Abstract OT3-05-04: A randomized, open-label, multi-center phase IV study evaluating palbociclib plus endocrine treatment versus a chemotherapy-based treatment strategy in patients with hormone receptor-positive, HER2-negative metastatic breast cancer in a real world setting (PADMA)

Background:

Although endocrine therapy (ET) is recommended as first-line therapy for hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC) up to 50% of patients receive chemotherapy in this setting. Meanwhile new targeted treatment options for combination with ET have been developed and endocrine-based therapy with the CDK4/6 inhibitor Palbociclib (P) improves the progression free survival (PFS) of ET alone by about 50%. So far, there is no data comparing chemotherapy with or without maintenance ET and ET in combination with P as first-line therapy. Patients included in clinical trials are often criticized not to mirror the general breast cancer population and every-day clinical practice due to rigid inclusion and exclusion criteria, limited number of treatment options, strict monitoring intervals and study assessments.

Methods:

PADMA trial is a so called low intervention trial with no rigid inclusion and exclusion criteria, and study assessments.Patients with first-line HR+/HER2- MBC who are candidate for mono-chemotherapy will be eligible to receive either P plus ET per label or mono-chemotherapy per investigator´s choice with or without maintenance ET (1:1 randomization). Primary objective is to compare the time-to-treatment failure (TTF) for patients randomized to receive the mono-chemotherapy treatment strategy versus those randomized to receive P and ET. TTF is defined as time from randomization to discontinuation of treatment due to disease progression, treatment toxicity, patient's preference, or death. Main secondary objectives are progression free survival, overall survival at 36 months, amongst other time to event endpoints as well as toxicity and compliance. All patients receive a specific mobile device (PADMA-Phone) and a validated wearable device (ActiWatch) in order to collect data regarding sleep and activity levels, patient well-being and health care utilization (number and duration of phone calls, and patient visits to investigator site) for assessment of daily monitoring treatment impact (DMTI).

Results:

Overall, 360 patients will be accrued to show an improved TTF for P in combination with ET compared to mono-chemotherapy of investigator´s choice with or without maintenance ET. Recruitment will start in QIII/2017 and is planned for approximately 18 months in 100 sites in Germany, Spain, Poland, Italy, France, UK and Canada.

Conclusions:

The aim of PADMA is to demonstrate that an endocrine-based strategy consisting of ET plus P is superior to a chemotherapy-based strategy as first-line therapy in women with HR+/HER2- MBC in a real world setting. Assessment of patient-reported outcome, health care utilization, and sleep and activity levels will deliver important information on the differences between endocrine-based and chemotherapy-based treatment.

Citation Format: Loibl S, Barinoff J, Seiler S, Decker T, Denkert C, Hardy-Bessard A-C, Senkus-Konefka E, Cognetti F, Palmieri C, Gelmon K, Luebbe K, Furlanetto J, Mueller V, Mundhenke C, Schmidt M, von Minckwitz G, Uhlig M, Burchardi N, Thill M. A randomized, open-label, multi-center phase IV study evaluating palbociclib plus endocrine treatment versus a chemotherapy-based treatment strategy in patients with hormone receptor-positive, HER2-negative metastatic breast cancer in a real world setting (PADMA) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-05-04.

Abstract P5-20-09: Pharmacokinetic results of a subcutaneous injection of trastuzumab into the thigh versus into the abdominal wall in patients with HER2-positive primary breast cancer (BC) treated within the neo-/adjuvant GAIN-2 study

Background

A new subcutaneous (s.c.) formulation of trastuzumab became available in 2013 based on equivalent efficacy, pharmacokinetic (PK) profile and safety with the standard intravenous (i.v.) administration, where the s.c. trastuzumab was administered only into the thigh. As an s.c. injection into the abdominal wall (abdw) might be more convenient for patients (pts) and health care professionals, the PK profile of s.c. trastuzumab injected into the thigh vs the abdw in pts with HER2+ early BC needs to be evaluated.

Methods

GAIN-2 study compared two intense dose-dense (idd) anthracycline/taxane containing regimens. After completion of the anthracycline and i.v. trastuzumab given concurrently with taxanes, HER2+ BC pts were randomized in a 1:1 ratio to continue adjuvant s.c. trastuzumab 600mg fixed dose injected every 3 weeks either into the thigh or the abdw. Randomization was stratified according to CT arm [(iddEnPC) vs tailored dd CT (dtEC-dtD)] and age (≤50 vs >50). Pts in the EnPC arm received 14 and in the dtEC-dtD arm 15 cycles of s.c. trastuzumab.

