Differential distribution of insulin-like growth factor-1 and insulin-like growth factor binding proteins in experimental diabetic rat kidney

Insulin-like growth factor-1 (IGF-1) is a peptide growth factor, and its activity is modulated by interaction with the family of IGF binding proteins (IGFBP-1 to 6). IGF-1 is detected in rat kidney and has metabolic and growth effects. To explore the possible involvement of IGFBPs in glomerular hypertrophy in streptozotocin (STZ)-induced diabetic rat, the immunolocalization of IGF-1 and IGFBPs were investigated. IGF-1 was gradually increased in the glomeruli of diabetic rats and correlated with glomerular hypertrophy. IGFBP-1 was transiently increased at 1 week after the STZ injection and declined to control level during the following period. In contrast, IGFBP-4 was increased in the diabetic glomeruli throughout the observation period. With insulin treatment, the levels of IGF-1, IGFBP-1 and 4 were normalized and glomerular hypertrophy was prevented. Initial glomerular hypertrophy of diabetic nephropathy is a related IGF-1 action, which may be modulated by IGFBP-1 and 4.     

缺氧诱导因子1和缺氧诱导因子2在人类着床前胚胎的表达

目的研究缺氧诱导因子1(HIF-1)和缺氧诱导因子2(HIF-2)在人类着床前胚胎各个阶段的表达,探讨这两个氧调节基因在人类早期胚胎发育过程中的作用和意义。方法收集不育症患者捐赠的胚胎,采用巢式逆转录聚合酶链反应(RT-PCR)和实时荧光定量PCR分别定性和定量在5%和20%O2条件下体外培养的人胚胎的HIF-1α和HIF-2αmRNA。采用免疫荧光染色检测人胚胎的HIF-1α和HIF-2α蛋白。结果巢式RT-PCR分别检测了5%和20%O2体外培养的2、4、6、8细胞胚胎和囊胚发现,所有34个胚胎均表达HIF-1α和HIF-2αmRNA。实时荧光定量PCR5%O2培养的人囊胚HIF-1α与18SrRNA的Ct比值为(1.22±0.05);20%O2培养的人囊胚,这一比值是(1.02±0.07);两者比较差异显著(P<0.05)。人胚胎在体外常氧培养条件下的HIF-1αmRNA水平显著高于低氧培养。5%O2培养的人囊胚HIF-2α与18SrRNA的Ct的比值为(1.29±0.04);20%O2培养的人囊胚,这一比值是(1.19±0.11);两者比较无显著差异(P>0.05)。人胚胎在体外低氧培养条件下的HIF-2αmRNA水平与常氧培养无显著差异。5%和20%O2体外培养的2、4、6、8细胞,各个发育阶段人胚胎的HIF-1α和HIF-2α免疫荧光染色均阳性。结论研究结果显示人类着床前胚胎在体外常氧和低氧培养时均表达HIF-1α和HIF-2α。二者可能通过广泛的靶基因系统参与早期胚胎的生长发育和着床过程,在早期胚胎的调控可能不在转录水平,而在转录后水平。     

胰岛素样生长因子-1对脑缺血大鼠神经功能及血管内皮细胞生长因子表达的影响

目的 观察胰岛素样生长因子(IGF)-1对脑缺血再灌注大鼠神经功能及血管内皮细胞生长因子(VEGF)蛋白和mRNA表达的影响.方法 SD大鼠随机分为假手术组、脑缺血/再灌注组和IGF-1治疗组,分别于脑缺血再灌注后12、24h、3、7d评价神经功能,采用免疫组织化学方法检测各组大鼠脑缺血皮层VEGF蛋白表达的变化,采用逆转录-聚合酶链反应(RT-PCR)技术检测各组大鼠脑缺血皮层VEGF mRNA表达的变化.结果 在12、24h、3、7d各时间点,IGF-1治疗组的改良神经功能评分( mNSS)分别为8.67±1.21、7.50±1.52、4.33±1.03、3.67±1.37,均低于脑缺血/再灌注组(11.00±1.26、9.83±1.33、7.83±1.17、7.17±1.72,P＜0.05).与脑缺血/再灌注组比较,IGF-1治疗组在脑缺血再灌注后12、24h、3、7dVEGF蛋白表达明显上调(P＜0.05),分别为88.78±6.67、95.83±7.61、26.88±4.22、16.30 ±4.69.与脑缺血/再灌注组比较,IGF-1治疗组在脑缺血再灌注后12、24h、3、7d,VEGF mRNA表达明显上调(P＜0.05),分别为0.474±0.035、0.417±0.044、0.326±0.025、0.265±0.040.结论 IGF-1可能通过调整脑缺血再灌注后VEGF蛋白表达和VEGFmRNA表达,从而调节神经功能的恢复,起到减轻缺血再灌注脑损伤的作用.     

