An investigation into murine pericyte shape change in response to inflammatory stimuli in vitro and in vivo

PhDLeukocyte transmigration through venular walls into the surrounding tissue is a crucial event during inflammatory responses. Despite increased understanding of the mechanisms associated with leukocyte migration through endothelial cells, little is known about the mechanisms mediating the subsequent migration through the pericyte layer and the basement membrane. We previously reported that gaps between adjacent pericytes are co-localised with matrix protein low expression regions in the basement membrane, regions that are preferentially used by leukocytes to penetrate venular walls (Wang et al., 2006; Voisin et al., 2009; Voisin et al., 2010). This study extended these findings to other vascular beds showing that pericyte morphology is heterogeneous in different tissues (Voisin et al., 2010). To investigate whether pericytes facilitate the transmigration process through direct morphological changes at sites of inflammation, neutrophil transmigration and pericyte shape change was analysed in whole mounted TNF-α- and IL-1β-stimulated murine cremaster muscles by immunofluorescence labelling and confocal microscopy. Post-capillary pericytes exhibited shape change resulting in a significant increase in mean gap size between adjacent cells. Time-course studies indicated that TNF-α-induced shape change preceded neutrophil transmigration. This response was PMN-independent as it was also noted in PMN depleted mice. Parallel studies investigated the effect of these cytokines on shape change of murine pericyte-like C3H/10T1/2 cells in vitro by time lapse microscopy. C3H/10T1/2 cells also exhibited significant shape change in response to direct TNF-α- and IL-1β-stimulation in vitro. Post-capillary venular pericytes in vivo and C3H/10T1/2 cells in vitro expressed the respective cytokine receptors, TNFRI, TNFRII and IL-1RI, indicating that pericytes can respond directly to pro-inflammatory cytokines. Finally, pericyte involvement in neutrophil transmigration in vivo was investigated in real time by confocal intra vital microscopy using α-SMA-RFPcherryxLys-EGFP mice. Neutrophils preferentially used enlarged gaps to migrate into the surrounding tissue

ICAM-2 facilitates luminal interactions between neutrophils and endothelial cells in vivo

This work was supported by funds from a Wellcome Trust Programme Grant [grant numbers PG081172/Z/06/, SIA 098291/Z/12/Z to S.N.]; and the Arthritis Research UK [grant number 19207 to J.W.]. K.H. was supported by a British Heart Foundation PhD studentship [grant number FS/07/006]. Deposited in PMC for immediate release

Effects of PI and PIII Snake Venom Haemorrhagic Metalloproteinases on the Microvasculature: A Confocal Microscopy Study on the Mouse Cremaster Muscle

The precise mechanisms by which Snake Venom Metalloproteinases (SVMPs) disrupt the microvasculature and cause haemorrhage have not been completely elucidated, and novel in vivo models are needed. In the present study, we compared the effects induced by BaP1, a PI SVMP isolated from Bothrops asper venom, and CsH1, a PIII SVMP from Crotalus simus venom, on cremaster muscle microvasculature by topical application of the toxins on isolated tissue (i.e., ex vivo model), and by intra-scrotal administration of the toxins (i.e., in vivo model). The whole tissue was fixed and immunostained to visualize the three components of blood vessels by confocal microscopy. In the ex vivo model, BaP1 was able to degrade type IV collagen and laminin from the BM of microvessels. Moreover, both SVMPs degraded type IV collagen from the BM in capillaries to a higher extent than in PCV and arterioles. CsH1 had a stronger effect on type IV collagen than BaP1. In the in vivo model, the effect of BaP1 on type IV collagen was widespread to the BM of arterioles and PCV. On the other hand, BaP1 was able to disrupt the endothelial barrier in PCV and to increase vascular permeability. Moreover, this toxin increased the size of gaps between pericytes in PCV and created new gaps between smooth muscle cells in arterioles in ex vivo conditions. These effects were not observed in the case of CsH1. In conclusion, our findings demonstrate that both SVMPs degrade type IV collagen from the BM in capillaries in vivo. Moreover, while the action of CsH1 is more directed to the BM of microvessels, the effects of BaP1 are widespread to other microvascular components. This study provides new insights in the mechanism of haemorrhage and other pathological effects induced by these toxins

ICAM-1-expressing neutrophils exhibit enhanced effector functions in murine models of endotoxemia

This work was supported by funds from the Wellcome Trust (098291/Z/12/Z and 101604/Z/13/Z) (S.N.) and the British Heart Foundation (FS/11/19/28761) (A.W.)

Just “Like Coffee” or Neuroenhancement by Stimulants?