For the PK profile of s.c. trastuzumab serum samples collected before cycle 7, on days 2, 4, 8, 15 and 21 of cycle 7 are evaluated. With a total sample size of 30 (15 per group), the simulated 90% two-sided CI for the area under the plasma concentration (AUC0-last) will be (0.79-1.27) and for the peak drug concentration (Cmax) will be (0.77-1.30). Allowing for a dropout rate of 15%, 18 pts per group will be included in the PK analysis.

The primary objective was to assess the PK profile of s.c. trastuzumab injected into the thigh vs the abdw. The secondary objectives included safety and tolerability.

Results

The per-protocol (pp) set consists of 30 pts (17 in the thigh group and 13 in the abdw group). Baseline characteristics were well balanced between the groups. The log-transformed Geometric Least Square Means (GLSM) for Cmax were 11.77 and 11.52 in the thigh and the abdw group, respectively. The geo-mean ratio (on the original scale) for Cmax was 1.29 (90% CI 1.05-1.58). The log-transformed GLSM for AUC0-last were 14.54 and 14.28 in the thigh and the abdw group, respectively. The geo-mean ratio for AUC0-last was 1.29 (90% CI 1.02-1.63).

Overall 29 pts (96.7%) reported any grade and 5 pts (16.7%) high grade adverse events (AEs). The incidence of any grade AEs was similar between the two groups. The most common AEs were anemia (70.6% for the thigh vs 61.5% for the abdw group, p=0.705), leukopenia (80.0% for both groups, p=1.000) and fatigue (47.1% for the thigh vs 76.9% for the abdw group, p=0.141). 6 serious AEs were reported (2 in the thigh vs 4 in the abdw group). The final PK results of s.c. trastuzumab will be presented at the meeting.

Conclusions

Bioavailability of s.c. trastuzumab as reflected by peak and total exposure measured in cycle 7 was approx. 30% higher if administered into the thigh than into the abdw in pts with HER2+ primary BC treated after dose-dense CT plus i.v. trastuzumab. However, no increased toxicity was observed. Study limitations were that no cross-over design was used and number of pts satisfying criteria for pp-set were different in the arms.

Citation Format: Möbus V, Mahlberg R, Janni W, Tomé O, Marmé F, Forstbauer H, Reimer T, von der Assen A, Reinisch M, Lorenz R, Schmatloch S, Schmidt M, Sinn B, Klutinus N, Stickeler E, Untch M, Seiler S, Burchardi N, von Minckwitz G, Loibl S. Pharmacokinetic results of a subcutaneous injection of trastuzumab into the thigh versus into the abdominal wall in patients with HER2-positive primary breast cancer (BC) treated within the neo-/adjuvant GAIN-2 study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-20-09.

Advances in in Vitro and in Vivo Models for Studying the Staphylococcal Factors Involved in Implant Infections

Implant infections due to staphylococci are one of the greatest threats facing patients receiving implant devices. For many years researchers have sought to understand the mechanisms involved in the adherence of the bacterium to the implanted device and the formation of the unique structure, the biofilm, which protects the indwelling bacteria from the host defence and renders them resistant to antibiotic treatment. A major goal has been to develop in vitro and in vivo models that adequately reflect the real-life situation. From the simple microtiter plate assay and scanning electron microscopy, tools for studying adherence and biofilm formation have since evolved to include specialised equipment for studying adherence, flow cell systems, real-time analysis of biofilm formation using reporter gene assays both in vitro and in vivo, and a wide variety of animal models. In this article, we discuss advances in the last few years in selected in vitro and in vivo models as well as future developments in the study of adherence and biofilm formation by the staphylococci.

