低密度脂蛋白免疫复合物对单核细胞来源的巨噬细胞脂质代谢的影响

目的:研究动脉粥样硬化过程中低密度脂蛋白免疫复合物(LDL-IC)对单核细胞来源的巨噬细胞内脂质含量的影响。方法:以佛波酯刺激分化的THP-1细胞作为单核细胞来源巨噬细胞模型。固定后的细胞以苏丹Ⅳ染色,观察细胞内脂质含量变化。通过胆固醇酶联法测定细胞内胆固醇含量。结果:与LDL-IC孵育能使单核细胞来源巨噬细胞内胆固醇堆积,呈现泡沫细胞的外观。细胞内胆固醇水平随着LDL-IC的浓度增加与作用时间的延长而升高。在4组平行对照实验中,LDL-IC组细胞内胆固醇水平明显高于阴性对照组、LDL组和IgG-IC组(P<0.01)。结论:LDL-IC能通过增加细胞内脂质而在动脉粥样硬化过程中发挥作用。     

miR-21-5p promotes NASH-related hepatocarcinogenesis

Background and Aims

The mechanisms governing the progression of non-alcoholic fatty liver disease (NAFLD) towards steatohepatitis (NASH) and hepatocellular carcinoma (HCC) remain elusive. Here, we evaluated the role of hsa-miRNA-21-5p in NASH-related hepatocarcinogenesis.

Methods

Hepatic hsa-miR-21-5p expression was evaluated in two cohorts of patients with biopsy-proven NAFLD (n = 199) or HCC (n = 366 HCC and n = 11 NAFLD-HCC). Serum/liver metabolomic profiles were correlated with hsa-miR-21-5p in NAFLD obese patients. Wild-type (WT) and Mir21 KO mice were fed a choline-deficient, amino acid-defined (CDAA) diet for 32 and 66 weeks to induce NASH and NASH-HCC, respectively.

Results

In obese individuals, hsa-miR-21-5p expression increased with NAFLD severity and associated with a hepatic lipotoxic profile. CDAA-fed WT mice displayed increased hepatic mmu-miR-21-5p levels and progressively developed NASH and fibrosis, with livers presenting macroscopically discernible pre-neoplastic nodules, hyperplastic foci and deregulated cancer-related pathways. Mir21 KO mice exhibited peroxisome-proliferator-activated receptor α (PPARα) activation, augmented mitochondrial activity, reduced liver injury and NAS below the threshold for NASH diagnosis, with the pro-inflammatory/fibrogenic milieu reversing to baseline levels. In parallel, Mir21 KO mice displayed reduced number of pre-neoplastic nodules, hepatocyte proliferation and activation of oncogenic signalling, being protected from NASH-associated carcinogenesis. The hsa-miRNA-21-5p/PPARα pathway was similarly deregulated in patients with HCC- or NASH-related HCC, correlating with HCC markers and worse prognosis.

Conclusions

Hsa-miR-21-5p is a key inducer of whole-spectrum NAFLD progression, from simple steatosis to NASH and NASH-associated carcinogenesis. The inhibition of hsa-miR-21-5p, leading to a pro-metabolic profile, might constitute an appealing therapeutic approach to ameliorate NASH and prevent progression towards HCC.     

Effects of reduced uterine perfusion pressure on blood pressure and metabolic factors in pregnant rats

BACKGROUND: Elements of metabolic syndrome (eg, dyslipidemia and impaired glucose metabolism) are often present in preeclamptic pregnancies. Currently it is unclear whether these metabolic aberrations presage preeclampsia, or if these manifestations result from placental ischemia and the ensuing proinflammatory state usually present in preeclampsia. METHODS: The present study employed chronic reductions in uterine perfusion pressure (RUPP) to generate a rat model of pregnancy-induced hypertension (PIH) for the evaluation of fasting plasma concentrations of triglycerides (TGs), glucose, resistin, insulin, and glucose tolerance in late-gestation rats. RESULTS: Mean arterial pressure was increased (130 +/- 2.1 mm Hg v 100 +/- 4.3 mm Hg; all values, mean +/- SEM), and fetal weight decreased (1.93 +/- 0.08 g v 2.19 +/- 0.06 g), in RUPP dams compared with normal pregnant (NP) control dams. Maternal fasting glucose (4.2 +/- 0.3 mmol L(-1) v 3.1 +/- 0.4 mmol L(-1); P < .05) was increased in RUPP compared with NP dams. Serum TGs (2.62 +/- 0.29 mmol L(-1) v 2.45 +/- 0.51 mmol L(-1)), insulin (9.9 +/- 0.7 microU mL(-1) v 8.5 +/- 0.7 microU mL(-1)), resistin (46.25 +/- 4.19 pg mL(-1) v 49.71 +/- 4.01 pg mL(-1)), and glucose area under the curve (650 +/- 35 mmol min L(-1) v 570 +/- 34 mmol min L(-1)) were not different between the RUPP and NP dams. CONCLUSIONS: Although these findings do not rule out the hypothesis that preexisting symptoms of metabolic syndrome may contribute to the onset of preeclampsia, these data clearly show that pregnancy-induced hypertension resulting from RUPP does not elicit manifestations of metabolic syndrome in late-gestation rat dams.     

