Haplotype of the Lipoprotein(a) Gene Variants rs10455872 and rs3798220 Is Associated with Parameters of Coagulation, Fibrinolysis, and Inflammation in Patients after Myocardial Infarction and Highly Elevated Lipoprotein(a) Values.

Lipoprotein(a) (Lp(a)) is an independent risk factor for future coronary events. Variants rs10455872 and rs3798220 in the gene encoding Lp(a) are associated with an increased Lp(a) concentration and risk of coronary artery disease. We aimed to determine whether in high-risk coronary artery disease patients these two genetic variants and the kringle IV type 2 (KIV-2) repeats are associated with impairment of inflammatory and hemostatic parameters. Patients after myocardial infarction with elevated Lp(a) levels were included. Blood samples underwent biochemical and genetic analyses. In carriers of the AC haplotype, the concentrations of tumor necrosis factor (TNF)-α (4.46 vs. 3.91 ng/L, p = 0.046) and plasminogen activator inhibitor-1 (PAI-1) (p = 0.026) were significantly higher compared to non-carriers. The number of KIV-2 repeats was significantly associated with the concentration of high-sensitivity C-reactive protein (ρ = 0.251, p = 0.038) and overall fibrinolytic potential (r = -0.253, p = 0.038). In our patients, a direct association between the AC haplotype and both TNF-α and PAI-1 levels was observed. Our study shows that the number of KIV-2 repeats not only affects proatherosclerotic and proinflammatory effects of Lp(a) but is also associated with its antifibrinolytic properties.

Knee and Peri-Knee Tissues of Post Mortem Donors Are Strategic Sources of Mesenchymal Stem/Stromal Cells for Regenerative Procedures.

Tissues of post mortem donors represent valuable alternative sources for the isolation of primary cells with mesenchymal stem/stromal cell (MSC)-like properties. However, the properties of primary cells derived from different tissues and at different post mortem times are poorly recognized. Here, we aim to identify the optimal tissue source between three knee and peri-knee tissues for the isolation of primary cells with MSC-like properties, and to define the influence of the time post mortem on the properties of these cells. We harvested tissues from subchondral bone marrow, synovium and periosteum from 32 donors at various post mortem times. Primary cells were evaluated using detailed in vitro analyses, including colony formation, trilineage differentiation, immunophenotyping and skeletal stem cell marker-gene expression profiling. These data show that the primary cells with MSC-like properties isolated from these three tissues show no differences in their properties, except for higher expression of CD146 in bone-marrow cells. The success rate of the primary cell isolation is dependent on the post mortem time. However, synovium and periosteum cells isolated more than 48 h post mortem show improved osteogenic and chondrogenic potential. This study suggests that knee and peri-knee tissues from donors even 3 days post mortem are strategic sources of MSCs for regenerative procedures.

Age-related alterations and senescence of mesenchymal stromal cells: Implications for regenerative treatments of bones and joints.

The most common clinical manifestations of age-related musculoskeletal degeneration are osteoarthritis and osteoporosis, and these represent an enormous burden on modern society. Mesenchymal stromal cells (MSCs) have pivotal roles in musculoskeletal tissue development. In adult organisms, MSCs retain their ability to regenerate tissues following bone fractures, articular cartilage injuries, and other traumatic injuries of connective tissue. However, their remarkable regenerative ability appears to be impaired through aging, and in particular in age-related diseases of bones and joints. Here, we review age-related alterations of MSCs in musculoskeletal tissues, and address the underlying mechanisms of aging and senescence of MSCs. Furthermore, we focus on the properties of MSCs in osteoarthritis and osteoporosis, and how their changes contribute to onset and progression of these disorders. Finally, we consider current treatments that exploit the enormous potential of MSCs for tissue regeneration, as well as for innovative cell-free extracellular-vesicle-based and anti-aging treatment approaches.

Silver Fir (Abies alba L.) Polyphenolic Extract Shows Beneficial Influence on Chondrogenesis In Vitro under Normal and Inflammatory Conditions.

