Lack of effect of indomethacin on mesenchymal limb-bud cells in vitro

Do nonsteroidal anti-inflammatory drugs affect bone healing? A critical analysis

Nonsteroidal anti-inflammatory drugs (NSAIDs) play an essential part in our approach to control pain in the posttraumatic setting. Over the last decades, several studies suggested that NSAIDs interfere with bone healing while others contradict these findings. Although their analgesic potency is well proven, clinicians remain puzzled over the potential safety issues. We have systematically reviewed the available literature, analyzing and presenting the available in vitro animal and clinical studies on this field. Our comprehensive review reveals the great diversity of the presented data in all groups of studies. Animal and in vitro studies present so conflicting data that even studies with identical parameters have opposing results. Basic science research defining the exact mechanism with which NSAIDs could interfere with bone cells and also the conduction of well-randomized prospective clinical trials are warranted. In the absence of robust clinical or scientific evidence, clinicians should treat NSAIDs as a risk factor for bone healing impairment, and their administration should be avoided in high-risk patients.

Heterotopic ossification about the elbow: a therapist's guide to evaluation and management

Heterotopic ossification (HO) is a form of pathologic bone that often occurs in the elbow after a substantial traumatic injury and can complicate the functional outcome of the affected upper extremity. This article is designed to help the treating therapist better understand the complex process of HO. The pathophysiology, causes, associated risk factors, and signs and symptoms of HO are discussed in depth. The physician's management, including a classification system, diagnostic tools, and prophylactic measures, are explained. An extensive review of the literature regarding the therapist's management of HO reveals current misconceptions about passive range of motion (PROM). Traditional thought has advocated that PROM is a contraindication when HO is present because it can lead to the development or exacerbate the formation of HO. A review of the literature only reveals a few scientific studies that concluded that forcible manipulation of stiff joints can lead to myositis ossification. Most of the articles that have concluded that PROM is contraindicated have been erroneously based on anecdotal findings. This conclusion is misleading because forcible manipulation of a joint is not synonymous with PROM exercises. This article challenges popular belief and offers some alternative thinking for the therapist treating an elbow injury with HO as well as guidelines for the rehabilitation program.

Quantitative analysis of angiogenesis and growth of bone: effect of indomethacin exposure in a combined in vitro-in vivo approach

Nonsteroidal anti-inflammatory agents have been used experimentally and clinically to suppress a variety of physiological events, including angiogenesis and formation of bone. The exact mechanisms by which indomethacin alters skeletal tissue generation are unknown, due in part to methodological limitations. By the use of an organ culture assay and an animal model using intravital microscopy in mice bearing dorsal skinfold chambers, the effect of indomethacin on growth and angiogenesis of neonatal femora was characterized over 16 days. In both assays, femora significantly elongated with time (P < 0.05). The in vitro growth rate was more rapid than in vivo and dependent on the serum concentration, culture medium and age of mice. Although enhancing the serum content promoted cellular proliferation in organ culture, it dose-dependently suppressed femoral elongation, leading at 20% fetal calf serum to growth rates identical to those observed in vivo. Indomethacin supplementation (2 and 10 mg l-1) significantly accelerated longitudinal femoral growth in organ culture (P < 0.05), whereas in vivo indomethacin (2 mg kg-1) did not modulate either angiogenesis or elongation of bone. Our in vitro data propose a central role of serum in the regulation of bone formation. Although indomethacin altered femoral growth in vitro, our findings do not suggest that indomethacin suppresses angiogenesis or growth of bone in vivo. The complexity of physiological events in vivo may be obscuring a detectable effect.

Histological and in vitro studies supporting decreased uteroplacental blood flow as explanation for digital defects after administration of vasodilators

In a recent study, the vasodilating drugs nifedipine, nitrendipine, felodipine, and hydralazine induced phalangeal defects in rabbits, when given on day 16 of pregnancy. Histologically, the changes were characterized by disturbed chondrogenesis. In order to elucidate mechanisms behind the defects, the fetal concentration of felodipine was measured, and the fetal limb plates were examined histologically, at 0, 2, 4, 8, 12, and 24 hours after single oral administration of felodipine (12 mumol/kg) on day 16 in pregnant rabbits. The effects of nifedipine, nitrendipine, and felodipine were also investigated in an in vitro system, in which chick embryonic mesenchymal limb bud cells differentiated into chondrocytes. In this system, no inhibition of chondrogenesis was observed below concentrations 3 x 10(5) M. At this concentration, unspecific cytotoxicity was found. The highest fetal concentrations of felodipine were more than 500 times lower than what was required for in vitro toxicity. Histologically, the digital areas of the limb plates showed extensive edema and dilatation of marginal sinus within 2 hours. After 8 hours, rupture of the thin-walled vessels occurred with hemorrhages. Finally, small necroses and blisters were observed. Similar early changes have been reported in experiments where digital defects were induced by clamping uterine vessels. This study thus indicates that the phalangeal defects after administration of high doses of vasodilators are secondary to pharmacological action (associated with a significant reduction in the uteroplacental blood flow), and not a direct effect on fetal chondrogenesis.

Nonsteroid anti-inflammatory drugs prevent the recurrence of heterotopic ossification after excision

The prophylactic effect of nonsteroid anti-inflammatory drugs on the recurrence of high-grade periarticular heterotopic ossification after resection was studied in ten patients operated on for loosening of one or both components of a cemented total hip prosthesis. These drugs, given at a standard dosage for 1-3 weeks after surgery, prevented the recurrence of heterotopic ossification. In some patients the range of motion of their joint increased following surgery, while it remained unaffected in the majority. At follow-up 2-5 years after surgery, all patients walked well and there were no clinical or radiographs signs of loosening of the prosthetic components. It is concluded that treatment with NSAIDs following resection of periarticular heterotopic ossification prevents recurrence.

A comparison of indomethacin and diclofenac in the inhibition of experimental heterotopic new bone formation

The effect of the two nonsteroidal antiinflammatory drugs Diclofenac and Indomethacin on the formation of heterotropic and orthotopic bone in rats was compared. Experimental heterotopic bone formation was induced by implanting demineralized bone matrix into the abdominal wall of rats. Indomethacin (3 mg/kg), Diclofenac (3, 6 or 12 mg/kg), or saline were given as daily subcutaneous injections. 3H-proline and 45Ca were given 24 h before the animals were killed. The net amount of bone formed by induction after three weeks was decreased by 15% by Indomethacin and Diclofenac in a dose of 3 mg/kg. The higher dose of 6 mg/kg of Diclofenac caused a higher degree of inhibition (30%), while 12 mg/kg produced toxic effects. Orthotopic bone was not affected by treatment with Indomethacin or Diclofenac. Although both drugs inhibit prostaglandin synthesis to a different degree, they exert similar effects on induced heterotopic bone, suggesting that this action is caused by an inhibition of the inflammatory response to trauma.