The potential effects of cholecalciferol on bone regeneration in dogs

The role of Vitamin D as an adjunct for bone regeneration: A systematic review of literature

Background and objectives

In spite of bone's healing capacity, critical-size bone defect regeneration and peri-implant osseointegration are challenging. Tissue engineering provides better outcomes, but requires expensive adjuncts like stem cells, growth factors and bone morphogenic proteins. Vitamin D (Vit.D) regulates calcium and phosphorus metabolism, and helps maintain bone health. Vit.D supplements in deficient patients, accentuates bone healing and regeneration. Therefore the aim of this systematic review was to evaluate the role of adjunctive Vit.D on bone defect regeneration.

Methods

Comprehensive database search of indexed literature, published between January 1990 and June 2022, was carried out. English language articles fulfilling inclusion criteria (clinical/in vivo studies evaluating bone regeneration including osseointegration and in vitro studies assessing osteogenic differentiation, with adjunct Vit.D) were identified and screened.

Results

Database search identified 384 titles. After sequential title, abstract and full-text screening, 23 studies (in vitro - 9/in vivo - 14) were selected for review. Vit.D as an adjunct with stem cells and osteoblasts resulted in enhanced osteogenic differentiation and upregulation of genes coding for bone matrix proteins and alkaline phosphatase. When used in vivo, Vit.D resulted in early and increased new bone formation and mineralization within osseous defects, and better bone implant contact and osseointegration, around implants. Adjunct Vit.D in animals with induced systemic illnesses resulted in bone defect regeneration and osseointegration comparable to healthy animals. While systemic and local administration of Vit.D resulted in enhanced bone defect healing, outcomes were superior with systemic route.

Conclusions

Based on this review, adjunct Vit.D enhances bone defect regeneration and osseointegration. In vitro application of Vit.D to stem cells and osteoblasts enhances osteogenic differentiation. Vit.D is a potentially non-invasive and inexpensive adjunct for clinical bone regeneration and osseointegration. Long term clinical trials are recommended to establish protocols relating to type, dosage, frequency, duration and route of administration.

Paracrine interactions between mesenchymal stem cells and macrophages are regulated by 1,25-dihydroxyvitamin D3

Mesenchymal stem cells (MSC) modulate the macrophage-mediated inflammatory response through the secretion of soluble factors. In addition to its classical effects on calcium homeostasis, 1,25-dihydroxyvitamin D3 (1,25D3) has emerged as an important regulator of the immune system. The present study investigates whether 1,25D3 modulates the paracrine interactions between MSC and macrophages. 1,25D3 stimulated MSC to produce PGE₂ and VEGF and regulated the interplay between macrophages and MSC toward reduced pro-inflammatory cytokine production. Conditioned media (CM) from co-cultures of macrophages and MSC impaired MSC osteogenesis. However, MSC cultured in CM from 1,25D3-treated co-cultures showed increased matrix maturation and mineralization. Co-culturing MSC with macrophages prevented the 1,25D3-induced increase in RANKL levels, which correlated with up-regulation of OPG secretion. MSC seeding in three-dimensional (3D) substrates potentiated their immunomodulatory effects on macrophages. Exposure of 3D co-cultures to 1,25D3 further reduced the levels of soluble factors related to inflammation and chemotaxis. As a consequence of 1,25D3 treatment, the recruitment of monocytes toward CM of 3D co-cultures decreased, while the osteogenic maturation of MSC increased. These data add new insights into the pleiotropic effects of 1,25D3 on the crosstalk between MSC and macrophages and highlight the role of the hormone in bone regeneration.

Vitamin D deficiency in early implant failure: two case reports

An association between vitamin D deficiency and early dental implant failure is not properly verified, but its role in osteoimmunology is discussed. This article illustrates two case reports with vitamin D deficiency and early implant failure. Prior to implant placement, the first patient received crestal bone grafting with autologous material. Both patients received dental implants from different manufacturers in the molar region of the mandible. In the case of bone grafting in the first patient, all implants were placed in a two-stage procedure. All implants had to be removed within 15 days after implant placement. Vitamin D serum levels were measured: Both patients showed a vitamin D deficiency (serum vitamin D level <20 μg/l). After vitamin D supplementation, implant placement was successful in both patients. Prospective, randomized clinical trials must follow to affirm the relationship between vitamin D deficiency, osteoimmunology, and early implant failure.