胃癌组织缺氧诱导因子-1α与胰岛素样生长因子-Ⅱ表达对肿瘤血管生成的影响及预后评估

目的探讨胃癌组织中缺氧诱导因子-1α（HIF-1α）及胰岛素样生长因子-Ⅱ（IGF—Ⅱ）mRNA的表达水平及其与血管生成和预后的关系。方法采用原位杂交检测118例胃癌组织中HIF-1αmRNA和IGF—ⅡmRNA的表达情况,用免疫组化SP法标记CD34单克隆抗体,计算肿瘤微血管密度（MVD）。结果HIF—1αmRNA和IGF—ⅡmRNA在胃癌组织中的阳性表达率分别为49．2％和47．4％。且与胃癌临床侵袭转移病理指标均相关。HIF-1αmRNA和IGF-ⅡmRNA阳性表达者的MVD值,均高于阴性表达者;HIF-1αmRNA和IGF-ⅡmRNA表达呈正相关,MVD分别与HIF-1αmRNA和IGF—ⅡmRNA的表达水平呈正相关。HIF—1αmRNA和IGF—ⅡmRNA表达阳性及MVD值≥41．5个／0．72mm^2的患者的平均生存时间及5年生存率均低于表达阴性及MVD值〈41．5个／0．72mm^2者。结论HIF-1α与IGF—Ⅱ对胃癌的浸润转移,特别是对肿瘤血管形成具有重要作用,可作为预测患者预后和指导治疗的新途径。     

低氧诱导因子-1α在绝经后骨质疏松中调控作用的实验研究

目的探讨在绝经后骨质疏松的发生、发展过程中,低氧诱导因子-1α（HIF-1α）对于成骨细胞功能的调控作用。方法2004年10月至2006年5月,应用Cre—Loxp重组酶技术,建立成骨细胞条件性敲除HIF-1α小鼠,取3个月龄雌性野生型和敲除型小鼠各24只行卵巢切除术,术后0、4、8周取材行HE染色、四环素荧光双标记、Micro-CT、RT—PCR、Western-blotting检测。结果与野生型小鼠相比,敲除型小鼠骨小梁的数目、体积、厚度,骨密度,骨矿沉积速度,血管内皮生长因子（VEGF）、RunX2、ALP、OC基因在mRNA水平的表达,VEGF、RunX2在蛋白水平的表达均明显降低,尤其以术后8周最为明显。结论在绝经后骨质疏松的发生、发展过程中,成骨细胞条件性敲除HIF-1α后成骨功能降低,HIF-1α能够调控成骨细胞的成骨功能。     

Ang2,HIF-1α及VEGF对肝癌血管形成的影响

摘要：目的:探讨促血管生成素2（Ang2）、缺氧诱导因子1α（HIF-1α）及血管内皮生长因子（VEGF）与肝细胞癌血管形成的关系。方法:检测52例肝癌组织中Ang2，HIF-1α及VEGF mRNA及蛋白的表达，对共表达的肝癌组织进行微血管计数。结果:RT-PCR 显示,52例肝癌组织中有38例共表达Ang2mRNA，HIF-1αmRNA 和VEGF mRNA，且两两之间呈明显正相关(分别为r=0.783，P<0.01；r=0.427，P<0.05；r=0.433，P<0.05)；免疫组化发现,52例肝癌组织36例共表达Ang2，HIF-1α和VEGF蛋白。共表达Ang2 mRNA，HIF-αmRNA 和VEGF蛋白的38例肝癌组织中,平均微血管数［(45.4±8.90) 个/HP］,明显高于非共表达组［(13.6±3.30)个/HP］（P<0.05)。结论:Ang2，HIF-1α和VEGF与肝癌的新生血管形成有关；肿瘤组织缺氧可能是其始动因素。     

