Firearm deaths in Sweden

BACKGROUND

Sweden's firearm legislation obligates physicians to report patients that are deemed unsuitable to possess a firearm. This study aimed to explore the involvement of firearm use in firearm fatalities and to evaluate physician reporting concerning cases of firearm deaths.

METHODS

Fatal firearm suicides and homicides in Sweden were studied for the years 2012-2013, accidental deaths and undetermined manner of deaths for the period 1987-2013. Police reports and autopsy protocols were collected from the National Board of Forensic Medicine, health care data in 1 year before the fatality from the National Board of Health, and information about physician reports and firearm licences from the Swedish Police.

RESULTS

A total of 291 firearm deaths (213 suicides, 52 accidental deaths, 23 solved homicides and 3 cases with undetermined manner of death) were identified. Firearm suicides were positively correlated with the number of licensed firearm owners. Legal firearm use predominated in firearm suicides and accidental deaths, illegal in homicides. No suicide victim or shooter in an accidental death was previously reported by a physician to the police according to the firearm law. The majority of the shooters in accidental deaths and suicides had no registered health care visits. Less than half (42%) of all suicide victims had a previous health care contact due to mental health problems.

CONCLUSIONS

Not one single suicide victim nor any shooter in accidental deaths in the present study had been reported according to the firearm law, bringing the evidence of a suboptimal framework.

The relationship between the MMP system, adrenoceptors and phosphoprotein phosphatases

The MMPs and their inhibitors [tissue inhibitor of MMPs (TIMPs)] form the mainstay of extracellular matrix homeostasis. They are expressed in response to numerous stimuli including cytokines and GPCR activation. This review highlights the importance of adrenoceptors and phosphoprotein phosphatases (PPP) in regulating MMPs in the cardiovascular system, which may help explain some of the beneficial effects of targeting the adrenoceptor system in tissue remodelling and will establish emerging crosstalk between these three systems. Although α- and β-adrenoceptor activation increases MMP but decreases TIMP expression, MMPs are implicated in the growth stimulatory effects of adrenoceptor activation through transactivation of epidermal growth factor receptor. Furthermore, they have recently been found to catalyse the proteolysis of β-adrenoceptors and modulate vascular tone. While the mechanisms underpinning these effects are not well defined, reversible protein phosphorylation by kinases and phosphatases may be key. In particular, PPP (Ser/Thr phosphatases) are not only critical in resensitization and internalization of adrenoceptors but also modulate MMP expression. The interrelationship is complex as isoprenaline (ISO) inhibits okadaic acid [phosphoprotein phosphatase type 1/phosphoprotein phosphatase type 2A (PP2A) inhibitor]-mediated MMP expression. While this may be simply due to its ability to transiently increase PP2A activity, there is evidence for MMP-9 that ISO prevents okadaic acid-mediated expression of MMP-9 through a β-arrestin, NF-κB-dependent pathway, which is abolished by knock-down of PP2A. It is essential that crosstalk between MMPs, adrenoceptors and PPP are investigated further as it will provide important insight into how adrenoceptors modulate cardiovascular remodelling, and may identify new targets for pharmacological manipulation of the MMP system.

Okadaic acid induces matrix metalloproteinase-9 expression in fibroblasts: crosstalk between protein phosphatase inhibition and β-adrenoceptor signalling

BACKGROUND AND PURPOSE

Interactions between protein phosphatase inhibition and matrix metalloproteinase (MMP)-9 expression have implications for tissue remodelling after injury. Stimulation of β-adrenoceptors could affect such interactions as isoprenaline increases protein phosphatase 2A (PP2A) activity and MMP-9 abundance. We investigated the effect of okadaic acid (OA) on MMP-9 expression to assess interactions between phosphatase inhibition and β-adrenoceptor signalling in fibroblasts.

EXPERIMENTAL APPROACH

Fibroblasts were exposed to OA alone and in combination with isoprenaline. Effects on MMP-9 expression and intracellular signalling were studied using promoter assays, Western blot analysis and siRNA methodologies.

KEY RESULTS

Okadaic acid increased MMP-9 abundance in human cardiac ventricular fibroblasts, NIH3T3 fibroblasts and hepatic stellate cells. This effect was unaffected by PP2A knockdown in NIH3T3 cells. OA increased phosphorylation of NF-κB, but not NF-κB promoter activity, IκBα degradation, or nuclear translocation of p65-NF-κB. Exposure to SB202190 (p38 MAPK), U0126 (ERK1/2) and NF-κB III inhibitor revealed that OA induced MMP-9 activity through p38 MAPK. Isoprenaline inhibited OA-mediated MMP-9 expression in NIH3T3, in a β-arrestin 2- and PP2A-dependent manner. Mutation of the activator protein-1 (AP-1) and NF-κB binding sites demonstrated that OA-induced MMP-9 activity was mediated through the AP-1 but not NF-κB sites. The latter mediated the inhibitory effect of isoprenaline on OA-induced MMP-9 promoter activity.

CONCLUSION AND IMPLICATIONS

Okadaic acid induced MMP-9 activity through p38 MAPK and was inhibited by isoprenaline via a pathway involving β-arrestin 2, PP2A and an NF-κB binding motif. These findings elucidate how phosphoprotein phosphatases and adrenoceptors may modulate tissue remodelling by affecting fibroblast function.

Expression of the stem cell marker nestin in peripheral blood of patients with melanoma

BACKGROUND

There is continued interest in markers indicative of circulating melanoma cells. Nestin is a neuroepithelial intermediate filament protein that was found to be expressed in melanoma and in various cancer stem cells.

OBJECTIVES

We investigated expression of nestin in peripheral blood of patients with melanoma.

