肾素-血管紧张素系统在骨生物学活性中的研究进展

经典肾素-血管紧张素系统(RAS)中各组分表达于骨组织,并对骨骼的生长、发育、代谢发挥着重要的调控作用。本文综述了RAS主要活性物质的骨生物学活性以及与骨质疏松症关系的研究进展。     

肾素血管紧张素系统与糖尿病性骨质疏松症的研究进展

肾素血管紧张素系统（RAS）包括Ang Ⅰ、Ang Ⅱ及其相应受体AT1R、AT2R、肾素、ACE等,Ang Ⅱ是RAS系统的主要活性物质,其各组分在骨组织上皆有所表达,在骨骼的生长、发育、代谢的过程中发挥着重要的调控作用。糖尿病性骨质疏松症是一种以骨量减少和骨组织微结构损毁为特征的骨骼疾病,是糖尿病最常见的并发症之一,也是致残率最高的疾病。目前治疗糖尿病性骨质疏松症都依托于已知的发病机制,但从长期的临床经验来看,这些治疗措施都存在很大的局限性,如价格昂贵、副作用大等。因此,我们需要进一步探索糖尿病性骨质疏松症发生、发展的病理机制,寻找潜在的治疗靶点,在防治方面有所突破。本文综述了肾素血管紧张素系统在糖尿病性骨质疏松症病程中的生物学作用,并就肾素血管紧张素对胰岛素抵抗、胰岛素抵抗对骨代谢、肾素血管紧张素对骨代谢、肾素血管紧张素拮抗剂对糖尿病性骨质疏松症四个方面进行重点阐述,为今后糖尿病性骨质疏松症的药物治疗提供依据。     

抑制血管紧张素Ⅱ药物的肾保护研究

肾素血管紧张素系统(RAS)是重要的内分泌系统，血管紧张素Ⅱ是该系统最主要的效应因子，它影响着肾脏疾病进展的各个环节，而越来越多的研究也表明应用血管紧张素转化酶抑制剂(ACEI)或血管紧张素受体1拮抗剂(AT1RA)阻断血管紧张素Ⅱ的效应可以延缓肾脏疾病的发展，有效改善预后。本文就阻断血管紧张素Ⅱ药物的肾保护作用及应用研究作一综述。     

肾素-血管紧张素系统的新概念（上）

近年来，在肾素-血管紧张素系统（R峪）方面的研究有了很大的进展，如发现血管紧张素酶-2（A（=E2）和糜蛋白酶作用的重要性，确认了血管紧张素17（Ang1-7）和血管紧张素Ⅳ（AngⅣ）的活性作用，这些活性物质与血管紧张素Ⅱ（AngⅡ）具相辅相成和相生相克作用，因此我们需更新对RAS的认识。     

抑制血管紧张素Ⅱ药物的肾保护研究

肾素血管紧张素系统 (RAS)是重要的内分泌系统 ,血管紧张素Ⅱ是该系统最主要的效应因子 ,它影响着肾脏疾病进展的各个环节 ,而越来越多的研究也表明应用血管紧张素转化酶抑制剂 (ACEI)或血管紧张素受体 1拮抗剂 (AT1RA)阻断血管紧张素Ⅱ的效应可以延缓肾脏疾病的发展 ,有效改善预后。本文就阻断血管紧张素Ⅱ药物的肾保护作用及应用研究作一综述。     

肾素血管紧张素系统与造血调控研究进展

肾素-血管紧张素系统（RAS）的主要生物学作用体现在对血压和水、电解质的调控上.近年来的研究表明,RAS参与造血调控,其主要活性物质血管紧张素Ⅱ（AngⅡ）促进红系造血,而其受体拮抗剂（ARB）和血管紧张素转换酶抑制剂（ACEI）抑制红系造血.     

血管紧张素转换酶在肺损伤中作用的研究进展

背景 急性肺损伤(acute lung injury,ALI)/急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)是一种炎性综合征,近年研究发现血管紧张素转换酶(angiotensin converting enzyme,ACE)在其发生发展过程中起着重要作用.目的 人们对于肾素血管紧张素系统(renin angiotensin system,RAS),特别是ACE在肺损伤中的作用研究日趋深入,有必要了解其研究现状和未来趋势. 内容 重点就近几年来国内外对ACE在各种原因导致的肺损伤中作用的研究作一综述. 趋向 血管紧张素转换酶抑制剂(angiotensin converting enzyme inhibitom,ACEI)和血管紧张素Ⅱ(angiotensinⅡ,ATⅡ)受体阻断剂在各种肺损伤中的应用已取得肯定成果,使人们对RAS和其在肺损伤中作用的认识不断加深.     