Osseoinductive elements around immediate implants for better osteointegration: a pilot study in foxhound dogs

OBJECTIVE

The aim of this study was to evaluate the effects on osseointegration of topical applications of melatonin vs. vitamin D over surfaces of immediate implants.

MATERIALS AND METHODS

Mandibular premolar distal roots (P₂ , P₃ , P₄ ) were extracted bilaterally from six American Foxhound dogs. Three conical immediate implants were randomly placed bilaterally in each mandible. Three randomized groups were created: melatonin 5% test group (MI), vitamin D 10% test group (DI), and Control group implants (CI). Block sections were obtained after 12 weeks and processed for mineralized ground sectioning. Bone-to-implant contact (total BIC), new bone formation (NBF), inter-thread bone (ITB), and histological linear measurements (HLM) were assessed.

RESULTS

At 12 weeks, all implants were clinically stable and histologically osseointegrated. Total BIC values were 49.20 ± 3.26 for the MI group, 49.86 ± 1.89 for DI group and 45.78 ± 4.21 for the CI group (P < 0.018) with statistically significant difference between the three groups. BIC percentage were 42.44 ± 2.18 for MI, 44.56 ± 1.08 for DI, and 41.95 ± 3.34 for CI groups respectively (P > 0.05). Inter-thread bone formation values were MI 17.56 ± 2.01, for DI 19.87 ± 0.92, and CI 14.56 ± 1.24 (P > 0.05). Statistically significant differences in peri-implant new bone formation were found between the three groups: MI 28.76 ± 1.98, DI 32.56 ± 1.11 and CI 25.43 ± 4.67, respectively (P < 0.045). Linear measurements showed that the MI group showed significantly less lingual crestal bone loss (CBL) (MI 0.59 ± 0.71), compared to DI (0.91 ± 1.21) and CI (0.93 ± 1.21) (P < 0.042), and less lingual peri-implant mucosa (PIM) (MI 3.11 ± 1.34),(DI 3.25 ± 0.18 compared with CI 3.54 ± 1.81 (P = 0.429). Linear measurements of buccal CBL showed significantly less buccal bone loss in test DI (0.36 ± 0.12) than CI (1.34 ± 1.23) and MI (1.11 ± 1.38) (P = 0.078).

CONCLUSIONS

Within the limitations of this animal study, topical applications of 5% Melatonin or 10% vitamin D improved bone formation around implants placed immediately after extraction and helped to reduce CBL after 12 weeks osseointegration.

Association of vitamin D3 with alveolar bone regeneration in dogs

Designed sockets prepared on the mandibles of nine Beagle dogs were divided into three groups: Calcitriol +Alloplast, Alloplast and Empty. Five of the nine dogs received Vit.D₃ and calcium supplement (Vit.D/Ca group), while the other four dogs without supplements were assigned to Non-Vit.D/Ca group. After 4 weeks, the extent of vertical ridge resorption (VRR), bone density (density), new bone formation (NBF) and implant stability quotient (ISQ) were measured. Following systemic Vit.D/Ca administration, the Empty subgroup showed significant differences from the Calcitriol + Alloplast subgroup on variants NBF/Density/VRR and the Alloplast subgroup on items NBF/Density/ISQ/VRR. Alternatively, the Calcitriol + Alloplast subgroup revealed higher values of NBF/Density/ISQ (P < 0.001) and a lower VRR value (P = 0.001) than the Alloplast subgroup. Although there were no significant differences in NBF (P = 0.349), density (P = 0.796), ISQ (P = 0.577) and VRR (0.979) comparisons on alloplast treatment between the Vit.D/Ca and Non-Vit.D/Ca groups, local application with Calcitriol + Alloplast demonstrated better NBF/Density/ISQ (P = 0.02 to <0.001) effects than which of Alloplast subgroups. Consequently, the results showed that both systemic and local vitamin D₃ treatment might accelerate bone regeneration in dogs. Within the using dose, systemic vitamin D₃ treatment displayed a superior stimulating effect than local vitamin D₃ application did.

