Bone metabolism during pregnancy

During pregnancy, mineral concentrations, of calcium and phosphorus in particular, are maintained at a high level in fetal blood so that the developing skeleton may accrete adequate mineral content. The placenta actively transports minerals for this purpose. Maternal intestinal absorption increases in order to meet the fetal demand for calcium, which is only partly dependent on calcitriol. Mineral regulation is essentially dependent on parathyroid hormone (PTH) and PTH-related protein (PTHrP). The calcium-sensing receptor (CaSR) regulates PTH and PTHrP production. If calcium intake is insufficient, the maternal skeleton will undergo resorption due to PTHrP. After birth, a switch from fetal to neonatal homeostasis occurs through increase in PTH and calcitriol, and developmental adaptation of the kidneys and intestines with bone turnover contributing additional mineral to the circulation. Calcium absorption becomes progressively active and dependent on calcitriol. The postnatal skeleton can transiently present with osteoposis but adequate mineral diet usually allows full restoration. Cases of primary osteoporosis must be identified. Loss of trabecular mineral content occurs during lactation in order to provide calcium to the newborn. This programmed bone loss is dependent on a “brain-breast-bone” circuit. The physiological bone resorption during reproduction does not normally cause fractures or persistent osteoporosis. Women who experience fracture are likely to have other causes of bone loss.     

左归丸抗乳腺癌转移及其作用机制

目的:观察左归丸的抗乳腺癌转移作用,探讨其作用机制。方法:采用股骨内注射法建立人乳腺癌细胞MDAMB-231骨转移裸鼠模型,受试裸鼠随机分为空白组(蒸馏水),左归丸低、高剂量(21,42 g·kg-1)组。连续给药8周后,采用巢式聚合酶链式反应(PCR)检测裸鼠骨髓组织中人细胞角蛋白(ck19)基因的表达,确定肿瘤转移情况;采用Oris法,检测左归丸含药血清对乳腺癌细胞MDA-MB-231体外迁移能力的影响;采用重组基底膜侵袭法,观察左归丸含药血清的体外抗侵袭作用;采用Alexa Fluor488标记的鬼笔环肽(Phalloidin)进行荧光染色,观察左归丸含药血清对乳腺癌细胞纤维型肌动蛋白(F-actin)聚合的影响;采用蛋白质印迹法(Western blot)检测左归丸含药血清对MDA-MB-231细胞甲状旁腺激素相关蛋白(PTHr P)和4型趋化因子受体(CXCR4)表达的影响。结果:与空白组比较,左归丸高、低剂量均可显著抑制小鼠骨髓组织中人ck19基因表达(P0.01)。Oris迁移表明,左归丸含药血清可显著抑制转化生长因子-β(TGF-β)诱导的MDA-MB-231细胞迁移;重组基底膜侵袭实验显示,左归丸含药血清也可显著抑制乳腺癌细胞对重组基底膜的侵袭能力。给药组侵袭细胞数较空白组显著降低(P0.01)。Phalloidin荧光染色结果显示,左归丸含药血清可显著抑制F-actin聚合,抑制F-actin聚合体的形成。Western blot结果表明,左归丸含药血清可显著抑制乳腺癌细胞PTHr P,CXCR4蛋白表达。结论:左归丸具有明显的抗乳腺癌骨转移作用,其机制与抑制肿瘤细胞PTHr P,CXCR4表达,从而直接抑制其体外运动活性相关。     

弥漫大B细胞淋巴瘤合并高钙危象1例并文献复习

目的 探讨合并高钙危象的弥漫大B细胞淋巴瘤病人的临床特点,提高对该疾病的认识。方法 回顾性分析临沂市人民医院于2021年11月收治的1例弥漫大B细胞淋巴瘤合并高钙危象的临床资料。结果 病人经腹腔肿物穿刺活检确诊弥漫大B细胞淋巴瘤,给予利妥昔单抗+环磷酰胺+多柔比星+长春地辛+甲泼尼龙（R-CHOP）化疗,化疗次日出现恶心、嗜睡、尿频,乏力,复查血钙4.31 mmol/L,合并高钙危象,并辅以水化、碱化、大量补液、护胃保肝、降血钙等治疗,血钙下降至正常,随访未再升高,后因病情恶化放弃治疗自动出院。结论 弥漫大B细胞淋巴瘤合并高钙危象少见且症状因人而异,预后不良,做到早期识别及诊断,将有利于提高这类病人的疗效。     

