Does Diabetes Induce the Vascular Endothelial Growth Factor (VEGF) Expression in Periodontal Tissues? A Systematic Review

Effect of non-surgical treatment in diabetes-associated periodontitis on immune/inflammatory and oxidative stress biomarkers: A pilot study

AIMS

To investigate the effects of non-surgical periodontal treatment on the levels of cytokines, sIgA, antimicrobial peptides, oxidative and antioxidative agents in comparison between patients with and without diabetes.

METHODS

A case-control study that included patients (n = 45) with periodontitis who have or do not have diabetes. Cytokine concentrations in crevicular gingival fluid (GCF) and saliva were determined using LUMINEX and ELISA assays, respectively. Salivary levels of lysozyme, cathelicidin (LL-37), total antioxidant capacity (TAC) and total peroxide were determined colorimetrically before (T0) and one month after completion of periodontitis treatment (T1).

RESULTS

There were no significant differences in the concentrations of cytokines in GCF between the groups and T0 and T1. Salivary concentrations of lysozyme and IL-10 were significantly reduced in T1 compared to T0 in the diabetes group (p = 0.0260 and p = 0.0034, respectively), whilst TNF-α concentration was higher in T1 (p = 0.0443). The salivary concentrations of TNF-α observed in the non-diabetes group at T1 decreased at T0 (p = 0.0313). The salivary concentration of TNF-α was increased in the diabetes group compared to the non-diabetes group at T1 (p = 0.0008).

CONCLUSIONS

An improvement in salivary inflammatory status was observed in the group without diabetes, which was not found in the group with diabetes after non-surgical periodontal treatment.

Comparing the therapeutic influence of bone marrow Mesenchymal stem cells versus its derived exosomes against diabetic hepatopathy in rats

Diabetes mellitus (DM) is a chronic widespread metabolic disorder, involving a high blood glucose level which causes multiple serious complications including liver, kidney, brain and peripheral nerves damage. Due to the undesirable side effects of the anti-diabetic drugs, the current studies directed to use stem cells and exosomes to overcome the limitations of traditional therapy. We aimed to compare the antidiabetic effect of Bone marrow mesenchymal stem cells (BMMSCs) and its derived exosomes against diabetic hepatopathy induced by streptozotocin (STZ) in albino rats. Our study was conducted on 28 male albino rats divided into 4 groups {control negative non diabetic group, control positive diabetic group, exosomes treated group received (5 × 109 particle/rat) through tail vein twice per week for one month} and Stem cell treated group received (107) BMMSCs through tail vein twice per week for one month. Hepatic structure together with blood glucose level, liver function enzymes were assayed in addition to a lipid profile tests, oxidative stress, and gene expression. Both treated groups by exosomes and stem cells expressed significantly low levels of fasting blood glucose, liver function parameters (ALT, AST, ALP), lipid profile tests (cholesterol and triglycerides), lipid peroxidation index (MDA), with substantial reduction in IL-1β expression compared to diabetic group. Significantly downregulating the VEGF and elevation of eNOS genes and GSH which suggest the effective role provided by BMMSCs and its derived exosomes for treatment of diabetic hepatopathy. Although, the results of both groups showed near average outcomes, the exosome treated group significantly enhanced liver function enzymes and triglyceride, cholesterol level compared to stem cells treated group. These findings were reinforced by the histopathological and immunohistochemistry examination. The latter showed slight but non-significant improvements in VEGF, eNOS, and IL-1β expression. These minor differences together with practical advantages of exosomes make it preferable over BMMSCs in treatment of diabetic hepatopathy.

Evaluation of vascular endothelial growth factor levels in periodontal tissues of patients suffering from periodontitis and/or diabetes mellitus: An immunohistochemical study

Background and Objectives

Pathogenesis of periodontal diseases over the years has been a subject of discussion in the field of periodontology. Search is on for novel biomarkers that designate the presence or absence of the disease. Vascular endothelial growth factor (VEGF) is one such marker investigated recently which has been seen to increase both in periodontitis and diabetes. Hence, this study was under taken to evaluate and compare the VEGF levels in periodontal tissues of patients having either periodontitis or diabetes mellitus (DM) with those having both.

Materials and Methods

The study group was divided into the four groups of 25 patients in each group. Group A were patients having healthy periodontium and without any systemic diseases. Group B were patients having periodontitis without any systemic diseases. Group C were patients having both periodontitis and DM. Group D were patients having only DM without any periodontitis. The VEGF levels were graded into three grades of 0, 1 and 2. They were evaluated through immunohistochemistry in tissue samples obtained from all the groups.