Autocrine/paracrine mechanism of insulin-like growth factor-1 secretion,and the effect of insulin-like growth factor-1 on proteoglycan synthesis in bovine intervertebral discs

The present study was undertaken to investigate the effect of insulin-like growth factor-1 on proteoglycan synthesis and the autocrine/paracrine mechanisms involving insulin-like growth factor-1 in the bovine coccygeal intervertebral disc. Insulin-like growth factor-1 stimulated proteoglycan synthesis in cultured cells of the nucleus pulposus of bovine intervertebral discs in a dose-dependent manner, and the effect was inhibited by an anti-insulin-like growth factor-1 monoclonal antibody. In situ hybridization histochemistry revealed the expression of insulin-like growth factor-1 mRNA in the cultured cells, and its production in these cells was demonstrated by radioimmunoassay. Insulin-like growth factor-1 receptor in the cultured cells was also demonstrated immunohistochemically. Scatchard analysis using an [¹²⁵I]insulin-like growth factor-1 binding assay showed that the cells cultured in monolayer had a single type of insulin-like growth factor-1 receptor, whose affinity and number were estimated to be 7.38 × 10⁸/M and 9.27 × 10⁴/cell, respectively. These results suggest that insulin-like growth factor-1 stimulates proteoglycan synthesis in cells of the nucleus pulposus and that these cells in culture have an insulin-like growth factor-1 autocrine/paracrine mechanism. The expressions of insulin-like growth factor-1 mRNA and insulin-like growth factor-1 receptor in disc tissue were greater in cells of the nucleus pulposus of fetal bovine intervertebral discs than in those of the adult discs. These findings suggest that the action of autocrine/paracrine insulin-like growth factor-1 is more active in cells of the young nucleus pulposus than in cells of mature subjects.     

Effect of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 complex in cavernous nerve cryoablation

The purpose of this work was to study the effect of insulin-like growth factor 1 (IGF-1) and its binding protein (IGFBP-3) on the recovery of erectile function in a rat model for neurogenic impotence. In all, 28 male Sprague-Dawley rats were divided into four groups: seven underwent a sham operation; seven underwent bilateral cavernous nerve freezing (control group); seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGF-1; and seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGFBP-3. Erectile response was assessed by cavernous nerve electrostimulation at 3 months, and samples of penile tissue were evaluated histochemically for nitric oxide synthase (NOS)-containing fibers. In the sham and IGF-1 group, there were significantly higher maximal intracavernous pressures compared to the IGFBP-3 complex and the control group. Correspondingly in the cavernosum, there were significantly more NOS-containing nerve fibers in the sham and IGF-1 groups. In conclusion, administration of IGF-1 can facilitate the regeneration of NOS-containing nerve fibers in penile tissue and enhance the recovery of erectile function after bilateral cavernous nerve cryoablation. The reverse effect was noted with the IGFBP-3 complex injection.     

Phosphorylated insulin-like growth factor binding protein 1 is increased in pregnant diabetic subjects.

