Inflammatory responses in the placenta upon SARS-CoV-2 infection late in pregnancy

The effect of SARS-CoV-2 infection on placental function is not well understood. Analysis of placentas from women who tested positive at delivery showed SARS-CoV-2 genomic and subgenomic RNA in 22 out of 52 placentas. Placentas from two mothers with symptomatic COVID-19 whose pregnancies resulted in adverse outcomes for the fetuses contained high levels of viral Alpha variant RNA. The RNA was localized to the trophoblasts that cover the fetal chorionic villi in direct contact with maternal blood. The intervillous spaces and villi were infiltrated with maternal macrophages and T cells. Transcriptome analysis showed an increased expression of chemokines and pathways associated with viral infection and inflammation. Infection of placental cultures with live SARS-CoV-2 and spike protein-pseudotyped lentivirus showed infection of syncytiotrophoblast and, in rare cases, endothelial cells mediated by ACE2 and Neuropilin-1. Viruses with Alpha, Beta, and Delta variant spikes infected the placental cultures at significantly greater levels.

SARS-CoV-2 Infects Syncytiotrophoblast and Activates Inflammatory Responses in the Placenta

SARS-CoV-2 infection during pregnancy leads to an increased risk of adverse pregnancy outcomes. Although the placenta itself can be a target of virus infection, most neonates are virus free and are born healthy or recover quickly. Here, we investigated the impact of SARS-CoV-2 infection on the placenta from a cohort of women who were infected late during pregnancy and had tested nasal swab positive for SARS-CoV-2 by qRT-PCR at delivery. SARS-CoV-2 genomic and subgenomic RNA was detected in 23 out of 54 placentas. Two placentas with high virus content were obtained from mothers who presented with severe COVID-19 and whose pregnancies resulted in adverse outcomes for the fetuses, including intrauterine fetal demise and a preterm delivered baby still in newborn intensive care. Examination of the placental samples with high virus content showed efficient SARS-CoV-2 infection, using RNA in situ hybridization to detect genomic and replicating viral RNA, and immunohistochemistry to detect SARS-CoV-2 nucleocapsid protein. Infection was restricted to syncytiotrophoblast cells that envelope the fetal chorionic villi and are in direct contact with maternal blood. The infected placentas displayed massive infiltration of maternal immune cells including macrophages into intervillous spaces, potentially contributing to inflammation of the tissue. Ex vivo infection of placental cultures with SARS-CoV-2 or with SARS-CoV-2 spike (S) protein pseudotyped lentivirus targeted mostly syncytiotrophoblast and in rare events endothelial cells. Infection was reduced by using blocking antibodies against ACE2 and against Neuropilin 1, suggesting that SARS-CoV-2 may utilize alternative receptors for entry into placental cells.

Dabigatran inhibits intravitreal thrombin activity

PURPOSE

Proliferative vitreoretinopathy (PVR) is a vitreoretinal disorder in which retinal pigment epithelial (RPE) cell activation contributes to both formation of fibrotic retinal membranes and inflammation. Vitreous of patients with PVR contains increased thrombin activity which induces profibrotic and proinflammatory programs in RPE cells. Inhibition of intravitreal thrombin activity may thus represent a therapeutic option for PVR. In this study, we examined the capacity of the clinically available direct thrombin inhibitor dabigatran to inhibit thrombin activity in vitreous fluids.

METHODS

ARPE-19 cells were cultured with the following: (i) thrombin, (ii) vitreous without thrombin activity and (iii) vitreous with elevated thrombin activity (PVR samples and thrombin spiked vitreous) either in the presence or absence of dabigatran (range: 10^-5 to 10^-7  M). Subsequently, CCL2, CXCL8, GMCSF, IL6 and PDGFB mRNA expression levels were determined by RQ-PCR and protein levels of 27 cytokines, chemokines and growth factors were detected in culture supernatants using a multiplex approach. In addition, the capacity of vitreous fluids obtained from patients after oral dabigatran intake was tested in an in vitro thrombin activity assay.

RESULTS

Thrombin and vitreous fluids containing thrombin activity induced CCL2, CXCL8, GM-CSF, IL-6 and PDGF-BB expression by ARPE-19 cells, which was inhibited by dabigatran. In addition, dabigatran that reached the vitreous after repeated oral intake did inhibit thrombin activity in the in vitro activity assay.