Antagonization of the Nogo-Receptor 1 Enhances Dopaminergic Fiber Outgrowth of Transplants in a Rat Model of Parkinson's Disease

Intrastriatal transplantation of fetal human ventral mesencephalic dopaminergic neurons is an experimental therapy for patients suffering from Parkinson’s disease. The success of this approach depends on several host brain parameters including neurotrophic factors and growth inhibitors that guide survival and integration of transplanted neurons. While the potential of neurotrophic factors has been extensively investigated, repression of growth inhibitors has been neglected, despite the significant effects reported in various CNS injury models. Recently, we demonstrated that infusion of neutralizing antibodies against Nogo-A into the lateral ventricles of hemi-parkinsonian rats significantly enhanced graft function. Since the Nogo-receptor 1 also interacts with other neurite growth inhibitors, we investigated whether a direct antagonization of the receptor would result in more robust effects. Therefore, rats with unilateral striatal 6-hydroxydopamine lesions were grafted with ventral mesencephalic tissue in combination with intraventricular infusions of the Nogo-receptor 1 antagonist NEP1-40. Transplanted rats receiving saline infusions served as controls. To test whether NEP1-40 treatment alone affects the remaining dopaminergic striatal fibers, rats with unilateral striatal 6-hydroxydopamine lesions were infused with NEP1-40 or saline without receiving a transplant. Motor behavior was assessed prior to the lesion as well as prior and 1, 3, and 5 weeks after the transplantations. At the end of the experimental period the number of graft-derived dopaminergic fibers growing into the host brain, the number of surviving dopaminergic neurons and graft volume were analyzed. In rats without a transplant, the density of dopaminergic fibers in the striatum was analyzed. We detected that NEP1-40 treatment significantly enhanced graft-derived dopaminergic fiber outgrowth as compared to controls while no effects were detected for graft volume and survival of grafted dopaminergic neurons. Notably, the enhanced dopaminergic fiber outgrowth was not sufficient to improve the functional recovery as compared to controls. Moreover, NEP1-40 infusions in hemi-parkinsonian rats without a transplant did not result in enhanced striatal dopaminergic fiber densities and consequently did not improve behavior. In sum, our findings demonstrate that antagonization of the Nogo-receptor 1 has the capacity to support the engraftment of transplanted mesencephalic tissue in an animal model of Parkinson’s disease.

Nogo-receptor 1 antagonization in combination with neurotrophin-4/5 is not superior to single factor treatment in promoting survival and morphological complexity of cultured dopaminergic neurons

Cell transplantation using ventral mesencephalic tissue is an experimental approach to treat Parkinson's disease. This approach is limited by poor survival of the transplants and the high number of dopaminergic neurons needed for grafting. Increasing the yield of dopaminergic neurons in donor tissue is of great importance. We have previously shown that antagonization of the Nogo-receptor 1 by NEP1-40 promoted survival of cultured dopaminergic neurons and exposure to neurotrophin-4/5 increased dopaminergic cell densities in organotypic midbrain cultures. We investigated whether a combination of both treatments offers a novel tool to further improve dopaminergic neuron survival. Rat embryonic ventral mesencephalic neurons grown as organotypic free-floating roller tube or primary dissociated cultures were exposed to neurotrophin-4/5 and NEP1-40. The combined and single factor treatment resulted in significantly higher numbers of tyrosine hydroxylase positive neurons compared to controls. Significantly stronger tyrosine hydroxylase signal intensity was detected by Western blotting in the combination-treated cultures compared to controls but not compared to single factor treatments. Neurotrophin-4/5 and the combined treatment showed significantly higher signals for the neuronal marker microtubule-associated protein 2 in Western blots compared to control while no effects were observed for the astroglial marker glial fibrillary acidic protein between groups, suggesting that neurotrophin-4/5 targets mainly neuronal cells. Finally, NEP1-40 and the combined treatment significantly augmented tyrosine hydroxylase positive neurite length. Summarizing, our findings substantiate that antagonization of the Nogo-receptor 1 promotes dopaminergic neurons but does not further increase the yield of dopaminergic neurons and their morphological complexity when combined with neurotrophin-4/5 hinting to the idea that these treatments might exert their effects by activating common downstream pathways.

Lower Magnetization Transfer Ratio in the Forceps Minor Is Associated with Poorer Gait Velocity in Older Adults

BACKGROUND AND PURPOSE

Gait disturbances in the elderly are disabling and a major public health issue but are poorly understood. In this multimodal MR imaging study, we used 2 voxel-based analysis methods to assess the voxelwise relationship of magnetization transfer ratio and white matter hyperintensity location with gait velocity in older adults.

