significantly reduced compared with the control subjects (P<0.05). Serum leptin levels were reduced in the low BMI and the high BMI groups compare with the normal BMI group [(7.89±3.16)ng/L and (10.52±5.98)ng/L vs. (13.04±5.73) ng/L,P<0.01 or P<0.05]. Leptin level in the low BMI group was lower than that in the high BMI group (P<0.05). Serum TNF-α levels were significantly increased in the low BMI group compared with the normal BMI and high BMI groups [(229.39±89.57)μg/L vs. (180.06±74.24) μg/L and (189.46±82.41) μg/L,P<0.01]. Serum TNF-α level in the COPD patients was significantly increased compared with the control subjects [(192.37±83.65) μg/L vs. (178.59±60.38) μg/L,P<0.05]. The IL-8 levels were not significant different among three BMI groups with COPD. The hs-CRP level in the high BMI group was higher than that in the low BMI and normal BMI groups (P<0.05). ConclusionLeptin and TNF-α may be involved in weight-loss of COPD malnutritional patients.
ObjectiveTo investigate the levels of nutritional status, serum leptin, TNF-α, IL-8 and C-reactive protein(CRP) in patients with two clinical phenotypes of COPD. MethodsNutritional parameters, including body mass index, percent ideal body weight, triceps skin-fold thickness, mid-upper arm circumference, albumin, lymphocytes count, serum leptin, TNF-α, IL-8 and CRP levels were determined in 40 healthy controls and 120 patients with COPD. The COPD patients were divided into a typical emphysema type(A group) and a bronchitis type(B group), both groups included COPD patients in acute exacerbation phase and in stable phase. ResultsThe nutritional parameters in B group were higher than those in A group(P < 0.05). Serum leptin level was lower in stable A group and stable B group than that in the control group[(7.76±2.93) ng/L and (10.04±5.11) ng/L vs. (14.93±8.47) ng/L, P < 0.05], higher in A group[(12.99±5.56) ng/L)] and B group in acute exacerbation phase[(13.52±5.82) ng/L] than that in stable phase(P < 0.05), and lower in stable A group than that in stable B group (P < 0.05). Serum TNF-αlevel was higher in A group with acute exacerbation than that in B group with acute exacerbation and the control group[(234.65±95.74)μg/L and(195.03±88.00)μg/L vs. (182.07±42.35)μg/L, P < 0.05], and higher in stable A group than that in stable B group[(225.31±84.14)μg/L vs. (188.17±72.62)μg/L, P < 0.05]. Serum IL-8 level in A and B groups in acute exacerbation phase and stable phase was higher than that in the control group(P < 0.05), and was not significantly different between A group and B group in acute exacerbation or stable phase(P > 0.05). The CRP level was higher in A group and B group with acute exacerbation than that in the control group[(46.87±35.89) mg/L and(70.11±65.50) mg/L vs. (5.05±4.49) mg/L, P < 0.01], and higher in B group with acute exacerbation than that in A group with acute exacerbation (P < 0.05). ConclusionsThere are differences in nutritional status, serum leptin, TNF-αand CRP levels between the emphysema type and bronchitis type of COPD, while the IL-8 level is not different between two phenotypes. Leptin and TNF-αmay be involved in weight-loss of malnutritional COPD patients.
Obesity is closely related to thyroid function. The concentration of thyroid stimulating hormone (TSH) in obese patients is higher than that in the general population, and TSH will decrease accordingly after weight loss. Leptin is a bridge linking obesity and thyroid hormones, which can affect the release of TSH. There are many kinds of weight-reducing drugs that target the thyroid gland. Among them, thyroid hormone receptor-specific agonists may be potential drugs for future obesity treatment, but further studies are still needed.