血管紧张素Ⅱ受体拮抗剂防治糖尿病肾病机制的研究进展

肾素-血管紧张素系统(RAS)激活在糖尿病肾病的发生发展中具有重要意义.体外、动物、临床前及临床试验均证实:血管紧张素Ⅱ受体拮抗剂(ARBs)具有防治糖尿病肾病和多重保护肾脏的作用,但其机制还未完全清楚.本文重点就血管紧张素Ⅱ受体拮抗剂(AT1)防治糖尿病肾病机制的研究进展作一综述.     

肾素血管紧张素系统与造血调控研究进展

肾素-血管紧张素系统(RAS)的主要生物学作用体现在对血压和水、电解质的调 控上。近年来的研究表明,RAS参与造血调控,其主要活性物质血管紧张素Ⅱ(AngⅡ)促进红系造 血,而其受体拮抗剂(ARB)和血管紧张素转换酶抑制剂(ACEI)抑制红系造血。     

肾素血管紧张素系统与腹膜纤维化

肾素血管紧张素系统（RAS）是机体调节血管张力和钠水代谢的内分泌系统，随血液循环发挥作用。在慢性腹膜透析所致腹膜纤维化发病过程中，腹膜局部RAS激活，血管紧张素Ⅱ（ATⅡ）增加，促进转化生长因子β1（TGF-β1）分泌很可能是其中的重要发病机制之一。     

New perspectives on traumatic bone infections

In this paper, we review the results of previous studies and summarize the effects of various factors on the regulation of bone metabolism in traumatic bone infections. Infection-related bone destruction incorporates pathogens and iatrogenic factors in the process of bone resorption dominated by the skeletal and immune systems. The development of bone immunology has established a bridge of communication between the skeletal system and the immune system. Exploring the effects of pathogens, skeletal systems, immune systems, and antibacterials on bone repair in infectious conditions can help improve the treatment of these diseases.     

Effects of angiotensin-converting enzyme inhibitor,captopril, on bone of mice with streptozotocin-induced type 1 diabetes

There are contradictory results about the effect of angiotensin-converting enzyme inhibitors (ACEIs) on bone. This study was performed to address the skeletal renin?angiotensin system (RAS) activity and the effects of the ACEI, captopril, on the bone of streptozotocin-induced type 1 diabetic mice. Histochemical assessment on bone paraffin sections was conducted by Safranin O staining and tartrate-resistant acid phosphatase staining. Micro-computed tomography was performed to analyze bone biological parameters. Gene and protein expression were determined by real-time polymerase chain reaction and immunoblotting, respectively. Type 1 diabetic mice displayed osteopenia phenotype and captopril treatment showed no osteoprotective effects in diabetic mice as shown by the reduction of bone mineral density, trabecular thickness and bone volume/total volume. The mRNA expression of ACE and renin receptor, and the protein expression of renin and angiotensin II were markedly up-regulated in the bone of vehicle-treated diabetic mice compared to those of non-diabetic mice, and these molecular changes of skeletal RAS components were effectively inhibited by treatment with captopril. However, treatment with captopril significantly elevated serum tartrate-resistant acid phosphatase 5b levels, reduced the ratio of osteoprotegerin/receptor activator of nuclear factor-κB ligand expression, increased carbonic anhydrase II mRNA expression and the number of matured osteoclasts and decreased transforming growth factor-β and osteocalcin mRNA expression in the tibia compared to those of diabetic mice. The present study demonstrated that the use of the ACEI, captopril, has no beneficial effect on the skeletal biological properties of diabetic mice. However, this could be attributed, at least partially, to its suppression of osteogenesis and stimulation of osteoclastogenesis, even though it could effectively inhibit high activity of local RAS in the bone of diabetic mice.     

