The role of receptor MAS in microglia-driven retinal vascular development

Objective

The receptor MAS, encoded by Mas1, is expressed in microglia and its activation has been linked to anti-inflammatory actions. However, microglia are involved in several different processes in the central nervous system, including the promotion of angiogenesis. We therefore hypothesized that the receptor MAS also plays a role in angiogenesis via microglia.

Approach and results

To assess the role of MAS on vascular network development, flat-mounted retinas from 3-day-old wild-type (WT) and Mas1^−/− mice were subjected to Isolectin B4 staining. The progression of the vascular front was reduced (− 24%, p < 0.0001) and vascular density decreased (− 38%, p < 0.001) in Mas1^−/− compared to WT mice with no change in the junction density. The number of filopodia and filopodia bursts were decreased in Mas1^−/− mice at the vascular front (− 21%, p < 0.05; − 29%, p < 0.0001, respectively). This was associated with a decreased number of vascular loops and decreased microglial density at the vascular front in Mas1^−/− mice (-32%, p < 0.001; − 26%, p < 0.05, respectively). As the front of the developing vasculature is characterized by reduced oxygen levels, we determined the expression of Mas1 following hypoxia in primary microglia from 3-day-old WT mice. Hypoxia induced a 14-fold increase of Mas1 mRNA expression (p < 0.01). Moreover, stimulation of primary microglia with a MAS agonist induced expression of Notch1 (+ 57%, p < 0.05), Dll4 (+ 220%, p  < 0.001) and Jag1 (+ 137%, p < 0.001), genes previously described to mediate microglia/endothelial cell interaction during angiogenesis.

Conclusions

Our study demonstrates that the activation of MAS is important for microglia recruitment and vascular growth in the developing retina.

Electronic supplementary material

The online version of this article (10.1007/s10456-019-09671-3) contains supplementary material, which is available to authorized users.

Wirkung von Milch und Diättränken mit und ohne HCO3 –-Ionen auf den intraluminalen pH-Wert im Labmagen und den systemischen Säuren-Basen-Status beim Kalb

Problemstellung: Bei Kälbern wird nach Zufuhrvon Diättränken mit Bikarbonat-Ionen eine besonders ausgeprägte Alkalisierung der Labmageningesta erwartet. Nachfolgend könnten die an saure pH-Werte gebundene abomasale Verdauung sowie unspezifische Infektabwehr beeinträchtigt sein. Material und Methode: Bei acht klinisch gesunden Kälbern wurde operativ eine Plastkanüle in den Labmagen eingesetzt. Danach erhielten die Tiere über sieben bisneun Tage als Nahrung alternierend 1) Kuhmilch, 2) bikarbonatfreie oder 3) bikarbonathaltige Diättränke. Außerdem wurde 4) das Gemisch aus gleichen Teilen bikarbo- nathaltige Diättränke und Milch verabreicht. In den über die Kanüle entnommenen Labmageningesta bestimmten wir dieWertefür pH, Fläche unter der pH-Wert-Kurve (AUC) und [SID3]. Weiterhin wurde vergleichend im arteriellen und venösen Blut der systemische Säuren-Basen-Status anhand traditioneller Hen- derson-Hasselbalch-Parameter sowie der Stewart-Variablen ermittelt. Ergebnisse: Die Fütterung von Milch bewirkte beiden Kälbern einen Anstieg des Labmagen-pH von Nüchternbefunden mit 2,00 ± 0,44 auf Werte bis 4,70 ± 0,41 über zwei Stunden. Die AUC-Werte bis vier Stunden postprandial betrugen 898 ± 87 (= 100%). Die in Milch zubereitete bikarbonatfreie Diättränke führte zur signifikant basischeren Auslenkung desabomasalen pH mit Werten bis 5,35 ± 0,31 sowieAUC = 1084 ± 89 (= 121%). Die mit Wasser hergestellte bikarbonathaltige Diättränke allein und ebenso ihr Gemisch mit Milch verursachten dentransient stärksten Anstieg des Labmagen-pH für 1,5 bzw. 0,5 Stunden auf Werte bis 6,59 ± 0,28 bzw. 6,22 ± 0,12. Die AUC- Werte unterschieden sich mit 1119 ± 45 (= 125%) und 1126 ± 44 (= 125%) signifikant von den Befunden nach Milchtränke, jedoch nichtvon den Resultaten nach Gabe der bikarbonatfreien Diättränke. Systemisch bewirkten die Fütterungen zum Zeitpunkt zwei Stunden postprandial eine im arteriellen und venösen Blut gleichermaßen nachweisbare geringe, teilweise signifikante basische Reaktion, wie ↑ pH, ↑ [HCO3 –, ↑ [BE], ↑ [SID3] und ↓ [Atot] bei unveränderten Werten für PCO2. Die postprandial im Blut der Kälber festgestellte “basische Flut” war nach Gabe der bikarbonathaltigen Diättränken relativ am deutlichsten ausgeprägt. Schlussfolgerung: Im Vergleich zur üblichen Milchfütterung verursachte die in Milch zubereitete bikarbonatfreie Diättränke postprandial signifikant stärkere basische Auslenkungen des Labmagen-pH. Mit Wasser hergestellte bikarbonathaltige Elektrolyttränken führten kurzfristig (≤ 2 h) zu noch stärkerem Anstieg des Labmagen-pH. Die AUC der pH-Wert-Kurve bisvierStunden postprandial (= zeitabhängige “Wirksamkeit”) differierte jedoch nicht signifikant von der nach Gabe der bikarbonatfreien Diättränken.

