Clodronate: mechanisms of action on bone remodelling and clinical use in osteometabolic disorders

Unraveling the complex roles of macrophages in obese adipose tissue: an overview

Macrophages, a heterogeneous population of innate immune cells, exhibit remarkable plasticity and play pivotal roles in coordinating immune responses and maintaining tissue homeostasis within the context of metabolic diseases. The activation of inflammatory macrophages in obese adipose tissue leads to detrimental effects, inducing insulin resistance through increased inflammation, impaired thermogenesis, and adipose tissue fibrosis. Meanwhile, adipose tissue macrophages also play a beneficial role in maintaining adipose tissue homeostasis by regulating angiogenesis, facilitating the clearance of dead adipocytes, and promoting mitochondrial transfer. Exploring the heterogeneity of macrophages in obese adipose tissue is crucial for unraveling the pathogenesis of obesity and holds significant potential for targeted therapeutic interventions. Recently, the dual effects and some potential regulatory mechanisms of macrophages in adipose tissue have been elucidated using single-cell technology. In this review, we present a comprehensive overview of the intricate activation mechanisms and diverse functions of macrophages in adipose tissue during obesity, as well as explore the potential of drug delivery systems targeting macrophages, aiming to enhance the understanding of current regulatory mechanisms that may be potentially targeted for treating obesity or metabolic diseases.

Analyzing One Cell at a TIME: Analysis of Myeloid Cell Contributions in the Tumor Immune Microenvironment

Tumor-mediated regulation of the host immune system involves an intricate signaling network that results in the tumor's inherent survival benefit. Myeloid cells are central in orchestrating the mechanisms by which tumors escape immune detection and continue their proliferative programming. Myeloid cell activation has historically been classified using a dichotomous system of classical (M1-like) and alternative (M2-like) states, defining general pro- and anti-inflammatory functions, respectively. Explosions in bioinformatics analyses have rapidly expanded the definitions of myeloid cell pro- and anti-inflammatory states with different combinations of tissue- and disease-specific phenotypic and functional markers. These new definitions have allowed researchers to target specific subsets of disease-propagating myeloid cells in order to modify or arrest the natural progression of the associated disease, especially in the context of tumor-immune interactions. Here, we discuss the myeloid cell contribution to solid tumor initiation and maintenance, and strategies to reprogram their phenotypic and functional fate, thereby disabling the network that benefits tumor survival.

Transient osteoporosis of the hip and subclinical hypothyroidism: an unusual dangerous duet? Case report and pathogenetic hypothesis

BACKGROUND

Transient osteoporosis of the hip (TOH) is a rare and temporary clinical condition characterised by bone marrow edema (BME), severe pain, and functional limitation. It commonly occurs in middle-aged men or in women in the last trimester of pregnancy. TOH usually resolves with conservative therapy but may predispose to hip fracture or progression to avascular necrosis (AVN). Etiology is still unclear, although several pathophysiological mechanisms underpinning this condition has been proposed. We describe the management of an unusual case of TOH occurred in a patient with subclinical hypothyroidism.

CASE PRESENTATION

A clinical case of a 46-year-old man with severe pain in the left anterior thigh is presented. After a comprehensive clinical and radiological approach, a TOH was diagnosed. Moreover, biochemical assessment suggested the presence of subclinical hypothyroidism. After 3 months of treatment with clodronate, physical therapy and hormone replacement therapy (HRT) a significant improvement of clinical and radiological outcomes was observed.

CONCLUSION

Several pathological conditions have been related to development of TOH. In our case, we suggested for the first time a role of subclinical hypothyroidism as novel contributory factor for the onset of this condition, providing pathophysiological mechanisms and a scientific rationale for pharmacological treatment.

Mechanically stimulated ATP release from mammalian cells: systematic review and meta-analysis

Body tissues are exposed to a complex mechanical environment, which is perceived by cells and converted to biochemical signals such as ATP release. We performed a meta-analysis of 278 systematically identified studies that investigated mechanically stimulated ATP release (MSAR) to quantify the amounts, kinetics and mechanisms of ATP release under normal and pathological conditions. Mechanically stimulated mammalian cells were shown to release 38.6 [95% confidence interval (CI): 18.2-81.8] amol ATP/cell on average with a characteristic time constant of 32 s (95% CI: 16-66). Analysis of ATP release mechanisms revealed the existence of conserved and tissue-specific release routes. We assessed ATP release in pathophysiological states, and found that ATP release was elevated in inflammation and injury, and attenuated in hereditary (such as cystic fibrosis) and metabolic (such as type II diabetes) conditions. Our study links cell-specific ATP release mechanisms to pathophysiological changes in ATP release and allows ATP release-targeting interventions to be mapped to site-specific effects. This work demonstrates that quantitative synthesis of basic research can generate non-trivial hypotheses and inform evidence-driven translational studies.

