The role of IL-6 trans-signaling in vascular leakage: implications for ovarian hyperstimulation syndrome in a murine model

Blockade of interleukin-6 trans-signaling prevents mitochondrial dysfunction and cellular senescence in retinal endothelial cells

Interleukin-6 (IL-6) is a multifaceted cytokine implicated in the pathogenesis of diabetic retinopathy (DR). Its activity extends through cis- and trans-signaling (TS) pathways, with cis-signaling limited to specific cell types possessing the membrane-bound IL-6 receptor, while trans-signaling broadly activates various cells without the membrane bound IL-6 receptor, including retinal endothelial cells. In this study, we determined the effects of interleukin-6 trans-signaling on mitochondrial dysfunction and cellular senescence in human retinal endothelial cells (HRECs). HRECs were cultured and treated with IL-6 + soluble IL-6R or Hyper IL-6 to activate trans-signaling, along with sgp130Fc for inhibition. RT-PCR was used to analyze gene expression changes associated with inflammation and senescence. Cellular senescence was assessed using SA β-gal staining. Mitochondrial function was evaluated using Seahorse XFe24 Bioanalyzer. IL-6 trans-signaling induced inflammatory gene expression as indicated by the upregulation of ICAM1, MCP1, and SERPINA3 levels. Additionally, it reduced mitochondrial respiration and oxidative phosphorylation, and these effects were counteracted by sgp130Fc. Moreover, IL-6 trans-signaling led to altered expression of apoptosis-associated genes, including downregulation of FIS1, BCL2, and MCL1, while promoting cellular senescence, a phenomenon mitigated by sgp130Fc. These results not only deepen our understanding of IL-6 in DR but also carry broader implications for age-related diseases and the aging process itself. This study underscores the potential therapeutic value of targeting IL-6 trans-signaling with sgp130Fc as a promising anti-inflammatory approach for DR and potentially other inflammatory conditions. Further in-vivo investigations are warranted to elucidate the function of IL-6 trans-signaling in aging-related pathologies and overall organismal health.

Dissecting Interleukin-6 Classic and Trans-signaling in Inflammation and Cancer

Interleukin-6 (IL-6) is a cytokine synthesized by many cells in the human body. IL-6 binds to a membrane-bound receptor (IL-6R), which is only present on hepatocytes, some epithelial cells, and some leukocytes. The complex of IL-6 and IL-6R binds to the ubiquitously expressed receptor subunit gp130, which forms a homodimer and thereby initiates intracellular signaling, e.g., the JAK/STAT and MAPK pathways. Proteases can cleave the membrane-bound IL-6R from the cell surface and generate a soluble IL-6R (sIL-6R), which retains its ability to bind IL-6. The IL-6/sIL-6R complex associates with gp130 and induces signaling even on cells which do not express the IL-6R. This paradigm has been called IL-6 trans-signaling, whereas signaling via the membrane-bound IL-6R is referred to as classic signaling. We have generated several molecular tools to differentiate between both pathways and to analyze the consequences of cellular IL-6 signaling in vivo. One of these tools is soluble gp130Fc, which selectively inhibits IL-6 trans-signaling. This protein under the WHO name Olamkicept has successfully undergone phase II clinical trials in patients with autoimmune diseases. Here, in this chapter, we describe several molecular tools to differentiate between IL-6 classic and trans-signaling and to analyze the consequences of cellular IL-6 signaling in vivo.

Global Transcriptional Profiling of Granulosa Cells from Polycystic Ovary Syndrome Patients: Comparative Analyses of Patients with or without History of Ovarian Hyperstimulation Syndrome Reveals Distinct Biomarkers and Pathways

Ovarian hyperstimulation syndrome (OHSS) is often a complication of polycystic ovarian syndrome (PCOS), the most frequent disorder of the endocrine system, which affects women in their reproductive years. The etiology of OHSS is multifactorial, though the factors involved are not apparent. In an attempt to unveil the molecular basis of OHSS, we conducted transcriptome analysis of total RNA extracted from granulosa cells from PCOS patients with a history of OHSS (n = 6) and compared them to those with no history of OHSS (n = 18). We identified 59 significantly dysregulated genes (48 down-regulated, 11 up-regulated) in the PCOS with OHSS group compared to the PCOS without OHSS group (p-value < 0.01, fold change >1.5). Functional, pathway and network analyses revealed genes involved in cellular development, inflammatory and immune response, cellular growth and proliferation (including DCN, VIM, LIFR, GRN, IL33, INSR, KLF2, FOXO1, VEGF, RDX, PLCL1, PAPPA, and ZFP36), and significant alterations in the PPAR, IL6, IL10, JAK/STAT and NF-κB signaling pathways. Array findings were validated using quantitative RT-PCR. To the best of our knowledge, this is the largest cohort of Saudi PCOS cases (with or without OHSS) to date that was analyzed using a transcriptomic approach. Our data demonstrate alterations in various gene networks and pathways that may be involved in the pathophysiology of OHSS. Further studies are warranted to confirm the findings.

The Interleukin-6 trans-signaling promotes progesterone production in human granulosa-lutein cells

As a critical paracrine regulator of multiple reproductive functions, the cytokine interleukin-6 (IL-6) is expressed in human granulosa cells and can be detected in follicular fluid. At present, the functional role of IL-6 in the regulation of ovarian steroidogenesis is controversial. Moreover, the detailed molecular mechanisms by which IL-6 regulates the production of progesterone in human granulosa cells remain to be elucidated. In the present study, we used primary and immortalized human granulosa-lutein (hGL) cells to investigate the effects of IL-6 on progesterone synthesis and the underlying molecular mechanisms. We found that IL-6 trans-signaling by the combined addition of IL-6 and soluble IL-6 receptor (sIL-6Rα) induced StAR expression and progesterone production in hGL cells. Additionally, IL-6/sIL-6Rα activated the phosphorylation of Janus activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), and the cellular effects were abolished by AG490 (JAK2 inhibitor), C188–9 (STAT3 inhibitor), or siRNA-mediated knockdown of STAT3. IL-6 trans-signaling-induced activation of JAK2/STAT3 also upregulated the expression of suppressor of cytokine signaling 3 (SOCS3), which, in turn, negatively regulated the JAK2/STAT3 pathway by suppressing STAT3 activation and its downstream effects. Our findings provide insight into the molecular mechanisms by which IL-6 trans-signaling modulates steroidogenesis in hGL cells.

