Anabolic role of lysyl oxidase like-2 in cartilage of knee and temporomandibular joints with osteoarthritis

Background

Lysyl oxidase like-2 (LOXL2) is a copper-dependent amine oxidase. Our previous studies showed that LOXL2 is elevated during mouse fracture healing. The goal of this study was to evaluate the potential of LOXL2 to act as an anabolic agent in cartilage affected by osteoarthritis (OA).

Methods

LOXL2 was visualized in tissues from human knee and hip joints and temporomandibular joints (TMJ) by immunofluorescence. The activity of LOXL2 in human articular and TMJ chondrocytes was assessed by cell-based assays, microarray analysis, and RT-qPCR, and LOXL2-mediated activation of NF-κB and extracellular signal-related kinase (ERK) signaling pathways was measured by western blotting. To examine LOXL2-induced effect in vivo, we implanted Matrigel-imbedded human chondrocytes into nude mice and exposed them to exogenous LOXL2 for 6 weeks. Finally, LOXL2-induced effects on collagen type 2 α1 (COL2A1) and phospho-SMAD2/3 were evaluated by immunofluorescence analysis.

Results

LOXL2 staining was detected in damaged regions of human TMJ, hip and knee joints affected by OA. Stimulation with transforming growth factor (TGF)-β1 upregulated LOXL2 expression, while pro-inflammatory cytokines IL-1β and TNF-α downregulated LOXL2, in human chondrocytes. Viral transduction of LOXL2 in OA chondrocytes increased the mRNA levels of chondroitin sulfate proteoglycan (CSPG4), aggrecan (ACAN), sex determining region Y-box containing gene 9 (SOX9), and COL2A1 but reduced the levels of extracellular matrix (ECM)-degrading enzymes matrix metalloproteinase (MMP)1, MMP3, and MMP13. Further, forced expression of LOXL2 promoted chondrogenic lineage-specific gene expression, increased the expression of COL2A1 in the presence of TNF-α, and inhibited chondrocyte apoptosis. LOXL2 expression also inhibited IL-1β-induced phospho-NF-κB/p65 and TGF-β1-induced ERK1/2 phosphorylation. Matrigel constructs of human chondrocytes from the knee joint and TMJ implanted in nude mice showed anabolic responses after LOXL2 transduction, including increased expression of SOX9, ACAN, and COL2A1. Finally, immunofluorescence staining revealed co-localization of LOXL2 with SOX9 in the nuclei of cells in the implants, decreased phospho-SMAD2/3, and increased COL2A1 staining.

Conclusion

Our results suggest that although LOXL2 is upregulated in cartilage affected by OA, this may be a protective response that promotes anabolism while inhibiting specific catabolic responses in the pathophysiology of OA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1388-8) contains supplementary material, which is available to authorized users.

Rice and chickpea GDPDs are preferentially influenced by low phosphate and CaGDPD1 encodes an active glycerophosphodiester phosphodiesterase enzyme

Rice and chickpea GDPD s are transcriptionally influenced by mineral deficiencies; especially, by phosphate starvation and CaGDP1 encodes an active glycerophosphodiester phosphodiesterase enzyme. Glycerophosphodiester phosphodiesterases (GDPDs) are enzymes involved in the degradation of glycerophosphodiesters into sn-glycerol-3-phosphate and corresponding alcohols. These phospholipid remodeling genes have been suggested to play important roles in phosphate homeostasis. However, comprehensive information about the role of GDPDs under low phosphate (P) and other nutrient deficiencies (N, K, Fe, Zn) in rice and chickpea is missing. Here, we identified 13 OsGDPDs and 6 CaGDPDs in rice and chickpea, respectively, and partly characterized their roles in multiple nutrient stresses. Expression profiling after 7 and 15 days of deficiency treatments revealed unique and overlapping differential expression patterns of OsGDPDs and CaGDPDs under different nutrient stresses. Principal component analysis on the expression patterns of OsGDPDs and CaGDPDs revealed their preferential role in P starvation. Some of the GDPDs were also induced by N, K, Fe and Zn deficiency in temporal manner in both crops suggesting their roles in multiple nutrient stresses. Biochemical characterization of highly responsive chickpea GDPD, CaGDPD1, confirmed its in vitro GDPD activity and revealed its optimal temperature, pH and cofactor requirements. Further, CaGDPD1 showed its accumulation in ER and endomembranes. We hereby propose CaGDPD1 and various OsGDPDs as low P responsive marker genes in chickpea and rice, respectively. Our data uphold role of GDPDs in multinutrient responses and suggest them as candidates for rice and chickpea improvement for tolerance to various nutrient deficiencies.

Is Alloplastic Temporomandibular Joint Reconstruction a Viable Option in the Surgical Management of Adult Patients With Idiopathic Condylar Resorption?

PURPOSE

Idiopathic condylar resorption (ICR) presents diagnostic and therapeutic challenges to practitioners because of the rarity of the condition, progressive deformity, and simultaneous involvement of skeletal, occlusal, and articular disorders. The objective of this study was to report clinical outcomes after prosthetic replacement of the temporomandibular joint (TMJ) for the management of ICR.