Targeting Macrophages as a Potential Therapeutic Intervention: Impact on Inflammatory Diseases and Cancer

Macrophages, cells belonging to the innate immune system, present a high plasticity grade, being able to change their phenotype in response to environmental stimuli. They play central roles during development, homeostatic tissue processes, tissue repair, and immunity. Furthermore, it is recognized that macrophages are involved in chronic inflammation and that they play central roles in inflammatory diseases and cancer. Due to their large involvement in the pathogenesis of several types of human diseases, macrophages are considered to be relevant therapeutic targets. Nanotechnology-based systems have attracted a lot of attention in this field, gaining a pivotal role as useful moieties to target macrophages in diseased tissues. Among the different approaches that can target macrophages, the most radical is represented by their depletion, commonly obtained by means of clodronate-containing liposomal formulations and/or depleting antibodies. These strategies have produced encouraging results in experimental mouse models. In this review, we focus on macrophage targeting, based on the results so far obtained in preclinical models of inflammatory diseases and cancer. Pros and cons of these therapeutic interventions will be highlighted.

Clodronate as a Therapeutic Strategy against Osteoarthritis

Osteoarthritis (OA), the most prevalent musculoskeletal pathology, is mainly characterized by the progressive degradation of articular cartilage due to an imbalance between anabolic and catabolic processes. Consequently, OA has been associated with defects in the chondrocitic differentiation of progenitor stem cells (PSCs). In addition, SOX9 is the transcription factor responsible for PSCs chondrogenic commitment. To evaluate the effects of the non-amino bisphosphonate clodronate in OA patients we investigated SOX9 gene expression in circulating progenitor cells (CPCs) and in an in vitro OA model. We evaluated pain intensity, mental and physical performance in OA patients, as well as serum biomarkers related to bone metabolism. In addition, in order to improve therapeutic strategies, we assayed nanoparticle-embedded clodronate (NPs-clo) in an in vitro model of chondrogenic differentiation. Our data showed upregulation of SOX9 gene expression upon treatment, suggesting an increase in chondrocytic commitment. Clodronate also reduced osteoarticular pain and improved mental and physical performance in patients. Furthermore, NPs-clo stimulated SOX9 expression more efficaciously than clodronate alone. Clodronate may therefore be considered a good therapeutic tool against OA; its formulation in nanoparticles may represent a promising challenge to counteract cartilage degeneration.

The efficacy and safety of vertebral fracture prevention therapies in post-menopausal osteoporosis treatment: Which therapies work best? a network meta-analysis

Objectives

Osteoporosis has become an increasing concern for older people as it may potentially lead to osteoporotic fractures. This study is designed to assess the efficacy and safety of ten therapies for post-menopausal women using network meta-analysis.

Methods

We conducted a systematic search in several databases, including PubMed and Embase. A random-effects model was employed and results were assessed by the odds ratio (OR) and corresponding 95% confidence intervals (CI). Furthermore, with respect to each outcome, each intervention was ranked according to the surface under the cumulative ranking curve (SUCRA) value.

Results

With respect to preventing new vertebral fractures (NVF), all ten drugs outperformed placebo, and etidronate proved to be the most effective treatment (OR 0.24, 95% CI 0.14 to 0.39). In addition, zoledronic acid and parathyroid hormone ranked higher compared with the other drugs. With respect to preventing clinical vertebral fractures (CVF), zoledronic acid proved to be the most effective drug (OR = 0.25, 95% CI 0.08 to 0.92), with denosumab as a desirable second option (OR = 0.48, 95% CI 0.22 to 0.96), when both were compared with placebo. As for adverse events (AE) and severe adverse events (SAE), no significant difference was observed. According to SUCRA, etidronate ranked first in preventing CVF; parathyroid hormone and zoledronic acid ranked highly in preventing NVF and CVF. Raloxifene was safe with a high rank in preventing AEs and SAEs though performed unsatisfactorily in efficacy.