Several plant polyphenols have been shown to reduce osteoarthritis symptoms due to their antioxidant, anti-inflammatory and immunomodulatory properties. We investigated the effects of two different polyphenolic extracts (Belinal, Pycnogenol) and two different polyphenols (resveratrol, quercetin) on the chondrogenic potential of bone-derived mesenchymal stem/stromal cells (MSCs) from healthy donors and patients with osteoarthritis. Our main aim was to determine whether Belinal, a commercially available polyphenolic extract from silver fir (Abies alba L.) branches, has comparable chondrogenic potential with the other tested extract and the polyphenols under inflammatory and non-inflammatory conditions. In our study, Belinal promoted significantly greater chondrogenesis compared to the untreated (p = 0.0289) and resveratrol-treated (p = 0.0468) MSCs from patients with hip osteoarthritis under non-inflammatory conditions. Under inflammatory conditions, chondrogenesis was significantly enhanced for MSCs treated with Belinal compared to the control (p = 0.0483). The other extract and the polyphenols did not show any significant effects on chondrogenesis under non-inflammatory or inflammatory conditions. None of the tested extracts and polyphenols showed significant effects on chondrogenesis in healthy donors, under either non-inflammatory or inflammatory conditions. Our data show that Belinal can boost the chondrogenesis of MSCs derived from patients with osteoarthritis, under both non-inflammatory and inflammatory conditions.

Comprehensive analysis of skeletal muscle- and bone-derived mesenchymal stem/stromal cells in patients with osteoarthritis and femoral neck fracture.

BACKGROUND: Mesenchymal stem/stromal cells (MSCs) can replenish the aged cells of the musculoskeletal system in adult life. Stem cell exhaustion and decrease in their regenerative potential have been suggested to be hallmarks of aging. Here, we investigated whether muscle- and bone-derived MSCs of patients with osteoarthritis and osteoporosis are affected by this exhaustion, compared to healthy donors. METHODS: Patients with primary osteoarthritis, femoral neck fractures due to osteoporosis, and healthy donors (controls) were included. MSCs were isolated from the skeletal muscle and subchondral bone from each patient and compared using ex vivo and in vitro analyses, including immunophenotyping, colony-forming unit fibroblast assays, growth kinetics, cell senescence, multilineage potential, and MSC marker gene expression profiling. RESULTS: Freshly isolated cells from muscle from patients with osteoarthritis showed a lower proportion of CD45/CD19/CD14/CD34-negative cells compared to patients with osteoporosis and healthy donors. Freshly isolated muscle cells from patients with osteoarthritis and osteoporosis also showed higher clonogenicity compared to healthy donors. MSCs from both tissues of osteoarthritis patients showed significantly reduced osteogenesis and MSCs from the bone also reduced adipogenesis. Chondrogenic pellet diameter was reduced in bone-derived MSCs from both patient groups compared to healthy donors. A significant positive correlation was observed between adipogenesis and CD271 expression in muscle-derived MSCs. CD73 was significantly lower in bone-derived MSCs from osteoarthritis patients, compared to osteoporosis patients. Gene expression profiling showed significantly lower expression of MSC marker gene leptin receptor, LEPR, previously identified as the major source of the bone and adipocytes in the adult bone marrow, in bone-derived MSCs from patients with osteoarthritis in comparison with osteoporotic patients and healthy donors. CONCLUSIONS: Our results show deficient ex vivo and in vitro properties of both skeletal muscle- and bone-derived MSCs in osteoarthritis and osteoporosis patients, compared to healthy donors. In bone-derived MSCs from patients with osteoarthritis, we also identified a lower expression of the leptin receptor, a marker of MSCs that present a major source of MSCs in the adult bone marrow. This suggests that exhaustion of skeletal muscle- and bone-derived MSCs is a hallmark of osteoarthritis and osteoporosis, which defines the need for further clinical trials of stem cell transplantation in these patients.

Increased Exhaustion of the Subchondral Bone-Derived Mesenchymal Stem/ Stromal Cells in Primary Versus Dysplastic Osteoarthritis.