During pregnancy, IGFs and their binding proteins (IGFBPs) are important for the growth of fetal and maternal tissues. IGFBP-1 normally circulates as a single, highly phosphorylated species (hpIGFBP-1). However, in pregnancy there are lesser phosphorylated isoforms (lpIGFBP-1) with decreased affinity for IGF-I, allowing for increased IGF bioavailability. Because regulation of IGFBP-1 is abnormal in type 1 diabetes, we examined the impact of this on IGFBP-1 and its phosphorylation status in diabetic pregnancy. We assessed IGFBP-1 in relation to birth weight, maternal weight gain, duration of diabetes, glycemic control, and the presence or absence of retinopathy in 44 diabetic and 11 nondiabetic subjects. We found that in type 1 diabetic patients there was a significant negative relationship between hpIGFBP-1 and birth weight (r = -0.42, P < 0.01) and between the ratio of hpIGFBP-1 to lpIGFBP-1 and birth weight (r = -0.38, P = 0.02) by week 18 of gestation. Multiple regression analysis confirmed that hpIGFBP-1 was the best single predictor of birth weight (R2 = 0.3, P = 0.001) in diabetic subjects using models including other parameters known to influence fetal size. In contrast to hpIGFBP-1 levels, lpIGFBP-1 levels were not associated with birth weight, but were significantly related to initial maternal BMI and maternal weight throughout gestation in diabetic subjects (r = -0.57, P < 0.001). hpIGFBP-1 levels were positively related to duration of diabetes (r = 0.38, P < 0.01). Diabetic subjects had significantly higher hpIGFBP-1 and lpIGFBP-1 levels than nondiabetic subjects (hpIGFBP-1: 215 +/- 21 vs. 108 +/- 13 microg/l, P = 0.01; lpIGFBP-1: 139 +/- 12 vs. 66 +/- 5 microg/l, P < 0.001), but the ratio of hpIGFBP-1 to lpIGFBP-1 was similar in both groups (2.1 +/- 0.3 [diabetic] vs. 1.7 +/- 0.2 [nondiabetic], NS). In summary, maternal IGFBP-1 levels were higher in diabetic than in normal pregnancies. Diabetic subjects with prolonged duration of diabetes and retinopathy had higher total IGFBP-1 levels than those with shorter disease duration. Thus hpIGFBP-1 in diabetic pregnancy is positively related to the duration of diabetes and inversely related to fetal growth, with lpIGFBP-1 being related to maternal weight and BMI. The ratio of hpIGFBP-1 to lpIGFBP-1 may be a more robust indicator of fetal outcome, since it was consistent between diabetic and nondiabetic subjects. Measurement of the different phosphorylated isoforms of IGFBP-1 may increase the usefulness of IGFBP-1 as a predictor of fetal growth in both normal and diabetic pregnancy.     

转化生长因子-β1和胰岛素样生长因子-1对人髓核细胞体外增殖活性的影响

目的：研究转化生长因子-β1（TGF—β1）和胰岛素样生长因子-1（IGF—1）单独及联合应用对人髓核细胞体外增殖活性的影响，并观察其量效和时效关系。方法：体外分离培养人髓核细胞．将传2代细胞种于96孔板，采用噻唑蓝（MTT）比色法，观察TGF—β1和IGF—1在1％和10％血清浓度下对人髓核细胞体外增殖的调节作用及其剂量、时间与作用效果的关系。结果：在1％血清条件下，IGF—1的作用不显著，TGF—B1具有促增殖作用。在10％血清条件下，TGF—B1和IGF—1均能提高细胞的增殖活性，并且在有效浓度范围内呈剂量效应关系，TGF—B1的作用强于IGF—1。二者联合应用效果更显著。结论：TGF—B1和IGF—1均能不同程度地促进入髓核细胞的体外增殖，其效应在一定范围内与剂量和时间呈正相关．联合应用促进增殖作用更显著。     

Experimental varicocele induces hypoxia inducible factor-1alpha, vascular endothelial growth factor expression and angiogenesis in the rat testis

PURPOSE: In this study we investigated hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) expression, and angiogenesis in an experimental model of varicocele in the rat testis. MATERIALS AND METHODS: A total of 30 adult male Sprague-Dawley rats were investigated in 3 groups, namely varicocele group 1 (13), sham operated group 2 (9) and control group 3 (8). At 30 days after surgery was completed in groups 1 and 2 orchiectomy was performed in all rats. Histological findings in the left testicles of rats from each group were compared. HIF-1alpha and VEGF expression was immunohistochemically studied and CD31 panendothelial antigen was used to identify the number of microvessels, that is microvessel density (MVD), in paraffin embedded sections of testis tissue. Data were analyzed using the chi-square test, Fisher's exact test, 1-way ANOVA and the Tukey HSD test for post hoc comparison. RESULTS: HIF-1alpha expression was detected in 12 specimens (92.3%) in group 1, 4 (44.4%) in group 2 and 2 (25%) in group 3. The frequency of HIF-1alpha positivity in group 1 was significantly higher than the rates in groups 2 (p = 0.023) and 3 (p = 0.003). VEGF expression was detected in 8 specimens (61.5%) in group 1 but none of the group 2 or 3 specimens were VEGF positive. The frequency of VEGF positivity in group 1 was significantly higher than that in groups 2 (p = 0.006) and 3 (p = 0.007). Mean MVD +/- SD in group 1 was 7.53 +/- 1.50 (range 6 to 12), and findings in groups 2 and 3 were 5.88+/-1.45 (range 4 to 8) and 5.12 +/-1.12 (range 4 to 7), respectively. Mean MVD in group 2 was higher than in group 3 but this difference was not significant (p = 0.509). Mean MVD in group 1 was significantly higher than the mean values in groups 2 (p = 0.030) and 3 (p = 0.002). CONCLUSIONS: Previous study of experimental varicocele models in rats documented HIF-1alpha and VEGF expression combined with angiogenesis in the testis. The results of this study show that varicocele can lead to tissue hypoxia and related pathophysiological events, such as angiogenesis.     