MATERIALS AND METHODS

We assessed 230 community-dwelling participants of the Austrian Stroke Prevention Family Study. Every participant underwent 3T MR imaging, including magnetization transfer imaging. Voxel-based magnetization transfer ratio-symptom mapping correlated the white matter magnetization transfer ratio of each voxel with gait velocity. To assess a possible relationship between white matter hyperintensity location and gait velocity, we applied voxel-based lesion-symptom mapping.

RESULTS

We found a significant association between the magnetization transfer ratio within the forceps minor and gait velocity (β = 0.134; 95% CI, 0.011-0.258; P = .033), independent of demographics, general physical performance, vascular risk factors, and brain volume. White matter hyperintensities did not significantly change this association.

CONCLUSIONS

Our study provides new evidence for the importance of magnetization transfer ratio changes in gait disturbances at an older age, particularly in the forceps minor. The histopathologic basis of these findings is yet to be determined.

A Subpopulation of Dopaminergic Neurons Coexpresses Serotonin in Ventral Mesencephalic Cultures But Not After Intrastriatal Transplantation in a Rat Model of Parkinson's Disease

Cell replacement therapy is a promising avenue into the investigation and treatment of Parkinson's disease (PD), and in some cases, significant long-term motor improvements have been demonstrated. The main source of donor tissue is the human fetal ventral mesencephalon (FVM), which consists of a mixed neuronal population, and its heterogeneity likely contributes to the inconsistent outcome observed in clinical trials. Therefore, detailed knowledge about the neuronal subpopulations in the VM seems essential for successful cell transplantation. Interestingly, it has been reported that some tyrosine hydroxylase-positive (TH+) neurons in the VM of adult rats and in cultured midbrain-derived neuroblasts coexpress additional neurotransmitters. Thus, the present study investigated, by means of colocalization analyses, the possible expression of GABA or serotonin in TH+ neurons. For that purpose, both fetal rat and human dissociated, organotypic and neurosphere FVM cultures as well as an animal model of PD were investigated. In dissociated rat FVM cultures, approximately 30% of the TH+ neurons coexpressed serotonin, while no colocalization with GABA was observed. Interestingly, coexpression of TH and serotonin was found to be dependent on the time in culture, the plating density, and the exposure to neurotrophic factors, that is, higher cell densities and treatment with brain-derived neurotrophic factor resulted in a significantly reduced coexpression rate. Notably, even though approximately 30% of the dopaminergic neurons in the donor tissue coexpressed serotonin, no colocalization could be detected in grafts 1 month after intrastriatal transplantation into hemiparkinsonian rats. In conclusion, a significant and susceptible subpopulation of dopaminergic neurons in FVM tissues coexpresses serotonin. This might have potential implications for the future selection and handling of cells prior to transplantation in PD.

Nogo-A Neutralization Improves Graft Function in a Rat Model of Parkinson's Disease

Transplantation of fetal human ventral mesencephalic (VM) dopaminergic neurons into the striatum is a promising strategy to compensate for the characteristic dopamine deficit observed in Parkinson’s disease (PD). This therapeutic approach, however, is currently limited by the high number of fetuses needed for transplantation and the poor survival and functional integration of grafted dopaminergic neurons into the host brain. Accumulating evidence indicates that contrasting inhibitory signals endowed in the central nervous system (CNS) might support neuronal regeneration. Hence, in the present study we aimed at improving survival and integration of grafted cells in the host brain by neutralizing Nogo-A, one of the most potent neurite growth inhibitors in the CNS. For that purpose, VM tissue cultures were transplanted into rats with a partial 6-hydroxydopamine (6-OHDA) lesion causing a hemi-PD model and concomitantly treated for 2 weeks with intra-ventricular infusion of neutralizing anti-Nogo-A antibodies. Motor behavior using the cylinder test was assessed prior to and after transplantation as functional outcome. At the end of the experimental period the number of dopaminergic fibers growing into the host brain, the number of surviving dopaminergic neurons in the grafts as well as graft size was examined. We found that anti-Nogo-A antibody infusion significantly improved the asymmetrical forelimb use observed after lesions as compared to controls. Importantly, a significantly three-fold higher dopaminergic fiber outgrowth from the transplants was detected in the Nogo-A antibody treated group as compared to controls. Furthermore, Nogo-A neutralization showed a tendency for increased survival of dopaminergic neurons (by two-fold) in the grafts. No significant differences were observed for graft volume and the number of dopaminergic neurons co-expressing G-protein-coupled inward rectifier potassium channel subunit two between groups. In sum, our findings support the view that neutralization of Nogo-A in the host brain may offer a novel and therapeutically meaningful intervention for cell transplantation approaches in PD.