Mesenchymal stem/ stromal cell (MSC) exhaustion has been suggested to be a hallmark of aging. Osteoarthritis has a complex etiology that comprises several factors. Dysplasia has been shown to be an individual risk factor for osteoarthritis. Subchondral bone changes are often the first detectable alterations in osteoarthritis. In this study, we aimed to determine whether skeletal MSCs are differentially affected in patients with primary versus dysplastic osteoarthritis. Patients undergoing hip arthroplasty due to primary osteoarthritis (n = 11) and osteoarthritis with hip dysplasia (n = 10) were included in the study. Femoral head subchondral bone was used for isolation of MSCs. The cells were compared using detailed ex-vivo and in-vitro analyses, which included immunophenotyping, colony-forming-unit fibroblast assay, growth kinetics, senescence, multilineage potential, immunophenotyping, and MSC marker-gene expression profiling. Isolated cells from primary osteoarthritis patients showed decreased viability in comparison with those from dysplasia patients, with similar mesenchymal fractions (i.e., CD45/ CD19/ CD14/ CD34-negative cells). In-vitro expanded MSCs from primary osteoarthritis patients showed reduced osteogenic and chondrogenic potential in comparison with dysplasia patients. There were no differences in clonogenicity, growth kinetics, senescence, adipogenic potential, and immunophenotype between these groups. Gene expression profiling showed well-known marker of bone marrow MSCs, the leptin receptor, to be significantly lower for primary osteoarthritis patients. Our study shows that the pathology of primary osteoarthritis is accompanied by bone MSC exhaustion, while biomechanical dysfunction associated with hip dysplasia can induce secondary osteoarthritis without this MSC impairment. Our study suggests that subchondral bone MSC exhaustion is implicated in the pathology of primary osteoarthritis.

Synovium-Derived Mesenchymal Stem/Stromal Cells and their Promise for Cartilage Regeneration.

Adult tissues are reservoirs of rare populations of cells known as mesenchymal stem/stromal cells (MSCs) that have tissue-regenerating features retained from embryonic development. As well as building up the musculoskeletal system in early life, MSCs also replenish and repair tissues in adult life, such as bone, cartilage, muscle, and adipose tissue. Cells that show regenerative features at least in vitro have been identified from several connective tissues. Bone marrow and adipose tissue are the most well recognized sources of MSCs that are already used widely in clinical practice. Regenerative medicine aims to exploit MSCs and their tissue regeneration even though the underlying mechanisms for their beneficial effects are largely unknown. Despite many studies that have used various tissue-derived MSCs, the most effective tissue source for orthopedic procedures still remains to be identified. Another question that needs to be addressed is how to evaluate autologous MSCs (i.e., patient derived). Previous studies have suggested the features of bone-marrow-derived MSCs can differ widely between individuals, and can be changed in particular in patients suffering from some forms of degenerative disorder, such as osteoarthritis. The synovium is a thin membrane that protects the synovial joints, and it is a rich source of MSCs that show great potential for regenerative medicine. Here, we review synovium-derived MSCs from reports on basic and clinical studies. We discuss their potential to treat cartilage defects caused by either degeneration or trauma, and what needs to be done in further research toward their better exploitation for joint regeneration.

Sex-determining region Y (SRY) attributes to gender differences in RANKL expression and incidence of osteoporosis.

Receptor activator of nuclear factor κB ligand (RANKL) plays a crucial role in bone metabolism. RANKL gene misregulation has been implicated in several bone and cancer diseases. Here, we aimed to identify novel transcription regulators of RANKL expression. We discovered that transcription factors, sex-determining region Y (SRY) and c-Myb, regulate RANKL expression. We demonstrated that c-Myb increases and male-specific SRY decreases RANKL expression through direct binding to its 5'-proximal promoter. These results are corroborated by the gene expression in human bone samples. In osteoporotic men, expression of RANKL is 17-fold higher, which correlates with the drastically reduced expression (200-fold) of Sry, suggesting that in osteoporotic men, the upregulation of RANKL is caused by a decrease of Sry. In healthy men, the expression of RANKL is 20% higher than that in healthy women. Our data suggest that gender differences in RANKL expression and bone quality could be due to the sex-specific transcription factor SRY.

Skeletal-muscle-derived mesenchymal stem/stromal cells from patients with osteoarthritis show superior biological properties compared to bone-derived cells.