CONCLUSION

Proliferative vitreoretinopathy (PVR) is associated with increased intravitreal thrombin activity that activates profibrotic and proinflammatory pathways in RPE cells. Our findings provide evidence that this activation pathway can potentially be inhibited by dabigatran.

Thrombin Generation in Vitreous and Subretinal Fluid of Patients with Retinal Detachment

PURPOSE

To measure prothrombin fragments (F1+2) and thrombin-antithrombin complex (TAT) in vitreous and subretinal fluid (SRF) of rhegmatogenous retinal detachment (RRD) patients and to validate and further specify our earlier finding of increased thrombin activity in patients with proliferative vitreoretinopathy (PVR).

METHODS

F1+2 and TAT were measured in 31 vitreous and 16 SRF samples using the Enzygnost® immunoassays.

RESULTS

We found significant levels of F1+2 and TAT in the vitreous of all patients with RRD compared to patients with macular hole or macular pucker. However, there was no significant difference between patients who would develop PVR in the future, had established PVR, and patients with uncomplicated RRD both in vitreous concentrations of F1+2 (Kruskal-Wallis p = 0.963) and TAT (p = 0.516).

CONCLUSION

The analysis of F1+2 and TAT confirmed significant thrombin generation in both vitreous and SRF of patients with RRD. An imbalance between the thrombin regulation mechanisms TAT and α2-macroglobulin possibly explains the difference from our previous findings.

Retinal pigment epithelial cells display specific transcriptional responses upon TNF-α stimulation

BACKGROUND/AIMS

Tumour necrosis factor-α (TNF-α) is a key mediator of ocular inflammation and its interaction with the retinal pigment epithelium (RPE) may be a driving force in vitreoretinal disorders such as age-related macular degeneration, proliferative vitreoretinopathy (PVR) and diabetic retinopathy. Under inflammatory conditions, the ability of RPE cells to maintain the blood-retinal barrier and immune privilege may be lost and proliferation of RPE cells is facilitated. To gain insight into the effects of TNF-α on RPE cells, a gene expression study was performed.

METHODS

ARPE-19 and HT-29 cells were stimulated with 50 ng/mL TNF-α for 6 h. Gene expression patterns were compared between stimulated and control cells using whole genome gene expression arrays. Data were analysed using Partek and OmniViz and validated using quantitative RT-PCR. Functional annotation analysis was performed using Ingenuity and DAVID.

RESULTS

A total of 97 genes were uniquely modulated by TNF-α in ARPE-19 cells compared with HT-29 cells (86 upregulated and 11 downregulated). Most commonly affected biological processes were apoptosis, cell motility and cell signalling. The highest upregulated gene was EFNA1. Among the downregulated genes were transcription factors implicated in ocular development (SIX3, PAX6) and modulation of p53-mediated apoptosis (CITED2).

CONCLUSIONS

This study provides insight into the unique responses of RPE cells to TNF-α stimulation and suggests a role for genes involved in apoptosis and retinal epithelial development. These findings contribute to our understanding of the behaviour of RPE cells under inflammatory conditions and the crucial role of RPE cells in vitreoretinal diseases.

The role of thrombin in proliferative vitreoretinopathy

PURPOSE

To determine the role of thrombin in the development of proliferative vitreoretinopathy (PVR).

METHODS

Vitreous was collected from patients undergoing a vitrectomy (macular holes and puckers, n = 11 [controls]; retinal detachment without PVR development following vitrectomy, n = 15 [RRD1]; retinal detachment with PVR development within 6 months after vitrectomy, n = 11 [RRD2]; and established PVR, n = 14 [PVR]). Thrombin activity in vitreous was determined using a thrombin-specific chromogenic substrate. ARPE-19 cells were stimulated with 8× diluted vitreous samples in the presence and absence of hirudin. The samples were analyzed at t = 0 and t = 24 hours for the presence of 27 cytokines/chemokines and growth factors using a multiplex approach. In comparable studies, ARPE-19 cells were stimulated for 2 hours, and mRNA expression levels for CCL2, CXCL8, GMCSF, IL6, and PDGFB were determined by real-time quantitative (RQ)-PCR.

