The effect of intravitreal anti-vascular endothelial growth factor injections on corneal endothelium in patients with diabetic macular oedema

PURPOSE

To evaluate the characteristics of corneal parameters in patients with diabetic macular oedema (DME) treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections.

METHODS

Participants in this study were 36 patients with DME, treated with either intravitreal ranibizumab (n = 16) or aflibercept (n = 20). All participants underwent best-corrected visual acuity (BCVA) measurement, optical coherence tomography and non-contact specular microscopy to evaluate corneal endothelium parameters (endothelial cell density-ECD, hexagonality, coefficient of variation of the cell size and central corneal thickness-CCT), at baseline and at months 6 and 12 after the first intravitreal injection. Comparisons between baseline and months 6 and 12 were performed.

RESULTS

There was no statistically significant difference regarding ECD, hexagonality, coefficient of variation of the cell size and CCT at month 6 and 12 post initial injection compared to baseline in patients with DME. BCVA improved significantly at month 6 and 12 compared to baseline (p < 0.001 for both comparisons). Central retinal thickness was significantly reduced at month 6 and 12 compared to baseline (p < 0.001 for both comparisons).

CONCLUSION

Intravitreal anti-VEGF injections in patients with DME were found not to affect corneal parameters, namely ECD, hexagonality, coefficient of variation of the cell size and CCT at the long-term follow-up of 12 months.

The Effect of Diabetes Mellitus on Corneal Endothelial Cells and Central Corneal Thickness: A Case-Control Study

PURPOSE

The aim of this study was to evaluate the characteristics of corneal endothelial cells and central corneal thickness (CCT) in patients with diabetes mellitus (DM), comparing them with those of healthy subjects (controls) and to determine potential factors affecting the corneal parameters in patients with DM.

METHODS

Participants in this study were 72 patients with DM and 88 healthy controls. Diabetic patients were further classified into groups depending on the severity of diabetic retinopathy (no retinopathy, mild, moderate, severe non-proliferative diabetic retinopathy, and proliferative diabetic retinopathy). All participants underwent non-contact specular microscopy to evaluate corneal endothelium parameters and CCT, while factors affecting endothelial cell density and CCT in patients with DM were also analyzed.

RESULTS

Patients with DM presented significantly decreased endothelial cell density compared to controls (2,297.9 ± 311.3 and 2,518.3 ± 243.7 cells/mm2, respectively; p < 0.001), while the two groups did not differ significantly in any other measured corneal parameter. In the diabetic group, the multivariate analysis showed a significant association between decreased endothelial cell density and increased HbA1c (p < 0.001), longer DM duration (p = 0.003), and more severe diabetic retinopathy status (p = 0.008).

CONCLUSION

DM seems to affect the corneal endothelium, since endothelial cell density was decreased in the diabetic group, while duration of disease, HbA1c levels, and severity of retinopathy were significantly associated with changes in endothelial cell density and should be taken into account.

Role of Hyperplasia of Gingival Lymphatics in Periodontal Inflammation

Lymphatic vessels are important for maintenance of tissue fluid homeostasis and afferent antigen transport. In chronic inflammation, lymphangiogenesis takes place and is characterized by lymphatic endothelial cell proliferation and lymphatic hyperplasia. Vascular endothelial growth factor C (VEGFC) is the main known lymphangiogenic growth factor, and its expression is increased in periodontitis, a common chronic infectious disease that results in tissue destruction and alveolar bone loss. The role of lymphangiogenesis during development of periodontitis is unknown. Here, we test if transgenic overexpression of epithelial VEGFC in a murine model is followed by hyperplasia of lymphatic vessels in oral mucosa and if the lymphatic drainage capacity is altered. We also test if lymphatic hyperplasia protects against periodontal disease development. Transgenic keratin 14 (K14)-VEGFC mice had significant hyperplasia of lymphatics in oral mucosa, including gingiva, without changes in blood vessel vasculature. The basal lymph flow was normal but slightly lower than in wild-type mice when oral mucosa was challenged with lipopolysaccharide from Porphyromonas gingivalis. Under normal conditions, K14-VEGFC mice exhibited an increased number of neutrophils in gingiva, demonstrated enhanced phagocyte recruitment in the cervical lymph nodes, and had more alveolar bone when compared with their wild-type littermates. After induction of periodontitis, no strain differences were observed in the periodontal tissues with respect to granulocyte recruitment, bone resorption, angiogenesis, cytokines, and bone-related protein expressions or in draining lymph node immune cell proportions and vascularization. We conclude that overexpression of VEGFC results in hyperplastic lymphatics, which do not enhance lymphatic drainage capacity but facilitate phagocyte transport to draining lymph nodes. Hyperplasia of lymphatics does not protect against development of ligature-induced periodontitis.

VEGFR-2 reduces while combined VEGFR-2 and -3 signaling increases inflammation in apical periodontitis

BACKGROUND

In apical periodontitis, oral pathogens provoke an inflammatory response in the apical area that induces bone resorptive lesions. In inflammation, angio- and lymphangiogenesis take place. Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key players in these processes and are expressed in immune cells and endothelial cells in the lesions.