Suppressing STAT3 activity protects the endothelial barrier from VEGF-mediated vascular permeability

Vascular permeability triggered by inflammation or ischemia promotes edema, exacerbates disease progression and impairs tissue recovery. Vascular endothelial growth factor (VEGF) is a potent inducer of vascular permeability. VEGF plays an integral role in regulating vascular barrier function physiologically and in pathologies, including cancer, stroke, cardiovascular disease, retinal conditions and COVID-19-associated pulmonary edema, sepsis and acute lung injury. Understanding temporal molecular regulation of VEGF-induced vascular permeability will facilitate developing therapeutics to inhibit vascular permeability, while preserving tissue-restorative angiogenesis. Here, we demonstrate that VEGF signals through signal transducer and activator of transcription 3 (STAT3) to promote vascular permeability. We show that genetic STAT3 ablation reduces vascular permeability in STAT3-deficient endothelium of mice and VEGF-inducible zebrafish crossed with CRISPR/Cas9-generated Stat3 knockout zebrafish. Intercellular adhesion molecule 1 (ICAM-1) expression is transcriptionally regulated by STAT3, and VEGF-dependent STAT3 activation is regulated by JAK2. Pyrimethamine, an FDA-approved antimicrobial agent that inhibits STAT3-dependent transcription, substantially reduces VEGF-induced vascular permeability in zebrafish, mouse and human endothelium. Collectively, our findings suggest that VEGF/VEGFR-2/JAK2/STAT3 signaling regulates vascular barrier integrity, and inhibition of STAT3-dependent activity reduces VEGF-induced vascular permeability.

This article has an associated First Person interview with the first author of the paper.

Summary: Genetic STAT3 ablation in mice and VEGF-inducible zebrafish reveals that VEGF signals through STAT3 to promote vascular permeability. Pyrimethamine reduces VEGF-induced permeability in animal models.

Pazopanib ameliorates acute lung injuries via inhibition of MAP3K2 and MAP3K3

Acute lung injury (ALI) causes high mortality and lacks any pharmacological intervention. Here, we found that pazopanib ameliorated ALI manifestations and reduced mortality in mouse ALI models and reduced edema in human lung transplantation recipients. Pazopanib inhibits mitogen-activated protein kinase kinase kinase 2 (MAP3K2)- and MAP3K3-mediated phosphorylation of NADPH oxidase 2 subunit p47^phox at Ser²⁰⁸ to increase reactive oxygen species (ROS) formation in myeloid cells. Genetic inactivation of MAP3K2 and MAP3K3 in myeloid cells or hematopoietic mutation of p47^phox Ser²⁰⁸ to alanine attenuated ALI manifestations and abrogates anti-ALI effects of pazopanib. This myeloid MAP3K2/MAP3K3-p47^phox pathway acted via paracrine H₂O₂ to enhance pulmonary vasculature integrity and promote lung epithelial cell survival and proliferation, leading to increased pulmonary barrier function and resistance to ALI. Thus, pazopanib has the potential to be effective for treating ALI.

The IL6/sIL-6Rα trans-signaling increases PGE2 production in human granulosa cells

As a potent autocrine regulator, the proinflammatory cytokine interleukin 6 (IL6) is expressed in granulosa cells and follicular fluid and is involved in the modulation of various follicular functions, including follicular development and ovulation. At present, the detailed molecular mechanisms by which IL6 regulates the event of ovulation remain to be elucidated. In the present study, primary and immortalized (SVOG) human granulosa-lutein (hGL) cells were used to investigate the effects of IL6 on the expression of prostaglandin-endoperoxide synthase 2 (PTGS2) and the subsequent synthesis of prostaglandin E2 (PGE2) and to investigate the underlying molecular mechanisms. We found that instead of classic signaling, IL6/sIL-6Rα trans-signaling induced the expression of PTGS2 and production of PGE2 in both SVOG cells and primary hGL cells. Moreover, IL6/sIL-6Rα activated the phosphorylation of Janus activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), which in turn induced STAT3 nuclear translocation. Additionally, these effects were suppressed by the addition of inhibitors (AG490 for JAK2 and C188-9 for STAT3) and by the siRNA-mediated knockdown of STAT3. Additionally, suppressor of cytokine signaling 3 (SOCS3) acts as a negative-feedback regulator in IL6/sIL-6Rα-induced cellular activities, including the activation and nuclear translocation of STAT3, upregulation of PTGS2 expression, and increase in PGE2 production in SVOG cells. In conclusion, IL6 trans-signaling upregulates the expression of PTGS2 and increases the production of PGE2 via the JAK2/STAT3/SOCS3 signaling pathway in hGL cells. Our findings provide insights into the molecular mechanisms by which IL6 trans-signaling may potentially modulate the event of ovulation in human ovaries.

Capillary Leak Syndrome From Rituximab Therapy of Lymphoma

Capillary leak syndrome (CLS) is characterized by plasma extravasation into the interstitium with resultant hypotension, anasarca, hemoconcentration, and hypoalbuminemia in the absence of albuminuria. Initially reported in Clarkson’s disease (systemic capillary leak syndrome), CLS has been observed in multiple disease settings, the most common being sepsis. In oncology, CLS has been reported more often as a complication from therapy, and less often from malignancy. In this case study, we documented clinical manifestation, laboratory features, and radiological findings of CLS from rituximab therapy when employed in combination with a multi-agent chemotherapy regimen (EPOCH-R). Differentiating drug-induced CLS from sepsis, which presents with the same clinical features, is important in avoiding further exposure to rituximab, which could be fatal to the patient.

Diabetes Induced Alterations in Murine Vitreous Proteome Are Mitigated by IL-6 Trans-Signaling Inhibition

Purpose

Diabetic retinopathy (DR) is a microvascular complication caused by prolonged hyperglycemia and characterized by leaky retinal vasculature and ischemia-induced angiogenesis. Vitreous humor is a gel-like biofluid in the posterior segment of the eye between the lens and the retina. Disease-related changes are observed in the biochemical constituents of the vitreous, including proteins and macromolecules. Recently, we found that IL-6 trans-signaling plays a significant role in the vascular leakage and retinal pathology associated with DR. Therefore, in this study, comprehensive proteomic profiling of the murine vitreous was performed to identify diabetes-induced alterations and to determine effects of IL-6 trans-signaling inhibition on these changes.

Methods

Vitreous samples from mice were collected by evisceration, and proteomic analyses were performed using liquid chromatography–tandem mass spectrometry (LC-MS/MS).

Results

A total of 154 proteins were identified with high confidence in control mice and were considered to be characteristic of healthy murine vitreous fluid. The levels of 72 vitreous proteins were significantly altered in diabetic mice, including several members of heat shock proteins, 14-3-3 proteins, and tubulins. Alterations in 52 out of 72 proteins in diabetic mice were mitigated by IL-6 trans-signaling inhibition.

Conclusions

Proteomic analysis of murine vitreous fluid performed in this study provides important information about the changes caused by diabetes in the ocular microenvironment. These diabetes-induced alterations in the murine vitreous proteome were mitigated by IL-6 trans-signaling inhibition. These findings further support that IL-6 trans-signaling may be an important therapeutic target for the treatment of DR.

