Joint bleeding in factor VIII deficient mice causes an acute loss of trabecular bone and calcification of joint soft tissues which is prevented with aggressive factor replacement

Abstract

While chronic degenerative arthropathy is the main morbidity of haemophilia, a very high prevalence of low bone density is also seen in men and boys with haemophilia. This study investigates bone degradation in the knee joint of haemophilic mice resulting from haemarthrosis and the efficacy of aggressive treatment with factor VIII in the period surrounding injury to prevent bone pathology. Skeletally mature factor VIII knock-out mice were subjected to knee joint haemorrhage induced by puncture of the left knee joint capsule. Mice received either intravenous factor VIII treatment or placebo immediately prior to injury and at hours 4, 24, 48, 72 and 96 after haemorrhage. Mice were killed 2-weeks after injury and the joint morphology and loss of bone in the proximal tibia was assessed using microCT imaging. Quantitative microCT imaging of the knee joint found acute bone loss at the proximal tibia following injury including loss of trabecular bone volumetric density and bone mineral density, as well as trabecular connectivity density, number and thickness. Unexpectedly, joint injury also resulted in calcification of the joint soft tissues including the tendons, ligaments, menisci and cartilage. Treatment with factor VIII prevented this bone and soft tissue degeneration. Knee joint haemorrhage resulted in acute changes in adjacent bone including loss of bone density and mineralization of joint soft tissues. The rapid calcification and loss of bone has implications for the initiation and progression of osteoarthritic degradation following joint bleeding.

Keywords: bone density; factor VIII; haemarthrosis; joint degradation; microCT; mineralization.

Conflict of interest statement

Conflict of Interest:

Paul E. Monahan has received remuneration for consulting and speaker work for Baxter Health Care Corporation.

Ted A. Bateman has received remuneration for consulting and speaker work for Baxter Health Care Corporation.

© 2014 John Wiley & Sons Ltd.

Figures

Figure 1

Properties of bone measured by microCT in the proximal tibia adjacent to the joint at two weeks following unilateral induced joint hemorrhage. Separate groups of FVIII−/− mice were treated with either Placebo (physiologic saline) or with recombinant FVIII. Trabecular bone volumetric density (BV/TV), Trabecular Thickness, Trabecular Connectivity Density, and Trabecular Number, Volumetric bone mineral density (vBMD) and Bone Tissue Mineral Density (mean±SEM) for injured/uninjured limbs of placebo-treated compared to FVIII-treated mice (* denotes statistical significance p<0.05 for the difference between injured and uninjured within each treatment group).

Figure 2

Three-dimensional rendering of the joint from microCT imaging for the uninjured (A & B) and injured (C & D) knee from the placebo (A & C) and FVIII treated (B & D) mice. The blue inset for each condition is an image of the trabecular bone region of analysis of the proximal tibia, demonstrating less bone in the injured, placebo-treated mouse.

Figure 3

Left: Injured knee joint from placebo-treated FVIII−/− mouse showing calcification of the patella, patellar tendon, menisci, ligaments, and cartilage. Calcifications rendered in green. Center: Injured knee from FVIII-treated mouse does not have this mineralization present. Right: Uninjured knee from placebo-treated mouse does not have mineralization present

Figure 4

Top: Axial, cross-sectional image of the distal femur from injured (left) and uninjured (right) limb from a placebo-treated mice. Calcifications of the patellar tendon and distal femur tendon insertion rendered in green. Profile analysis line spans from the endosteal surface (circle) to the edge of the calcification (arrow). Bottom: Corresponding intensity values along the red (injured limb)and blue (uninjured limb) profile lines shown in above images (location of the circle is at x=0 on the graph). Areas of calcification had lower density (1086 mgHA/cc) than the cortical bone (1449mgHA/cc).