HMG CoA reductase inhibitors and the skeleton: a comprehensive review

Recent studies suggest that the mevalonate pathway plays an important role in skeletal metabolism. HMG CoA reductase inhibitors ("statins"), which inhibit a key enzyme in the mevalonate pathway, are widely used for the treatment of hyperlipidemia. In vitro and animal studies demonstrate that statins stimulate the production of BMP-2, a potent regulator of osteoblast differentiation and activity, suggesting that statins may have an anabolic effect on bone. Statin use in most, but not all observational studies is associated with a reduced risk of fracture, particularly hip fracture, even after adjustment for the confounding effects of age, weight and other medication use. This beneficial effect has not been observed in clinical trials designed to assess cardiovascular endpoints. The effects of statins on bone mass and bone turnover are controversial, but increased bone mass and reduced bone turnover have been observed in controlled studies. Further studies of the skeletal effects of statins are needed, particularly their effects on surrogate markers such as bone mass, bone turnover, and microarchitecture, to determine the optimal formulation, dosing and route of administration. Clinical trials with fracture endpoints are needed before statins can be recommended as therapeutic agents for osteoporosis.     

Where Wnts Went: The Exploding Field of Lrp5 and Lrp6 Signaling in Bone

Wnt signaling has emerged as a central regulator of skeletal modeling and remodeling. Loss‐ or gain‐of‐function mutations in two Wnt co‐receptors, Lrp5 and (more recently) Lrp6, have drawn attention to the importance of the Wnt pathway in bone biology. This review summarizes our current understanding of how the Wnt pathway operates on bone and the implications this has for skeletal physiology and drug discovery. Over the past 9 yr, rapid advances have been made in our understanding of the cellular targets for Wnt signaling and of the important regulatory molecules in this metabolic pathway. Both canonical and noncanonical signaling pathways seem to be important for mediating the effects of Wnt in bone. A rapidly expanding catalog of genetically engineered mice has been used to establish the importance of downstream effector molecules (such as β‐catenin) in the Wnt pathway, as well as the critical role of endogenous inhibitors of Wnt signaling (such as Dkk1 and sclerostin) in bone metabolism. Indeed, regulation of sclerostin in osteocytes is emerging as an important final pathway for regulating bone anabolism in response to diverse trophic stimuli, from mechnotransduction to the anabolic actions of PTH. From the outset, it had been assumed that the effects of Wnt signaling in bone were caused by direct actions in osteoblast precursors, osteoblasts, and osteocytes. However, startling recent findings have challenged this view and suggest that a key target, at least in mice, is the duodenal enterochromaffin cell. There, Wnt signaling transduced by Lrp5 regulates serotonin synthesis, which acts in an endocrine fashion to regulate bone cell metabolism. It will take time to reconcile this new information with the considerable body of information we already have regarding the actions of Wnt in bone. The Wnt pathway has rapidly emerged as a therapeutic target for drug discovery. Neutralizing antibodies and small‐molecule inhibitors of endogenous Wnt inhibitors have shown early promise as bone anabolic agents. However, given the central role of the Wnt pathway in regulating growth and development in extraskeletal tissues, as well as our still rudimentary understanding of how this signaling cascade actually affects bone metabolism, considerable work will be needed to ensure the safety of these new therapies.     

Bone Metabolism After Bariatric Surgery

Bariatric surgery is a popular and effective treatment for severe obesity but may have negative effects on the skeleton. This review summarizes changes in bone density and bone metabolism from animal and clinical studies of bariatric surgery, with specific attention to Roux‐en‐Y gastric bypass (RYGB), adjustable gastric banding (AGB), and sleeve gastrectomy (SG). Skeletal imaging artifacts from obesity and weight loss are also considered. Despite challenges in bone density imaging, the preponderance of evidence suggests that bariatric surgery procedures have negative skeletal effects that persist beyond the first year of surgery, and that these effects vary by surgical type. The long‐term clinical implications and current clinical recommendations are presented. Further study is required to determine mechanisms of bone loss after bariatric surgery. Although early studies focused on calcium/vitamin D metabolism and mechanical unloading of the skeleton, it seems likely that surgically induced changes in the hormonal and metabolic profile may be responsible for the skeletal phenotypes observed after bariatric surgery. © 2014 American Society for Bone and Mineral Research.     