肥胖及2型糖尿病患者血清apelin水平及其相关因素分析

目的测定肥胖及新诊断2型糖尿病患者血清apelin水平，探讨apelin与体脂、糖、脂代谢、胰岛素抵抗等的相关性。方法62例2型糖尿病患者和72例正常糖调节（NGR）者按体重指数（BMI）≥25kg／m^2或〈25kg／m^2又各自分为超重／肥胖与正常体重亚组，采用放射免疫分析法检测空腹血清apelin水平，同时检测空腹血糖（FPG）、HbA1C、血脂各项指标及空腹胰岛素（FINS）水平，计算BMI和腰臀比，并以稳态模型计算胰岛素抵抗指数（HOMA-IR）。结果校正年龄及性别后，2型糖尿病组血清apelin水平高于NGR组[（317．9±99．6vs279．0±66．8）ng／L，P〈0．01]，2型糖尿病组和NGR组中的超重／肥胖者均高于非肥胖者[（354．0±114．4vs274．1±53．0）ng／L，（299．2±74．5vs252．8±48．9）ng／L，均P〈0．05]，且2型糖尿病超重／肥胖组明显高于NGR肥胖组（P〈0．01）；偏相关分析显示，空腹血清apelin与BMI、ln（HOMA-IR）、FPG、总胆固醇（TC）呈正相关（r=0．353，r=0．355，r=0．224，r=0．241，均P〈0．01），与腰围、收缩压呈正相关（r=0．263，r=0．183，P〈0．05）。多元逐步回归分析发现，BMI、ln（HOMA—IR）和TC是血清apelin的独立相关因素。结论血清apelin水平在肥胖和初发的2型糖尿病人群中升高，且与BMI、HOMA-IR及脂代谢相关，推测apelin可能参与构成胰岛素抵抗综合征的病理生理基础。     

Effects of lowering dialysate calcium concentration on mineral metabolism and parathyroid hormone secretion: a multicentric study

This prospective study was conducted with the aim of examining the efficacy of lowering dialysate calcium (dCa) in order to: (i) stimulate bone turnover in hemodialysis patients with biochemical signs of adynamic bone disease (ABD) (hypercalcemia, normal alkaline phosphatase and intact parathyroid hormone (iPTH) <150 pg/mL); and (ii) diminish hypercalcemia in patients with secondary hyperparathyroidism (sHPT) (hypercalcemia, high alkaline phosphatase and iPTH > 400 pg/mL), thus permitting the use of calcium-containing phosphorus binders and vitamin D metabolites. Patients were divided into: an ABD-treated group (24 patients), a sHPT-treated group (18 patients), an ABD-control group (12 patients) and a sHPT-control group (11 patients). For the ABD- and sHPT-treated patients, hemodialysis was conducted with dCa 1.5 mmol/L for three months and then with dCa 1.25 mmol/L for an additional three months, while in the control groups hemodialysis was conducted with dCa 1.75 mmol/L during the entire study. Reduction of dCa in patients with ABD caused a slight but insignificant decrease of Ca, but a significant and permanent increase of bone-specific alkaline phosphatase and intact parathyroid hormone level serum levels. Reduction of dCa in patients with sHPT slightly but insignificantly decreased Ca and intact parathyroid hormone level values. Nevertheless, this enabled the calcium-based phosphate binder dose to be raised and vitamin D3 metabolites to be introduced. Logistic regression analysis indicated that milder bone disease (both ABD and sHPT) was associated with more the favorable effect of dCa reduction. Thus, low dCa stimulated parathyroid glands and increased bone turnover in ABD patients, and enabled better control of mineral metabolism in sHPT patients.     