The Cytoprotective Effects of Human Endothelial Progenitor Cell-Conditioned Medium Against an Ischemic Insult Are Not Dependent on VEGF and IL-8

Endothelial progenitor cells (EPCs) promote revascularization and tissue repair mainly by paracrine actions. In the present study, we investigated whether EPC-secreted factors in the form of conditioned medium (EPC-CM) can protect cultured brain microvascular endothelial cells against an ischemic insult. Furthermore, we addressed the type of factors that are involved in the EPC-CM-mediated functions. For that purpose, rat brain-derived endothelial cells (rBCEC4 cell line) were exposed to EPC-CM pretreated with proteolytic digestion, heat inactivation, and lipid extraction. Moreover, the involvement of VEGF and IL-8, as canonical angiogenic factors, was investigated by means of neutralizing antibodies. We demonstrated that EPC-CM significantly protected the rBCEC4 cells against an ischemic insult mimicked by induced oxygen-glucose deprivation followed by reoxygenation. The cytoprotective effect was displayed by higher viable cell numbers and reduced caspase 3/7 activity. Heat inactivation, proteolytic digestion, and lipid extraction resulted in a significantly reduced EPC-CM-dependent increase in rBCEC4 viability, tube formation, and survival following the ischemic challenge. Notably, VEGF and IL-8 neutralization did not affect the actions of EPC-CM on rBCEC4 under both standard and ischemic conditions. In summary, our findings show that paracrine factors released by EPCs activate an angiogenic and cytoprotective response on brain microvascular cells and that the activity of EPC-CM relies on the concerted action of nonproteinaceous and proteinaceous factors but do not directly involve VEGF and IL-8.

Using static and dynamic canonical correlation coefficients as quantitative EEG markers for Alzheimer's disease severity

We analyzed the relation between Alzheimer's disease (AD) severity as measured by Mini-Mental State Examination (MMSE) scores and quantitative electroencephalographic (qEEG) markers that were derived from canonical correlation analysis. This allowed an investigation of EEG synchrony between groups of EEG channels. In this study, we applied the data from 79 participants in the multi-centric cohort study PRODEM-Austria with probable AD. Following a homogeneous protocol, the EEG was recorded both in resting state and during a cognitive task. A quadratic regression model was used to describe the relation between MMSE and the qEEG synchrony markers. This relation was most significant in the δ and θ frequency bands in resting state, and between left-hemispheric central, temporal and parietal channel groups during the cognitive task. Here, the MMSE explained up to 40% of the qEEG marker's variation. QEEG markers showed an ambiguous trend, i.e. an increase of EEG synchrony in the initial stage of AD (MMSE>20) and a decrease in later stages. This effect could be caused by compensatory brain mechanisms. We conclude that the proposed qEEG markers are closely related to AD severity. Despite the ambiguous trend and the resulting diagnostic ambiguity, the qEEG markers could provide aid in the diagnostics of early-stage AD.

Non-canonical actions of Nogo-A and its receptors

Nogo-A is a myelin associated protein and one of the most potent neurite growth inhibitors in the central nervous system. Interference with Nogo-A signaling has thus been investigated as therapeutic target to promote functional recovery in CNS injuries. Still, the finding that Nogo-A presents a fairly ubiquitous expression in many types of neurons in different brain regions, in the eye and even in the inner ear suggests for further functions besides the neurite growth repression. Indeed, a growing number of studies identified a variety of functions including regulation of neuronal stem cells, modulation of microglial activity, inhibition of angiogenesis and interference with memory formation. Aim of the present commentary is to draw attention on these less well-known and sometimes controversial roles of Nogo-A. Furthermore, we are addressing the role of Nogo-A in neuropathological conditions such as ischemic stroke, schizophrenia and neurodegenerative diseases.