RNA-Seq analysis reveals gene expression changes induced by IL-6 trans-signaling activation in retinal endothelial cells

BACKGROUND

Increasing evidence suggests that interleukin-6 (IL-6) trans-signaling plays a critical role in the pathogenesis of diabetic retinopathy (DR). We have previously shown that activation of IL-6 trans-signaling induces barrier dysfunction in human retinal endothelial cells (HRECs). However, the molecular mechanisms underlying these effects are not clear. The purpose of this study was to discover global gene expression changes in HRECs following activation of IL-6 trans-signaling.

METHODS

HRECs were treated with IL-6 and soluble IL-6R to activate IL-6 trans-signaling, and sgp130Fc treatment was used for IL-6 trans-signaling inhibition. RNA-Seq analyses were performed for global gene expression profiling. Differential expression was determined using DESeq2, and bioinformatic analyses were performed to associate the differentially expressed genes with biological functions and pathways.

RESULTS

Our analyses revealed 445 differentially expressed genes (318 upregulated and 127 downregulated) in HRECs after IL-6 trans-signaling activation. We identified several novel genes not previously associated with IL-6 signaling or endothelial dysfunction. Leukocyte adhesion, diapedesis and chemokine signaling pathways are highly enriched in differentially expressed genes. Inhibition of IL-6 trans-signaling with sgp130Fc abrogated these changes, thus highlighting the therapeutic potential of this drug.

CONCLUSIONS

This study identified significant gene expression changes caused by IL-6 trans-signaling activation in HRECs. Identification of such changes has the potential to uncover the precise molecular mechanisms of IL-6 trans-signaling mediated effects in the pathology of DR.

Suppressing STAT3 activity protects the endothelial barrier from VEGF-mediated vascular permeability

Vascular permeability triggered by inflammation or ischemia promotes edema, exacerbates disease progression, and impairs tissue recovery. Vascular endothelial growth factor (VEGF) is a potent inducer of vascular permeability. VEGF plays an integral role in regulating vascular barrier function physiologically and in pathologies, such as cancer, ischemic stroke, cardiovascular disease, retinal conditions, and COVID-19-associated pulmonary edema and sepsis, which often leads to acute lung injury, including acute respiratory distress syndrome. However, after initially stimulating permeability, VEGF subsequently mediates angiogenesis to repair damaged tissue. Consequently, understanding temporal molecular regulation of VEG-Finduced vascular permeability will facilitate developing therapeutics that achieve the delicate balance of inhibiting vascular permeability while preserving tissue repair. Here, we demonstrate that VEGF signals through signal transducer and activator of transcription 3 (STAT3) to promote vascular permeability. Specifically, we show that genetic STAT3 ablation reduces vascular permeability in STAT3-deficient endothelium of mice and VEGF-inducible zebrafish crossed with CRISPR/Cas9 generated genomic STAT3 knockout zebrafish. Importantly, STAT3 deficiency does not impair vascular development and function in vivo. We identify intercellular adhesion molecule 1 (ICAM-1) as a STAT3-dependent transcriptional regulator and show VEGF-dependent STAT3 activation is regulated by JAK2. Pyrimethamine, an FDA-approved antimicrobial agent that inhibits STAT3-dependent transcription, substantially reduces VEGF-induced vascular permeability in zebrafish, mouse, and human endothelium. Indeed, pharmacologically targeting STAT3 increases vascular barrier integrity using two additional compounds, atovaquone and C188-9. Collectively, our findings suggest that the VEGF, VEGFR-2, JAK2, and STAT3 signaling cascade regulates vascular barrier integrity, and inhibition of STAT3-dependent activity reduces VEGF-induced vascular permeability in vertebrate models.

Phospho-Tyr705 of STAT3 is a therapeutic target for sepsis through regulating inflammation and coagulation

BACKGROUND

Sepsis is an infection-induced aggressive and life-threatening organ dysfunction with high morbidity and mortality worldwide. Infection-associated inflammation and coagulation promote the progression of adverse outcomes in sepsis. Here, we report that phospho-Tyr705 of STAT3 (pY-STAT3), not total STAT3, contributes to systemic inflammation and coagulopathy in sepsis.

METHODS

Cecal ligation and puncture (CLP)-induced septic mice were treated with BP-1-102, Napabucasin, or vehicle control respectively and then assessed for systemic inflammation, coagulation response, lung function and survival. Human pulmonary microvascular endothelial cells (HPMECs) and Raw264.7 cells were exposed to lipopolysaccharide (LPS) with pharmacological or genetic inhibition of pY-STAT3. Cells were assessed for inflammatory and coagulant factor expression, cell function and signaling.

RESULTS

Pharmacological inhibition of pY-STAT3 expression by BP-1-102 reduced the proinflammatory factors, suppressed coagulation activation, attenuated lung injury, alleviated vascular leakage and improved the survival rate in septic mice. Pharmacological or genetic inhibition of pY-STAT3 diminished LPS-induced cytokine production in macrophages and protected pulmonary endothelial cells via the IL-6/JAK2/STAT3, NF-κB and MAPK signaling pathways. Moreover, the increase in procoagulant indicators induced by sepsis such as tissue factor (TF), the thrombin-antithrombin complex (TAT) and D-Dimer were down-regulated by pY-STAT3 inhibition.

CONCLUSIONS

Our results revealed a therapeutic role of pY-STAT3 in modulating the inflammatory response and defective coagulation during sepsis. Video Abstract.

Successful reversal of ovarian hyperstimulation syndrome in a mouse model by rapamycin, an mTOR pathway inhibitor

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening, iatrogenic complication of ovarian stimulation in assisted reproduction technology. This complex syndrome is characterised by enlarged ovaries with multiple corpora luteum, elevated sex steroid hormones in serum and increased capillary permeability. Until now, the pathogenesis of OHSS remains obscure, and no absolute strategy can fully prevent OHSS without any side effect on ovulation and clinical pregnancy. Using cultured human or mouse granulosa cells, our study revealed the time-dependent activation of the mTOR signaling pathway after human chorionic gonadotropin (hCG) treatment. The involvement of the mTOR signaling pathway was also observed in the development of OHSS in a mouse model. Selectively inhibiting mTOR signals by only two injections of rapamycin (2 mg/kg body weight), before or just after hCG treatment, significantly reduced vascular leakage and the severity of OHSS symptoms. Although ovarian angiogenesis was significantly inhibited, rapamycin could not decrease the elevated levels of vascular endothelial growth factor, IL-6 and IL-11 in OHSS ovaries. Further study showed the functional roles of the mTOR signaling pathway in the hyperstimulation-induced ovarian extracellular matrix remodeling as the expression of α2M, a broad proteolytic inhibitor in both ovary and serum, was dramatically decreased after rapamycin treatment. Since a single injection of rapamycin during superovulation had no side effects on ovulation and early embryonic development, we propose rapamycin may be a good candidate to lower and prevent the risk of OHSS in the future.

