Novel Nox inhibitor VAS2870 attenuates PDGF-dependent smooth muscle cell chemotaxis, but not proliferation

OBJECTIVE: Reactive oxygen species (ROS) produced by NAD(P)H oxidases (Nox) play a significant role in the pathophysiology of cardiovascular diseases. Expression and activity of NAD(P)H oxidases are regulated by growth factors such as angiotensin II and platelet-derived growth factor (PDGF). We characterized the effects of the novel Nox inhibitor VAS2870 on PDGF-dependent ROS liberation and cellular events in vascular smooth muscle cells (VSMC). METHODS AND RESULTS: PDGF-BB increased NAD(P)H oxidase activity (lucigenin-enhanced chemiluminescence) and intracellular ROS levels (detected by confocal laserscanning microscopy using 2,7-DCF) to 229+/-9% and 362+/-54% at 1 and 2 h, respectively. Preincubation with VAS2870 (10 and 20 microM) completely abolished PDGF-mediated NAD(P)H oxidase activation and ROS production. Since ROS are involved in various growth factor-induced cellular functions, the influence of VAS2870 on PDGF-induced DNA synthesis and chemotaxis was determined. PDGF promoted a 4.2+/-0.2-fold increase of VSMC migration (modified Boyden chamber, p<0.01) and increased DNA synthesis by maximally 3.2+/-0.4-fold (BrdU incorporation, p<0.01) in a concentration-dependent manner. Preincubation with VAS2870 (0.1-20 microM) did not affect PDGF-induced cell cycle progression. However, it abolished PDGF-dependent chemotaxis of VSMC in a concentration-dependent manner (100% inhibition at 10 microM). These findings were related to PDGF-dependent signaling events. Western blot analyses using phospho-specific antibodies revealed that the downstream signaling molecules Akt, Erk, and Src were activated by PDGF. However, VAS2870 blocked PDGF-dependent activation of Src, but not of Akt and Erk, in a concentration-dependent manner. CONCLUSIONS: VAS2870 effectively suppresses growth factor-mediated ROS liberation in VSMC. Furthermore, it completely inhibits PDGF-dependent VSMC migration, whereas it does not affect DNA synthesis. These divergent effects reflect the critical role of Src activity, which-in contrast to Akt and Erk-appears to be redox-sensitive and is absolutely required for PDGF-induced chemotaxis, but not cell cycle progression.     

Left Ventricular Dysfunction and Cerebral Infarction from Vasospasm After Subarachnoid Hemorrhage

Background

Although neurogenic stunned myocardium (NSM) after aneurysmal subarachnoid hemorrhage (SAH) is well described, its clinical significance remains poorly defined. We investigated the influence of left ventricular (LV) dysfunction and cerebral vasospasm on cerebral infarction, serious cardiovascular events, and functional outcome after SAH.

Methods

Of the 481 patients enrolled in the University Columbia SAH Outcomes Project between 10/96 and 05/02, we analyzed a subset of 119 patients with at least one echocardiogram, serial transcranial Doppler (TCD) data, and with no prior history of cardiac disease. LV dysfunction was defined as an ejection fraction <40% on echocardiography. Infarction from vasospasm was adjudicated by the study team after comprehensive review of all clinical and imaging data. Functional outcome was assessed at 15 and 90 days with the modified Rankin Scale (mRS).

Results

Eleven percent of patients had LV dysfunction (N = 13). Younger age, hydrocephalus, and complete filling of the quadrigeminal and fourth ventricles were associated with LV dysfunction (all P < 0.05). Despite a similar frequency of pre-existing hypertension, 0% of patients with LV dysfunction reported taking antihypertensive medication, compared to 35% of those without (P = 0.009). There was a significant association between LV dysfunction and infarction from vasospasm after adjusting for clinical grade, age, and peak TCD flow velocity (P = 0.03). Patients with LV dysfunction also had higher rates of hypotension requiring vasopressors (P = 0.001) and pulmonary edema (P = 0.002). However, there was no association between LV dysfunction and outcome at 14 days after adjustment for established prognostic variables.

Conclusions

LV dysfunction after SAH increases the risk of cerebral infarction from vasospasm, hypotension, and pulmonary edema, but with aggressive ICU support does not affect short-term survival or functional outcome. Antihypertensive medication may confer cardioprotection and reduce the risk of catecholamine-mediated injury after SAH.     

