Safety study: is there a pathologic IGF-1, PDGF and TGF-β cytokine expression caused by adjunct BMP-7 in tibial and femoral non-union therapy?

A systematic scoping review of the latest data on orthobiologics in the surgical treatment of non-union

INTRODUCTION

Recent studies have shown a growing concern regarding the cost-effectiveness and the lack of supporting data for the biologic agents that are being increasingly used in the orthopedic field. Our aim was to conduct a systematic scoping review of recent publications (last five years) on the use of orthobiologics to treat fracture non-union and summarize the latest available data.

PATIENTS AND METHODS

The inclusion criteria for this review were articles published in English, from 2016 to 2022, and focusing on the use of orthobiologics for the surgical treatment of non-union. Searches were conducted in March 2023 using Pubmed/MEDLINE and Embase. Studies on spinal fusion or gene therapy were excluded. Reviews, case reports with five cases or less, conference proceedings, preliminary reports, pediatric or non-human studies were excluded as well.

RESULTS

The search found 1807 articles, 15 were eligible after PRISMA checklist and exclusions. The evidence was heterogenous and there was only one level II RCT. Recent data suggests that bone morphogenic protein (BMP-2) products could be effective for septic and aseptic tibial non-unions. However, the evidence was not conclusive regarding BMP-7, plasma rich platelets (PRP), stem cells or demineralized bone matrix (DBM).

DISCUSSION

Every non-union case is different in terms of bone defect, biology, mechanical stability, surgical technique and host factors, which contributes to the conflicting reports on the efficacy of orthobiologics in the literature. We might never see a level 1, high powered and robust study defining the efficacy, safety profile and cost-effectiveness of such products.

LEVEL OF EVIDENCE

IV.

Tissue engineering in growth plate cartilage regeneration: Mechanisms to therapeutic strategies

The repair of growth plate injuries is a highly complex process that involves precise spatiotemporal regulation of multiple cell types. While significant progress has been made in understanding the pathological mechanisms underlying growth plate injuries, effectively regulating this process to regenerate the injured growth plate cartilage remains a challenge. Tissue engineering technology has emerged as a promising therapeutic approach for achieving tissue regeneration through the use of functional biological materials, seed cells and biological factors, and it is now widely applied to the regeneration of bone and cartilage. However, due to the unique structure and function of growth plate cartilage, distinct strategies are required for effective regeneration. Thus, this review provides an overview of current research on the application of tissue engineering to promote growth plate regeneration. It aims to elucidates the underlying mechanisms by which tissue engineering promotes growth plate regeneration and to provide novel insights and therapeutic strategies for future research on the regeneration of growth plate.

Effects of ergosteroside combined risedronate on fracture healing and BMP-2, BMP-7 and VEGF expression in rats

Purpose

To evaluate the effect of ergosterol combined with risedronate on fracture healing.

Methods

Sixty male Sprague Dawley fracture model rats were assigned into group A (n=20), group B (n=20), and group C (n=20) at random. All rats were fed by gavage until their sacrifice as it follows: group A with ergosteroside and risedronate, group B with risedronate, and group C with saline solution. At weeks 2 and 4, 10 rats of each group were sacrificed. Healing effect and bone tissue changes in the fractures site were assessed by using hematoxylin and eosin stain histology. Enzyme-linked immunosorbent assay was used to detect the expression of serum bone morphogenetic protein-2 (BMP-2), bone morphogenetic protein-7 (BMP-7), and vascular endothelial growth factor (VEGF). Reverse transcriptase polymerase chain reaction was applied to detect the expression of osteoprotegerin (OPG) mRNA, osteocalcin (OCN) mRNA and core-binding factor subunit-?1 (CBF-?1) mRNA.

Results

In terms of serum BMP-2, BMP-7, and VEGF expression at weeks 2 and 4 after gavage, group A < group B < group C (P<0.05). At week 4 after gavage, serum VEGF expression in the three groups harbored positive relationship with serum BMP-2 and BMP-7 expression (P<0.05). Regarding serum OPG, OCN and CBF-?1 mRNA expression at weeks 2 and 4 after gavage, group A <group B <group C (P<0.05). Hematoxylin and eosin staining results showed that the recovery effect of trabecular bone and callus in the cases of group A was better than the other two groups after intragastric administration.

Conclusion

Ergosteroside combined risedronate can patently ameliorate the healing effect of fracture in rats.

The Effect of Waterpipe Tobacco Smoking on Bone Healing Following Femoral Fractures in Male Rats

Background: Given the increasing use of waterpipe tobacco smoking in the world and its unknown effects on bone healing, this study investigated the repairing of femoral bone fractures in rats exposed to waterpipe tobacco smoking (WTS).

Main Methods: This study involved 40 male Wistar rats that were divided into two groups, including the femoral fracture (Fx) and the Fx + WTS groups. Each group was divided into two subgroups that were evaluated for bone healing 28 and 42 days after femoral fracture. After fixing the fractured femur, the healing process was evaluated by radiography, pathological indicators, and a measurement of the blood levels of vascular endothelial growth factor (VEGF), parathyroid hormone (PTH), Ca ++, transforming growth factor-beta (TGF-β), and insulin-like growth factor 1 (IGF-1). Additionally, the density of VEGF and CD34 in fracture tissue was investigated by immunohistochemistry.

Key Findings: Radiographic findings showed that factors related to the earlier stages of bone healing had higher scores in the Fx + WTS28 and 42 subgroups in comparison to the Fx groups. The density of VEGF and CD34 showed that the angiogenesis processes were different in the bone fracture area and callus tissue in the Fx +WTS subgroups. The serum levels of VEGF, TGF-β, and IGF-1 were significantly lower in the Fx +WTS42 group, and PTH in the Fx +WTS28 group was higher than that in the other groups.

Significance: The findings showed the disturbance and delay in the femoral fracture union in rats exposed to hookah smoke. This is partly due to the reduction of molecular stimuli of bone synthesis and the attenuation of quantitative angiogenesis.

Enlightenment of Growth Plate Regeneration Based on Cartilage Repair Theory: A Review

The growth plate (GP) is a cartilaginous region situated between the epiphysis and metaphysis at the end of the immature long bone, which is susceptible to mechanical damage because of its vulnerable structure. Due to the limited regeneration ability of the GP, current clinical treatment strategies (e.g., bone bridge resection and fat engraftment) always result in bone bridge formation, which will cause length discrepancy and angular deformity, thus making satisfactory outcomes difficult to achieve. The introduction of cartilage repair theory and cartilage tissue engineering technology may encourage novel therapeutic approaches for GP repair using tissue engineered GPs, including biocompatible scaffolds incorporated with appropriate seed cells and growth factors. In this review, we summarize the physiological structure of GPs, the pathological process, and repair phases of GP injuries, placing greater emphasis on advanced tissue engineering strategies for GP repair. Furthermore, we also propose that three-dimensional printing technology will play a significant role in this field in the future given its advantage of bionic replication of complex structures. We predict that tissue engineering strategies will offer a significant alternative to the management of GP injuries.