Plasma pentraxin 3 is higher in early ovarian hyperstimulation syndrome than in uncomplicated in vitro fertilization cycle of high-risk women

Purpose

Pentraxin 3 (PTX3) is a locally secreted, quicker responsive pro-inflammatory protein than C-reactive protein (CRP). We evaluated the value of PTX3 in the prediction of ovarian hyperstimulation syndrome (OHSS), a severe complication of in vitro fertilization (IVF).

Methods

This two-year prospective follow-up study included 27 women with uncomplicated IVF-cycles (IVF group) and 31 patients diagnosed with moderate or severe early OHSS (OHSS group). PTX3 was analysed from follicular fluid (FF) and serial blood samples with enzyme-linked immunoassay and CRP with particle-enhanced immunoturbidimetric assay. The value of PTX3 and CRP in detecting OHSS was examined with receiver operating characteristic (ROC) curve analysis and expressed as the area under the curve (AUC).

Results

The circulating PTX3 level peaked at two days after oocyte pick-up (OPU2), and in the OHSS group the level was 1.9 times higher (P = 0.006) than in the IVF group. However, in ROC curve analysis PTX3 (AUC 0.79, best cut off 1.1 µg/L) was not superior to CRP (AUC 0.87; best cut off 9.5 mg/L) in predicting early OHSS. In the IVF group, the FF-PTX3 concentration was 15–20 times higher than in the plasma. PTX3 level at OPU2 correlated with the number of punctured follicles (r = 0.56, n = 22, P = 0.006). Triggering with human chorionic gonadotrophin or early pregnancy had no effect on PTX3 level.

Conclusion

The elevated PTX3 concentration in OHSS at OPU2, when freeze-all embryos strategy is still possible to consider, indicates that PTX3 level could provide additional benefit in the risk assessment for early OHSS.

Adipose Tumor Microenvironment

The term "adipose tissue" represents a multicellular and multifunctional organ involved in lipid storage, in hormone and temperature regulation, and in the protection of bones and vital organs from impact-based damage. Emerging evidence now suggests a more malignant role of adipose tissue in promoting cancer onset and progression via the release of secreted factors such as interleukin-6 (IL6) and extracellular vesicles (EVs). These adipose-source factors subsequently affect various aspects of tumorigenesis and/or cancer progression by either directly enhancing the tumor cell oncogenic phenotype or indirectly by the stimulating adjacent normal cells to adopt a more pro-cancer phenotype. Due to the recent growing interest in the role of IL6 and EVs released by adipose tissue in cancer promotion and progression, we are focusing on the protumorigenic impact of fat tissue via IL6 and EV secretion.

Effect and Relationship of Seasons on the High Risk of Ovarian Hyperstimulation Syndrome After Oocyte Retrieval in Patients With Polycystic Ovary Syndrome

OBJECTIVE

To investigate the effect of seasons on the incidence of high risk of ovarian hyperstimulation syndrome (OHSS) after in oocyte retrieval in patients with polycystic ovarian syndrome (PCOS) and to establish a nomogram to predict the risk of OHSS.

DESIGN

Single-center, retrospective study.

SETTING

University-affiliated reproductive medicine center.

PATIENTS

A total of 2,030 infertility patients with PCOS underwent the follicular phase long-acting long protocol IVF/ICSI in the reproductive medicine center from January 2017 to December 2019.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Logistic regression analysis was used to analyze the factors associated with a high risk of OHSS. We established a nomogram to predict the risk of OHSS in infertility patients with PCOS after oocyte retrieval.

RESULTS

The incidence of patients at high risk of OHSS was significantly different from season-to-season and was especially higher in the summer and winter. Multivariate logistic analysis showed that gonadotropin dosage, number of retrieved oocytes, estradiol level, average bilateral ovarian diameter on the day human chorionic gonadotropin was administered, type of infertility, and average temperature were independent risk factors for OHSS after oocyte retrieval in PCOS patients. Based on the above independent risk factors, we constructed a prediction model for OHSS risk. To evaluate the efficiency of the prediction model, we calculated the C-index (0.849), area under the receiver operating characteristic curve (0.849), and internal validation C-index (0.846). Decision curve analysis suggested that the prediction model exhibited significant net benefits.

CONCLUSIONS

The incidence of PCOS patients at high risk for OHSS after oocyte retrieval fluctuated with seasonal temperature changes, and was significantly higher in extreme climates. The prediction model had favorable predictive performance and clinical application value.

Modelling Macular Edema: The Effect of IL-6 and IL-6R Blockade on Human Blood-Retinal Barrier Integrity In Vitro

Purpose

Macular edema (ME) is a leading cause of visual loss in a range of retinal diseases and despite the use of antivascular endothelial growth factor (anti-VEGF) agents, its successful treatment remains a major clinical challenge. Based on the indirect clinical evidence that interleukin-6 (IL-6) is a key additional candidate mediator of ME, we interrogated the effect of IL-6 on blood–retinal barrier (BRB) integrity in vitro.

Methods

Human retinal pigment epithelial cell (ARPE-19) and human retinal microvascular endothelial cell (HRMEC) monolayers were used to mimic the outer and inner BRB, respectively. Their paracellular permeability was assessed by measuring the passive permeation of 40 kDa fluorescein isothiocyanate (FITC)-dextran across confluent cells in the presence of IL-6. Transendothelial/epithelial electrical resistance (TEER) then was measured and the distribution of the tight junction protein ZO-1 was assessed by immunofluorescence using confocal microscopy.

Results

Treatment with IL-6 for 48 hours significantly increased the diffusion rate of FITC-dextran, decreased TEER, and disrupted the distribution of ZO-1 in ARPE-19 cells, which constitutively express the IL-6 transmembrane receptor, and this was reversed with IL-6R blockade. In contrast, IL-6 did not affect the paracellular permeability, TEER, or ZO-1 distribution in HRMECs.

Conclusions

These in vitro data support the hypothesis that IL-6 reversibly disrupts the integrity of ARPE-19 cells, but it does not affect HRMECs.

Translational Relevance

IL-6 is a candidate therapeutic target in the treatment of outer BRB driven ME.