Subcutaneous Trastuzumab for HER2-positive Breast Cancer - Evidence and Practical Experience in 7 German Centers

A subcutaneous formulation of trastuzumab to treat patients with HER2-positive breast cancer is available since August 2013. The subcutaneous formulation is administered as a fixed dose of 600 mg over a period of up to 5 minutes. The HannaH trial compared subcutaneous with intravenous administration and found comparable pharmacokinetics, efficacy and tolerability for both administration forms of trastuzumab in the neoadjuvant setting. The randomized crossover study PrefHer reported a clear preference from the patient's point of view for subcutaneous over intravenous administration of trastuzumab. The accompanying time-and-motion study reported a reduction concerning the total time spent for the institution as well as for the patient receiving trastuzumab s. c.. The experience of 7 German centers largely corresponded with the results of these studies. Patients expressed a clear preference for subcutaneous trastuzumab administration, with the time saved by the subcutaneous administration route cited as the greatest benefit. Although the existing reimbursement terms mean that centers will receive a lower remuneration, the centers' overall evaluation of the subcutaneous administration route for trastuzumab was overwhelmingly positive. The greatest benefit cited by the centers was the flexibility in scheduling patient appointments. This increased flexibility improved conditions in some centers which were experiencing pressures due to a shortage of staff, particularly at peak times. The general consensus, however, was that the remuneration systems for oncological treatments urgently need to be amended to ensure that the real costs of treatment are covered, even if the administration route has changed.

Characterization of fetal antigen 1/delta-like 1 homologue expressing cells in the rat nigrostriatal system: effects of a unilateral 6-hydroxydopamine lesion

Fetal antigen 1/delta-like 1 homologue (FA1/dlk1) belongs to the epidermal growth factor superfamily and is considered to be a non-canonical ligand for the Notch receptor. Interactions between Notch and its ligands are crucial for the development of various tissues. Moreover, FA1/dlk1 has been suggested as a potential supplementary marker of dopaminergic neurons. The present study aimed at investigating the distribution of FA1/dlk1-immunoreactive (-ir) cells in the early postnatal and adult midbrain as well as in the nigrostriatal system of 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian adult rats. FA1/dlk1-ir cells were predominantly distributed in the substantia nigra (SN) pars compacta (SNc) and in the ventral tegmental area. Interestingly, the expression of FA1/dlk1 significantly increased in tyrosine hydroxylase (TH)-ir cells during early postnatal development. Co-localization and tracing studies demonstrated that FA1/dlk1-ir cells in the SNc were nigrostriatal dopaminergic neurons, and unilateral 6-OHDA lesions resulted in loss of both FA1/dlk1-ir and TH-ir cells in the SNc. Surprisingly, increased numbers of FA1/dlk1-ir cells (by 70%) were detected in dopamine-depleted striata as compared to unlesioned controls. The higher number of FA1/dlk1-ir cells was likely not due to neurogenesis as colocalization studies for proliferation markers were negative. This suggests that FA1/dlk1 was up-regulated in intrinsic cells in response to the 6-OHDA-mediated loss of FA1/dlk1-expressing SNc dopaminergic neurons and/or due to the stab wound. Our findings hint to a significant role of FA1/dlk1 in the SNc during early postnatal development. The differential expression of FA1/dlk1 in the SNc and the striatum of dopamine-depleted rats could indicate a potential involvement of FA1/dlk1 in the cellular response to the degenerative processes.

Loss of Nogo-A-expressing neurons in a rat model of Parkinson's disease

The myelin-associated protein Nogo-A is among the most potent neurite growth inhibitors in the adult CNS. Recently, Nogo-A expression was demonstrated in a number of neuronal subpopulations of the adult and developing CNS but at present, little is known about the expression of Nogo-A in the nigrostriatal system, a brain structure severely affected in Parkinson's disease (PD). The present study sought to characterize the expression pattern of Nogo-A immunoreactive (ir) cells in the adult ventral mesencephalon of control rats and in the 6-hydroxydopamine (6-OHDA) rat model of PD. Immunohistochemical analyses of normal adult rat brain showed a distinct expression of Nogo-A in the ventral mesencephalon, with the highest level in the substantia nigra pars compacta (SNc) where it co-localized with dopaminergic neurons. Analyses conducted 1week and 1 month after unilateral striatal injections of 6-OHDA disclosed a severe loss of the number of Nogo-A-ir cells in the SNc. Notably, at 1week after treatment, more dopaminergic neurons expressing Nogo-A were affected by the 6-OHDA toxicity than Nogo-A-negative dopaminergic neurons. However, at later time points more of the surviving dopaminergic neurons expressed Nogo-A. In the striatum, both small and large Nogo-A-positive cells were detected. The large cells were identified as cholinergic interneurons. Our results suggest yet unidentified functions of Nogo-A in the CNS beyond the inhibition of axonal regeneration and plasticity, and may indicate a role for Nogo-A in PD.

