SARS-CoV-2 infection induces mixed M1/M2 phenotype in circulating monocytes and alterations in both dendritic cell and monocyte subsets

Clinical manifestations of SARS-CoV-2 infection range from mild to critically severe. The aim of the study was to highlight the immunological events associated with the severity of SARS-CoV-2 infection, with an emphasis on cells of innate immunity. Thirty COVID-19 patients with mild/moderate symptoms and 27 patients with severe/critically severe symptoms were recruited from the Clinical Center of Kragujevac during April 2020. Flow cytometric analysis was performed to reveal phenotypic and functional alterations of peripheral blood cells and to correlate them with the severity of the disease. In severe cases, the number of T and B lymphocytes, dendritic cells, NK cells, and HLA-DR-expressing cells was drastically decreased. In the monocyte population proportion between certain subsets was disturbed and cells coexpressing markers of M1 and M2 monocytes were found in intermediate and non-classical subsets. In mild cases decline in lymphocyte number was less pronounced and innate immunity was preserved as indicated by an increased number of myeloid and activated dendritic cells, NK cells that expressed activation marker at the same level as in control and by low expression of M2 marker in monocyte population. In patients with severe disease, both innate and adoptive immunity are devastated, while in patients with mild symptoms decline in lymphocyte number is lesser, and the innate immunity is preserved.

Histochemical, immunohistochemical and ultrastructural analysis of aortic wall in neonatal coarctation

The neonatal type of coarctation is characterized by the presence of the ductal sling and coarctational shelf placed proximally in relation to the ductal orifice. Those morphological features are not described in detail yet from immunohistochemical and transmission electron microscopy (TEM) aspects, so the aim of this study was to investigate the smooth muscle cells (SMCs) phenotype in aortic intimal thickening, presence of inflammatory cells and contents of intimal and medial, and adventitial connective tissue. We examined samples of coarctation segments excised at surgery after end-to-end anastomosis from 30 patients, ages from 14 days to three months, histochemicaly, immunocytochemically and by TEM. In all samples, it is noticed focal intimal thickening on the posterior aortic wall, with accumulation of SMCs, which show immunoreactivity on alpha-smooth muscle actin (α-SMA) and vimentin (but not on desmin) and also expressed proliferating cell nuclear antigen (PCNA) and S-100 protein. At TEM analysis, those SMCs show a fibroblast-like morphology, so their functions could be to proliferate and secrete extracellular matrix (ECM) components (a synthetic phenotype). In all studied samples of the coarctation, on the posterior wall, the immunocytochemical and TEM examination revealed the presence of SMCs of the synthetic phenotype. Results also showed an increase of the cell number in intima of this part of aortic wall, followed by proliferated SMCs in inner media and absence of inflammatory cells. This finding suggests that proliferation of the SMCs, their synthetic activity and increase of the cell number could lead to formation of the intimal thickening on the posterior wall.

Autonomic innervation of the periglomerular arteries

OBJECTIVE

To explore spatial and volume relations of the calcitonine gene-related peptide (CGRP)-positive and tyrosine hydroxylase (TH)-positive nerve fibers in the wall of cortical blood vessels.

STUDY DESIGN

Kidney specimens from 10 rats were processed for confocal microscopy. Nerve fibers were stained with anti-CGRP and anti-TH antibodies and image stacks were collected. Three-dimensional reconstruction and quantification of labeled fibers were performed to reveal their distribution and spatial relations.

RESULTS

CGRP- and TH-immunoreactive nerve fibers were distributed throughout the kidney cortex. TH-positive fibers were dominant in the small periglomerular arteries (up to 4.6-fold). Examined nerves were finely intertwined in the wall of small blood vessels of the kidney and ran in the same nerve bundle but without co-localization. Extensive, web-like branching and varicosities of the TH nerves were observed. Sensory fibers prevailed in the wall of the larger arteries "embedded" into tubules near the medullary rays, and their endings can be verified in the muscularis layer of the interlobular arteries.

CONCLUSION

Characteristics of the investigated fibers emphasize their role in the regulation of kidney blood vessel diameter and their influence on hypertension onset.

Morphometric analysis of muscularis proper and myenteric plexus of the normal human oesophagus. Age related changes

BACKGROUND

Oesophagus is a muscular tube that transports food and liquids by coordinated contraction of its muscular lining led by stimuli from the nerve plexus. Its muscularis proper layer consists of muscle cells, connective tissue and myenteric plexus. The aim of our histomorphometric study was to reveal detailed characteristics of this layer, cell number, volume, orientation, properties of myenteric plexus as well as changes related to aging.

MATERIALS AND METHODS

Oesophagus tissue samples from 17 male cadavers were taken from the cranial and thoracic parts. Samples were divided in 2 groups: younger(ages 21-45) and older (ages 66-78). The tissue was routinely processed,embedded and serially sectioned. Sections were stained with Masson-Goldner and Cresyl-violet dyes. Digital images were analysed with the image analysis software.Statistics were performed with SPSS software.

RESULTS

The average thickness of the cranial part of the oesophageal wall and muscularis proper was 2590 μm and 1197 μm, respectively in the younger and 2453 μm and 1144 μm in the older group. Overall volume of the muscle tissue was slightly larger in the thoracic part, and in the younger group compared to the cranial part and the older group. The average number of the striated muscle cells per 100 μm in the cranial part was 771.5 and 749.7 in the younger and the older group, respectively. Striated cells were significantly less present only in the lower thoracic part of the oesophagus. In the older group,smaller striated muscle cells dominated over the larger ones. In the younger group, majority of the striated muscle cells were mid-sized. The thickness of the circular layer of muscularis proper was more affected by aging than the longitudinal one. Ganglion cells number was lower in the older group, but plexus area was unchanged.

CONCLUSIONS

Aging affects muscularis proper and myenteric plexus of the oesophagus.Major differences can be observed in the striated muscle cells size, volume of the circular layer and number of the ganglionic cells in the myenteric plexus.