RESULTS

Thrombin activity was significantly (P < 0.05) higher in vitreous of the PVR group compared to the other groups. Proliferative vitreoretinopathy vitreous stimulated the production of chemokine (C-C motif) ligand (CCL)2, chemokine (C-X-C motif) ligand (CXCL)8, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and platelet-derived growth factor (PDGF)-BB by ARPE-19 to significantly (P < 0.05) higher levels than vitreous from the RRD1 and RRD2 groups. These effects of PVR vitreous were significantly (P < 0.05) reduced by hirudin. These data were confirmed by mRNA studies.

CONCLUSIONS

Thrombin activity is increased in vitreous of patients with established PVR and is involved in the activation of proinflammatory and profibrotic pathways in RPE cells. Inhibition of thrombin activity may therefore represent a potential treatment option for proliferative vitreoretinopathy.

Thrombin induces epithelial-mesenchymal transition and collagen production by retinal pigment epithelial cells via autocrine PDGF-receptor signaling

PURPOSE

De-differentiation of RPE cells into mesenchymal cells (epithelial-mesenchymal transition; EMT) and associated collagen production contributes to development of proliferative vitreoretinopathy (PVR). In patients with PVR, intraocular coagulation cascade activation occurs and may play an important initiating role. Therefore, we examined the effect of the coagulation proteins factor Xa and thrombin on EMT and collagen production by RPE cells.

METHODS

Retinal pigment epithelial cells were stimulated with factor Xa or thrombin and the effect on zonula occludens (ZO)-1, α-smooth muscle actin (α-SMA), collagen, and platelet-derived growth factor (PDGF)-B were determined by real-time quantitative-polymerase chain reaction (RQ-PCR), immunofluorescence microscopy, and HPLC and ELISA for collagen and PDGF-BB in culture supernatants, respectively. PDGF-receptor activation was determined by phosphorylation analysis and inhibition studies using the PDGF-receptor tyrosine kinase inhibitor AG1296.

RESULTS

Thrombin reduced ZO-1 gene expression (P < 0.05) and enhanced expression of the genes encoding α-SMA and the pro-alpha1 chain of collagen type-1 (P < 0.05), indicating EMT. Also, ZO-1 protein expression declined on thrombin stimulation, whereas production of α-SMA and collagen increased. In contrast to thrombin, factor Xa hardly stimulated EMT by RPE. Thrombin clearly induced PDGF-BB production and PDGF-Rβ chain phosphorylation in RPE. Moreover, AG1296 significantly blocked the effect of thrombin on EMT and collagen production.

CONCLUSIONS

Our findings demonstrate that thrombin is a potent inducer of EMT by RPE via autocrine activation of PDGF-receptor signaling. Coagulation cascade-induced EMT of RPE may thus contribute to the formation of fibrotic retinal membranes in PVR and should be considered as treatment target in PVR.

Highly efficient gene targeting in Penicillium chrysogenum using the bi-partite approach in deltalig4 or deltaku70 mutants

Inactivating the non-homologous end-joining (NHEJ) pathway is a well established method to increase gene targeting (GT) efficiencies in filamentous fungi. In this study we have compared the effect of inactivating the NHEJ genes ku70 or lig4 on GT in the industrial penicillin producer Penicillium chrysogenum. Deletion of both genes resulted in strongly increased GT efficiencies at three different loci but not higher than 70%, implying that other, yet uncharacterized, recombination pathways are still active causing a part of the DNA to be integrated via non-homologous recombination. To further increase the GT efficiency we applied the bi-partite approach, in which the DNA fragment for integration was split in two non-functional overlapping parts that via homologous recombination invivo can form a functional selection marker. The combined NHEJ mutant and bi-partite approach further increased GT frequencies up to approximately 90%, which will enable the efficient high throughput engineering of the P. chrysogenum genome. We expect that this combined approach will function with similar high efficiencies in other filamentous fungi.