Mesenchymal stem/stromal cells (MSCs) are being exploited for patient-derived stem-cell therapies. As the biological properties of MSCs derived from skeletal muscle of osteoarthritis patients are poorly understood, the aim of this study was to compare muscle MSCs with well-recognized bone and bone marrow-derived MSCs from these patients. Paired samples of skeletal muscle and trabecular bone tissue were obtained from 21 patients with osteoarthritis. Isolated cells were compared using ex vivo immunophenotyping and detailed in vitro analyses. These included the colony forming unit fibroblast assay, growth kinetics, senescence, multilineage potential, immunophenotyping, and MSC marker gene expression profiling. Freshly isolated MSCs from muscle showed improved viability over bone-derived MSCs, with similar mesenchymal fraction. Muscle-derived MSCs showed superior clonogenicity, higher growth rates, and lower doubling times. Muscle-derived MSCs also showed superior osteogenic and myogenic properties and a positive correlation between CD271 expression and adipogenesis. Senescence rate as well as adipogenic and chondrogenic potentials were similar. Skeletal muscle-derived MSCs of osteoarthritis patients have superior clonogenicity and growth kinetics compared to bone-derived MSCs, making them a good candidate for autologous stem-cell therapies. Moreover, the positive correlation between CD271 and adipogenesis suggest that CD271 expressing muscle MSCs might contribute to muscle steatosis observed in osteoarthritis.

Surface Antigen-Based Identification of In Vitro Expanded Skeletal Muscle-Derived Mesenchymal Stromal/Stem Cells Using Flow Cytometry.

Mesenchymal stem/stromal cells (MSCs) can be isolated from several connective tissues in the adult organism by harnessing their propensity for plastic adherence in vitro. Upon culture expansion, the resulting cell cultures are composed of many different cell types at different stages of differentiation. Hence, their identity must be confirmed. Flow cytometry is an indispensable method for accurate quantification of MSC surface antigens. Here, we present a protocol that uses flow cytometry for the identification of MSCs based on the set of surface antigens required by the International Society for Cellular Therapy.

Human Synovium-Derived Mesenchymal Stem Cells: Ex Vivo Analysis.

Synovium-derived mesenchymal stem/stromal cells (MSCs) have been shown to have superior features in comparison with MSCs from other tissue sources. As they are far less recognised compared to bone marrow- or adipose tissue-derived MSCs, I provide here a detailed procedure on how to isolate MSCs from human synovium. This includes determination of the proportions of viable cells in ex vivo isolated fractions before the seeding of the cells and a description of how to carry out colony-forming fibroblast assays to quantify the clonogenicity of these cells.

Human Skeletal Muscle-Derived Mesenchymal Stem/Stromal Cell Isolation and Growth Kinetics Analysis.

The most studied sources of mesenchymal stem/stromal cells (MSCs) are bone marrow and adipose tissue. However skeletal muscle represents an interesting source of diverse subpopulations of MSCs, such as paired box 7 (Pax-7)-positive satellite cells, fibro-/adipogenic progenitors, PW1-positive interstitial cells and others. The specific properties of some of these muscle-derived cells have encouraged the development of cell therapies for muscle regeneration. However, the identity and multilineage potential of the diverse muscle-resident cells should first be evaluated in vitro, followed by in vivo clinical trials to predict their regenerative capacity. Here, we present protocols for the isolation of MSCs from skeletal muscle using enzymatic digestion and mechanical trituration. We also provide a method to determine their specific growth rate, a feature that is of particular interest when designing cell therapies.

Complete Assessment of Multilineage Differentiation Potential of Human Skeletal Muscle-Derived Mesenchymal Stem/Stromal Cells.

The minimal criteria for mesenchymal stem/stromal cell (MSC) identification set by the International Society for Cellular Therapy include plastic adherence, presence and absence of a set of surface antigens and in vitro multilineage differentiation. This differentiation is assessed through stimulation of MSCs with defined combination and concentration of growth factors towards specific lineages and histological confirmation of the presence of differentiated cells. Here we provide protocols for multilineage differentiation, namely, osteogenesis, adipogenesis, chondrogenesis and myogenesis. We also provide their respective histological analyses.

Epigenetic enzymes influenced by oxidative stress and hypoxia mimetic in osteoblasts are differentially expressed in patients with osteoporosis and osteoarthritis.