Functional Characterization of Colon Cancer-Associated Mutations in ADAM17: Modifications in the Pro-Domain Interfere with Trafficking and Maturation

Colorectal cancer is one of the most commonly diagnosed malignancies in the Western world and is associated with elevated expression and activity of epidermal growth factor receptors (EGF-R). The metalloproteinase ADAM17 is involved in EGF-R activation by processing EGF-R ligands from membrane-bound pro-ligands. Underlining the link between colon cancer and ADAM17, genetic intestinal cancer models in ADAM17-deficient mice show a reduced tumor burden. In this study, we characterize point mutations within the ADAM17 gene found in the tissue of colon cancer patients. In order to shed light on the role of ADAM17 in cancer development, as well as into the mechanisms that regulate maturation and cellular trafficking of ADAM17, we here perform overexpression studies of four ADAM17 variants located in the pro-, membrane-proximal- and cytoplasmic-domain of the ADAM17 protein in ADAM10/17-deficient HEK cells. Interestingly, we found a cancer-associated point mutation within the pro-domain of ADAM17 (R177C) to be most impaired in its proteolytic activity and trafficking to the cell membrane. By comparing this variant to an ADAM17 construct lacking the entire pro-domain, we discovered similar functional limitations and propose a crucial role of the pro-domain for ADAM17 maturation, cellular trafficking and thus proteolytic activity.

Vasculature Remodeling in a Rat Model of Cerebral Ischemia. The Fate of the BrdU-Labeled Cells Prior to Stroke

Despite the clinical significance of post-stroke angiogenesis, a detailed phenotypic analysis of pre-stroke vascular remodeling and post-stroke angiogenesis had not yet been done in a model of focal ischemia. In this study, using BrdU-labeling of proliferating cells and immunofluorescence of pre- and post-stroke rats, we found that, (i) BrdU administered before stroke was incorporated preferentially into the nuclei of endothelial cells lining the lumen of existing blood vessels and newly born neurons in the dentate gyrus but not in the subventricular zone or proliferating microglia, (ii) BrdU injection prior to stroke led to the patchy distribution of the newly incorporated endothelial cells into existing blood vessels of the adult rat brain, (iii) BrdU injection prior to stroke specifically labeled neuronal precursors cells in a region of soft tissue beyond the inhibitory scar, which seems to be permissive to regenerative events, (iv) BrdU injection after stroke led to labeling of endothelial cells crossing or detaching from the disintegrating blood vessels and their incorporation into new blood vessels in the stroke region, scar tissue and the region beyond, (v) BrdU injection after stroke led to specific incorporation of BrdU-positive nuclei into the "pinwheel" architecture of the ventricular epithelium, (vi) blood vessels in remote areas relative to the infarct core and in the contralateral non-lesioned cortex, showed co-labeled BrdU/RECA⁺ endothelial cells shortly after the BrdU injection, which strongly suggests a bone marrow origin of the endothelial cells. In the damaged cortex, a BrdU/prolyl 4-hydroxylase beta double labeling in the close proximity to collagen IV-labeled basement membrane, suggests that, in addition to bone marrow derived endothelial cells, the disintegrating vascular wall itself could also be a source of proliferating endothelial cells, (vii) By day 28 after stroke, new blood vessels were observed in the perilesional area and the scar tissue region, which is generally considered to be resistant to regenerative events. Finally, (viii) vigorous angiogenesis was also detected in a region of soft tissue, also called "islet of regeneration," located next to the inhibitory scar. Conclusion: BrdU administered prior to, and after stroke, allows to investigate brain vasculature remodeling in the adult brain.

Inhibition of interleukin-6 trans-signaling prevents inflammation and endothelial barrier disruption in retinal endothelial cells

Vascular inflammation plays a critical role in the pathogenesis of diabetic retinopathy. Recently, Interleukin-6 (IL-6) trans-signaling via soluble IL-6 receptor (sIL-6R) has emerged as a prominent regulator of inflammation in endothelial cells. This study was designed to test the hypothesis that selective inhibition of the IL-6 trans-signaling pathway will attenuate inflammation and subsequent barrier disruption in retinal endothelial cells. Human retinal endothelial cells (HRECs) were exposed to IL-6 and sIL-6R to induce IL-6 trans-signaling and the commercially available compound sgp130Fc (soluble gp-130 fused chimera) was used to selectively inhibit IL-6 trans-signaling. IL-6 trans-signaling activation caused a significant increase in STAT3 phosphorylation, expression of adhesion molecules, ROS production and apoptosis in HRECs whereas a significant decrease in mitochondrial membrane potential and NO production was observed in IL-6 trans-signaling activated cells. These changes were not observed in cells pre-treated with sgp130Fc. IL-6 trans-signaling activation was sufficient to cause barrier disruption in endothelial monolayers and pre-treatment of HRECs with sgp130Fc, maintained endothelial barrier function similar to that of untreated cells. Thus, in conclusion, these results indicate that IL-6 trans-signaling is an important mediator of inflammation, apoptosis and barrier disruptive effects in the retinal endothelial cells and inhibition of the IL-6 trans-signaling pathway using sgp130-Fc attenuates vascular inflammation and endothelial barrier disruption.

Liver X Receptors: A Possible Link between Lipid Disorders and Female Infertility

A close relationship exists between cholesterol and female reproductive physiology. Indeed, cholesterol is crucial for steroid synthesis by ovary and placenta, and primordial for cell structure during folliculogenesis. Furthermore, oxysterols, cholesterol-derived ligands, play a potential role in oocyte maturation. Anomalies of cholesterol metabolism are frequently linked to infertility. However, little is known about the molecular mechanisms. In parallel, increasing evidence describing the biological roles of liver X receptors (LXRs) in the regulation of steroid synthesis and inflammation, two processes necessary for follicle maturation and ovulation. Both of the isoforms of LXRs and their bona fide ligands are present in the ovary. LXR-deficient mice develop late sterility due to abnormal oocyte maturation and increased oocyte atresia. These mice also have an ovarian hyper stimulation syndrome in response to gonadotropin stimulation. Hence, further studies are necessary to explore their specific roles in oocyte, granulosa, and theca cells. LXRs also modulate estrogen signaling and this could explain the putative protective role of the LXRs in breast cancer growth. Altogether, clinical studies would be important for determining the physiological relevance of LXRs in reproductive disorders in women.

In vivo and in vitro analyses of the effects of a novel high-nitrogen low-nickel coronary stent on reducing in-stent restenosis

Currently, percutaneous coronary intervention is an important treatment for coronary heart disease. However, the in-stent restenosis rate is still approximately 10–30% after stenting. Nickel ions from the stent are considered to be associated with in-stent restenosis. Therefore, in the present study, we quantitatively evaluated in-stent restenosis after implanting the novel high-nitrogen low-nickel coronary stent (HNS) and studied the mechanism underlying the reduction in in-stent restenosis by using ELISA and Western blot. The in vivo results showed that the HNS could significantly reduce neointima formation and inflammation as compared to SUS316L stents (316L) at 180 days after implantation in porcine coronary arteries and that vascular endothelial growth factor-A expression in porcine coronary arteries after HNS implantation also decreased. The in vitro results showed that, in the case of the HNS, human umbilical vein endothelial cell (HUVEC) proliferation was lower and lesser IL-6 release was noted from HUVECs at one and three days after culture than in the 316L group. Furthermore, p-STAT3 expression in HUVECs on the HNS surface was downregulated after culture for seven days. Thus, we conclude that the HNS could be a promising alternative coronary stent for percutaneous coronary intervention.

