Absence of lymphatic vessels in non-functioning bleb capsules of glaucoma drainage devices

Purpose. To evaluate the presence and appearance of blood and lymphatic vessels in nonfunctioning bleb capsules of glaucoma drainage devices (GDD). Materials and methods. Non-functioning (n=14) GDD-bleb capsules of 12 patients were analyzed by immunohistochemistry for blood vessels (CD31, vascular endothelium), lymphatic vessels (lymphatic vessel endothelial hyaluronan receptor-1 [LYVE-1] and podoplanin) and macrophages (CD68). Results. CD31+++ blood vessels and CD68+ macrophages were detected in the outer layer of all specimens. LYVE-1 immunoreactivity was registered in single non-endothelial cells in 8 out of 14 (57%) bleb capsule specimens. Podoplanin-immunoreactivity was detected in all cases, located in cells and profiles of the collagen tissue network of the outer and/or the inner capsule layer. However, a colocalization of LYVE-1 and podoplanin as evidence for lymphatic vessels was not detected. Conclusions. We demonstrate the presence of bloodvessels but absence of lymphatic vessels in nonfunctioning bleb capsules after GDD-implantation. While the absence of lymphatic vessels might indicate a possible reason for drainage device failure, this needs to be confirmed in upcoming studies, including animal experiments

Choroidal melanocytes: subpopulations of different origin?

Background: The human choroid derives from the mesectoderm, except the melanocytes originating from the neuroectoderm. To date, it is unclear whether all choroidal melanocytes share the same origin or might have different origins. The purpose of this study was to screen immunohistochemically for mesenchymal elements in the adult healthy human choroid, in the malignant melanoma of the choroid, as well as in the developing human fetal choroid. Methods: Human choroids were obtained from cornea donors and prepared as flat whole mounts for paraffin-and cryoembedding. Globes enucleated for choroidal melanoma and eyes from human fetuses between 11 and 20 weeks of gestation were also embedded in paraffin. Sections were processed for immunohistochemistry of the mesenchymal marker vimentin, the melanocyte marker Melan-A, and the macrophage marker CD68, followed by light-, fluorescence-, and confocal laser scanning-microscopy. Results: The normal choroid contained 499 +/- 139 vimentin, 384 +/- 78 Melan-A, and 129 +/- 57 CD68 immunoreactive cells/mm(2). The vimentin immunopositive cell density was significantly higher than the density of Melan-A and CD68 immunopositive cells (p < 0.001, respectively). By confocal microscopy, 24 +/- 8% of all choroidal melanocytes displayed vimentin immunoreactivity. In choroidal melanomas, numerous melanoma cells of the epithelioid and spindle cell type revealed immunopositivity for both vimentin and Melan-A. The intratumoral density of vimentin immunoreactive cells was 1758 +/- 106 cells/mm(2), significantly higher than the density of Melan-A and CD68 immunopositive cells (p < 0.001, respectively). Comparing to healthy choroidal tissue, the choroidal melanomas revealed significantly higher densities of vimentin, Melan-A, and CD68 immunoreactive cells (p < 0.001, respectively). In the developing human fetal choroid, numerous vimentin and Melan-A immunopositive cells were detected not before the 16th week of gestation, with some of them showing colocalization of vimentin and Melan-A. Conclusions: The adult healthy human choroid is endowed with a significant number of vimentin immunopositive mesenchymal structures, including a subpopulation of vimentin immunoreactive choroidal melanocytes. These vimentin immunopositive melanocytic cells are also present in choroidal melanomas as well as in the developing human fetal choroid. Therefore, different embryologic origins can be considered for choroidal melanocytes. (C) 2021 Elsevier GmbH. All rights reserved

Thermal experience during embryogenesis contributes to the induction of dwarfism in whitefish <i>Coregonus lavaretus</i>

