Leptin is the protein product encoded by the obese (ob)gene. It is a circulating hormone produced primarily by the adipose tissue. ob/ob mice with mutations of the gene encoding leptin become morbidly obese, infertile...Leptin is the protein product encoded by the obese (ob)gene. It is a circulating hormone produced primarily by the adipose tissue. ob/ob mice with mutations of the gene encoding leptin become morbidly obese, infertile, hyperphagic, hypothermic,and diabetic. Since the cloning of leptin in 1994, our knowledge in body weight regulation and the role played by leptin has increased substantially. We now know that leptin signals through its receptor, OB-R, which is a member of the cytokine receptor superfamily. Leptin serves as an adiposity signal to inform the brain the adipose tissue mass in a negative feedback loop regulating food intake and energy expenditure. Leptin also plays important roles in angiogenesis, immune function, fertility and bone formation. Humans with mutations in the gene encoding leptin are also morbidly obese and respond to leptin treatment,demonstrating that enhancing or inhibiting leptin’s activities in vivo may have potential therapeutic benefits.展开更多
AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia. METHODS: By immunohistochemical staining using specifi c antibodies, we evaluated the expression of leptin and O...AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia. METHODS: By immunohistochemical staining using specifi c antibodies, we evaluated the expression of leptin and OB-R in 207 gastric carcinomas (100 early and 107 advanced carcinomas) and analyzed their relationship with clinicopathological features. RESULTS: Both normal gastric epithelium and carci- noma cells expressed a significant level of leptin. In cases with OB-R staining, carcinoma cells showed OB-R- positive expression, but the intensity was weaker than that in normal mucosa. The expression of OB-R showed a signifi cant correlation with the level of leptin expres- sion. The expression levels of both leptin and OB-R tend- ed to increase as the depth of tumor invasion or TMN stage increased (P < 0.01). Lymph node metastasis was detected in 49.5% (47/95) of leptin-strong cases and in 50.5% (48/95) of OB-R-positive cases, and the rate was 33% (37/112) in leptin-weak cases and 17% (19/112) in OB-R-negative cases. Both venous and lymphatic inva- sion also tended to be observed frequently in positive tumors as compared with negative tumors. Interestingly, in the 96 leptin- or OB-R-positive tumors, hematogenous metastasis was detected preoperatively in 3 (3.1%) pa- tients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis. CONCLUSION: Overexpression of leptin and expres- sion of OB-R may play a positive role in the process of progression in gastric cancer. Functional upregulation of leptin/OB-R may have a positive role in the development and initial phase of progression in gastric cancer.展开更多
AIM： To investigate the expression of leptin and leptin receptor （ob-R） in intestinal-type gastric cancer and precancerous lesions, and to explore the possible mechanism and role of the leptin system in developing ...AIM： To investigate the expression of leptin and leptin receptor （ob-R） in intestinal-type gastric cancer and precancerous lesions, and to explore the possible mechanism and role of the leptin system in developing intestinal-type gastric adenocarcinoma.METHODS： Immunohistochemistry was performed to examine the expression of leptin and leptin receptor in archival samples of gastric adenocarcinoma and preneoplastic lesions, including intestinal metaplasia and mild to severe gastric epithelial dysplasia. Positive staining was identified and percentage of positive staining was graded.RESULTS： Dual expression of leptin and leptin receptor were detected in 80% （16/20） intestinal metaplasia, 86.3% （25/30） mild gastric epithelial dysplasia, 86.7% （26/30） moderate gastric epithelial dysplasia, 93.3% （28/30） severe gastric epithelial dysplasia, 91.3% （55/60） intestinal-type gastric adenocarcinoma and 30.0% （9/30） diffuse-type gastric carcinoma. The percentage of dual expression of leptin and leptin receptor in intestinal-type gastric adenocarcinoma was significantly higher than that in diffuse-type gastric adenocarcinoma （χ^2 = 37.022, P〈0.01）.CONCLUSION： Our results indicate the presence of an autocrine loop of leptin system in the development of intestinal-type gastric adenocarcinoma.展开更多
The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular activities.Hematoxylin-eosin staining showed ...The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular activities.Hematoxylin-eosin staining showed all types of elongated spermatids and spermatogenic cells existed in the testis in April,while the primary spermatocytes and spermatogonia were most advanced stages of germ cells in June.In addition,the primary spermatocytes,secondary spermatocytes,and spermatogonia were most advanced stages of germ cells in September.The highest circulating leptin concentration was consistent with the maximum body weight results from accumulation of adipose tissue in September.The mRNA expression level of leptin receptor(Ob-R)and STAT3 was lowest in June,raised in September,and remained increased in April.Ob-R and STAT3 were stronger staining in the Leydig cells in July.Moreover,the concentrations of testosterone(T)showed the maximum values in April,the minimum values in June,and significant increases in September.Furthermore,it is worth noting that the levels of T increased with the mRNA levels of Ob-R,STAT3,StAR,and testicular steroidogenic enzymes(3β-HSD,P450c17,and P450scc).Moreover,RNA-seq analyses of testis during the different periods showed that a total of 4209 genes were differ-entially expressed genes(DEGs);further analysis revealed that DEGs related with the Jak/STAT pathways and reproduction were altered.Taken together,the results suggested that the leptin regulated testicular function through the Jak/STAT pathways and testicular steroidogenic factor expressions.展开更多
文摘Leptin is the protein product encoded by the obese (ob)gene. It is a circulating hormone produced primarily by the adipose tissue. ob/ob mice with mutations of the gene encoding leptin become morbidly obese, infertile, hyperphagic, hypothermic,and diabetic. Since the cloning of leptin in 1994, our knowledge in body weight regulation and the role played by leptin has increased substantially. We now know that leptin signals through its receptor, OB-R, which is a member of the cytokine receptor superfamily. Leptin serves as an adiposity signal to inform the brain the adipose tissue mass in a negative feedback loop regulating food intake and energy expenditure. Leptin also plays important roles in angiogenesis, immune function, fertility and bone formation. Humans with mutations in the gene encoding leptin are also morbidly obese and respond to leptin treatment,demonstrating that enhancing or inhibiting leptin’s activities in vivo may have potential therapeutic benefits.