An accident at work? Traumatic lesions in the skeleton of a 4th millennium BCE "wagon driver" from Sharakhalsun, Russia

The study of ante-mortem trauma is a popular and important aspect of palaeopathological analysis. The majority of publications focus on a particular assemblage, skeletal element or type of fracture, with case studies of single individuals with multiple/unusual traumata being much rarer in the literature. This paper presents the case of an adult male from the Bronze Age site of Sharakhalsun, Russia, buried, uniquely, in a sitting position on a fully assembled wagon, who displayed evidence for multiple healed ante-mortem fractures of the cranium, axial and appendicular skeleton. The mechanisms and likely etiologies of the fractures are presented, with reference to modern and 19th century clinical literature, and possible interpretations suggested: that the individual was involved in a severe accident involving a wagon or draft animals, or both, a number of years before his death. The suggestion is also made that the unique burial position of the individual was a form of commemoration by the community of the survival and recovery of the individual from such a serious incident.

FOXP3+ regulatory T-cells in renal allografts: correlation with long-term graft function and acute rejection

BACKGROUND

The interpretation of a cellular infiltrate as cytotoxic or tolerogen represents an unsolved challenge in current transplantation. The so-called regulatory CD4+ CD25+ T-cells which express the FOXP3 gene have received increasing interest with respect to this question. The existing studies concerning the role of FOXP3+ Tregs for transplant tolerance yielded contradictory results.

METHODS

We examined the numbers of the FOXP3+ Tregs in two groups of renal allograft biopsies both showing cellular infiltration, but either without (n=29) or with signs of acute cellular rejection (n=26), by means of immunofluorescence and correlated the amount of FOXP3+ Tregs to renal function at the time of biopsy and after 1 and 2 years of follow up.

RESULTS

The number of FOXP3+ Tregs within infiltrates in non-rejecting biopsies did not correlate with renal function after 1 and 2 years. There were no significant differences in the numbers of FOXP3+ Tregs between biopsies with or without borderline infiltrates. Increased numbers of FOXP3+ Tregs were not associated with an ameliorated severity of graft rejection and did not correlate with outcome after the rejection episode and renal function after 1 and 2 years.

CONCLUSIONS

The identification of the FOXP3+ regulatory cells within the allograft cannot be considered as an appropriate marker for the interpretation of infiltrates as cytotoxic or tolerogenic or as a prognostic marker for later transplant function.

[Brugada syndrome]

BACKGROUND

A high take-off descending ST segment associated with right bundle branch block is the typical ECG criterion of the Brugada-Brugada syndrome. It leads to ventricular fibrillation or syncopes in case of a familiar disposition.

CASE REPORT

We describe a 56-year-old man in whom oral prajmalium bitartrate therapy previously prescribed for symptomatic ventricular extrasystoles unmasked an electrographic pattern characteristic of a Brugada syndrome. After the ongoing invasive diagnostic a right ventricular dysplasia in the same case is possible. The patient was treated with an ICD pacemaker.

