Percutaneous Vertebroplasty is no Risk Factor for New Vertebral Fractures and Protects Against Further Height Loss (VERTOS IV).

BACKGROUND: Percutaneous vertebroplasty (PV) is an alternative option to treat pain after an osteoporotic vertebral compression fracture (OVCF). Controversy exists as to whether PV increases the risk of new OVCFs or prevents further vertebral height loss in treated levels. We assessed both during 1-year follow-up in patients with acute OVCF randomised to PV or a sham procedure. METHODS: VERTOS IV is a prospective, multicentre, randomised controlled trial comparing PV with sham therapy in 180 patients. New OVCFs and further vertebral height loss were assessed at 3, 6, and 12 months. RESULTS: After a median follow-up of 12 months (interquartile range (IQR) = 12-12) 31 new fractures were reported in 15 patients from the PV group and 28 new fractures in 19 patients from the sham group. The occurrence of new vertebral fractures did not significantly differ between the groups (χ2(1) = 0.83, p = 0.36, OR = .71, 95%CI = 0.33-1.50). There was no higher fracture risk of adjacent versus distant vertebrae. After sham procedure, further height loss of treated vertebrae occurred more frequently (7 patients (8%) in the PV group and 39 (45%) in the sham group (χ2(1) = 28.85, p < 0.001, OR = 9.84, 95%CI = 4.08-23.73)) and was more severe (p < .001) than after PV. CONCLUSIONS: The risk of further vertebral height loss is significantly lower after PV compared to a sham intervention, i.e. PV protects against progressive vertebral height loss. In addition, PV does not increase the risk of new adjacent and distant OVCFs. LEVEL OF EVIDENCE: Level 1a, therapeutic study. ClinicalTrials.gov number, NCT01200277.

Premature differentiation of vascular smooth muscle cells in human congenital diaphragmatic hernia.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly characterized by the herniation of abdominal organs into the chest cavity. The high mortality and morbidity of CDH patients are primarily caused by the associated pulmonary hypertension (PH), characterized by the thickening of the vascular media and adventitia. The media consist of heterogeneous populations of vascular smooth muscle cells (VSMC), ranging from synthetic to the characteristic contractile cells. VSMCs are influenced by developmental and environmental cues and may play a role in the development of the structural changes observed in CDH patients. Therefore, we hypothesized that the distribution of the VSMC populations may already be different at the origin of CDH development. METHODOLOGY: We analyzed the protein expression of specific markers associated with synthetic and contractile VSMC phenotypes in human lungs at different developmental stages. Next, we compared lungs of premature and term CDH patients, as well as patients with lung hypoplasia due to renal agenesis or PROM, with age-matched controls. RESULTS: Synthetic and contractile VSMCs are distributed in a temporal and spatial specific pattern along the proximodistal axis of the lung. CDH patients have more abundant contractile VSMCs which are also more distally distributed. This different distribution pattern is already observed from 19 weeks of gestation onwards. CONCLUSION: Our data suggest that the more extensive distribution of contractile VSMCs is associated with an early maturation of the pulmonary vasculature, contrasting the concept that CDH might be the result of delayed maturation of the epithelium.

Expression of hypoxia-inducible factors, regulators, and target genes in congenital diaphragmatic hernia patients.

Congenital diaphragmatic hernia (CDH) is associated with lung hypoplasia and pulmonary hypertension and has high morbidity and mortality rates. The cause and pathophysiology of CDH are not fully understood. However, impaired angiogenesis appears to play an important role in the pathophysiology of CDH. Therefore, we examined different components of an important pathway in angiogenesis: hypoxia-inducible factors (HIFs); HIF regulators von Hippel-Lindau (VHL) and prolyl 3-hydroxylase (PHD3); and HIF target genes vascular endothelial growth factor A ( VEGF-A ) and vascular endothelial growth factor receptor 2 ( VEGFR-2 ). Quantitative polymerase chain reaction of lung tissue showed a significantly decreased expression of VEGF-A mRNA in the alveolar stage of lung development in CDH patients compared with matched control patients. In the canalicular stage, no differences for VEGF-A were seen between the lungs of CDH patients and those of control patients. Other components of angiogenesis (VHL, HIF-1α, HIF-2α, HIF-3α, VEGFR-2 mRNA, PHD3 protein) that were analyzed showed no differences in expression between CDH and control patients, independent of the developmental stage. A lower expression of VEGF mRNA in CDH patients in the alveolar stage, possibly as a result of downregulation of HIF-2α might indicate a role for these factors in the pathophysiology of CDH.