The secretome of endothelial progenitor cells promotes brain endothelial cell activity through PI3-kinase and MAP-kinase

Background

Angiogenesis and vascular remodelling are crucial events in tissue repair mechanisms promoted by cell transplantation. Current evidence underscores the importance of the soluble factors secreted by stem cells in tissue regeneration. In the present study we investigated the effects of paracrine factors derived from cultured endothelial progenitor cells (EPC) on rat brain endothelial cell properties and addressed the signaling pathways involved.

Methods

Endothelial cells derived from rat brain (rBCEC4) were incubated with EPC-derived conditioned medium (EPC-CM). The angiogenic response of rBCEC4 to EPC-CM was assessed as effect on cell number, migration and tubular network formation. In addition, we have compared the outcome of the in vitro experiments with the effects on capillary sprouting from rat aortic rings. The specific PI3K/AKT inhibitor LY294002 and the MEK/ERK inhibitor PD98059 were used to study the involvement of these two signaling pathways in the transduction of the angiogenic effects of EPC-CM.

Results

Viable cell number, migration and tubule network formation were significantly augmented upon incubation with EPC-CM. Similar findings were observed for aortic ring outgrowth with significantly longer sprouts. The EPC-CM-induced activities were significantly reduced by the blockage of the PI3K/AKT and MEK/ERK signaling pathways. Similarly to the outcome of the rBCEC4 experiments, inhibition of the PI3K/AKT and MEK/ERK pathways significantly interfered with capillary sprouting induced by EPC-CM.

Conclusion

The present study demonstrates that EPC-derived paracrine factors substantially promote the angiogenic response of brain microvascular endothelial cells. In addition, our findings identified the PI3K/AKT and MEK/ERK pathways to play a central role in mediating these effects.

Prognostic impact of renal function in precapillary pulmonary hypertension

BACKGROUND

Impairment of renal function is associated with adverse outcome in various diseases. Patients with pulmonary hypertension (PH) show diminished cardiac function and organ perfusion. The aim of this study was to investigate the associations between renal function and both haemodynamic parameters and long-term survival in patients with PH.

METHODS

Blood was collected from 64 patients with PH (Dana Point class 1, 3 and 4) during right heart catheterization, and plasma was prepared. Creatinine, blood urea nitrogen (BUN), cystatin C, neutrophil-gelatinase-associated lipocalin (NGAL), fibroblast growth factor 23 (FGF-23) and α-Klotho levels were determined, and glomerular filtration rate (GFR) was estimated (eGFR). Parameters were evaluated using c-statistics and dichotomized for survival analysis based on receiver operating characteristic curves.

RESULTS

The median follow-up time was 9.92 years with all-cause mortality as the primary end-point. Elevated BUN, cystatin C and creatinine levels were associated with decreased survival, with hazard ratios (HRs) of 3.237, 4.514 and 2.006, respectively, and equivalent performance according to c-statistics. Estimating GFR by CKD-EPI, MDRD and Cockcroft-Gault formulas resulted in HRs of 2.942, 2.694 and 3.306, respectively. Amongst these formulas, eGFR (Cockcroft-Gault) had the highest c-statistics of 0.674. There was a correlation between BUN and both cardiac index (τ = -0.39) and pulmonary vascular resistance index (τ = 0.249), whereas eGFR (CKD-EPI) was correlated with cardiac index (τ = 0.225). No correlations between either BUN or eGFR and right atrial pressure (RAP) were observed. NGAL, FGF-23 and α-Klotho had no prognostic impact or association with haemodynamic parameters.

CONCLUSION

Comparison of markers of renal function for prognosis in PH demonstrated superiority of creatinine, cystatin C and BUN over NGAL, FGF-23 and α-Klotho. Minor decreases in eGFR influence long-term prognosis, and measurement of cystatin C levels might be useful to detect renal impairment in patients with a normal serum concentration of creatinine. Renal function in patients with PH is linked to cardiac index rather than RAP.