FTY 720A mediates reduction of lymphocyte counts in human renal allograft recipients by an apoptosis-independent mechanism

The novel immunosuppressive compound FTY 720A posseses a mode of action which is different from all other immunosuppressive drugs. The most prominent feature is a reversible decrease in peripheral lymphocyte counts observed in animal experiments. We investigated in the first human trial (phase 1) whether FTY 720A induces apoptosis of peripheral blood mononuclear cells (PBMC) in stable renal allograft recipients. Monitoring of lymphocyte counts revealed a significant and dose-dependent decrease within 6 h post-FTY 720A dose: placebo 5.1%; 0.25 mg 36.4%; 0.5 mg 40.8%; 0.75 mg 39.4%; 1 mg 45.8%; 2 mg 67.2%; 3.5 mg 64.9%. PBMC apoptosis rates did not change, as determined before intake of FTY 720A and 2 h, 6 h, 24 h and 96 h post-FTY 720A dose. We detected no significant difference in apoptosis rates between patients who received placebo or FTY 720A. However, in vitro experiments showed that high concentrations of FTY 720 A induced apoptosis in human PBMC.

Effectiveness in learning complex problem solving and salivary ion indices of psychological stress and activation

Following Hinton et al. (1992, Biol. Psychol. 33, 63-71) and Richter et al. (1995, Biol. Psychol. 39, 131-142) ionic concentration of [K+] in unstimulated saliva was predicted to rise with perceived challenge, while lowered [Na+] was expected when experiencing psychological stress (PS). Subjects had to learn an engaging complex problem-solving 'game', via positive and negative feed-back on three 'games' lasting 2.5-3.0 h overall. Comparisons were made between three groups: (1) high success; (2) partial success ('strugglers'); and (3) total failure to learn. Saliva was sampled after resting and after each of three 'games'. Successful learners had a significant rise in [K+] on the first 'game' followed by a significant fall, consistent with task-challenge reaction followed by fast autonomic adaptation with successful learning. The 'strugglers' [Na+] fell significantly over the 'games', indicating mineralocorticoid-induced PS response of Na+ reabsorption. The 'total failure' subjects had generally significantly higher [K+] than the successful ones, showing raised tonic sympathetic relative to parasympathetic activity--this outcome being interpreted from interference theories. The 'failures' also had significantly higher tonic [Na+] on 'games'--indicating low PS as predicted from McGrath's (1976) theory.

[Prenatal diagnosis of malignant intracranial teratoma in the fetus]

At 24 weeks of gestation, an intracranial cystic lesion of 3 cm diameter, without further associated foetal malformations, was detected by ultrasound in a 25-year old nullipara prima gravida, during routine prenatal care. Within 5 weeks, the cystic mass developed into a predominantly solid tumour located at the 3rd ventricle, showing patterns of a rapidly growing malignant intracerebral process. At 29 weeks of gestation, pregnancy was terminated by sectio parva because of a progressive hydrocephalus with a biparietal diameter of 10.2 cm. Autopsy confirmed a malignant teratoma. Foetal intracranial teratomas are rare. Diagnosis and therapy should be carried out in perinatal centres.

[Basic diagnostic program in dizziness and syncope symptoms: value of electrophysiologic studies of the heart]

Syncopes and preceding signs and symptoms, particularly also in form of appearances of giddiness, are, including specialists of various branches, among others ENT, neurology, orthopaedics and ophthalmology, always to be classified according to the fact whether or not a cardiovascular disease is to be regarded as cause. If there is the suspicion, both special non-invasive investigations and such ones which possibly are to be performed invasively are indicated. The latter come after the non-invasive investigations partly on account of the expenditure (technique of heart catheterization) and the possibilities of complication. The testing of the sinus node with the highly frequent atrial stimulation and single stimulus technique, the lead of the His-potential and the performance of a ventricular programmed stimulation are the fundamental programmes of an electrophysiologic investigation. In an analysis carried out more than 3 years could be found that in two thirds of the 45 invasively examined patients the diagnosis could be precised and enhanced, respectively, and that the main disturbances related to the signs and symptoms were a sick sinus syndrome, AV-asequences and ventricular arrhythmias.