Expression of parathyroid hormone/parathyroid hormone-related peptide receptor 1 in normal and diseased bladder detrusor muscles: a clinico-pathological study

Background

To investigate the expression of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor 1 (PTH1R) in clinical specimens of normal and diseased bladders. PTHrP is a unique stretch-induced endogenous detrusor relaxant that functions via PTH1R. We hypothesized that suppression of this axis could be involved in the pathogenesis of bladder disease.

Methods

PTH1R expression in clinical samples was examined by immunohistochemistry. Normal kidney tissue from a patient with renal cancer and bladder specimens from patients undergoing ureteral reimplantation for vesicoureteral reflux or partial cystectomy for urachal cyst were examined as normal control organs. These were compared with 13 diseased bladder specimens from patients undergoing bladder augmentation. The augmentation patients ranged from 8 to 31 years old (median 15 years), including 9 males and 4 females. Seven patients had spinal disorders, 3 had posterior urethral valves and 3 non-neurogenic neurogenic bladders (Hinman syndrome).

Results

Renal tubules, detrusor muscle and blood vessels in normal control bladders stained positive for PTH1R. According to preoperative urodynamic studies of augmentation patients, the median percent bladder capacity compared with the age-standard was 43.6% (range 1.5–86.6%), median intravesical pressure at maximal capacity was 30 cmH₂O (range 10–107 cmH₂O), and median compliance was 3.93 ml/cmH₂O (range 0.05–30.3 ml/cmH₂O). Detrusor overactivity was observed in five cases (38.5%). All augmented bladders showed negative stainings in PTH1R expression in the detrusor tissue, but positive staining of blood vessels in majority of the cases.

Conclusions

Downregulation of PTH1R may be involved in the pathogenesis of human end-stage bladder disease requiring augmentation.     

Investigational parathyroid hormone receptor analogs for the treatment of osteoporosis

Introduction: Intermittent parathyroid hormone (PTH) administration, acting through multiple signaling pathways, exerts an osteoanabolic effect on the skeleton that surpasses the effect of other antiosteoporotic agents. However, its efficacy is limited by the coupling effect and relatively common adverse events. Thus, the development of more sophisticated PTH receptor analogs seems imperative.

Areas covered: In this review, the authors summarize the role of PTH signaling pathway in bone remodeling. The authors also summarize investigational analogs targeting this pathway, which may be potential treatments for osteoporosis.

Expert opinion: β-arrestins are multifunctional cytoplasmic molecules that are decisive for regulating intracellular PTH signaling. Recently, in preclinical studies, arrestin analogs have achieved the anabolic bone effect of PTH without an accompanying increase in bone resorption. However, it is not yet known whether these analogs have adverse effects and there are no clinical data for their efficacy to date. On the other hand, several molecules derived either from PTH and PTH-related protein (PTHrP) molecules have been developed. Alternative routes of PTH 1 – 34 delivery (oral, transdermal), the PTH analog ostabolin and the N-terminal PTHrP analogs PTHrP 1 – 36 and abaloparatide, have recently been or are currently being tested in clinical trials and are more likely to become available for use in the near future.     

Effects of parathyroid hormone-related peptide receptor in tibial growth plate on tibial extension in chronic renal insufficiency rats