Retinol-binding protein 4 is associated with components of the metabolic syndrome, but not with insulin resistance, in men with type 2 diabetes or coronary artery disease

Aims/hypothesis Retinol-binding protein 4 (RBP4) has recently been reported to be associated with insulin resistance and the metabolic syndrome. This study tested the hypothesis that RBP4 is a marker of insulin resistance and the metabolic syndrome in patients with type 2 diabetes or coronary artery disease (CAD) or in non-diabetic control subjects without CAD. Methods Serum RBP4 was measured in 365 men (126 with type 2 diabetes, 143 with CAD and 96 control subjects) and correlated with the homeostasis model assessment of insulin resistance index (HOMA-IR), components of the metabolic syndrome and lipoprotein metabolism. RBP4 was detected by ELISA and validated by quantitative Western blotting. Results RBP4 concentrations detected by ELISA were shown to be strongly associated with the results gained in quantitative Western blots. There were no associations of RBP4 with HOMA-IR or HbA_1c in any of the groups studied. In patients with type 2 diabetes there were significant positive correlations of RBP4 with total cholesterol, LDL-cholesterol, VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity. In patients with CAD, there were significant associations of RBP4 with VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity, while non-diabetic control subjects without CAD showed positive correlations of RBP4 with VLDL-cholesterol and plasma triacylglycerol. Conclusions/interpretation RBP4 does not seem to be a valuable marker for identification of the metabolic syndrome or insulin resistance in male patients with type 2 diabetes or CAD. Independent associations of RBP4 with pro-atherogenic lipoproteins and enzymes of lipoprotein metabolism indicate a possible role of RBP4 in lipid metabolism.     

Progesterone impairs cell respiration and suppresses a compensatory increase in glucose transport in isolated rat skeletal muscle: a non-genomic mechanism contributing to metabolic adaptation to late pregnancy?

Aims/hypothesis The aim of the study was to gain better insight into the mechanisms responsible for impaired glucose metabolism during late pregnancy. We explored the direct effects of progesterone on glucose metabolism of skeletal muscle. Methods Specimens of skeletal muscle from untreated rats were incubated with progesterone and rates of substrate fluxes through the various pathways of glucose metabolism were analysed. Results Progesterone dose-dependently reduced the rates of glucose and pyruvate oxidation (insulin-stimulated rates after 5 h of exposure to 1 and 10 μmol/l progesterone: glucose oxidation, −6 ± 4%, NS, and −39 ± 4%, p < 0.001; pyruvate oxidation, −28 ± 2% and −55 ± 4%, p < 0.001 each) and increased lactate release (+28 ± 4% and +58 ± 9%, p < 0.005 each), which indicated inhibition of mitochondrial respiratory function. Impairment of cell respiration, e.g. by the specific inhibitor rotenone, is known to trigger a compensatory increase in glucose transport, but this response was blunted in the case of progesterone (change of glucose transport in response to 10 μmol/l progesterone vs 60 nmol/l rotenone, both causing a reduction in glucose oxidation by −39%: progesterone, +14 ± 8% vs rotenone, +84 ± 23%, p < 0.03). Further experiments dealt with the underlying mechanisms and revealed a rapid mode of action (50 μmol/l progesterone, reduction in insulin-stimulated glucose oxidation after 30 min: −29 ± 7%, p < 0.01) not affected by blockers of gene expression or the nuclear progesterone receptor. Conclusions/interpretation Progesterone inhibits cell respiration and at the same time suppresses a compensatory increase in glucose transport, causing cellular carbohydrate deficiency in isolated rat skeletal muscle. This effect is mediated by a direct, rapid and non-genomic mechanism and could contribute to pregnancy-associated changes in glucose homeostasis. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorised users.     