Conclusions

This study suggests that, taking efficacy and safety into account, parathyroid hormone and zoledronic acid had the highest probability of satisfactory performance in preventing osteoporotic fractures.

Cite this article: G. Wang, L. Sui, P. Gai, G. Li, X. Qi, X. Jiang. The efficacy and safety of vertebral fracture prevention therapies in post-menopausal osteoporosis treatment: Which therapies work best? a network meta-analysis. Bone Joint Res 2017;6:452–463. DOI: 10.1302/2046-3758.67.BJR-2016-0292.R1.

Clodronate news of efficacy in osteoporosis

Clodronate belongs to Bisphosphonates family and it has been studied especially for osteoporosis treatment, Paget's disease, osteolytic metastases, hypercalcemia malignancy and some childhood skeletal diseases. Besides the osteoporosis treatment, it has been successfully used for treating tumoral osteolysis and for bone localization of multiple myeloma, hypercalcemia malignancy, primary hyperparathyroidism, Paget's disease and algodystrophy. Filipponi study showed a statistically significant reduction of the incidence of vertebral fractures after 4 years of treatment with clodronate, intravenously administered at a dose of 200 mg every three weeks. Frediani study, published in 2003 on BONE, proved the clodronate efficacy in the prevention of fractures caused by glucocorticoid-induced osteoporosis (GIO). Clodronate doses of 800 mg/day per os and 100 mg i.m./week are substantially equivalent, because the oral absorption is about 1,9%. A higher efficacy on BMD was documented in various works, especially in cohorts of patients with a greater fracture risk, using higher doses (1600 mg per os). This has led to the hypothesis of using clodronate 200 mg i.m. formulation. Clodronate is an osteoporosis drug that can be assumed in different doses (100 mg i.m./week, clodronate 200 mg i.m. every 2 weeks) considering the risk band, identified by algorithms (FRAX o DeFRA), by BMD and by the presence of at least one risk factor. That means that it is possible to envisage a differentiated use of clodronate adapting the doses to the fracture risk and to the severity of pain symptoms, thus promoting a greater adherence to the therapy. To conclude clodronate is helpful in reducing fracture risk, is safe, well tolerated, and has a good rate cost/effectiveness in patients with fracture risk over 7% established with FRAX.

Back pain-related disability and quality of life in patients affected by vertebral fractures: data from baseline characteristics of population enrolled in Denosumab In Real Practice (DIRP)

BACKGROUND

Spine fragility fractures lead to a significant acute and/or chronic pain and worsening of quality of life. Denosumab is effective in reducing the risk of new vertebral fractures, but its effectiveness on pain relief and improvement of the quality of life in patients with spine fractures are not well known.

AIM

The aim of this paper is to describe the baseline demographic and clinical characteristics, back pain-related disability and quality of life of the Denosumab In Real Practice (DIRP) study population.

METHODS

DIRP is a multicenter prospective observational study evaluating the effectiveness of denosumab in reducing back pain-related disability and Health-Related Quality of Life (HRQoL) of women with postmenopausal osteoporosis who had already experienced at least one vertebral fragility fracture. Our evaluation protocol includes history of fractures, Spine Pain Index (SPI), HRQoL, bone mineral density (BMD) and radiological assessment of vertebral fragility fractures.

RESULTS

Two hundred and twenty-three post-menopausal women, who received a prescription for denosumab, were enrolled. The mean SPI score was 58.6 ± 21.4 SD, and 187 (83.86%) women experienced a moderate-severe pain. The mean HRQoL health state value was 0.54 ± 0.27 SD using EQ-5D index, whereas the mean Physical and Mental Health Composite Scale scores derived from the SF-12 were 31.06 ± 7.77 SD and 39.20 ± 11.03 SD.

DISCUSSION AND CONCLUSIONS

Baseline characteristics of DIRP study cohort indicate that patients who received a prescription of denosumab in Campania region are affected by severe osteoporosis with highly prevalent vertebral fractures, disabling back pain and poor health-related quality of life. This is in contradiction with what it is expected by a front-line drug for osteoporosis.

