Cytokines and Insulin Resistance after Zoledronic Acid-Induced Acute Phase Response

Osteoporosis, bisphosphonates, and ocular inflammation

BACKGROUND

Osteoporosis, as a musculoskeletal disease, is very common, especially in the era of aging society. It is described by a reduction in bone strength and increased risk of fractures, which are linked to considerable morbidity, mortality, and high healthcare burdens. Bisphosphonates are the most commonly used drugs to manage osteoporosis and they consequently reduce fracture risk. However, one of the clinical challenges is fear of side effects in patients who are using bisphosphonates as the administration of these drugs is lengthy. Ocular inflammation has been reporting as one of the potential vision-threatening side effects of bisphosphonates.

PURPOSE

To review previously reported ocular inflammation in patients taking bisphosphonates.

METHOD

A literature survey was conducted using databases in order to collect data for a narrative review of published reports regarding ocular side effects of bisphosphonates.

RESULTS

People taking bisphosphonates were at a relatively low risk of ocular inflammation, with the onset from a few hours after exposure up to more than 3 years. The release of inflammatory mediators mainly by activated gamma delta T cells in response to bisphosphonates was the main cause of ocular inflammation.

CONCLUSION

Strategies for treating patients with osteoporosis should consider the potential ocular side effects of bisphosphonates. Ocular inflammation, as one of the side effects of bisphosphonates, is a serious sight-threatening sign and should be taken seriously. Greater awareness of the association between bisphosphonate use and ocular inflammation may allow for earlier identification and timely treatment of future cases.

Adiponectin signaling and its role in bone metabolism

Adiponectin, the most prevalent adipo-cytokine in plasma plays critical metabolic and anti-inflammatory roles is fast emerging as an important molecular target for the treatment of metabolic disorders. Adiponectin action is critical in multiple organs including cardio-vascular system, muscle, liver, adipose tissue, brain and bone. Adiponectin signaling in bone has been a topic of active investigation lately. Human association studies and multiple mice models of gene deletion/modification failed to define a clear cause and effect of adiponectin signaling in bone. The most plausible reason could be the multimeric forms of adiponectin that display differential binding to receptors (adipoR1 and adipoR2) with cell-specific receptor variants in bone. Discovery of small molecule agonist of adipoR1 suggested a salutary role of this receptor in bone metabolism. The downstream signaling of adipoR1 in osteoblasts involves stimulation of oxidative phosphorylation leading to increased differentiation via the likely suppression of wnt inhibitor, sclerostin. On the other hand, the inflammation modulatory effect of adiponectin signaling suppresses the RANKL (receptor activator of nuclear factor κ-B ligand) - to - OPG (osteprotegerin) ratio in osteoblasts leading to the suppression of osteoclastogenic response. This review will discuss the adiponectin signaling and its role in skeletal homeostasis and critically assess whether adipoR1 could be a therapeutic target for the treatment of metabolic bone diseases.

Complex interplay among adiposity, insulin resistance and bone health

Obesity and osteoporosis are common public health problems. Paradoxically, while obesity is associated with higher bone density, type 2 diabetic obese individuals have an increased fracture risk. Although obesity and insulin resistance co-exist, some obese individuals remain insulin-sensitive. We suggest that the apparent paradox relating obesity, bone density and fracture risk in type 2 diabetes may be at least partly influenced by differences in bone strength and quality between insulin-resistant and insulin-sensitive obese individuals. In this review, we focus on the complex interplay between, adiposity, insulin resistance and osteoporotic fracture risk and suggest that this is an important area of study that has implications for individually tailored and targeted treatment to prevent osteoporotic fracture in obese type 2 diabetic individuals.

Effect of a single intravenous zoledronic acid administration on biomarkers of acute kidney injury (AKI) in patients with osteoporosis: a pilot study

AIMS

The pilot study was designed to evaluate the early effect of intravenous (i.v.) zoledronic acid (ZA) on renal function.

METHODS

Five mg i.v. ZA was administered to 23 patients with osteoporosis (17 women and 6 men, mean age 73 ± 7 SD years). Urinary NGAL, KIM-1, and MCP-1, plasma (p) MCP-1 and serum (s) IL-18, serum calcium (sCa), Creatinine clearance (CrCl), parathyroid hormone (PTH), plasma C-terminal FGF23 (pFGF23), serum (s) Klotho, calcium excretion (CaEx) and renal threshold phosphate concentration/GFR (TmPO₄ /GFR) were assessed at baseline, 24 h and Day 30 after administration.

RESULTS

There was a significant decrease in sCa and CaEx at 24 h (-4.1 ± 2.8%, P < 0.01 and -28 ± 59%, P < 0.05, respectively) and Day 30 (-3.9 ± 4%, P < 0.001 and -26 ± 43%, P < 0.01) and a significant increase in PTH (79.8 ± 95.8%) at Day 30 (P < 0.001) compared to baseline. TmPO₄ /GFR decreased significantly at 24 h and Day 30 (-8.6 ± 15.9%, P < 0.05 and -11.3 ± 13.5%, P < 0.001) compared to baseline. We observed no difference in the concentration of pFGF23, sKlotho and urinary AKI biomarkers at any time points. Mean levels of sIL-18 and pMCP-1 increased significantly at 24 h (44 ± 88%; P < 0.01 and 198 ± 237%; P < 0.001) and returned to baseline at Day 30.