IGF-1、IGF-bp-3在去势大鼠阴茎海绵体中的表达及其意义

目的探讨胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGF-BP-3)在去势大鼠阴茎海绵体中的表达及其意义。方法取16只成年雄性大鼠随机分为去势组、对照组。1周后取阴茎海绵体, 比色法测定阴茎海绵体一氧化氮(NO)含量(ΜG／G);原位细胞凋亡标记检测细胞凋亡数;逆转录多聚酶链聚合反应检测IGF-1、IGF-BP-3MRNA表达。结果 IGF-1MRNA在对照组中表达(1．44±0．29)而在去势组未检测到表达。IGF-BP-3MRNA在去势组表达量(3．52±1．4)较对照组(1．10±0．51)升高(P<0．01)。去势组阴茎海绵体细胞凋亡数(26．02±5．25)较对照组(12．51±1．81)高(P<0．05);凋亡细胞积分光密度去势组(33931．54±2459．36)较对照组(18766．37±3040．42)高(P<0．05)。去势组阴茎海绵体 NO浓度(14．45±2．38)较对照组(39．8±3．28)显著降低(P<0．01)。结论去势1周后阴茎海绵体细胞发生凋亡。去势后阴茎海绵体细胞凋亡可能与IGF-1MRNA表达降低及IGF-BP-3MRNA表达增高有关。     

Circulating levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 in patients with severe head injury

There is evidence to suggest that fractures heal more rapidly in patients with a head injury as a result of systemic factors released from the site of this injury. We have measured the circulating level of insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) in serum because of their known involvement in the stimulation of the activity of osteoblasts and the healing of fractures. The serum level of IGF-1 was significantly lower in patients with both head injury and fracture and fracture only compared with that in healthy volunteers (p < 0.01 and p < 0.02, respectively). The level of IGFBP-3 was also significantly lower in patients with both head injury and fracture (p < 0.01). Our findings showed, however, that the level of IGF-1 and IGFBP-3 varied from week to week in both the patients and healthy control subjects. These results indicate that the levels of circulating IGF-1 and IGFBP-3 are unlikely to be responsible for the altered healing of fractures seen in conjunction with head injury.     

结直肠癌中缺氧诱导因子1-α与FasL 表达相关性的研允

目的 探讨结直肠癌侵袭转移过程中缺氧诱导因子1-α(alpha,HIF-1α)与FasL表达的相关性.方法 采用分子克隆方法,将我室已构建的FasL-pcD-NA3.1(+)质粒与pcDNA3.1(一)质粒进行重组,得到新的FasL-pcDNA3.1(一)质粒并加以鉴定;通过脂质体转染法将空质粒、FasL-pcDNA3.1(+)与FasL-pcDNA3.1(一)质粒分别转染人直肠癌HR-8348细胞,构建侵袭力不同的结直肠癌细胞HR-8348L、HR一8348F和HR一8348As,未转染细胞HR一8348B为空白对照,应用Tran-swell,小室检测各组细胞的侵袭能力;采用化学缺氧法构建四组细胞的缺氧模型,Western blot方法定量检测缺氧0h、6h、12h及24h各组细胞内HIF-1α的表达.结果 FasL-pcDNA3.1(一)质粒符合要求,FasL片段大小约900bp,测序结果正确率99.2%;单层细胞体外侵袭实验见HR一8348F细胞穿透Transwell滤膜的细胞数目为(12.930±2.434),显著多于HR-8348B(8.133±1.959)、HR-8348L(7.670±2.093)和HR-8348As(7.870±1.685)细胞(P<0.05);Western blot检测示HIF-1α蛋白于120kD处显色,缺氧0h与6h,各组样品中HIF-α仅表达微量,HIF-1α水平无显著性差异(P>0.05);缺氧12h与24h,HR一8348F细胞内HIF-1α水平较0h和6h时明显增高(P<0.05),而HR-8348B、HR-8348L及HR-8348As细胞内HIF-1α表达与6h时无明显变化(P>0.05),HR-8348F细胞HIF-1α水平显著高于HR-8348B、HR-8348L及HR-8348As细胞(P<0.01).结论 缺氧环境中结直肠癌细胞FasL表达增强是除低氧分压外另一个诱导HIF-1α表达增高的因素,FasL与 HIF-1α水平呈正相关,高侵袭能力的结直肠癌细胞对缺氧的适应能力加强,促进肿瘤的远处转移.     