Rationale for combining blockers of the renin-angiotensin system

Blockade of the renin-angiotensin system (RAS) with angiotensin I-converting enzyme (ACE) inhibitors and AT1-receptor (AT1R) blockers has become one of the most successful therapeutic approaches in medicine. The question is no longer whether RAS inhibition helps, but rather how we can optimize inhibition to achieve optimal cardiovascular and renal protection. Indeed, numerous data have shown that the RAS is not blocked fully over 24 hours with current doses of RAS blockers because they trigger a counter-regulatory renin release that can offset pharmacologic inhibition of the RAS. This absence of full blockade may have clinical implications. Combination therapy with ACE inhibitors and AT1R antagonists thus has been proposed to inhibit the biological effects of the reactive renin release triggered by single-site RAS inhibition. By using this approach, numerous experimental and clinical studies have suggested that this combination therapy has additive or synergistic effects on blood pressure and on the prevention of cardiovascular and renal lesions. Although similar intensity of RAS blockade can be achieved by either combination therapy or by using high doses of an AT1-receptor antagonist given alone, the ACE inhibitor present in the combination interferes with the bradykinin-nitric oxide pathway and the N-acetyl-Ser-Asp-Lys-Pro metabolism, which both may have additional biological effects.     

Effects of Incretin-Based Therapies and SGLT2 Inhibitors on Skeletal Health

Anti-diabetic drugs are widely used and are essential for adequate glycemic control in patients with type 2 diabetes. Recently, marketed anti-diabetic drugs include incretin-based therapies (GLP-1 receptor agonists and DPP-4 inhibitors) and sodium-glucose co-transporter 2 (SGLT2) inhibitors. In contrast to well-known detrimental effects of thiazolidinediones on bone metabolism and fracture risk, clinical data on the safety of incretin-based therapies is limited. Based on meta-analyses of trials investigating the glycemic-lowering effect of GLP-1 receptor agonists and DPP4 inhibitors, it seems that incretin-based therapies are not associated with an increase in fracture risk. Sodium-glucose co-transporter 2 inhibitors may alter calcium and phosphate homeostasis as a result of secondary hyperparathyroidism induced by increased phosphate reabsorption. Although these changes may suggest detrimental effects of SGLT-2 inhibitors on skeletal integrity, treatment-related direct effects on bone metabolism seem unlikely. Observed changes in BMD, however, seem to result from increased bone turnover in the early phase of drug-induced weight loss. Fracture risk, which is observed in older patients with impaired renal function and elevated cardiovascular disease risk treated with SGLT2 inhibitors, seems to be independent of direct effects on bone but more likely to be associated with falls and changes in hydration status secondary to osmotic diuresis.     

Bone and joint alterations in acromegaly

Growth hormone (GH) is fundamental for the maintenance of bone mass and metabolism both during childhood and in adulthood. This effect is due to a complex interaction between circulating GH and IGF-I produced peripherally. In vitro data and experimental animal models have clarified many of the regulatory mechanisms underlying the characteristic skeletal changes occurring in acromegaly. This review focuses on the effects of GH excess on bone metabolism and mass in acromegalic patients and, in particular, on the influence of factors such as hypogonadism, gender, age and therapy on bone metabolism and arthropathy.     

单味中药及其有效成分组织蛋白酶K抑制剂研究进展

组织蛋白酶K(Cathepsin K,CTSK)属于半胱氨酸蛋白酶,是抗骨质疏松药物研发的重要靶点,在破骨细胞中特异性高表达,对降解骨胶原基质至关重要。与临床常用的抑制骨吸收药物相比,CTSK抑制剂具有在不影响骨形成的情况下有效减少骨吸收的优点。迄今为止,CTSK抑制剂的研发均因安全性不足而失败,原因是对皮肤和血管系统等非骨组织造成副作用。传统中药富含抑制骨吸收的活性物质,一些文献表明中药来源的CTSK抑制剂抗骨质疏松作用明显,且没有明显的不良反应。笔者拟综述近10年中药来源的CTSK抑制剂的研究进展,资料主要来源于中国知网、万方和Web of Science数据库,为开发中药CTSK抑制剂和治疗CTSK相关疾病提供参考。