Ovarian Follicular Theca Cell Recruitment, Differentiation, and Impact on Fertility: 2017 Update

The major goal of this review is to summarize recent exciting findings that have been published within the past 10 years that, to our knowledge, have not been presented in detail in previous reviews and that may impact altered follicular development in polycystic ovarian syndrome (PCOS) and premature ovarian failure in women. Specifically, we will cover the following: (1) mouse models that have led to discovery of the derivation of two precursor populations of theca cells in the embryonic gonad; (2) the key roles of the oocyte-derived factor growth differentiation factor 9 on the hedgehog (HH) signaling pathway and theca cell functions; and (3) the impact of the HH pathway on both the specification of theca endocrine cells and theca fibroblast and smooth muscle cells in developing follicles. We will also discuss the following: (1) other signaling pathways that impact the differentiation of theca cells, not only luteinizing hormone but also insulinlike 3, bone morphogenic proteins, the circadian clock genes, androgens, and estrogens; and (2) theca-associated vascular, immune, and fibroblast cells, as well as the cytokines and matrix factors that play key roles in follicle growth. Lastly, we will integrate what is known about theca cells from mouse models, human-derived theca cell lines from patients who have PCOS and patients who do not have PCOS, and microarray analyses of human and bovine theca to understand what pathways and factors contribute to follicle growth as well as to the abnormal function of theca.

Interleukin-6 Family Cytokines

The interleukin (IL)-6 family cytokines is a group of cytokines consisting of IL-6, IL-11, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), oncostatin M (OSM), cardiotrophin 1 (CT-1), cardiotrophin-like cytokine (CLC), and IL-27. They are grouped into one family because the receptor complex of each cytokine contains two (IL-6 and IL-11) or one molecule (all others cytokines) of the signaling receptor subunit gp130. IL-6 family cytokines have overlapping but also distinct biologic activities and are involved among others in the regulation of the hepatic acute phase reaction, in B-cell stimulation, in the regulation of the balance between regulatory and effector T cells, in metabolic regulation, and in many neural functions. Blockade of IL-6 family cytokines has been shown to be beneficial in autoimmune diseases, but bacterial infections and metabolic side effects have been observed. Recent advances in cytokine blockade might help to minimize such side effects during therapeutic blockade.

Interleukin-6 promotes a sustained loss of endothelial barrier function via Janus kinase-mediated STAT3 phosphorylation and de novo protein synthesis

Vascular leakage is a hallmark of the inflammatory response. Acute changes in endothelial permeability are due to posttranslational changes in intercellular adhesion and cytoskeleton proteins. However, little is known about the mechanisms leading to long-term changes in vascular permeability. Here, we show that interleukin-6 (IL-6) promotes an increase in endothelial monolayer permeability that lasts over 24 h and demonstrate that activation of Src and MEK/ERK pathways is required only for short-term increases in permeability, being dispensable after 2 h. In contrast, Janus kinase (JAK)-mediated STAT3 phosphorylation at Y705 (but not S727) and de novo synthesis of RNA and proteins are required for the sustained permeability increases. Loss of junctional localization of VE-cadherin and ZO-1 is evident several hours after the maximal IL-6 response, thus suggesting that these events are a consequence of IL-6 signaling, but not a cause of the increased permeability. Understanding the mechanisms involved in sustaining vascular permeability may prove crucial to allow us to directly target vascular leakage and minimize tissue damage, thus reducing the rates of mortality and chronic sequelae of excessive edema. Targeting endothelial-specific mechanisms regulating barrier function could provide a new therapeutic strategy to prevent vascular leakage while maintaining the immune response and other beneficial aspects of the inflammatory response that are required for bacterial clearance and tissue repair.

Dissecting Interleukin-6 Classic- and Trans-Signaling in Inflammation and Cancer

Interleukin-6 is a cytokine synthesized by many cells in the human body. IL-6 binds to a membrane bound IL-6R, which is only present on hepatocytes, some epithelial cells and some leukocytes. The complex of IL-6 and IL-6R binds to the ubiquitously expressed receptor subunit gp130, which forms a homodimer and thereby initiates intracellular signaling via the JAK/STAT and the MAPK pathways. IL-6R expressing cells can cleave the receptor protein to generate a soluble IL-6R (sIL-6R), which can still bind IL-6 and can associate with gp130 and induce signaling even on cells, which do not express IL-6R. This paradigm has been called IL-6 trans-signaling whereas signaling via the membrane bound IL-6R is referred to as classic signaling. We have generated several molecular tools to differentiate between IL-6 classic- and trans-signaling and to analyze the consequence of cellular IL-6 signaling in vivo.

IL-6 Trans-Signaling Links Inflammation with Angiogenesis in the Peritoneal Membrane

Vascular endothelial growth factor (VEGF) is implicated in the peritoneal membrane remodeling that limits ultrafiltration in patients on peritoneal dialysis (PD). Although the exact mechanism of VEGF induction in PD is unclear, VEGF concentrations in drained dialysate correlate with IL-6 levels, suggesting a link between these cytokines. Human peritoneal mesothelial cells (HPMCs), the main source of IL-6 and VEGF in the peritoneum, do not bear the cognate IL-6 receptor and are thus unable to respond to classic IL-6 receptor signaling. Here, we investigated whether VEGF release by HPMCs is controlled by IL-6 in combination with its soluble receptor (IL-6 trans-signaling). Although treatment with either IL-6 or soluble IL-6 receptor (sIL-6R) alone had no effect on VEGF production, stimulation of HPMCs with IL-6 in combination with sIL-6R promoted VEGF expression and secretion through a transcriptional mechanism involving STAT3 and SP4. Conditioned medium from HPMCs cultured with IL-6 and sIL-6R promoted angiogenic endothelial tube formation, which could be blocked by silencing SP4. In vivo, induction of peritoneal inflammation in wild-type and IL-6-deficient mice showed IL-6 involvement in the control of Sp4 and Vegf expression and new vessel formation, confirming the role of IL-6 trans-signaling in these processes. Taken together, these findings identify a novel mechanism linking IL-6 trans-signaling and angiogenesis in the peritoneal membrane.