Inhibitory effect of bisphosphonate on osteoclast function contributes to improved skeletal pain in ovariectomized mice

The aim of this study was to evaluate skeletal pain associated with osteoporosis and to examine the inhibitory effect of bisphosphonate (BP) on pain in an ovariectomized (OVX) mouse model. We evaluated skeletal pain in OVX mice through an examination of pain-like behavior as well as immunohistochemical findings. In addition, we assessed the effects of alendronate (ALN), a potent osteoclast inhibitor, on those parameters. The OVX mice showed a decrease in the pain threshold value, and an increase in the number of c-Fos immunoreactive neurons in laminae I-II of the dorsal horn of the spinal cord. Alendronate caused an increase in the pain threshold value and inhibited c-Fos expression. The serum level of tartrate-resistant acid phosphatase 5b, a marker of osteoclast activity, was significantly negatively correlated with the pain threshold value. Furthermore, we found that an antagonist of the transient receptor potential channel vanilloid subfamily member 1, which is an acid-sensing nociceptor, improved pain-like behavior in OVX mice. These results indicated that the inhibitory effect of BP on osteoclast function might contribute to an improvement in skeletal pain in osteoporosis patients.

Effect of clodronate treatment on risk of fracture: a systematic review and meta-analysis

A systematic review and a meta-analysis of data of literature were performed to evaluate the efficacy of clodronate in the reduction of risk of fractures in patients with osteoporosis or tumour diseases. A systematic review was conducted to identify original articles, reviews, and any other literature report suitable for the purposes of the meta-analysis, limited to prospective randomized trials that included a placebo or an untreated control arm. The search has identified 18 trials, 13 of which in patients with cancer diseases (breast cancer and multiple myeloma were prevalent), 4 in patients with osteoporosis/low BMD, and 1 in elderly women living in community. A placebo control arm was used in 13 trials. Treatment and follow-up duration ranged from 3 months to 5 years. The meta-analysis showed that treatment with clodronate was associated with a reduction of the probability of new fractures compared with controls (OR = 0.572, 95% CI 0.465-0.704 for new vertebral fractures; OR = 0.668, 95% CI 0.494-0.905 for new non-vertebral fractures; and OR = 0.744, 95% CI 0.635-0.873 for new overall fractures in those articles where vertebral and non-vertebral new fractures were not considered separately). Similar findings were observed in the separate analysis in patients with cancer forms or osteoporosis. The results of the meta-analysis have demonstrated that clodronate is effective in reducing the risk of vertebral, non-vertebral, and overall fractures in patients with skeletal fragility.

Bilateral renal ischemia after kyphoplasty and clodronate treatment: a case report

INTRODUCTION

The most common adverse effects associated with bisphosphonates are renal toxicity, acute-phase reactions, gastrointestinal toxicity, osteonecrosis of the jaw, transitory fever and uveitis. We report a unique adverse case of vasculitis induced by clodronate.

CASE PRESENTATION

A 61-year-old Caucasian woman developed bilateral renal ischemia after kyphoplasty and clodronate treatment for lumbar vertebral fracture. Tests revealed a vasculitis due to clodronate treatment. The antithrombotic and immunosuppressive drugs allowed us to reduce the extent of the renal ischemia. In the following months the increased auto-antibodies returned to the healthy physiological range, but the chronic renal failure persisted.

CONCLUSIONS

Drug-induced vasculitis is an inflammation of blood vessels caused by the use of various pharmaceutical agents. The spectrum of drug-induced vasculitis can range from cutaneous rashes to fatal multi-organ involvement. To the best of our knowledge this is the first documented case of drug-induced vasculitis caused by clodronate in the literature. Previously, it was verified that clodronate injection could increase the pro-apoptotic action on immune cells. Further studies are necessary to clarify the role of bisphosphonates on drug-inducing vasculitis.

Treatment for experimental autoimmune neuritis with clodronate (Bonefos)

Experimental autoimmune neuritis (EAN) serves as an animal model for human Gullain-Barre syndrome (GBS), an autoimmune disease causing demyelination and inflammation of peripheral nerves. Macrophages, which play a major role in this autoimmune inflammatory process, can be selectively targeted by high doses of bisphophonates. The goal of this study was to examine the effect of the bisphosphonate, clodronate, on the severity of the EAN model. EAN was induced in female adult rats by immunization with bovine peripheral myelin. A number of treatment protocols with clodronate were used based on the common dosage regimen of 20 mg/kg in humans starting with the appearance of clinical signs on day 10 post-immunization. The clinical parameters measured included a clinical score, a motor performance test performed on a Rotarod and body weight. The expression of the matrix metaloprotease (MMP-9) in the sciatic nerves was measured as a marker of inflammatory macrophages. Treatment with clodronate, 20 mg/kg daily and 40 mg/kg every 2 days, significantly reduced the disease severity (a 75% decrease in severity, p < 0.01 by ANOVA) as measured by the clinical score compared to controls. Performance on the Rotarod test and body weight confirmed the clinical score findings. MMP-9 expression levels were significantly lower in the sciatic nerves of clodronate-treated rats. The present findings support the efficiency of clodronate in inflammatory diseases of the peripheral nervous system. The mechanism of action includes inhibition of inflammatory macrophages. The results suggest the use of bisphosphonates be considered in humans with GBS.

