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.
Objective To investigate the role of inflammatory factors like serumleptin, adiponectin,interleukin-6( IL-6) , and C-reactive protein ( CRP) in the systemic inflammatory response of smokinginduced COPD. Methods Thirty male Wistar rats were randomly divided into three groups, ie. a high-dose smoking group, a low-dose smoking group, and a control group. Serum leptin, adiponectin, IL-6, and CRP levels were measured by ABC-ELISA. Results The serum leptin and adiponectin levels in both smoking groups decreased significantly compared with the control group( P lt; 0. 05) , while the difference was not significant between the two smoking groups ( P gt; 0. 05) . The serum IL-6 and CRP levels in both smoking groups increased significantly compared with the control group( P lt; 0. 05) , which were higher in the highdosesmoking group than those in the low-dose smoking group( P lt;0. 05) . Conclusions Smoking increases the serum levels of IL-6 and CRP, but reduces the serum levels of leptin and adiponectin in rats. These results suggest that leptin, adiponectin, IL-6, and CRP may be involved in the systemic inflammatory response of smoking-induced COPD.
Objective To discuss the correlation between the letpin level and the pathogenesis of avascular necrosis of the femoral head (ANFH) by measuring the leptin expression of the femoral head in patients with ANFH. Methods Between July 2009 and February 2011, 16 patients with ANFH (including 10 cases of steroid-induced ANFH and 6 cases of alcohol-induced ANFH, ANFH group) and 11 patients with proximal femur fracture (control group) were included in the experiment. There was no significant difference in age, weight, and body mass index between 2 groups (P gt; 0.05). The peripheral blood and bone marrow were extracted to measure the blood lipid level and the free fat (FF) content, respectively. ELISA was used to detect the levels of the leptin, soluble leptin receptor (sLR), osteoprotegerin (OPG), and soluble receptor activator of nuclear factor κB (sRANKL); the leptin biological activity and the activity of osteoclasts were calculated. The femoral head specimens were harvested to count leptin-positive cells by immunohistochemical staining. Results No significant difference in the blood lipid level was found between 2 groups (P gt; 0.05), but the FF content in ANFH group was significantly lower than that in control group (t= — 14.230, P=0.000). The intramedullary leptin expression was found in both groups; however, the intramedullary leptin level in ANFH group decreased significantly when compared with the level in control group (t=4.425, P=0.002). There were significant differences in the levels of leptin, OPG, and sRANKL between 2 groups (P lt; 0.05). The leptin biological activity of ANFH group was significantly lower than that of control group (P lt; 0.05), but the activity of osteoclasts of ANFH group was significantly higher than that of control group (P lt; 0.05). There was a positive correlation between the leptin level and leptin biological activity (r=0.922 7, P=0.000 0), and a negative correlation between the leptin level and OPG content (r= — 0.396 2, P=0.040 8), FF content (r= — 0.806 1, P=0.000 0), while it had no correlation between the leptin level and sLR and sRANKL content (P gt; 0.05). Conclusion Intramedullary expression and bioactivity of the leptin decrease significantly in ANFH patients, which may play an important role in the pathogenesis of ANFH.
Objective To investigate the effect and mechanism of leptin (LEP) on the osteoblastic differentiation of hBMSCs in vitro. Methods Whole bone marrow culture method was appl ied to culture hMBSCs and hBMSCs at passage 3 were divided into groups A, B, C, D, E and F, and when cell attachment was evident, 400, 200, 100 and 50 ng/mL LEP, 100 ng/mLBMP and common nutrient medium were added into each group, respectively. ALP staining and mineral ized nodules staining were conducted at 7 and 21 days after culture, respectively. And inverted phase contrast microscope observation was performed. ALP activity and osteocalcin (OCN) level of hBMSCs in each group was detected at 7, 14 and 21 days after culture to select the best induced concentration of LEP on osteoblastic differentiation. For groups of B, E and F at 7 days after culture, RT-PCR was adopted to detect the expression of such osteogenesis-related genes as core-binding factor α 1 (Cbfα1), ALP, Col I and OCN mRNA. Results At 7 days after induced culture, the ALP staining result showed that the endochylema in groups A, B, C, D and E were stained blue and the endochylema in the group F was sl ightly positive. At 21 days after induced culture, the mineralized nodules staining showed that cells in groups A, B, C, D and E were stained positively and cells in group F were negative. At 7, 14 and 21 days after culture, ALP and OCN activities in group B were less than that of group E (P lt; 0.05), but significant higher than that of groups A, C, D and F (P lt; 0.05), the optimal concentration of LEP was 200 ng/mL. At 7 days after culture, group F witnessed no expression of Cbfα1, ALP, Col I and OCN mRNA, while groups B and E witnessed expressions of all those indexes, but the expressions in group B were less than those of group E. Conclusion LEP can stimulate osteoblastic differentiation of hBMSCs in vitro, and the possible mechanism is its role of promoting the expression of osteoblastic related genes.
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 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.
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.
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.