Alveolar bone regeneration in response to local application of calcitriol in vitamin D deficient rats

AIM

Vitamin D deficiency is considered to diminish bone regeneration. Yet, raising the serum levels takes months. A topic application of the active vitamin D metabolite, calcitriol, may be an effective approach. Thus, it becomes important to know the effect of vitamin D deficiency and local application on alveolar bone regeneration.

MATERIAL AND METHODS

Sixty rats were divided into three groups; two vitamin depletion groups and a control group. Identical single defects (2 mm diameter) were created in the maxilla and mandible treated with calcitriol soaked collagen in one deficiency group while in the other two groups not. Histomorphometric analysis and micro CTs were performed after 1 and 3 weeks. Serum levels of 25(OH)D3 and PTH were determined.

RESULTS

Bone formation rate significantly increased within the observation period in all groups. Bone regeneration was higher in the maxilla than in the mandible. However, bone regeneration was lower in the control group compared to vitamin depletion groups, with no significant effects by local administration of calcitriol (micro CT mandible p = 0.003, maxilla p < 0.001; histomorphometry maxilla p = 0.035, mandible p = 0.18).

CONCLUSION

Vitamin D deficiency not necessarily impairs bone regeneration in the rat jaw and a single local calcitriol application does not enhance healing.

Vitamin D and bone fracture healing

AIM: To examine whether vitamin D is of potential relevance in the healing process of fractures.

METHODS: The present narrative review examined the bulk of the evidence based literature on the topic of vitamin D and bone healing in key electronic data bases from 1980 onwards using the terms vitamin D and bone healing, callus, fracture healing. All data were examined carefully and categorized according to type of study. A summary of the diverse terms and approaches employed in the research, as well as the rationale for hypothesizing vitamin D has a role in fracture healing was detailed.

RESULTS: The results show very few human studies have been conducted to examine if vitamin D is effective at promoting post fracture healing, and the different animal models that have been studied provide no consensus on this topic. The terms used in the related literature, as well as the methods used to arrive at conclusions on this clinical issue are highly diverse, there is no standardization of either of these important terms and methodologies, hence no conclusive statements or clinical guidelines can be forthcoming. There is a strong rational for continuing to examine if vitamin D supplements should be administered post-fracture, and ample evidence vitamin D is an essential hormone for functioning in general, as well as bone health and muscle as this relates to bone density.

CONCLUSION: Whether those with low vitamin D levels can benefit from supplements if their nutritional practices do not cover recommended daily amounts, remains in question.

The effect of vitamin D supplementation on bone formation around titanium implants in diabetic rats

BACKGROUND

Diabetes has become the next most widespread disease after cancer. Recent studies have found that diabetes and moderate to severe vitamin D deficiency are associated with reduced bone mineral content; therefore administration of vitamin D may correct these conditions. The purpose of this research is to compare the effect of vitamin D administration on bone to implant contact in diabetic rats with control group.

MATERIALS AND METHODS

In this randomized placebo-controlled trial, 48 Wistar rats were rendered diabetic (130≤ blood sugar ≤200 mg/dl) by IV injection of 35 mg/kg Alloxan. Implants were inserted in tibial bone; Then rats were divided into study and control groups and received oral vitamin D3 (160 IU) or placebo respectively for one week. Bone to implant contact value was measured under light microscope at 3 and 6 weeks.

RESULTS

Analysis of data indicated that vitamin D had no significant effect on bone to implant contact (BIC). At 3 weeks, the control group (n = 5) reported BIC level at 44 ± 19 and study group (n = 7) at 57 ± 20. At 6 weeks, the control group (n = 5) reported BIC level at 70 ± 29, and study group (n = 10) at 65 ± 22. Twenty one samples were missed because of death or incorrect lab processes.

CONCLUSION

It seems that vitamin D supplement has no significant effect on BIC in 130 mg/dL ≤ blood sugar ≤200 mg/dL (P = 0.703) andwas also not time dependent (P = 0.074).