Clinical utility of clodronate in the prevention and management of osteoporosis in patients intolerant of oral bisphosphonates

Bisphosphonates have a long history in the treatment of osteoporosis and bone-related disease. This review focuses on the use of a specific nonaminobisphosphonate, clodronate, which appears to be much better tolerated than other bisphosphonates and free of high-risk contraindications. Specifically, this paper reviews its use in the prevention of osteoporosis in postmenopausal women, taking into account its tolerability profile and recent safety issues arising regarding the use of bisphosphonates.

"Twice-a-month" clodronate 200 mg IM: a new dosing regimen and improved therapy adherence in the treatment of postmenopausal osteoporosis

INTRODUCTION

The identification of therapeutic strategies aimed both at preventing and treating osteoporosis and osteoporotic fractures has become increasingly important; in particular, it is essential to promote adequate patient adherence to treatment. The primary aim of this study was to evaluate the effects on lumbar and femoral bone mass density (BMD) after two different intramuscular (IM) dosing regimens of clodronate (CLD), a bisphosphonate shown to be efficacious in reducing the incidence of both vertebral and nonvertebral fractures. Secondary aims were the assessments of bone resorption markers, safety, tolerability, pain, and patient compliance.

METHODS

Sixty women with postmenopausal osteoporosis were randomized to two groups: group A (CLD 100 mg IM weekly for 12 months), and group B (CLD 200 mg IM every 2 weeks for 12 months). All patients received 1 g of calcium supplemented with 800 IU vitamin D(3), orally, once daily for 12 months Lumbar and femoral BMD, measured by DEXA Norland XR-36 (Norland Co., Fort Atkinson, WI), and bone turnover markers were assessed at baseline and at 12 months. Each patient was administered a visual analog scale of pain at baseline and after 6 and 12 months of treatment.

RESULTS

A significant increase of BMD in both groups and in both skeletal sites was observed at 12 months versus baseline. In group A (n=28), lumbar BMD increased by 3.5% and femoral BMD by 2.1%; in group B (n=32), lumbar and femoral BMD rose by 3.4% and 2.2%, respectively. No difference was observed between groups. Bone resorption markers significantly reduced from baseline. Pain significantly improved as early as after 6 months of therapy and even more after 12 months, although no significant difference between the two groups was observed. The most common side effect was pain at the injection site, particularly in group B. Six patients in group A discontinued treatment and failed adherence to the therapeutic protocol. Conversely, no patient from group B discontinued therapy.

CONCLUSION

In agreement with published data, in our two groups of patients, therapy with IM CLD at the doses of 100 mg/week and 200 mg/2 weeks was shown to be effective in increasing BMD, without differences between the two dosing regimens in all assessed efficacy parameters. Therefore, the "twice-a-month" regimen with 200 mg IM CLD may well promote an improved adherence with the same clinical efficacy and safety profile.

Clodronic acid formulations available in Europe and their use in osteoporosis: a review

Clodronic acid (Cl(2)-MBP [dichloromethylene bisphosphonic acid], clodronate) is a halogenated non-nitrogen-containing bisphosphonate with antiresorptive efficacy in a variety of diseases associated with excessive bone resorption. The drug is believed to inhibit bone resorption through induction of osteoclast apoptosis, but appears also to possess anti-inflammatory and analgesic properties that contrast with the acute-phase and inflammatory effects seen with nitrogen-containing bisphosphonates. Clodronic acid has been shown to be effective in the maintenance or improvement of bone mineral density when given orally, intramuscularly or intravenously in patients with osteoporosis. Use of the drug is also associated with reductions in fracture risk. The intramuscular formulation, which is given at a dose of 100 mg weekly or biweekly, is at least as effective as daily oral therapy and appears more effective than intermittent intravenous treatment. Intramuscular clodronic acid in particular has also been associated with improvements in back pain. The drug is well tolerated, with no deleterious effects on bone mineralization, and use of parenteral therapy eliminates the risk of gastrointestinal adverse effects that may be seen in patients receiving bisphosphonate therapy.

