Mesenchymal stem cells and bovine bone mineral in sinus lift procedures--an experimental study in sheep

INTRODUCTION

New reconstructive and less invasive methods have been searched to optimize bone formation and osseointegration of dental implants in maxillary sinus augmentation.

PURPOSE

The aim of the presented ovine split-mouth study was to compare bovine bone mineral (BBM) alone and in combination with mesenchymal stem cells (MSCs) regarding their potential in sinus augmentation.

MATERIAL AND METHODS

Bilateral sinus floor augmentations were performed in six adult sheep. BBM and MSCs were placed into the test side and only BBM in the contra-lateral control side of each sheep. Animals were sacrificed after 8 and 16 weeks. Augmentation sites were analyzed by computed tomography, histology, and histomorphometry.

RESULTS

The initial volumes of both sides were similar and did not change significantly with time. A tight connection between the particles of BBM and the new bone was observed histologically. Bone formation was significantly (p = 0.027) faster by 49% in the test sides.

CONCLUSION

The combination of BBM and MSCs accelerated new bone formation in this model of maxillary sinus augmentation. This could allow early placement of implants.

[The influence of various adjuvant drugs used in intensive care on monocyte chemotaxis]

OBJECTIVE

Monocytes play an important part in all phases of both humoral and cell-mediated immune responses. In our study, we examined the influence of various drugs used in intensive care (omeprazole, ranitidine, potassium canrenoate, furosemide, clonidine, verapamil, and metamizole) on monocyte chemotaxis in vitro. The 0,1 fold, 1 fold, and 10 fold concentrations, which are detectable in serum after a clinically efficacious bolus injection of the respective drug, were tested.

METHODS

Using centrifugation, mononuclear cells were isolated from venous blood samples obtained from 10 healthy volunteers. Monocyte chemotaxis was determined by means of a microchemotaxis chamber. N-formyl-methionylleucylphenylalanine served as chemoattractant.

RESULTS

Omeprazole, ranitidine, and potassium canrenoate did not influence monocyte chemotaxis. While the 10 fold concentrations of the clinically efficacious serum concentrations of furosemide and verapamil caused a significant inhibition, the 10 fold concentrations of the clinically efficacious serum concentrations of clonidine and metamizole significantly stimulated monocyte motility.

CONCLUSION

Clinically relevant concentrations of the drugs tested did not alter monocyte chemotaxis in vitro. However, 10 fold concentrations of the clinically efficacious serum concentrations, which might occur in vivo due to drug interaction, cumulation, altered elimination, or accidental overdose, caused an inhibition (furosemide, verapamil) or a stimulation (clonidine, metamizole). An in vitro investigation does never permit to jump to clinical conclusions. However, our study gives impulses to conduct intensive care examinations concerning the influence of drugs on monocyte functions particularly since these cells are of great prognostical importance regarding sepsis.