Decreased plasma myonectin levels in female patients with type 2 diabetes mellitus and its correlation with lipid and glycemic parameters.

OBJECTIVE: Myonectin is a novel myokine which has significant implications on diabetes. This study aimed to investigate plasma myonectin levels in patients with type 2 diabetes mellitus (T2DM), and their correlation with body composition, lipid and glycemic parameters. PATIENTS AND METHODS: The study participants included 40 diabetic and 33 non-diabetic healthy adult Saudi females matched for their BMI and age. Body composition was assessed by bioelectrical impedance analysis. Fasting blood samples were used to investigate plasma myonectin levels by ELISA, along with lipid and glycemic parameters. RESULTS: We found that plasma myonectin levels were significantly decreased in diabetic patients (40.90±4.13 ng/ml, p<0.05) compared to non-diabetic participants (59.58±4.41). Diabetic patients with poor glycemic parameters had significantly decreased myonectin levels (35.18±4.03 ng/ml p<0.05) compared to non-diabetic healthy subjects. There was no significant difference in myonectin levels between diabetic patients with good glycemic control (55.76±8.09 ng/ml p>0.05) and non-diabetic healthy participants. Pearson correlation analysis indicated a significant negative correlation with fasting blood sugar (R=-0.366, p=0.001), HbA1c (R=-0.406, p<0.0001), triglycerides (R=-0.264, p=0.024), insulin (R=-0.278, p=0.017), and HOMA-IR (R=-0.409, p<0.0001). CONCLUSIONS: Our findings highlight an important aspect of myonectin in the pathophysiology of T2DM. They also show that myonectin has the potential to be a useful biomarker and therapeutic target in T2DM.

Adjunctive techniques for enhancing mandibular growth in Class II malocclusion.

Class II malocclusions are generally characterized by mandible retrusion. For this reason, forward bite jumping appliances, also known as functional appliances were originally designed to enhance mandibular forward projection. However, there is still insufficient evidence to support the effectiveness, predictability and stability of functional appliances in modifying mandibular growth. This article was aimed at presenting evidences and hypotheses that mandibular growth may be enhanced through the use of adjunctive methods in conjunction with functional appliances. In formulating our hypothesis, we considered relevant data, mostly derived from animal studies, concerning alternative methods, such as low-intensity ultrasound and light-emitting diode, as well as their related cellular and molecular mechanisms. According to the evidences covered in this article, we suggest that both methods are potentially effective, and theoretically able to act in synergistic way to enhance functional appliances treatment on mandibular and condylar additional growth. The rationale for the use of these methods as adjunctive therapies for mandibular underdevelopment is attributed to their abilities on stimulating angiogenesis, cell differentiation, proliferation, and hypertrophy, as well as enhancing matrix production and endochondoral bone formation, especially on the condyle of growing animals. This article also proposed a study design which would be able to either prove or refute our hypothesis. If ratified, it would represent a significant scientific accomplishment which provides support for further investigations to be carried out on well-designed clinical trials.

Tissue-engineered neogenesis of human-shaped mandibular condyle from rat mesenchymal stem cells.

The temporomandibular joint is susceptible to diseases and trauma that may ultimately lead to structural degeneration. Current approaches for replacing degenerated mandibular condyles suffer from deficiencies such as donor site morbidity, immunorejection, implant wear and tear, and pathogen transmission. The hypothesis of this study was that a human-shaped mandibular condyle can be tissue-engineered from rat mesenchymal stem cells (MSCs) encapsulated in a biocompatible polymer. Rat bone marrow MSCs were isolated and induced to differentiate into chondrogenic and osteogenic cells in vitro, and encapsulated in poly(ethylene glycol)-based hydrogel in two stratified layers molded into the shape of a cadaver human mandibular condyle. Eight weeks following in vivo implantation of the bilayered osteochondral constructs in the dorsum of immunodeficient mice, mandibular condyles formed de novo. Microscopic evaluation of the tissue-engineered mandibular condyle demonstrated two stratified layers of histogenesis of cartilaginous and osseous phenotypes. The current approach is being refined for ultimate therapeutic applications.