METHODS

We analysed nestin expression by flow cytometry and by quantitative reverse transcription-polymerase chain reaction both in tissues (n = 23) and in blood samples (n = 102) from patients with American Joint Committee on Cancer stage III-IV melanoma. Forty-six negative controls were also added.

RESULTS

Flow cytometry did not reveal nestin-expressing cells in peripheral blood of healthy volunteers. In patients with melanoma, however, nestin protein was expressed in a proportion of melanoma cells enriched from peripheral blood by immunomagnetic sorting. In melanoma tissue samples a significant correlation was found between mRNAs coding for nestin and tyrosinase (P = 0.001) and melan-A (P = 0.002), whereas in blood a significant correlation was observed only for tyrosinase (P = 0.015), but not for melan-A (P = 0.53). Nestin expression was higher in stage IV patients compared with stage III/IV with no evidence of disease, in patients with high tumour burden, and was positively correlated to expression of tyrosinase and melan-A.

CONCLUSIONS

Nestin was found to be an additional marker of interest for circulating melanoma cells. Prospective studies should investigate its potential added informative value in comparison with markers already in use for melanoma cell detection.

Expression of stem cell markers in circulating melanoma cells

e22056

Background: Within circulating tumor cells there may be a subset of cell with stem cell (tumor initiating) characteristics able to develop distant metastasis. Several markers including nestin and CD133 have been found to be possible candidates to identify such a kind of subpopulation in other experimental models. We evaluated the presence of melanoma cells bearing stem cell phenotype in the bloodstream of patients with cutaneous or uveal melanoma after depletion of the leukocytes fraction. Methods: Between 50 and 100 ml of peripheral blood were collected from 12 melanoma patients with various tumor burden as well as three healthy volunteers. Blood samples were enriched for tumour cells by CD45 depletion of the leukocyte fraction using magnetic beads separation (EasySep, Stem Cell Technologies. Inc.). The remaining material was stained with antibodies for the markers Melan-A/Mart-1 (Dako) and HMB45 (Dako), CD133 (Miltenyi Biotec) and nestin (R&D System) and analysed by flow cytometry (BD FACSCalibur). Ten ml of blood were further processed and CD133, nestin, Melan-A/Mart-1 transcripts were quantified by Real Time RT-PCR (LightCycler, Roche Diagnostic). Results: CD45-depleted fractions in healthy controls were negative for melanoma markers. Melan-A/Mart-1 and/or HMB45 positive cells were detectable in 11 out of 12 melanoma patients. The absolute number of melanoma cells identified ranged from 6 to 176 per 10 ml of blood. Nestin expressing cells were more represented compared to CD133 expressing cells (median 27.4%, range 0.3% to 65.1% vs. median 9.3%, range 0.1% to 16.8%) within the melanoma fraction of cells positive for Melan-A/Mart-1 and/or HMB45. In one patient two different melanoma cell populations were detectable. The population of cells with lower expression of the melanoma markers showed at the same time higher expression of nestin and CD133 (5.9% vs. 1.3% and 10.2% vs. 6.7% respectively). Nestin results were in good accordance to the FACS data (nestin: r=0.55; CD133: r=0.23; Pearson test). Conclusions: The novel negative separation technique allows reliable isolation of melanoma cells from peripheral blood of patients with metastatic disease. A significant fraction of melanoma cells in peripheral blood bears a stem cell phenotype.

No significant financial relationships to disclose.

Immune self-tuning in renal cell carcinoma patients

e22069

Background: Renal cell carcinoma (RCC) cells can inhibit protective antitumor immunity by secretion of immunosuppressive factors leading to the induction of regulatory T cells. The objective of this study was to investigate the prognostic impact of mRNA expression levels of IL10, TGFβ and forkhead box transcription factor (FoxP3) mRNA in peripheral blood mononuclear cells (PBMCs) of metastatic RCC patients before receiving treatment with sorafenib. Methods: PBMCs of 46 patients were assessed for their expression levels of TGFβ, IL10 and FoxP3 by quantitative RT-PCR. Clinical features considered included ECOG performance status, hemoglobin, alkaline phosphatase, and calcium concentrations. Disease evaluation was performed every 8 weeks following RECIST criteria. Relationship between pre-treatment factors and survival were examined in univariate analyses and subsequently by multivariate analysis using a stepwise Cox regression model. Results: In contrast to FoxP3, mRNA expression levels of IL10 and TGFβ were significantly higher in the 46 RCC patients compared to healthy volunteers: Median expression levels [ratio marker /housekeeping gene PBGD] were 5.56E-05 vs 2.05E-04 (P=0.034) for IL10 and 7.38E-02 vs 3.04E- 01 (P=0.023) for TGFβ. Univariate analysis revealed a negative prognostic influence of IL10 on progression free survival (p=0.04) and on overall survival, although not significant (P= 0.063). Surprisingly, high TGFβ and FoxP3 expression levels had a positive influence on progression free (P<0.001 and P=0.047, respectively) and overall survival (P<0.001 and P= 0.031, respectively). In the multivariate analysis low ECOG performance status and high TGFβ mRNA expression levels were independently associated with worse progression free (P=0.001 and P=0.054,) and worse overall survival (P=0. 006 and P< 0.001, respectively). Conclusions: RCC caused an immune-suppressive phenotype in PBMC characterized by increased mRNA expression levels of IL10 and TGFβ. Surprisingly, in contrast to IL10, a high TGFβ mRNA expression level was an independent good prognostic factor. Whether this observation can be attributed to recently described immune promoting functions of TGFβ needs to be determined.

No significant financial relationships to disclose.