Gut ischemia/reperfusion induced acute lung injury is an alveolar macrophage dependent event

BACKGROUND

Although the role of the lung alveolar macrophage (AM) as a mediator of acute lung injury (ALI) after lung ischemia/reperfusion (I/R) has been suggested by animal experiments, it has not been determined whether AMs mediate ALI after intestinal I/R. The objective of this study was to determine the effect of AM elimination on ALI after intestinal I/R in rats.

METHODS

Male Wistar rats (n = 90) were randomly divided into three groups: the clodronate-liposomes (CLOD-LIP) group received intratracheal treatment with CLOD-LIP; the liposomes (LIP) group received intratracheal treatment with LIP; and the nontreated (UNTREAT) group received no treatment. Twenty-four hours later each group was randomly divided into three subgroups: the intestinal I/R subgroup was subjected to 45-minute intestinal ischemia and 2-hour reperfusion; the laparotomy (LAP) subgroup was subjected to LAP and sham procedures; the control (CTR) subgroup received no treatment. At the end of reperfusion, ALI was quantitated in all the animals by the Evans blue dye (EBD) method.

RESULTS

ALI values are expressed as EBD lung leakage (microg EBD/g dry lung weight). EBD lung leakage values in the CLOD-LIP group were 32.59 +/- 12.74 for I/R, 27.74 +/- 7.99 for LAP, and 33.52 +/- 10.17 for CTR. In the LIP group, lung leakage values were 58.02 +/- 18.04 for I/R, 31.90 +/- 8.72 for LAP, and 27.17 +/- 11.48 for CTR. In the UNTREAT group, lung leakage values were 55.60 +/- 10.96 for I/R, 35.99 +/- 6.89 for LAP, and 30.83 +/- 8.41 for CTR. Within each group, LAP values did not differ from CTR values. However, in the LIP and UNTREAT groups, values for both the LAP and CTR subgroups were lower than values for the I/R subgroup (p < 0.001). The CLOD-LIP I/R subgroup value was less (p < 0.001) than the I/R subgroup values in the LIP and UNTREAT groups. These results indicated that I/R provokes ALI that can be prevented by CLOD-LIP treatment, and further suggested that AMs are essential for ALI occurrence induced by intestinal I/R in rats.

Depletion of alveolar macrophages by clodronate-liposomes aggravates ischemia-reperfusion injury of the lung

BACKGROUND

Macrophages play an important role in ischemia-reperfusion injury of various organs. Liposome-encapsulated dichloromethylene diphosphonate (clodronate-liposome) depletes local macrophages in vivo. However, the effect of this approach on alveolar macrophages in pulmonary ischemia-reperfusion injury has not yet been evaluated.

METHODS

Clodronate-liposomes in Hanks' balanced salt solution (HBSS) or HBSS alone were given intratracheally to anesthetized male Lewis rats in the clodronate or the control group (n = 6/each group). After 3 days, we subjected the lungs to ischemia (37 degrees C, 60 minutes) and reperfusion (60 minutes) in an isolated blood-perfused rat lung model. Analysis during reperfusion included gas exchange, hemodynamics, and airway mechanics. At the end of reperfusion, we determined leukocyte recruitment and macrophage inflammatory protein-2 (MIP-2) in bronchoalveolar lavage fluid.

RESULTS

In the clodronate group, 4 experiments had to be terminated within 10 minutes of reperfusion because of severe lung injury, whereas all lungs of the controls could be studied during the 60-minute reperfusion period (p < 0.05). Clodronate significantly decreased dynamic airway compliance (p < 0.05) and increased airway resistance. Besides a tendency toward greater pulmonary vascular resistance, this was associated with recruitment of polymorphonuclear neutrophils (p < 0.05) and increased MIP-2 concentrations in the bronchoalveolar lavage fluid (p < 0.05).

CONCLUSIONS

Intratracheal administration of liposome-encapsulated clodronate does not benefit, but aggravates, warm ischemia-reperfusion injury of the lung, increasing MIP-2-associated alveolar neutrophil recruitment and airway mechanical dysfunction.