Laxative management in ambulatory cancer patients on opioid therapy: a prospective, open-label investigation of polyethylene glycol, sodium picosulphate and lactulose

WIRZ S., NADSTAWEK J., ELSEN C., JUNKER U. & WARTENBERG H.C. (2012) European Journal of Cancer Care 21 , 131–140. Laxative management in ambulatory cancer patients on opioid therapy: a prospective, open‐label investigation of polyethylene glycol, sodium picosulphate and lactulose Constipation and the laxatives polyethylene glycol (PEG), sodium picosulphate (SPS) and lactulose (L) were investigated in outpatients with cancer and on opioid therapy. Randomly selected patients were enrolled in a prospective, controlled, open‐label trial. Endpoints were number of patients taking laxatives >28 days, number of patients with a stool‐free interval >72 h (sfi72), dosage, numerical rating scale (NRS) for constipation, and European Organization for Research and Treatment of Cancer (EORTC) Quality of Life (QoL) questionnaire scores. The 348 patients had comparable demographic and medical data. In this ambulatory population, mobility scores remained unaffected. Constipation incidence was 5.7%, with sfi72 42, mean NRS 2.3557 and mean QoL 2.1. A total of 53.2% discontinued their laxative medication. Laxative use correlated with higher opioid usage (morphine‐equivalent mg/day: no laxative 98.2, SPS 128.2, PEG 139.9, L 154.5). PEG was the most frequently prescribed laxative (PEG 27.3%, SPS 10.3%, L 9.2%). PEG (sfi72 12.6%, NRS 2.2, QoL 2.1) and SPS (sfi72 11.1%, NRS 2.7, QoL 2.2) proved more effective than L (sfi72 15.5%, NRS 3.8, QoL 2.5). In spite of opioid therapy, the incidence of constipation was low in these ambulatory cancer pain patients at an early disease stage. For prevention of constipation, PEG or SPS is recommended instead of L.     

PET/CT-guided biopsies of metabolically active bone lesions: applications and clinical impact

Purpose  

In a minority of cases a definite diagnosis and stage grouping in cancer patients is not possible based on the imaging information of PET/CT. We report our experience with percutaneous PET/CT-guided bone biopsies to histologically verify the aetiology of hypermetabolic bone lesions.     

The attitudes of physicians and oncologists towards unconventional cancer therapies (UCT)

Physicians represent the main providers of unconventional cancer therapies (UCT) in Germany. However, little is known about providers' characteristics, as well as their attitudes towards UCT. 833 questionnaires on this topic answered by general practitioners and hospital physicians were analysed. Providers differed significantly from non-providers with respect to gender (male>female, i.e. more male providers), age (older>younger), amount of subjective knowledge about UCT, place of work (office>hospital>university clinic), greater wish for coverage of UCT costs, the belief in future positive trends concerning UCT, the recognition of patients' demand for UCT, the number of patients seen per month and medical specialty (GPs>oncologists and radiation oncologists). UCT were not considered to be highly effective, but estimations varied considerably. Further investigations in this area, better education about UCT, training in coping strategies with the fate of cancer patients, and reasonable complementary treatments appear to be of the utmost importance.     

Mitotic arrest of female germ cells during prenatal oogenesis. A colcemid-like, non-apoptotic cell death

The sequence of events and a possible reason for germ cell death during oogenesis in the prenatal ovary were studied in rat and mouse embryos. ED 14–22 rat and ED 14–16 mouse embryos were studied using semithin sections for light microscopy and serial ultrathin sections for electron microscopy. In addition, the rat material was 3H-thymidine labelled for historadioautography and cytospin preparations of freshly obtained gonads were immunohistochemically analysed. During the transition from the proliferating oogonial stage to the meiotic prophase about 16% of the postmitotic oocytes do not pass the initial meiotic checkpoint on ED 18/19 in the rat (ED 15/16 in the mouse). These germ cells first show structural signs of mitosis; the diploid number of ’super-condensed’ chromosomes are globally formed and are concentrated in the center of the cell. Although the germ cells show all morphological signs of living cells they never have mitotic spindles; the micro-tubulus-organisation-centres (MTOCs) are found peripherally and become concentrated, forming a single centrosomal body (acentriolar MTOC) as detected by immunohistochemistry for the centrosomal protein MPM2 and γ-tubulin. EM studies show 25 nm tubule-like profiles within the MTOC bodies. The centrioles frequently lie separate from the MTOC material or are not present at all; the germ cells are apparently arrested in a prophase- or metaphase-like stage when they have reached the postmitotic G2/preleptotenal transition and are unable to enter meiosis. Forty-eight to 72 h after the first mitotically arrested germ cells are found, degeneration is seen in these germ cells. This second event, the germ cell death proper, shows neither criteria of apoptosis (cell shrinkage, marginal condensation of chromatin, DNA fragmentation) nor signs of necrosis (cell swelling, pycnosis, inflammation). Both arrested pro- and metaphase-like stages are found with signs of cell death and phagocytosis. The morphological signs of phagocytosis are found in neighbouring pregranulosa cells. The final heterocytotic bodies contain the remnants of the centrosomal (MTOC) material and DAPI-positive DNA material. The pregranulosa cells are mitotically silent during the phase when mitotic arrest and germ cell degeneration is found. The results suggest the presence of a hypothetical ’anti-spindle’ factor, which under normal conditions is necessary for induction of meiotic prophase. The structural events of ’arrested mitosis’ is reminiscent of those induced by the antimitotic, tubule-degrading drug colcemid. This type of arrest may inhibit meiosis of more than 33% prenatal germ cells and induce their cell death. Accepted: 30 July 2001