文摘AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia. METHODS: By immunohistochemical staining using specifi c antibodies, we evaluated the expression of leptin and OB-R in 207 gastric carcinomas (100 early and 107 advanced carcinomas) and analyzed their relationship with clinicopathological features. RESULTS: Both normal gastric epithelium and carci- noma cells expressed a significant level of leptin. In cases with OB-R staining, carcinoma cells showed OB-R- positive expression, but the intensity was weaker than that in normal mucosa. The expression of OB-R showed a signifi cant correlation with the level of leptin expres- sion. The expression levels of both leptin and OB-R tend- ed to increase as the depth of tumor invasion or TMN stage increased (P < 0.01). Lymph node metastasis was detected in 49.5% (47/95) of leptin-strong cases and in 50.5% (48/95) of OB-R-positive cases, and the rate was 33% (37/112) in leptin-weak cases and 17% (19/112) in OB-R-negative cases. Both venous and lymphatic inva- sion also tended to be observed frequently in positive tumors as compared with negative tumors. Interestingly, in the 96 leptin- or OB-R-positive tumors, hematogenous metastasis was detected preoperatively in 3 (3.1%) pa- tients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis. CONCLUSION: Overexpression of leptin and expres- sion of OB-R may play a positive role in the process of progression in gastric cancer. Functional upregulation of leptin/OB-R may have a positive role in the development and initial phase of progression in gastric cancer.
文摘AIM： To investigate the expression of leptin and leptin receptor （ob-R） in intestinal-type gastric cancer and precancerous lesions, and to explore the possible mechanism and role of the leptin system in developing intestinal-type gastric adenocarcinoma.METHODS： Immunohistochemistry was performed to examine the expression of leptin and leptin receptor in archival samples of gastric adenocarcinoma and preneoplastic lesions, including intestinal metaplasia and mild to severe gastric epithelial dysplasia. Positive staining was identified and percentage of positive staining was graded.RESULTS： Dual expression of leptin and leptin receptor were detected in 80% （16/20） intestinal metaplasia, 86.3% （25/30） mild gastric epithelial dysplasia, 86.7% （26/30） moderate gastric epithelial dysplasia, 93.3% （28/30） severe gastric epithelial dysplasia, 91.3% （55/60） intestinal-type gastric adenocarcinoma and 30.0% （9/30） diffuse-type gastric carcinoma. The percentage of dual expression of leptin and leptin receptor in intestinal-type gastric adenocarcinoma was significantly higher than that in diffuse-type gastric adenocarcinoma （χ^2 = 37.022, P〈0.01）.CONCLUSION： Our results indicate the presence of an autocrine loop of leptin system in the development of intestinal-type gastric adenocarcinoma.
基金supported by the National Natural Science Foundation of China(31872320,21806010)the Young Scientist Start-up funding of Beijing Forestry University(BLX201714).
文摘The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular activities.Hematoxylin-eosin staining showed all types of elongated spermatids and spermatogenic cells existed in the testis in April,while the primary spermatocytes and spermatogonia were most advanced stages of germ cells in June.In addition,the primary spermatocytes,secondary spermatocytes,and spermatogonia were most advanced stages of germ cells in September.The highest circulating leptin concentration was consistent with the maximum body weight results from accumulation of adipose tissue in September.The mRNA expression level of leptin receptor(Ob-R)and STAT3 was lowest in June,raised in September,and remained increased in April.Ob-R and STAT3 were stronger staining in the Leydig cells in July.Moreover,the concentrations of testosterone(T)showed the maximum values in April,the minimum values in June,and significant increases in September.Furthermore,it is worth noting that the levels of T increased with the mRNA levels of Ob-R,STAT3,StAR,and testicular steroidogenic enzymes(3β-HSD,P450c17,and P450scc).Moreover,RNA-seq analyses of testis during the different periods showed that a total of 4209 genes were differ-entially expressed genes(DEGs);further analysis revealed that DEGs related with the Jak/STAT pathways and reproduction were altered.Taken together,the results suggested that the leptin regulated testicular function through the Jak/STAT pathways and testicular steroidogenic factor expressions.