Introduction: Pharmacological neuroenhancement (PN) is a topic of increasing importance and prevalence among students. However, there is a lack of differentiating PN substances, according to their psychoactive effects. In particular, there is a lack of data about PN by caffeinated drinks, even if coffee is a common and broadly used Neuroenhancer because of its cognitively enhancing effects regarding wakefulness, alertness and concentration. Materials and Methods: A web-survey was developed for German students and alumni about the non-medical use of caffeine for PN contained questions about coffee, caffeinated drinks and energy drinks, caffeine pills and methylxanthine tea regarding frequency and further contextual factors. Results: Six hundred and eighty-three participants completed the survey. Nearly all participants knew about PN (97.7%). 88.1% admitted using some over-the-counter substances. For PN purposes, coffee was used by 72.9% followed by energy drinks (68.2%) and cola drinks (62.4%). Methylxanthine containing tea was used for PN purposes, too (black tea 52.3%, green tea 51.7%). 1.8% admitted using illegal substances or prescription drugs, too. Discussion: Using legal methylxanthine containing drinks for PN seems to be extremely common with coffee and energy drinks being the preferred substances, while illegal and prescription drugs are only minimally used. Further studies should investigate the awareness of methylxanthine containing drinks as well as its character to be a flavoring drink or a neuroenhancer

Treatment outcome, cognitive function, and psychopathology in methamphetamine users compared to other substance users

BACKGROUND: The rising number of people using methamphetamine leads to an increasing need for treatment options for this patient group. Evidence-based research on the efficacy of treatment programs for methamphetamine users is limited. Due to specific characteristics of methamphetamine users, the question arises whether established treatment methods for individuals using other substances can be effective for the treatment of methamphetamine dependence as well. We hypothesize that there are significant differences between the two groups that may affect the effectiveness of treatment and worsen the prognosis of treatment outcomes for methamphetamine users compared to consumers of other substances. AIM: To investigate potential differences in cognitive functioning and psychopathology between methamphetamine users and other substance users and possible correlations with treatment outcomes. METHODS: A total of 110 subjects were recruited for an observational, longitudinal study from a German inpatient addiction treatment center: 55 patients with methamphetamine dependence and 55 patients with dependence of other substances (“OS group”). Both groups were examined at beginning (baseline) and end of treatment (after 6 mo) with regard to treatment retention, craving, cognitive functioning, psychosocial resources, personality traits, depression, and other psychiatric symptoms. Instruments used were Raven’s IQ test, Mannheimer craving scale, cognitrone cognitive test battery, NEO personality factors inventory, Hamilton depression scale, Becks depression inventory, and a symptom checklist. The statistical methods used were χ(2)-test, t-test and multiple mixed ANOVAs. RESULTS: A total drop-out rate of 40% (methamphetamine-group: 36.4%; OS-group: 43.6%) was observed without significant differences between groups. At baseline, methamphetamine-group subjects significantly differed from OS-group individuals in terms of a lower intelligence quotient, fewer years of education, slower working speed, and decreased working accuracy, as well as less cannabinoid and cocaine use. Methamphetamine-group subjects further showed a significantly lower score of conscientiousness, depressive, and psychiatric symptoms than subjects from the OS-group. In both groups, a reduction of craving and depressive symptoms and an improvement of working speed and working accuracy was noted after treatment. CONCLUSION: There are differences between methamphetamine users and users of other drugs, but not with regard to the effectiveness of treatment in this inpatient setting. There are differences in cognitive function and psychopathology between methamphetamine and other drugs users. The existing treatment options seem to be an effective approach in treating methamphetamine dependence

Timing of complementary feeding for early childhood allergy prevention: An overview of systematic reviews.

OBJECTIVE: To summarise and critically appraise systematic review (SR) evidence on the effects of timing of complementary feeding (CF) on the occurrence of allergic sensitisation and disease. DESIGN: Overview of SRs. AMSTAR-2 and ROBIS were used to assess methodological quality and risk of bias (RoB) of SRs. RoB 2 Tool was used to assess RoB of primary randomised controlled trials (RCTs) (or extracted). The certainty of evidence (CoE) was assessed using GRADE. Findings were synthesised narratively. DATA SOURCES: MEDLINE (via PubMed and Ovid), the Cochrane Library and Web of Science Core Collection (2010 to 27 February 2023). ELIGIBILITY CRITERIA: SRs investigating the effects of timing of CF in infants or young children (0-3 years) on risk of developing food allergy (FA), allergic sensitisation, asthma, allergic rhinitis, atopic eczema and adverse events based on RCT evidence. RESULTS: Eleven SRs were included. Only two SRs had low RoB; common issues were failure to report on funding of primary studies and failure to provide a list of excluded trials. Common limitations of included trials were lack of blinding of outcome assessment or detailed trial preregistration, and inadequate handling of high loss to follow up. Primary study overlap was very high for specific FA and slight to moderate for FA in general and other primary outcomes. Introducing specific foods (peanut, cooked egg) early probably reduces the risk of specific FA. Evidence for other allergic outcomes was mostly very uncertain and based on few primary studies. Trials varied regarding timing of CF, nature of complementary foods and population risk, which limited comparability between SRs. CONCLUSIONS: For developing guidelines to support decision-making on the timing of CF as a preventive strategy, early introduction of specific foods (i.e. egg and peanut) seems promising and safe, whereas more extensive research is required regarding other allergic outcomes and potential adverse events