Objective To observe the expression of parathyroid hormone-related peptide (PTHrp) receptor in tibial growth plate and its effects on tibial extension in chronic renal insufficiency rats. Methods Two-week-old male Sprague-Dawley rats were randomly divided into sham group, model group and enalapril group, each with 20 rats. In model group and enalapril group rats had chronic renal insufficiency induced by left ureteral obstruction, and rats were respectively given saline and enalapril by gavage after the operation. In sham group, left ureter was only exposed without ligation, and rats were given saline. The urine was collected 4 weeks after the operation and the total protein content was measured. Then all rats were killed. The concentrations of PTHrp, creatinine and urea nitrogen in intracardiac blood were detected. HE staining and Masson staining were performed on the left kidney to observe pathological changes of glomeruli and renal tubules. The total length of bilateral tibia was measured. The number of columnar cells in the growth plate proliferative zone was measured by safranin O staining and the expression of PTHrp receptor in the growth plate was detected by immunohistochemistry. Results The 24 h urine total protein, creatinine and urea nitrogen in model group were higher than those in sham group (all P＜0.05), while these 3 renal functional parameters in enalapril group were lower than those in model group (all P＜0.05). In model group and enalapril group rats had higher blood concentrations of PTHrp than that in sham group (all P＜0.05), but blood PTHrp in enalapril group was lower than that in model group (P＜0.05). HE staining and Masson staining showed that in the model group rats had severe tubular dilation, inflammatory cell infiltration and the tissue fibrosis, while in enalapril group renal tubules slightly dilated and had a few inflammatory cell infiltration and tissue fibrosis. Compared with those in the sham group, in model group the tibia length, the chondrocyte number of column structure in the growth plate proliferative zone and the PTHrp receptor decreased (all P＜0.05). But in enalapril group those indexes increased than model group (all P＜0.05). Conclusions Chronic renal insufficiency rats had increased PTHrp concentration in the blood but decreased PTHrp receptors expression in tibial growth plate, which lead to their limited tibial extension.     

正弦波电磁场对鼠骨骺干细胞分化的生物学影响

目的 研究50Hz正弦波电磁场对大鼠骨骺干细胞分化的生物学影响。方法 取生长良好的第4代骨骺干细胞，随机分为实验组和对照组，实验组采用50Hz正弦波电磁场间断刺激。分别绘制2组细胞生长曲线，MTT法测定细胞增殖活性，流式细胞仪检测细胞凋亡情况，Western Blot法检测细胞甲状旁腺激素相关蛋白（PTHrp）的表达，并进行定量分析。结果 曝磁早期细胞增殖活性的改变不明显，正弦波电磁场刺激4d和6d能明显促进细胞的增殖，2组OD值比较，差异有统计学意义（P〈0.05）。与对照组比较，实验组骨骺干细胞的早期凋亡率、晚期凋亡率和总凋亡率均明显降低（P〈0．05）．PTHrp蛋白的表达增强。结论 适当参数的工频正弦波电磁场能促进骨骺干细胞PTHrp蛋白的表达，从而调节其增殖能力，增强分化稳定性，抑制细胞凋亡。     

甲状旁腺激素及其受体与骨关节炎的关系研究进展

骨关节炎是一种以关节软骨破坏、软骨下骨的硬化和滑膜反应为特征的慢性疾病.目前发现甲状旁腺激素(Parathyroid hormone,PTH)能够抑制骨关节炎患者软骨细胞终末期成熟分化,有明显软骨保护、延缓骨关节炎进展的作用.通过研究PTH、PTHR与骨关节炎的关系,对骨关节炎治疗及预后将起到重要的指导作用.     

血浆PTH/PTHrP、钙离子浓度变化与胆囊胆固醇结石形成相关的研究

目的：进一步探讨了血浆中甲状旁腺激素（PTH）及其相关蛋白（PTHrP）、钙离子和胆汁中钙离子在胆囊胆固醇结石形成中的可能机制,为胆囊胆固醇结石防治提供理论根据和临床参考。方法：随机选择胆囊胆固醇结石患者45例为研究对象,同期同院随机选择健康体检人群35例,同期同院非胆囊结石患者（息肉组）30例。PTH采用ELISA检测,PTHrP采用RIA试剂盒（DSL-8100）,血清中Ca^2＋和胆汁中Ca^2＋用自动生化分析仪检测,胆囊结石利用叶氏化学分析。结果：胆石组血清Ca2＋较正常组明显增高（P〈0.05）,其血清PTH比正常组PTH明显降低,PTHrP相应比正常组PTHrP明显增高（P〈0.05）。胆石组胆汁Ca^2＋比息肉组胆汁中Ca^2＋明显增高（P〈0.05）。结论：其各种浓度变化在胆囊胆固醇结石形成中存在相互影响,从而影响了胆汁代谢的异常,胆囊收缩功能的异常和胆汁中的成核因子三个基本环节发生共同致石作用。