Objective To evaluate the relationship between leptin level in serum and clinicopathologic features of colorectal cancer. Methods ABC-ELLSA was used to detect the leptin level in 30 cases of colorectal cancer without dystrophy (cancer group) and 24 normal controls (control group). The expressions of K-ras， p53， adenomatous polyposis coli （APC） gene and delete in colorectal carcinoma gene (DCC) mRNA of the tumor were examined by RT-PCR, the levels of serum CEA and CA19-9, and other clinicopathologic features were also recorded. Results The leptin level in cancer group 〔（3.53±1.72） μg/L〕 was higher than that in control group 〔（2.27±1.01） μg/L〕, P＜0.05, and the difference was independent on gender. There were no significant differences of leptin level in different tumor stages and different tumor location （Pgt;0.05）. Leptin level of poorly differentiated tumor was obviously lower than that of well differentiated and moderately differentiated tumor （P＜0.05）. There were no associations between leptin level and the levels of CEA and CA19-9, likewise there were no associations between leptin level and the expressions of K-ras, p53, APC and DCC in tumor （Pgt;0.05）. Conclusion The leptin level of colorectal cancer patient is higher than that of normal person, which is affected by the differentiation of tumor. But there are no significant correlations between the level of leptin in serum and TNM stage, tumor location, tumor markers of serum, K-ras, p53, APC or DCC in tumor.
Objective To study the leptin-mediated intracellular signal pathways and their effects on wound healing.Methods The literature was reviewed extensively, concerning the physical and chemical characters of leptin, the mechanism of its receptor action, the receptor-related intracellular signal pathways and their roles on wound healing. Results Leptin was a protein hormone expressed by ob gene with relative molecular mass 16×103, it could activate the main singal pathways such as Janus kinase/signal transducer and activator of transcription, mitogenactivated protein kinases and phosphoinositide-3-kinase pathways through binding with its specific receptor, to participate in the modulation of multiple functions including energy metabolism, weight balance and wound healing. Leptin receptors were widely distributed in various tissues, which suggest the multiple functions of leptin. Local leptin expression was increased after skin injured, and it could stimulate keratinocytes proliferation, epithelialization, fibroblast proliferation and collagen synthesis, resulting in accelarated wound repair. Leptin expression was significantly increased after mucosal injury or bacteria infections, leading to accelarated mucosal repair through modulation of mucosal glandular secretion, improvment of mucosal blood flow, and synergistic action with endothelin-1.Conclusion Leptin can promote wound healing through activating its receptor-related intracellular signal pathways.
Objective To investigate the relatingship between leptin receptor gene Gln223Arg polymorphism and obstructive sleep apnea hyponea syndrome (OSAHS) in Han population in Southwest China. Methods Two hundred and fifteen cases of subjects (including 116 cases in OSAHS group and 99 cases in control group) were selected in Han population in Southwest China. Polymerase chain reaction (PCR) was used to analyse Gln223Arg leptin receptor gene polymorphism. The levels of serum LEP and TI were determined by double antibody sandwich enzyme-linked immunosorbent assay (ELISA). Simultaneous determination of body mass index (BMI) and neck circumference (NC) and waist circumference (WC) were conducted. Results In the OSAHS group, the leptin receptor gene polymorphism Gln223Arg GG, AA and GA genotype frequency was 0.854, 0.017 and 0.129, respectively. G allele and A allele frequency frequency was 0.918 and 0.082, respectively. In the control group, leptin receptor gene polymorphisms Gln223Arg GG, AA and GA genotype frequency was 0.840, 0.020 and 0.14,respectively. G allele and A allele frequency was 0.90 and 0.10, respectively. Genotype frequencies of the two groups were not statistically significant (χ2=0.784, P>0.05). There were differences in BMI, WC and NC between the OSAHS patients with GG and the OSAHS patients with (GA+AA) genotype (P<0.05), but no difference was found in LEP and TI levels (allP>0.05). In control, mild, moderate and severe OSAHS group, the levels of serum LEP and TI were increased gradually, and the difference was statistically significant (allP<0.05). Conclusions Gln223Arg leptin receptor genotype polymorphisms may be involved in obesity, but they have no relationship with the incidence of OSAHS in Han population in Southwest China. In OSAHS patients, Gln223Arg polymorphism has no relationship with LEP or TI. Patients with OSAHS have hyperleptinemia and hyperinsulinemia.