Results

Healthy patients generally had Grade 0 level whereas patients having only periodontitis or only DM had primarily Grade 1. Most of the patients having both periodontitis and diabetes had Grade 2 level of VEGF.

Conclusion

The outcome of this cross-sectional study to assess the relationship between periodontitis, diabetes and VEGF levels is declarative toward a positive correlation between periodontitis, diabetes and increase in the VEGF levels.

The KDR Gene rs2071559 and the VEGF Gene rs6921438 May Be Associated with Diabetic Nephropathy in Caucasians with Type 2 Diabetes Mellitus

The aim of our study was to investigate an association between polymorphisms of either the VEGF (vascular endothelial growth factor) gene (rs6921438) or the KDR (kinase insert domain receptor) gene (rs2071559, rs2305948) and DN (diabetic nephropathy) in Caucasians with T2DM (type 2 diabetes mellitus). The second aim was to investigate the effect of either the VEGF gene (rs6921438) or the KDR gene (rs2071559, rs2305948) on the immune expression of either VEGF or KDR in the renal tissues of T2DM subjects (to test the functional significance of tested polymorphisms). The study included 897 Caucasians with T2DM for at least ten years (344 patients with DN and 553 patients without DN). Each subject was genotyped and analyzed for KDR (rs1617640, rs2305948) and VEGF (rs6921438) polymorphisms. Kidney tissue samples taken from 15 subjects with T2DM (autopsy material) were immunohistochemically stained for the expression of VEGF and KDR. We found that the rs2071559 KDR gene was associated with an increased risk of DN. In addition, the GG genotype of the rs6921438 VEGF gene had a protective effect. We found a significantly higher numerical area density of VEGF-positive cells in T2DM subjects with the A allele of the rs6921438-VEGF compared to the homozygotes for wild type G allele (7.0 ± 2.4/0.1 mm2 vs. 1.24 ± 0.5/0.1 mm2, respectively; p < 0.001). Moreover, a significantly higher numerical area density of KDR-positive cells was found in T2DM subjects with the C allele of rs2071559 (CC + CT genotypes) compared to the homozygotes for wild type T allele (9.7± 3.2/0.1 mm2 vs. 1.14 ± 0.5/0.1 mm2, respectively; p < 0.001) To conclude, our study showed that the presence of the C allele of the rs2071559 KDR gene was associated with a higher risk of DN, while the G allele of the rs6921438-VEGF conferred protection against DN in Slovenian T2DM subjects.

Porphyromonas gingivalis under palmitate-induced obesogenic microenvironment modulates the inflammatory transcriptional signature of macrophage-like cells

Metabolic diseases and low-grade chronic inflammation are interconnected: obese persons are at higher risk of developing periodontitis. However, the molecular mechanisms involved in the development and progression of periodontitis in an obesogenic microenvironment in response to periodontopathogens are still lacking. This study aims to investigate the combined effects of palmitate and Porphyromonas gingivalis on the secretion of pro-inflammatory cytokines and on transcriptional landscape modifications in macrophage-like cells. U937 macrophage-like cells were treated with palmitate and stimulated with P. gingivalis for 24h. Cytokines IL-1β, TNF-α and IL-6 were measured by ELISA in the culture medium and cell extracted RNA was submitted to a microarray analysis followed by Gene Ontology analyses. P. gingivalis, in presence of palmitate, potentiated IL-1β and TNF-α secretion in comparison to palmitate alone. Gene Ontology analyses also revealed that the combination palmitate-P. gingivalis potentiated the number of gene molecular functions implicated in the regulation of immune and inflammatory pathways compared to macrophages treated with palmitate alone. Our results provide the first comprehensive mapping of gene interconnections between palmitate and P. gingivalis during inflammatory responses in macrophage-like cells. These data highlight the importance of considering systemic conditions, specifically obesogenic microenvironment, in the management of periodontal disease in obese patients.

miRNAs as cornerstones in diabetic microvascular complications

Diabetes mellitus is usually accompanied by nephropathy, retinopathy, and neuropathy as microvascular complications. MicroRNAs (miRNAs) can affect the kidney, retina, and peripheral neurons through their implication in pathways involved in angiogenesis, inflammation, apoptosis, as well as fibrosis within these tissues and hence, play a crucial role in the pathogenesis of microvascular complications. In this review, the updated knowledge of the role of miRNAs in the pathogenesis of diabetic microvascular complications was summarized. PubMed Central was searched extensively to retrieve data from a wide range of reputable biomedical reports/articles published after the year 2000 to systematically collect and present a review of the key molecular pathways mediating the hyperglycemia-induced adverse effects on vascular tissues, particularly in persons with T2DM. In the present review, miR-126, miR-29b, and miR-125a are implicated in diabetes-induced microvascular complications, while miR-146a is found to be connected to all these complications. Also, vascular endothelial growth factors are noted to be the most impacted targets by miRNAs in all diabetic microvascular problems.