OBJECTIVE

We aimed at testing the role of VEGFR-2 and -3 in periapical lesion development and investigated their role in lymphangiogenesis in the draining lymph nodes.

DESIGN

We induced lesions by pulp exposure in the lower first molars of C57BL/6 mice. The mice received IgG injections or blocking antibodies against VEGFR-2 (anti-R2), VEGFR-3 (anti-R3), or combined VEGFR-2 and -3, starting on day 0 until day 10 or 21 post-exposure.

RESULTS

Lesions developed faster in the anti-R2 and anti-R3 group than in the control and anti-R2/R3 groups. In the anti-R2 group, a strong inflammatory response was found expressed as increased number of neutrophils and osteoclasts. A decreased level of pro-inflammatory cytokines was found in the anti-R2/R3 group. Lymphangiogenesis in the draining lymph nodes was inhibited after blocking of VEGFR-2 and/or -3, while the largest lymph node size was seen after anti-R2 treatment.

CONCLUSIONS

We demonstrate an anti-inflammatory effect of VEGFR-2 signaling in periapical lesions which seems to involve neutrophil regulation and is independent of angiogenesis. Combined signaling of VEGFR-2 and -3 has a pro-inflammatory effect. Lymph node lymphangiogenesis is promoted through activation of VEGFR-2 and/or VEGFR-3.

Leukocyte transmigration into tissue-engineered constructs is influenced by endothelial cells through Toll-like receptor signaling

Introduction

Inflammation plays a crucial role in tissue regeneration, wound healing, and the success of tissue-engineered constructs. The aim of this study was to investigate the influence of human umbilical vein endothelial cells (ECs) on leukocyte transmigration when co-cultured with primary human bone marrow-derived multipotent stromal cells (MSCs).

Methods

MSCs with and without ECs were cultured in poly (L-lactide-co-1, 5-dioxepan-2-one) (poly (LLA-co-DXO)) scaffolds for 1 week in vitro in a bioreactor system, after which they were implanted subcutaneously in non-obese diabetic/severe combined immunodeficient mice. After 1 and 3 weeks, scaffolds were retrieved, and the mRNA expression of interleukin 1-beta (IL-1β), IL-6, IL-10, hypoxia-inducible factor 1-alpha (HIF-1α), HIF-1β, and mammalian target of rapamycin was examined by real-time reverse transcription-polymerase chain reaction. Furthermore, immunofluorescent staining was performed for IL-1β, IL-6, neutrophils, and CD11b. In addition, Western blotting was done for IL-1β and IL-6. Leukocyte transmigration genes and genes in Toll-like receptor pathways, expressed by MSCs cultured in vitro with or without ECs, were further investigated with a microarray dataset.

Results

In vitro, genes involved in leukocyte transmigration and Toll-like receptor pathways were clearly influenced by the addition of ECs. Platelet/endothelial cell adhesion molecule-1 (PECAM-1) and cadherin-5 (CDH5), both genes involved in leukocyte transmigration, were expressed significantly higher in the MSC/EC group.

In vivo, the MSC/EC group showed higher mRNA expression of hypoxia-inducible factors HIF-1α and HIF-1β. The mRNA expression of anti-inflammatory cytokine IL-10 showed no significant difference, whereas the mRNA and protein expression of pro-inflammatory cytokines IL-1β and IL-6 were lower in the MSC/EC group. The quantitative analysis of immunofluorescent staining revealed a significant difference in the number of neutrophils migrating into constructs, with the highest density found in the MSC/EC group. The number of macrophages positive for IL-6 and CD11b was significantly reduced in the MSC/EC group.

Conclusions

The recruitment of leukocytes into tissue-engineered constructs with MSCs is strongly influenced by the addition of ECs via activation of leukocyte transmigration and Toll-like receptor pathways.

The radiographic localization of impacted maxillary canines: a comparison of methods

This study compared two different radiographic techniques for localization of impacted maxillary canines: vertical parallax (from a panoramic and a maxillary anterior occlusal radiograph) and magnification (from a single panoramic radiograph). The radiographs and the information regarding the impacted canines were obtained retrospectively from records of patients treated in the Day Stay Unit of the Eastman Dental Hospital. The two different radiographic techniques were tested blind and compared for localization of the impacted canine by six examiners. The 'gold standard' used for the radiographic comparisons was the true position of the canine as recorded at operation. The results showed a wide variation between the six examiners in the prediction of the canine position with the two different techniques. Localization with vertical parallax was more successful overall than with magnification, although the difference failed to reach significance. Seventy-six per cent of the impacted canines could be successfully located with vertical parallax and 66 per cent with magnification. Further analysis showed that, while almost 90 per cent of the palatally impacted canines could be correctly detected with both techniques, less than half of the buccal canines could be detected with parallax and only one in 10 buccal canines could be detected with magnification. If a canine is suspected to be buccally placed from its appearance on a panoramic film and cannot be palpated, further views are justified.