Expression and function of phosphodiesterases in nitrofen-induced congenital diaphragmatic hernia in rats.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is an anomaly associated with pulmonary hypoplasia and pulmonary hypertension (PH). The limited efficacy of current approaches to treat PH in CDH, including inhaled nitric oxide (NO), drives the search for other therapies. Phosphodiesterases (PDEs) degrade cyclic nucleotide second messenger cAMP and cGMP downstream of NO thereby limiting the vasodilatory response to NO. OBJECTIVE: To identify therapeutic targets by cataloguing the expression and function of PDE isoforms in the pulmonary vasculature in nitrofen-induced CDH in fetal rats. METHODS/RESULTS: Quantitative RT-PCR revealed PDE1-5 and PDE9 mRNA expression in pulmonary arteries (PAs) of control and nitrofen-induced CDH term fetal rats. In this order of potency, the PDE inhibitors Sildenafil (PDE5) > EHNA (PDE2) > Rolipram (PDE4) > Cilostamide (PDE3) all dilated isolated third generation PA after pre-constriction with the thromboxane analog U46619. Hyperoxic pre-incubation of PAs significantly attenuated vasodilatation induced by the PDE5 inhibitor Sildenafil (65% vs. 33%, P < 0.004). CDH PAs dilated significantly less to PDE2 inhibitor EHNA compared to control (51% vs. 72%, P < 0.05). Subsequently PDE2 protein expression was higher in PAs of CDH animals. CONCLUSION: Most PDE isoforms exist in the PAs of fetal rats and their inhibition causes pulmonary vasodilatation. PDE5 inhibition was the most potent vasodilator, however, there were no differences between groups. PDE5-induced vasodilatation was attenuated by hyperoxic pre-incubation. PDE inhibitors might be considered therapeutic targets in combination with iNO in neonates with CDH.

Lysyl oxidase activity is dysregulated during impaired alveolarization of mouse and human lungs.

RATIONALE: Disordered extracellular matrix production is a feature of bronchopulmonary dysplasia (BPD). The basis of this phenomenon is not understood. OBJECTIVES: To assess lysyl oxidase expression and activity in the injured developing lungs of newborn mice and of prematurely born infants with BPD or at risk for BPD. METHODS: Pulmonary lysyl oxidase and elastin gene and protein expression were assessed in newborn mice breathing 21 or 85% oxygen, in patients who died with BPD or were at risk for BPD, and in control patients. Signaling by transforming growth factor (TGF-beta) was preemptively blocked in mice exposed to hyperoxia using TGF-beta-neutralizing antibodies. Lysyl oxidase promoter activity was assessed using plasmids containing the lox or loxl1 promoters fused upstream of the firefly luciferase gene. MEASUREMENTS AND MAIN RESULTS: mRNA and protein levels and activity of lysyl oxidases (Lox, LoxL1, LoxL2) were elevated in the oxygen-injured lungs of newborn mice and infants with BPD or at risk for BPD. In oxygen-injured mouse lungs, increased TGF-beta signaling drove aberrant lox, but not loxl1 or loxl2, expression. Lox expression was also increased in oxygen-injured fibroblasts and pulmonary artery smooth muscle cells. CONCLUSIONS: Lysyl oxidase expression and activity are dysregulated in BPD in injured developing mouse lungs and in prematurely born infants. In developing mouse lungs, aberrant TGF-beta signaling dysregulated lysyl oxidase expression. These data support the postulate that excessive stabilization of the extracellular matrix by excessive lysyl oxidase activity might impede the normal matrix remodeling that is required for pulmonary alveolarization and thereby contribute to the pathological pulmonary features of BPD.

Expression of hypoxia-inducible factors in normal human lung development.

Pulmonary vascular development is essential for proper lung development, and its disturbance can lead to neonatal morbidity and mortality, as exemplified in congenital diaphragmatic hernia. Hypoxia-inducible factors (HIFs) appear to be key molecules in physiologic angiogenesis and in certain forms of lung pathology, such as bronchopulmonary dysplasia. Little is known about the qualitative and quantitative expression of HIFs in normal human fetal lung development. Therefore, we investigated the expression of HIF-1alpha, HIF-2alpha, and HIF-3alpha, along with their upstream regulators and downstream targets, von Hippel-Lindau protein, vascular endothelial growth factor A (VEGF-A), and its receptor, VEGFR-2, in 20 normal human fetal lungs (13.5 weeks in gestation until term) and 5 adult lungs. Quantitative polymerase chain reaction demonstrated a positive correlation between HIF-2alpha and VEGF-A expression and gestational age. Although there appeared to be a decreasing trend in HIF-3alpha expression during pregnancy, it did not reach statistical significance. Immunohistochemistry for HIF-1alpha and HIF-2alpha revealed that HIF-1alpha is expressed in the epithelium, while HIF-2alpha is expressed in both interstitium and epithelium. Our data indicate that HIFs, most notably HIF-2alpha, appear to exert an important role in angiogenesis during human fetal lung development, especially in the last phases of pregnancy, preparing the fetus for extrauterine life. As such, our results form the baseline data for the evaluation and interpretation of abnormal pulmonary vascular development.