Biological Roles of Fibroblasts in Periodontal Diseases

Periodontal diseases include periodontitis and gingival overgrowth. Periodontitis is a bacterial infectious disease, and its pathological cascade is regulated by many inflammatory cytokines secreted by immune or tissue cells, such as interleukin-6. In contrast, gingival overgrowth develops as a side effect of specific drugs, such as immunosuppressants, anticonvulsants, and calcium channel blockers. Human gingival fibroblasts (HGFs) are the most abundant cells in gingival connective tissue, and human periodontal ligament fibroblasts (HPLFs) are located between the teeth and alveolar bone. HGFs and HPLFs are both crucial for the remodeling and homeostasis of periodontal tissue, and their roles in the pathogenesis of periodontal diseases have been examined for 25 years. Various responses by HGFs or HPLFs contribute to the progression of periodontal diseases. This review summarizes the biological effects of HGFs and HPLFs on the pathogenesis of periodontal diseases.

Novel Insight into the Mechanisms of the Bidirectional Relationship between Diabetes and Periodontitis

Periodontitis and diabetes are two major global health problems despite their prevalence being significantly underreported and underestimated. Both epidemiological and intervention studies show a bidirectional relationship between periodontitis and diabetes. The hypothesis of a potential causal link between the two diseases is corroborated by recent studies in experimental animals that identified mechanisms whereby periodontitis and diabetes can adversely affect each other. Herein, we will review clinical data on the existence of a two-way relationship between periodontitis and diabetes and discuss possible mechanistic interactions in both directions, focusing in particular on new data highlighting the importance of the host response. Moreover, we will address the hypothesis that trained immunity may represent the unifying mechanism explaining the intertwined association between diabetes and periodontitis. Achieving a better mechanistic insight on clustering of infectious, inflammatory, and metabolic diseases may provide new therapeutic options to reduce the risk of diabetes and diabetes-associated comorbidities.

Exploring the molecular role of endostatin in diabetic neuropathy

For over a decade, diabetic neuropathy has exhibited great emergence in diabetic patients. Though there are numerous impediments in understanding the underlying pathology it is not that enough to conclude. Initially, there was no intricate protocol for diagnosis as its symptoms mimic most of the neurodegenerative disorders and demyelinating diseases. Continuous research on this, reveals many pathological correlates which are also detectable clinically. The most important pathologic manifestation is imbalanced angiogenesis/neo-vascularization. This review is completely focused on established pathogenesis and anti-angiogenic agents which are physiological signal molecules by the origin. Those agents can also be used externally to inhibit those pathogenic pathways. Pathologically DN demonstrates the misbalanced expression of many knotty factors like VEGF, FGF2, TGFb, NF-kb, TNF-a, MMP, TIMP, and many minor factors. Their pathway towards the incidence of DN is quite interrelated. Many anti-angiogenic agents inhibit neovascularization to many extents, but out of them predominantly inhibition of angiogenic activity is shared by endostatin which is now in clinical trial phase II. It inhibits almost all angiogenic factors and it is possible because they share interrelated pathogenesis towards imbalanced angiogenesis. Endostatin is a physiological signal molecule produced by the proteolytic cleavage of collagen XVIII. It has also a broad research profile in the field of medical research and further investigation can show promising therapeutic effects for benefit of mankind.

Vascular Endothelial Growth Factor: A Translational View in Oral Non-Communicable Diseases

Vascular endothelial growth factors (VEGFs) are vital regulators of angiogenesis that are expressed in response to soluble mediators, such as cytokines and growth factors. Their physiologic functions include blood vessel formation, regulation of vascular permeability, stem cell and monocyte/macrophage recruitment and maintenance of bone homeostasis and repair. In addition, angiogenesis plays a pivotal role in chronic pathologic conditions, such as tumorigenesis, inflammatory immune diseases and bone loss. According to their prevalence, morbidity and mortality, inflammatory diseases affecting periodontal tissues and oral cancer are relevant non-communicable diseases. Whereas oral squamous cell carcinoma (OSCC) is considered one of the most common cancers worldwide, destructive inflammatory periodontal diseases, on the other hand, are amongst the most prevalent chronic inflammatory conditions affecting humans and also represent the main cause of tooth loss in adults. In the recent years, while knowledge regarding the role of VEGF signaling in common oral diseases is expanding, new potential translational applications emerge. In the present narrative review we aim to explore the role of VEGF signaling in oral cancer and destructive periodontal inflammatory diseases, with emphasis in its translational applications as potential biomarkers and therapeutic targets.