CONCLUSIONS

Our pilot study suggests that there is no direct acute effect of ZA on kidney function. The increase in plasma MCP-1 and serum IL-18 concentration could be associated with the stimulation of immunity mechanisms occurring soon after the administration of the drug. Secondary hyperparathyroidism develops shortly after the infusion of ZA and is maintained even after 1 month.

First cases of calcium pyrophosphate deposition disease after zoledronic acid therapy

A number of medications promote the development of calcium pyrophosphate deposition disease (CPDD). We report 2 cases of acute CPDD after intravenous zoledronic acid therapy. Case #1: a 63-year-old female was admitted for vertebroplasty at the site of an osteoporotic fracture. She received an intravenous infusion of zoledronic acid 5mg on the day after the procedure. Acute CPDD developed in her right knee 24hours later. Findings from joint aspiration and standard radiography confirmed the diagnosis. Case #2: this 79-year-old woman had a history of CPDD was on glucocorticoid and hydroxychloroquine therapy for lupus. She was given an intravenous infusion of zoledronic acid 5mg as prophylaxis of glucocorticoid-induced osteoporosis. Joint pain and a fever developed later on the same day. After 5 days, she had arthritis of the right wrist, laboratory evidence of systemic inflammation, and hypocalcemia. Radiographs showed evidence of CPDD. A Medline search identified 6 cases of bisphosphonate-related CPDD, including 2 due to pamidronate, 2 to etidronate, 1 to alendronic acid, and 1 to neridronic acid. The features were similar to those in our patients, with a short time to onset, systemic inflammation in many cases, a tendency toward hypocalcemia, and radiographs that often showed evidence of CPDD. Bisphosphonate-induced CPDD is a rare eventuality that should nevertheless be borne in mind by rheumatologists. Also, in patients with CPDD while taking bisphosphonate therapy, a role for the drug in the symptoms should be considered.

Oral Bisphosphonates and Risk of Wet Age-Related Macular Degeneration

PURPOSE

To examine the risk of age-related macular degeneration (AMD) with oral bisphosphonates.

DESIGN

Three study designs were used: (1) disproportionality analysis; (2) case-control study; (3) self-controlled case series (SCCS).

METHODS

setting: (1) Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) Database; (2) 2 patient cohorts from British Columbia, Canada.

STUDY POPULATION

(1) All reports of AMD to the FDA with oral bisphosphoantes; (2) patients with wet AMD in British Columbia (2009-2013) and 1 million controls (2000-2007).

INTERVENTION

Oral bisphosphonates.

MAIN OUTCOME MEASURES

(1) Reports of AMD to the FDA; (2) first diagnosis of wet AMD verified by a retina specialist in British Columbia.

RESULTS

In the disproportionality analysis there were 133 cases of AMD reported with alendronate, 20 with ibandronate, and 14 with risedronate. The reported odds ratios (RORs) for alendronate, ibandronate, and risedronate were 3.82 (95% CI: 2.94-4.96), 2.40 (95% CI: 1.49-3.86), and 2.87 (95% CI: 1.58-5.19), respectively. In the case-control analysis there were 6367 cases and 6370 corresponding controls. The adjusted OR for wet AMD among regular users of bisphosphonates in the 1, 2, and 3 years prior to the index date were 1.24 (1.12-1.38), 1.38 (1.22-1.56), and 1.59 (1.38-1.82), respectively. In the SCCS analysis there were 198 cases of wet AMD on continuous bisphosphonate therapy. The rate ratio for wet AMD for continuous bisphosphonate use was 1.99 (95% CI: 1.41-2.79). We did not have information on intravenous bisphosphonates.

CONCLUSIONS

Continuous users of oral bisphosphonates are at a higher risk of developing wet AMD. Given the observational nature of this study and limitation of the data, future studies are needed to confirm these findings.

Zoledronic acid induces apoptosis and autophagy in cervical cancer cells

Cervical cancer is one of the most common gynecological cancers in association with high mortality and morbidity. The present study was aimed to investigate the in vitro effects of zoledronic acid (ZA) on viability and induction of apoptosis and autophagy as well as inflammatory effects in three human cervical cancer cell lines (HeLa, SiHa, and CaSki). Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. Induction of apoptosis was determined by quantitation of expression level of B cell lymphoma 2 (Bcl-2) and Bax messenger RNA (mRNA) and identification of the proteolytic cleavage of poly (ADP)-ribose polymerase (PARP) and caspase-3. Autophagic effects were examined by quantitation of mRNA expression of autophagy protein 5 (ATG5) and beclin1 and identifying accumulation of microtubule-associated protein 1 light chain 3 (LC3)-II. Inflammatory effect was determined by measuring expression and production of IL-6 and cyclooxygenase-2 (Cox-2). The results showed ZA significantly inhibited cell viability of cervical cancer cells. ZA-induced cell death displayed features characteristic to both apoptosis and autophagy and was associated with different changes in the levels of Bcl-2 and Bax in the various cervical cancer lines. Expression of metastatic cytokines, IL-6 and Cox-2, was upregulated in the presence of ZA at low concentration. Our data revealed that ZA inhibits cervical cancer cells through the synergistic effect of apoptosis induction and autophagy activation.