<div><p>Ecotype pairs provide well-suited model systems for study of intraspecific phenotypical diversification of animals. However, little is still known about the processes that account for the development of different forms and sizes within a species, particularly in teleosts. Here, embryos of a normal-growing ‘large’ form and a dwarf form of whitefish <i>Coregonus lavaretus</i> were incubated at two temperatures that are usually experienced at their own spawning sites (2°C for the normal and 6°C for the dwarf form). All fish were subjected to similar thermal treatment after hatching. The present data demonstrate for the first time that different thermal experience in embryonic life has lasting effects on body and muscle growth of this ecotype pair and contributes to the development of the dwarf form. Thus, juvenile fish of the regular form are much smaller and have less muscle mass when pre-hatching thermal conditions were similar to those typical for the spawning sites of the dwarf form (6°C) than when subjected to conditions of their own spawning sites (2°C). Surprisingly, fish of the dwarf form exhibit a similar pattern of response to thermal history (2°-fish much larger than 6°-fish), indicating that in their case, normal spawning site temperature (6°C) is indeed likely to act as a growth limiting factor. Results also demonstrate that the hypertrophic and hyperplastic muscle growth modes are similarly affected by thermal history. Immunolabelling experiments for Pax7, H3P and Mef2 provide evidence that the cellular mechanisms behind the increased growth rates after cold incubation in both ecotypes are increased proliferation and reduced differentiation rates of muscle precursor cells. This is of major significance to aspects of ecological and developmental biology and from the evolutionary perspective.</p></div

Development of slow and fast muscle fibre numbers.

<p>Relationship between fibre number in one epaxial trunk quadrant of normal-sized fish (NF, open bars) and dwarf fish (DF, dashed bars) imprinted at 2° (blue) and 6°C (red) and developmental time (8 individuals per thermal group of each ecotype). (A) Fast fibres, (B) slow fibres, (C) fast fibres > 200 μm², (D) fast fibres ≤ 50 μm²; whiskers indicate s.e., differences between thermal groups significant at p≤0.05 (*).</p

Relationship of nuclei to fibre volume of isolated fast fibres.

<p>Myonuclear densities at hatching (A) and 80 dph (B). Regression line equations: (A) NF-2: y = 3.9e^-6x + 5.5 (r² = 0.25) (356 fibres from 6 individuals), NF-6: y = 3.0e^-6x + 6.5 (r² = 0.38) (126 fibres from 6 individuals), DF-2: y = 8.0e^-6x + 5.1 (r² = 0.48) (303 fibres from 6 individuals), DF-6: y = 2.9e^-6x + 5.9 (r² = 0.26) (197 fibres from 6 individuals); (B): NF-2: y = 1.3e^-6x + 15.4 (r² = 0.28) (376 fibres from 8 individuals), NF-6: y = 3.5e^-6x + 8.2 (r² = 0.27) (236 fibres from 7 individuals), DF-2: y = 9.4e^-6x + 11.0 (r² = 0.59) (552 fibres from 8 individuals), DF-6 y = 2.6e^-6x + 10.0 (r² = 0.29) (332 fibres from 8 individuals).</p

Development of body lengths and muscle mass.

<p>(A) Total body lengths of normal-sized fish (NF, open bars) and dwarf fish (DF, dashed bars) imprinted at 2 (blue) and 6°C (red) at the end of the imprinting period (0 dph) and in the juvenile stage (80 dph). Values at bottom of bars provide number of individuals included in length measurement. Total fast (B) and slow (C) muscle csa in one half of the trunk (8 individuals per thermal group of each ecotype); whiskers indicate s.e., significant differences are assigned at p≤0.05 (*). (D) Correlation of slow muscle relative proportion (fast-to-slow muscle ratio) with fish size as given by total muscle csa; regression line equations: NF-2: y = 7.3x + 3.9 (r² = 0.87), NF-6: y = 12.2x + 7.6 (r² = 0.95), DF-2: y = 11.7x + 7.2 (r² = 0.94), DF-6: y = 15.9x + 10.3 (r² = 0.97).</p

Quantification of muscle precursor cells (MPCs).

<p>Numbers of labelled cells (means + s.e.) in double-immunostained 10 μm myotomal cross-sections of fish of the normal-sized form (NF, open bars) and dwarf fish (DF, dashed bars) imprinted at 2° (blue) and 6°C (red) at hatching and at 80 dph. Values at bottom of bars provide total numbers of evaluated quadrants (fish at hatching) and somite/myotome areas delimited by 2 successive myosepta (fish at 80 dph), respectively. Data at hatching derived from 16 2°-fish and 6°- fish each in the normal form, and from 8 2°-fish and 6°-fish each in the dwarf form; data at 80 dph derived from 7 individuals in all four groups. (A) Total numbers of Pax7+ cells per 100 μm distance within the DM and the lateral fast muscle. (B,C) Percentages of Pax7+ cells that have entered proliferation (Pax7+/H3P+) (B) or differentiation (Pax7+/Mgn+) (C). (*) Intergroup differences significant at p≤0.05.</p