Critical Ovarian Hyperstimulation Syndrome After In Vitro Fertilization Treatment in a Renal Transplant Recipient: A Case Report

OBJECTIVE

The study sought to describe a case of critical ovarian hyperstimulation syndrome (OHSS) after in vitro fertilization treatment in a renal transplant recipient.

PATIENT

A 35-year-old woman with a 5-year history of renal transplantation underwent in vitro fertilization treatment with a midluteal pituitary downregulation regimen.

RESULT

There are only 7 cases published regarding successful pregnancies outcomes after in vitro fertilization treatment in renal transplant recipients. In the most of the case reports, there was no deterioration of graft function. However, our patient developed critical OHSS. After effective treatment, her serum creatinine level decreased from 668 μmol/L to baseline.

CONCLUSIONS

Our case demonstrates that the highly specialized care and close cooperation of transplantation and perinatology teams are required when undergoing in vitro fertilization treatment in renal transplant recipients.

C-reactive protein response is higher in early than in late ovarian hyperstimulation syndrome

OBJECTIVES

Many in vitro fertilization (IVF) complications are inflammatory by nature, some of which are even life-threatening. We evaluated the response of C-reactive protein (CRP) in IVF complications, especially in early and late ovarian hyperstimulation syndrome (OHSS), to support clinical decision making in gynecological emergency policlinics.

STUDY DESIGN

In a prospective two-year study at Helsinki University Hospital, Finland, we recruited patients with IVF complications including moderate or severe OHSS (n=47 patients: 36 early and 14 late OHSS cases), or other IVF complications (n=13). As controls, we recruited women in an uncomplicated IVF cycle (n=27). Serial blood samples (CRP, blood count, platelets, albumin, estradiol, creatinine, and electrolytes) were collected from patients upon admission to the emergency polyclinic and during and after treatment on the ward, and from the controls prior, during, and after the IVF protocol. All samples were categorized according to oocyte pick-up (OPU). The statistics included comparisons between and within the study groups, and receiver-operating characteristic (ROC) curve analysis for diagnostic accuracy of CRP for early OHSS at emergency polyclinics.

RESULTS

On admission, CRP did not differentiate OHSS from other IVF complications, but CRP was higher in early (median 21; IQR 8-33mg/L) than in late (6; 3-9mg/L, p=0.001) OHSS. In ROC analysis for CRP (12mg/L), the area under the curve (AUC) was 0.74 (p=0.001) with sensitivity of 69% and specificity of 71% for early OHSS. CRP was significantly higher (28; 10-46mg/L) in patients with early OHSS two days after oocyte pick-up (OPU) than in the controls (5; <3-9mg/L, p<0.001). The level normalized by 12 days, similarly to the controls. On the ward, the peak CRP was higher if early OHSS was complicated with infection (108; 49-166mg/L) than without infection (20; 8-32mg/L, p=0.001). Late OHSS was associated with hypoalbuminemia (19.6; 16.2-23.1g/L, p<0.001) and thrombocytosis (494; 427-561 E9/L, p=0.004; comparisons to early OHSS).

CONCLUSIONS

Early OHSS associates with a distinct rise in CRP level beyond that induced by uncomplicated oocyte pick-up, whereas the CRP levels in late OHSS are comparable to those in the control cycles. CRP identifies, but cannot distinguish IVF complications.

Enhanced Inflammatory Transcriptome in the Granulosa Cells of Women With Polycystic Ovarian Syndrome

CONTEXT

Polycystic ovarian syndrome (PCOS), the most common endocrine disorder of reproductive-aged women, is associated with systemic low-grade inflammation.

OBJECTIVE

We propose that increased or altered intrafollicular inflammatory reactions also occur in periovulatory follicles of PCOS patients.

DESIGN

Gene profiling and quantitative PCR (qPCR) analyses in granulosa-lutein cells (GCs) collected from PCOS and non-PCOS women undergoing in vitro fertilization were compared with serum and follicular fluid (FF) levels of cytokines and chemokines.

SETTING

This was a university-based study.

PATIENTS

Twenty-one PCOS and 45 control patients were recruited: demographic, hormone, body mass index, and pregnancy outcomes were abstracted from patient data files.

INTERVENTIONS

GC cytokine/chemokine mRNAs were identified and analyzed by gene-chip microarrays/qPCR before and after culture with human chorionic gonadotropin, DHT, IL-6, or IL-8; serum/FF cytokine levels were also analyzed.

MAIN OUTCOME MEASURES

Relative serum/FF cytokine levels and GC cytokine expression before and after culture were compared and related to body mass index.

RESULTS

The following results were found: 1) PCOS GCs express elevated transcripts encoding cytokines, chemokines, and immune cell markers, 2) based on gene profiling and qPCR analyses, obese PCOS patients define a distinct PCOS disease subtype with the most dramatic increases in proinflammatory and immune-related factors, and 3) human chorionic gonadotropin and DHT increased cytokine production in cultured GCs, whereas cytokines augmented cytokine and vascular genes, indicating that hyperandrogenism/elevated LH and obesity in PCOS women augment intrafollicular cytokine production.

CONCLUSIONS

Intrafollicular androgens and cytokines likely comprise a local regulatory loop that impacts GC expression of cytokines and chemokines and the presence of immune cells; this loop is further enhanced in the obese PCOS subtype.

Diminution of signal transducer and activator of transcription 3 signaling inhibits vascular permeability and anaphylaxis

BACKGROUND

During IgE-mediated immediate hypersensitivity reactions, vascular endothelial cells permeabilize in response to mast cell mediators. We have demonstrated previously that patients and mice with signal transducer and activator of transcription 3 (STAT3) mutations (autosomal dominant hyper-IgE syndrome [AD-HIES]) are partially protected from anaphylaxis.

OBJECTIVES

We sought to study the mechanism by which STAT3 contributes to anaphylaxis and determine whether small-molecule inhibition of STAT3 can prevent anaphylaxis.

METHODS

Using unaffected and STAT3-inhibited or genetic loss-of-function samples, we performed histamine skin prick tests, investigated the contribution of STAT3 to animal models of anaphylaxis, and measured endothelial cell permeability, gene and protein expression, and histamine receptor-mediated signaling.

RESULTS

Although mouse mast cell degranulation was minimally affected by STAT3 blockade, mast cell mediator-induced anaphylaxis was blunted in Stat3 mutant mice with AD-HIES and in wild-type mice subjected to small-molecule STAT3 inhibition. Histamine skin prick test responses were diminished in patients with AD-HIES. Human umbilical vein endothelial cells derived from patients with AD-HIES or treated with a STAT3 inhibitor did not signal properly through Src or cause appropriate dissolution of the adherens junctions made up of the proteins vascular endothelial-cadherin and β-catenin. Furthermore, we found that diminished STAT3 target microRNA17-92 expression in human umbilical vein endothelial cells from patients with AD-HIES is associated with increased phosphatase and tensin homolog (PTEN) expression, which inhibits Src, and increased E2F transcription factor 1 expression, which regulates β-catenin cellular dynamics.