Prognostic value of insulin-like growth factor 1 and insulin-like growth factor binding protein 3 blood levels in breast cancer

High circulating insulin-like growth factor 1 (IGF-1) levels are firmly established as a risk factor for developing breast cancer, especially estrogen positive tumors. The effect of circulating IGF-1 on prognosis once a tumor is established is unknown. The authors explored the effect of IGF-1 blood levels and of it's main binding protein, IGFBP-3, on overall survival and occurrence of second primary breast tumors in breast cancer patients, as well as reproductive and lifestyle factors that could modify this risk. Patients were accrued from six hospitals in the Netherlands between 1998 and 2003. Total IGF-1 and IGFBP-3 were measured in 582 plasma samples.No significant association between IGF-1 and IGFBP-3 plasma levels and overall survival was found. However, in a multivariate Cox regression model including standard prognostic variables high IGF-1 levels were related to worse overall survival in patients receiving endocrine therapy (HR = 1.37, 95% CI: 1.11, 1.69, P 0.004). These data at least indicate that higher IGF-1 levels, and as a consequence most likely IGF-1-induced signaling, are related to a less favorable overall survival in breast cancer patients treated with endocrine therapy. Interventions aimed at reducing circulating levels of IGF-1 in hormone receptor positive breast cancer may improve survival.     

Disruption of the insulin-like growth factor-1 gene in osteocytes impairs developmental bone growth in mice

This study evaluated the role of osteocyte-derived insulin-like growth factor 1 (IGF-1) in developmental bone growth by assessing the bone phenotype of osteocyte Igf1 conditional knockout (KO) mice, generated by crossing the Dmp1-driven Cre-expressing transgenic mice with Igf1 floxed mice containing loxP sites that flank exon 4 of the Igf1 gene. The periosteal diameter of femurs of homozygous conditional KO mutants was 8–12% smaller than wild-type (WT) littermates. The conditional mutants had 14–20%, 10–21%, and 15–31% reduction in total, trabecular, and cortical bone mineral contents, respectively. However, there were no differences in the total, trabecular, or cortical bone mineral densities, or in trabecular bone volume, thickness, number, and separation at secondary spongiosa between the mutants and WT littermates. The conditional KO mutants showed reduction in dynamic bone formation parameters at both periosteal and endosteal surfaces at the mid-diaphysis and in trabecular bone formation rate and resorption parameters at secondary spongiosa. The lower plasma levels of PINP and CTx in conditional KO mice support a regulatory role of osteocyte-derived IGF-1 in the bone turnover. The femur length of conditional KO mutants was 4–7% shorter due to significant reduction in the length of growth plate and hypertropic zone. The effect on periosteal expansion appeared to be bigger than that on longitudinal bone growth. The conditional KO mice had 14% thinner calvaria than WT littermates, suggesting that deficient osteocyte IGF-1 production also impairs developmental growth of intramembraneous bone. Conditional disruption of Igf1 in osteocytes did not alter plasma levels of IGF-1, calcium, or phosphorus. In summary, this study shows for the first time that osteocyte-derived IGF-1 plays an essential role in regulating bone turnover during developmental bone growth.