Enhanced mitochondrial metabolism may account for the adaptation to insulin resistance in islets from C57BL/6J mice fed a high-fat diet

Aim/hypothesis Hyperinsulinaemia maintains euglycaemia in insulin-resistant states. The precise cellular mechanisms by which the beta cells adapt are still unresolved. A peripherally derived cue, such as increased circulating fatty acids, may instruct the beta cell to initiate an adaptive programme to maintain glucose homeostasis. When this fails, type 2 diabetes ensues. Because mitochondria play a key role in beta cell pathophysiology, we tested the hypothesis that mitochondrial metabolism is critical for beta cell adaptation to insulin resistance. Methods C57BL/6J mice were given high-fat (HF) diet for 12 weeks. We then analysed islet hormone secretion, metabolism in vivo and in vitro, and beta cell morphology. Results HF diet resulted in insulin resistance and glucose intolerance but not frank diabetes. Basal insulin secretion was elevated in isolated islets from HF mice with almost no additional response provoked by high glucose. In contrast, a strong secretory response was seen when islets from HF mice were stimulated with fuels that require mitochondrial metabolism, such as glutamate, glutamine, alpha-ketoisocaproic acid and succinate. Moreover, while glucose oxidation was impaired in islets from HF mice, oxidation of glutamine and palmitate was enhanced. Ultrastructural analysis of islets in HF mice revealed an accumulation of lipid droplets in beta cells and a twofold increase in mitochondrial area. Conclusions/interpretation We propose that beta cells exposed to increased lipid flux in insulin resistance respond by increasing mitochondrial volume. This expansion is associated with enhanced mitochondrial metabolism as a means of beta cell compensation. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorised users.     

特发性高尿钙症对病人骨密度及骨代谢指标的影响

目的：探讨不同亚型的特发性高尿钙症（IH）对患者骨代谢的影响。方法：采用双能X线骨密度仪,测定72例IH患者和72例年龄、性别、体重指数与之相匹配的健康体检者的腰椎及左髋部骨密度（BMD）值,并行骨代谢生化指标的检测。结果：IH患者的尿Ca/Cr、尿DPD/Cr水平明显高于对照组,具有极显著性差异（P<0.01）;肠吸收型组的血清BALP、PTH和BGP水平与对照组比较无显著差异,而肾脏漏出型组的BALP、PTH与BGP水平高于正常对照组,差异有统计学意义（P<0.05）。肾脏漏出型组患者的股骨颈BMD和腰椎BMD值均较肠吸收型组及对照组低;指标BGP、BALP及DPD与各部位BMD之间均呈负相关关系。结论：对于泌尿系结石患者,应注意IH的可能。IH患者常存在骨量减少和骨代谢紊乱,合理检测骨密度和骨代谢生化指标,有助于IH患者骨代谢紊乱的早期诊断和监测。     

静脉补铁与口服补铁治疗维持性血液透析患者肾性贫血的疗效观察

目的比较促红细胞生成素联合蔗糖铁注射液及加服维生素E或口服琥珀酸亚铁两种补铁方法治疗维持性血液透析（MHD）患者肾性贫血的临床疗效。方法选择MHD合并肾性贫血患者36例,随机分为A组（促红细胞生成素＋静脉补铁＋口服维生素E）和B组（促红细胞生成素＋口服补铁）,每组18例。A组静脉用蔗糖铁（前4周2次／周,以后1次／周,均每次100mg）,同时加服维生素E200mg,2次／d,总疗程12周。B组口服琥珀酸亚铁200mg,3次／d,总疗程12周。两组患者均同时使用促红细胞生成素,剂量6000—9000IU／周,皮下注射。检测两组患者治疗前后的红细胞相关指标、血清铁指标、氧化应激指标及血脂。结果治疗12周后,两组患者Hb、Hct都有明显升高,但B组相对较慢,两组比较差异有统计学意义,而Ret两组治疗前后差异无统计学意义;SF两组患者均较治疗前有明显升高,A组更加显著,两组差异有统计学意义（P〈0．05）;hs—CRP两组治疗前后差异均无统计学意义。两组患者治疗12周后,TG、LDL及Lp（a）水平与治疗前比较均升高（P〈0．05）,且A组比同期B组也略高,但两者比较差异无统计学意义;CH、HDL、ApoAl和ApoB的含量治疗后与治疗前相比差异无统计学意义。结论静脉使用蔗糖铁可有效地纠正MHD患者铁缺乏,能有效改善贫血,且安全性较好,而口服维生素E可以改善MHD患者因静脉补铁所诱导的氧化应激及脂代谢紊乱。