CONCLUSIONS

These data demonstrate that STAT3-dependent transcriptional activity regulates critical components for the architecture and functional dynamics of endothelial junctions, thus permitting vascular permeability.

A potential role of endoplasmic reticulum stress in development of ovarian hyperstimulation syndrome

Vascular endothelial growth factor A (VEGFA) is crucial for ovarian angiogenesis, but its excess production induces ovarian hyperstimulation syndrome (OHSS). The aim of this study was to determine whether endoplasmic reticulum (ER) stress regulates VEGFA expression in granulosa cells, and whether its activation is involved in OHSS development. The expression of the spliced form of X-box-binding protein 1 [XBP1(S)], induced by ER stress, in cumulus cells from OHSS patients was higher than that in cumulus cells from non-OHSS patients. The ER stress inducer tunicamycin increased human chorionic gonadotropin-induced VEGFA production in human granulosa cells through the induction of XBP1(S), and pretreatment with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) abrogated the effect of tunicamycin. In OHSS model rats, TUDCA administration prevented the OHSS development, reducing ovarian VEGFA production. Our findings suggest ER stress upregulates hCG-induced VEGFA production in granulosa cells, indicating that ER stress might be involved in OHSS development.

Electroacupuncture decreases the progression of ovarian hyperstimulation syndrome in a rat model

This study aimed to elucidate the effect of electroacupuncture treatment on preventing early ovarian hyperstimulation syndrome (OHSS) and the potential mechanisms involved using an induced rat model. The ovarian response was examined by measuring ovary weight, vascular permeability, levels of inflammation (interleukin-6), tumour necrosis factor alpha, chemokine ligand 2 (also known as monocyte chemoactic protein 1), vascular endothelial growth factor and hormone concentrations (oestradiol, progesterone, testosterone and prolactin). Sprague-Dawley female rats underwent ovarian stimulation to induce OHSS. Hyperstimulated rats received consecutive electroacupuncture treatment from 3 days before the beginning of pregnant mare serum gonadotrophin treatment or the time point of pregnant mare serum gonadotrophin treatment respectively, and last until 3 days after HCG administration. Electroacupuncture treatment reduced ovary weight and vascular permeability in hyperstimulated rats. Electroacupuncture treatment also reduced the levels of serum steroid hormones (progesterone and testosterone), inflammatory cytokines (interleukin-6, tumour necrosis factor alpha and monocyte chemotactic protein 1 and vascular endothelial growth factor in hyperstimulated rats. The results indicate that electroacupuncture can modulate endocrine hormone secretion and affect the secretion of inflammatory cytokines and vascular endothelial growth factor, and thus prevent the progress of OHSS. Electroacupuncture may provide a simple and effective method for the prevention and treatment of OHSS.

Elevated Serum Levels of Soluble TNF Receptors and Adhesion Molecules Are Associated with Diabetic Retinopathy in Patients with Type-1 Diabetes

Aims. To examine the association of the serum levels of TNF receptors, adhesion molecules, and inflammatory mediators with diabetic retinopathy (DR) in T1D patients. Methods. Using the multiplex immunoassay, we measured serum levels of eight proteins in 678 T1D subjects aged 20–75 years. Comparisons were made between 482 T1D patients with no complications and 196 T1D patients with DR. Results. The levels of sTNFR-I, sTNFR-II, CRP, SAA, sgp130, sIL6R, sVCAM1, and sICAM1 were significantly higher in the T1D patients with DR as compared to T1D patients with no complications. Multivariate logistic regression analysis revealed significant association for five proteins after adjustment for age, sex, and disease duration (sTNFR-I: OR = 1.57, sgp130: OR = 1.43, sVCAM1: OR = 1.27, sICAM1: OR = 1.42, and CRP: OR = 1.15). Conditional logistic regression on matched paired data revealed that subjects in the top quartile for sTNFR-I (OR = 2.13), sTNFR-II (OR = 1.66), sgp130 (OR = 1.82), sIL6R (OR = 1.75), sVCAM1 (OR = 1.98), sICAM1 (OR = 2.23), CRP (OR = 2.40) and SAA (OR = 2.03), had the highest odds of having DR. Conclusions. The circulating markers of inflammation, endothelial injury, and TNF signaling are significantly associated with DR in patients with T1D. TNFR-I and TNFR-II receptors are highly correlated, but DR associated more strongly with TNFR-I in these patients.

Transcriptomics of post-stroke angiogenesis in the aged brain

Despite the obvious clinical significance of post-stroke angiogenesis in aged subjects, a detailed transcriptomic analysis of post-stroke angiogenesis has not yet been undertaken in an aged experimental model. In this study, by combining stroke transcriptomics with immunohistochemistry in aged rats and post-stroke patients, we sought to identify an age-specific gene expression pattern that may characterize the angiogenic process after stroke. We found that both young and old infarcted rats initiated vigorous angiogenesis. However, the young rats had a higher vascular density by day 14 post-stroke. “New-for-stroke” genes that were linked to the increased vasculature density in young animals included Angpt2, Angptl2, Angptl4, Cib1, Ccr2, Col4a2, Cxcl1, Lef1, Hhex, Lamc1, Nid2, Pcam1, Plod2, Runx3, Scpep1, S100a4, Tgfbi, and Wnt4, which are required for sprouting angiogenesis, reconstruction of the basal lamina (BL), and the resolution phase. The vast majority of genes involved in sprouting angiogenesis (Angpt2, Angptl4, Cib1, Col8a1, Nrp1, Pcam1, Pttg1ip, Rac2, Runx1, Tnp4, Wnt4); reconstruction of a new BL (Col4a2, Lamc1, Plod2); or tube formation and maturation (Angpt1, Gpc3, Igfbp7, Sparc, Tie2, Tnfsf10), had however, a delayed upregulation in the aged rats. The angiogenic response in aged rats was further diminished by the persistent upregulation of “inflammatory” genes (Cxcl12, Mmp8, Mmp12, Mmp14, Mpeg1, Tnfrsf1a, Tnfrsf1b) and vigorous expression of genes required for the buildup of the fibrotic scar (Cthrc1, Il6ra, Il13ar1, Il18, Mmp2, Rassf4, Tgfb1, Tgfbr2, Timp1). Beyond this barrier, angiogenesis in the aged brains was similar to that in young brains. We also found that the aged human brain is capable of mounting a vigorous angiogenic response after stroke, which most likely reflects the remaining brain plasticity of the aged brain.