Epigenetic mechanisms including posttranslational histone modifications and DNA methylation are emerging as important determinants of bone homeostasis. With our case-control study we aimed to identify which chromatin-modifying enzymes could be involved in the pathology of postmenopausal osteoporosis and osteoarthritis while co-regulated by estrogens, oxidative stress and hypoxia. Gene expression of HAT1, KAT5, HDAC6, MBD1 and DNMT3A affected by oxidative stress and hypoxia in an in vitro qPCR screening step performed on an osteoblast cell line was analysed in trabecular bone tissue samples from 96 patients. Their expression was significantly reduced in patients with postmenopausal osteoporosis and osteoarthritis as compared to autopsy controls and significantly correlated with bone mineral density and several bone histomorphometry-derived parameters of bone quality and quantity as well as indicators of oxidative stress, RANK/RANKL/OPG system and angiogenesis. Furthermore, oxidative stress increased DNA methylation levels at the RANKL and OPG promoters while decreasing histone acetylation levels at these two genes. Our study is the first to show that higher expression of HAT1, HDAC6 and MBD1 is associated with superior quantity as well as quality of the bone tissue having a more favourable trabecular structure.

Genetic effects on bone health.

PURPOSE OF REVIEW: In recent years, the lower costs of arrays and sequencing technologies, and the better availability of data from genome-wide association studies (GWASs) have led to more reports on genetic factors that are associated with bone health. However, there remains the need for a summary of the newly identified genetic targets that are associated with bone metabolism, and the status of their functional characterization. RECENT FINDINGS: GWASs revealed dozens of novel genetic loci that are associated with bone mineral density (BMD). Some of these targets have been functionally characterized, although the vast majority have not. Glypican 6, a membrane surface proteoglycan involved in cellular growth control and differentiation, was identified as a novel determinant of BMD and represents a possible drug target for treatment of osteoporosis. Pathway analysis also showed that cell-growth pathways and the SMAD proteins associated with low BMD. SUMMARY: Hits that were significantly associated with BMD in different studies represent likely candidates (e.g. SOST, WNT16, ESR1 and RANKL) for functional characterization and development of osteoporosis treatments. Indeed, currently available treatment for osteoporosis (antibody against RANKL) appeared a significant target in four recent GWAS studies indicating their applicability and importance for future treatment development.

Mesenchymal Stem Cells in the Musculoskeletal System: From Animal Models to Human Tissue Regeneration?

The musculoskeletal system includes tissues that have remarkable regenerative capabilities. Bone and muscle sustain micro-damage throughout the lifetime, yet they continue to provide the body with the support that is needed for everyday activities. Our current understanding is that the regenerative capacity of the musculoskeletal system can be attributed to the mesenchymal stem/ stromal cells (MSCs) that reside within its different anatomical compartments. These MSCs can replenish various tissues with progenitor cells to form functional cells, such as osteoblasts, chondrocytes, myocytes, and others. However, with aging and in certain disorders of the musculoskeletal system such as osteoarthritis or osteoporosis, this regenerative capacity of MSCs appears to be lost or diverted for the production of other non-functional cell types, such as adipocytes and fibroblasts. In this review, we shed light on the tissue sources and subpopulations of MSCs in the musculoskeletal system that have been identified in animal models, discuss the mechanisms of their anti-inflammatory action as a prerequisite for their tissue regeneration and their current applications in regenerative medicine. While providing up-to-date evidence of the role of MSCs in different musculoskeletal pathologies, in particular in osteoporosis and osteoarthritis, we share some thoughts on their potential as diagnostic markers in musculoskeletal health and disease.

The role of artichoke leaf tincture (Cynara scolymus) in the suppression of DNA damage and atherosclerosis in rats fed an atherogenic diet.

CONTEXT: Polyphenols and flavonoids in artichoke leaf tincture (ALT) protect cells against oxidative damage. OBJECTIVES: We examined ALT effects on deoxyribonucleic acid (DNA) damage and lipid profiles in rat plasma and gene expression in rat aorta [haemeoxygenase-1 (HO1), haemeoxygenase-2 (HO2), NADPH oxidase 4 (NOX-4), monocyte chemoattractant protein-1 (MCP-1) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)]. MATERIALS AND METHODS: Eighteen male Wistar albino rats were divided into three groups (n = 6/group): The control group (CG) was fed with standard pellet chow for 11 weeks; the AD group was fed for a similar period of time with pellet chow supplemented with 2% cholesterol, 3% sunflower oil and 1% sodium cholate. The ADA group was fed with pellet chow (for 1 week), the atherogenic diet (see above) for the following 4 weeks and then with ALT (0.1 mL/kg body weight) and atherogenic diet for 6 weeks. According to HPLC analysis, the isolated main compounds in ALT were chlorogenic acid, caffeic acid, isoquercitrin and rutin. RESULTS: Normalized HO-1 [0.11 (0.04-0.24)] and MCP-1 [0.29 (0.21-0.47)] mRNA levels and DNA scores [12.50 (4.50-36.50)] were significantly lower in the ADA group than in the AD group [0.84 (0.35-2.51)], p = 0.021 for HO-1 [0.85 (0.61-3.45)], p = 0.047 for MCP-1 and [176.5 (66.50-221.25)], p = 0.020 for DNA scores. HO-1 mRNA was lower in the ADA group than in the CG group [0.30 (0.21-0.71), p = 0.049]. CONCLUSIONS: Supplementation with ALT limited the effects of the atherogenic diet through reduced MCP-1 expression, thereby preventing oxidative damage.