PATIENTS AND METHODS

A retrospective analysis of patients with ICR managed by bilateral total TMJ replacement and concomitant mandibular advancement with or without maxillary surgery was performed using data gathered from medical records. The primary treatment outcomes of interest were 1) correction of anterior open bite malocclusion, 2) mandibular advancement, and 3) increase in posterior facial height. Secondary outcomes included subjective assessment of pain, dietary restrictions, and functional disability and objective evaluations of TMJ sounds, occlusal relation, mandibular range of motion, cranial nerve VII injury, and objectionable scarring. Radiographs were used to measure surgical change and relapse.

RESULTS

Twenty-one patients met the inclusion criteria for this retrospective study. The average patient age was 25.6 years (range, 22 to 32 yr) and mean follow-up was 6.2 years (range, 5 to 12 yr). Mean mandibular advancement at the B point was 24.3 mm and mean change in occlusal plane was -10.2°. Sixteen patients (76%) underwent maxillary orthognathic surgery for posterior downgrafting with rigid fixation and grafting. Long-term follow-up showed excellent stability of surgical movements with a decrease in TMJ and myofascial pain, headaches, and dietary restrictions.

CONCLUSIONS

Patients with ICR can be effectively treated using total TMJ prostheses with maxillary orthognathic surgery when indicated for the correction of an associated dentofacial deformity. Use of alloplastic joint prostheses allows for the execution of large mandibular advancements in a predictable and accurate manner with a meaningful decrease in symptoms of TMJ dysfunction.

Soft tissue surgery for implants

Adequate quality and quantity of soft tissue plays an integral part in the esthetic outcome of dental implants. Adequate band of attached tissue decreases the incidence of mucositis and improves hygiene around implants. This article discusses a variety of techniques for soft tissue augmentation. Soft tissue grafting can be achieved at various stages of implant therapy. Epithelial connective tissue grafts are commonly used to increase the band of attached tissue. Subepithelial connective tissue grafts are great for increasing soft tissue thickness and improving the gingival biotype.

Effects of cuts in Medicaid on dental-related visits and costs at a safety-net hospital

We used data from Boston Medical Center, Massachusetts, to determine whether dental-related emergency department (ED) visits and costs increased when Medicaid coverage for adult dental care was reduced in July 2010. In this retrospective study of existing data, we examined the safety-net hospital's dental-related ED visits and costs for 3 years before and 2 years after Massachusetts Health Care Reform. Dental-related ED visits increased 2% the first and 14% the second year after Medicaid cuts. Percentage increases were highest among older adults, minorities, and persons receiving charity care, Medicaid, and Medicare.

Piezosurgery-assisted, flapless split crest surgery for implant site preparation

INTRODUCTION

Bucco-lingual resorption of the alveolar ridge can, at times, be predictably corrected at the time of implant placement. Among the different options available to achieve this are a group of surgical techniques described as split crest or split ridge procedures. Most of these procedures require the use of a mallet and some type of chisels and/or osteotomes; they are very technique-sensitive and can be uncomfortable for patients. Recently, alternative tools to split the crest have been presented, and these include the newer bone expanders and the piezoelectric scalpel. A flapless approach to implant dentistry has become popular with the aim to alleviate post treatment side effects, accelerate healing and avoid bone resorption caused by flap elevation.

METHODS

We present a technique combining the use of a piezoelectric scalpel and a tapered bone expander in a flapless fashion as a novel way to perform split crest procedures with an aim to optimize outcomes and acceptability by patients.

RESULTS

All implants were successfully placed and the resorbed ridge expanded in the same setting. Findings were confirmed by postoperative cone beam cat scan (CBCT) evaluation.

CONCLUSIONS

This new technique is a predictable approach for split crest procedures and has high acceptability by patients and is technically simple for surgeons.

Serum nutrient deficiencies in the patient with complex temporomandibular joint problems

This study evaluated serum nutrients in 23 patients who had previous Proplast/Teflon implants to their temporomandibular joints (TMJ) and continued to remain in chronic, severe, irresolvable pain despite subsequent surgical reconstruction. All of the patients were women, and their average age was 40.6 years (range, 28-55 years). Standard blood assays were performed for beta-carotene (vitamin A), folate, serum iron, ferritin, zinc, magnesium, and vitamins B1, B6, B12, and C. Each patient was deficient in at least one of these 10 elements, with an average of 3.3 elements. Some factors that may be responsible for the deficiency state include inadequate nutritional intake, malabsorption, utilization dysfunction, increased requirements, or drug interactions. In conclusion, the patient who has had multiple, complex TMJ operations with a history of TMJ Proplast/Teflon implants and poor treatment results may be suffering from an unrecognized malnutrition state, substantially adding to the patient's morbidity. Nutritional evaluations, dietary counseling, and appropriate medical management may improve the treatment outcomes for these patients.