The first appearance of Rodlet cells in carp (Cyprinus carpio L.) ontogeny and their possible roles during stress and parasite infection

The origin and function of rodlet cells (RCs) are still a matter of discussion. Whereas the exogenous hypothesis considers them parasites, the endogenous hypothesis regards them as a genuine fish cell population with a secretory and/or leukocyte function. In order to shed more light on these questions we focused on the location and appearance of RCs during carp (Cyprinus carpio) ontogeny. Typical RCs were seen at 5days post fertilisation (dpf) between kidney and intestine, at 6dpf in the intestine and at 8dpf in both anterior and posterior kidney and in the abdominal cavity among the mesothelial cells. The RC number increased with age and after 14dpf they were also present in gills. The early appearance of the RCs during carp ontogeny support the endogenous hypothesis stating that RCs are genuine constituents of fish tissue and suggest that they are 'immune cells'. The fact that the RCs of the gills secrete their content into the surrounding water, combined with the strategic location around blood vessels in kidney and within intestinal epithelium, would also support an important role in host defense. To investigate whether RC numbers in gills and kidney are related to typical fluctuations in the physiology during stress and infection we counted their number in gills and kidney after parasite infection and stress. In the gills the number of RCs increased after infection but did not change after stress while in the kidney their number increased after stress and no significant changes were observed after infection.

Treatment of acute opioid withdrawal with ibogaine

Ibogaine is an alkaloid with putative effect in acute opioid withdrawal. Thirty-three cases of treatments for the indication of opioid detoxification performed in non-medical settings under open label conditions are summarized involving an average daily use of heroin of .64 +/- .50 grams, primarily by the intravenous route. Resolution of the signs of opioid withdrawal without further drug seeking behavior was observed within 24 hours in 25 patients and was sustained throughout the 72-hour period of posttreatment observation. Other outcomes included drug seeking behavior without withdrawal signs (4 patients), drug abstinence with attenuated withdrawal signs (2 patients), drug seeking behavior with continued withdrawal signs (1 patient), and one fatality possibly involving surreptitious heroin use. The reported effectiveness of ibogaine in this series suggests the need for systematic investigation in a conventional clinical research setting.

Psychosocial factors as strong predictors of mortality from cancer, ischaemic heart disease and stroke: the Yugoslav prospective study

We investigated the relation of psychosocial risk factors to mortality in a prospective study of 1353 inhabitants of Crvenka, 619 of whom died between 1966 and 1976. All 38 lung cancer deaths occurred in those with high scores for rationality and antiemotionality (R/A), a factor related to suppression of aggression. Compared with lower R/A, high R/A was also associated with a relative risk of mortality of 29 for other cancer, 4.3 for ischaemic heart disease and 6.5 for stroke. Standardising for R/A reduced the smoking/lung cancer association, virtually eliminated the smoking/other cancer and smoking/heart disease relationships and reduced the association of heart disease with blood cholesterol, blood sugar and hypertension. Long lasting hopelessness was also independently associated with cancer as was anger with heart disease, though not so strongly as for R/A. Psychosocial variables are important predictors of mortality and decisively modify the effect of physical risk factors such as smoking.

On freedom and induction

Traumatizing events and traumatizing conflicts may lead to defense mechanisms which in the course of time become part of character formation. In psychosomatic medicine much attention has been paid in the past to the so-called psychosomatic character profiles. Though discussions about psychosomatic specificity have remained controversial, it still seems advisable to take into account the power of induction of specific defense strategies. In this paper special attention is paid to the fact that asthmatics, patients suffering from hypertension or coronary heart disease, as well as patients suffering from other psychosomatic syndromes, and even patients suffering from carcinoma may induce their own defense strategies in interviewers and therapists, who usually are not sufficiently aware of the fact of such transference phenomena. A distortion of the normal psychotherapeutic process is more often a result of induction processes than has been thought of.

Microanalysis of the first interview with psychosomatic patients

Microanalysis of the first interview is a technique developed by the author for the subtle translation of the verbal aspects of the doctor-patient contact. Every bit of information, derived from the patient, is translated in the traditional historical dimension, e.g., when did the complaint start, and in the here and now dimension, e.g., in how far does the information imply a cry for help and understanding. Psychosomatic patients, who are usually well adapted, suppress or repress their problems and emotions so much that they are hardly able to express these quite openly. Psychosomatic symptoms reflect the effort of the patient not to behave in a hysterical way. This means that the overt cry for help and attention, which is so characteristic for hysterical patients, is warded off. Especially the microanalytic translation of this hidden cry may be used by the interviewer to detect what the basic problems of the patient are and how the optimal climate for an efficient therapeutic contact can be established. In the Leyden Department of Psychiatry the technique is used to facilitate the training in interview technique. In the paper models will be given for the understanding of the interrelationship of psychiatric and psychosomatic symptoms.