VEGF-A is associated with early degenerative changes in cartilage and subchondral bone.

Paired cartilage and subchondral bone of subjects with no clinical history of joint disorders were analyzed to determine whether antioxidant enzymes, inflammatory cytokines and growth factors can be linked to a pre-osteoarthritis. Tissue explants were phenotyped according to Osteoarthritis Research Society International grading and micro-computed tomography, and also screened for the expression of several markers using quantitative polymerase chain reaction. The expression of these same genes was measured in SW1353 cells treated with hydrogen peroxide, to gain insight into the pathways involved with oxidative stress responses. Vascular endothelial growth factor A (VEGF-A) was up-regulated in the cartilage samples that showed early cartilage or bone degeneration. Oxidative stress in chondrocytes provoked up-regulation of interleukin-1ß, interleukin-6, aggrecan, and SRY-box containing gene 9. Our results confirm the hitherto evidence of the deteriorating effects of the oxidative stress on cartilage and suggest the link between VEGF-A and pre-osteoarthritis.

Joint morphogenetic cells in the adult mammalian synovium.

The stem cells that safeguard synovial joints in adulthood are undefined. Studies on mesenchymal stromal/stem cells (MSCs) have mainly focused on bone marrow. Here we show that lineage tracing of Gdf5-expressing joint interzone cells identifies in adult mouse synovium an MSC population largely negative for the skeletal stem cell markers Nestin-GFP, Leptin receptor and Gremlin1. Following cartilage injury, Gdf5-lineage cells underpin synovial hyperplasia through proliferation, are recruited to a Nestin-GFPhigh perivascular population, and contribute to cartilage repair. The transcriptional co-factor Yap is upregulated after injury, and its conditional ablation in Gdf5-lineage cells prevents synovial lining hyperplasia and decreases contribution of Gdf5-lineage cells to cartilage repair. Cultured Gdf5-lineage cells exhibit progenitor activity for stable chondrocytes and are able to self-organize three-dimensionally to form a synovial lining-like layer. Finally, human synovial MSCs transduced with Bmp7 display morphogenetic properties by patterning a joint-like organ in vivo. Our findings further the understanding of the skeletal stem/progenitor cells in adult life.

Bone remodeling during orthodontic tooth movement in rats with type 2 diabetes.

INTRODUCTION: Type 2 diabetes is known to affect bone metabolism. In this study, we aimed to determine the effects of type 2 diabetes on bone remodeling during orthodontic tooth movement. METHODS: The 48 rats were divided into 4 groups: Wistar control group (n = 8), Goto-Kakizaki (GK) control group (n = 8), Wistar appliance group (n = 16), and GK appliance group (n = 16). The distances between the teeth were measured weekly. On day 42, maxillary alveolar bone specimens were obtained for histologic evaluation and determination of the gene expression levels of the receptor activator of nuclear factor Ò¡B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG). RESULTS: No significant difference was observed in the levels of tooth movement between the 2 appliance groups. After orthodontic force application, the alveolar bone volume and osteoblast surface in the GK rats were diminished compared with those in the Wistar rats. The increase in the osteoclast surface relative to the control groups was 2.4-fold greater in the GK rats than in the Wistar rats. Significant upregulations of the RANK and OPG gene expression levels in the Wistar appliance group were observed. The RANKL/OPG ratio was increased in the GK appliance group compared with the Wistar appliance group. CONCLUSIONS: Diminished bone formation and slightly increased bone resorption were observed during orthodontic tooth movement in the rats with type 2 diabetes.