Mucosal irritative and healing impairment action of risedronate in rat stomachs: comparison with alendronate

Symptoms and Upper Gastrointestinal Mucosal Injury Associated with Bisphosphonate Therapy

Objective The incidence of osteoporosis is increasing with the rapid aging of the Japanese population. Bisphosphonates are first-line agents used for the treatment of osteoporosis, but they can cause upper gastrointestinal mucosal injury. This study investigated symptoms and upper gastrointestinal mucosal injury associated with oral bisphosphonates. Methods Symptoms were evaluated using the F-scale questionnaire, and esophageal mucosal injury and gastroduodenal ulceration were assessed by endoscopy. Patients were stratified by the type of bisphosphonate (alendronate, risedronate, or minodronate), treatment schedule (once weekly or every four weeks), and the concomitant use of other medications [antithrombotic agents, nonsteroidal anti-inflammatory drugs (NSAIDs), or acid suppressants]. Patients The subjects included 221 patients treated with oral bisphosphonates for at least one month. Results The median F-scale total score was 4 (0-34), reflux score was 2 (0-20), and the mean dyspepsia score was 2 (0-16). Endoscopy showed esophageal mucosal injury of Grade A or worse (Los Angeles classification) in 22/221 patients (10.0%) and gastroduodenal ulcers in 9 patients (4.1%). The dyspepsia score in patients who took minodronate every four weeks was significantly lower (p<0.05) in comparison to patients who took other bisphosphonates. The dyspepsia score was significantly higher (p<0.05) and mucosal injury was significantly more frequent in patients who also used antithrombotic agents and NSAIDs. Conclusion Symptoms and upper gastrointestinal mucosal damage were not necessarily frequent or severe in patients treated with bisphosphonates. However, the concomitant use of bisphosphonates with antithrombotic agents and NSAIDs increased both symptoms and mucosal injury. The symptoms were milder in patients using minodronate once monthly.

Pharyngolaryngeal ulcers associated with the improper use of alendronate

Bisphosphonates can cause mucosal irritation. Although esophageal ulceration is a well-recognized adverse effect of bisphosphonates, pharyngolaryngeal ulcers associated with the improper use of oral bisphosphonates have rarely been described. A previously healthy 78-year-old woman presented with refractory pharyngolaryngeal ulcers. Extensive evaluation, including biopsy, bacterial culture, and blood tests did not identify any findings that indicated a specific disease diagnosis. Antibiotics and oral prednisolone were ineffective. Ultimately, it was found that the patient regularly took a tablet of alendronate, a type of bisphosphonate, by dissolving it in the oral cavity. Within 2 weeks after withdrawal of the use of the medication, her symptoms were eliminated, and the lesions were completely healed. This case illustrates the importance of correct administration of bisphosphonates. Given the widespread use of bisphosphonates, physicians need to be aware that their improper use can cause pharyngolaryngeal ulcers.

Protective Effects of Simvastatin Against Alendronate-Induced Gastric Mucosal Injury in Rats

BACKGROUND

It has been reported that simvastatin, a statin commonly prescribed for its anti-inflammatory and antioxidant effects, has gastroprotective effects in indomethacin and ethanol-induced gastric ulcers. However, the effects of simvastatin on alendronate-induced gastric mucosal injury remain unexplored.

AIM

This study investigated the use of simvastatin for the treatment of alendronate-induced gastric ulcers in rats.

METHODS

Female rats were pretreated with vehicle or simvastatin (20 and 60 mg/kg p.o.). After 1 h, the rats received alendronate (50 mg/kg p.o.). Simvastatin was administered once daily for 7 days, and from the fourth day of simvastatin treatment, alendronate was administered once daily for 4 days. On the final day of treatment, 4 h after alendronate administration, animals were euthanized, their stomachs were removed, and gastric damage was measured. Samples of the stomach were fixed in 10 % formalin immediately after their removal for subsequent histopathological assessment. Unfixed samples were weighed, frozen at -80 °C until assayed for glutathione (GSH), malondialdehyde (MDA), and cytokine levels and myeloperoxidase (MPO) activity. A third group was used to measure mucus and gastric secretion.

RESULTS

Pretreatment with simvastatin prevented alendronate-induced macroscopic gastric damage and reduced the levels of MDA and GSH, TNF-α and IL-1β, MPO activity, and mucus levels, in the stomach.

CONCLUSIONS

This study demonstrates the protective effects of simvastatin against alendronate-induced gastric ulceration. Maintenance of mucosal integrity, inhibition of neutrophil activity, and reduced oxidative stress associated with decreased gastric acidity may explain the gastroprotective effects of simvastatin.

Alendronate induces gastric damage by reducing nitric oxide synthase expression and NO/cGMP/K(ATP) signaling pathway

Chronic use of alendronate has been linked to gastrointestinal tract problems. Our objective was to evaluate the role of the NO/cGMP/KATP signaling pathway and nitric oxide synthase expression in alendronate-induced gastric damage. Rats were either treated with the NO donor, sodium nitroprusside (SNP; 1, 3, and 10 mg/kg), or the NO synthase (NOS) substrate, L-arginine (L-Arg; 50, 100, and 200 mg/kg). Some rats were pretreated with either ODQ (a guanylate cyclase inhibitor; 10 mg/kg) or glibenclamide (KATP channels blocker; 10 mg/kg). In other experiments, rats were pretreated with L-NAME (non-selective NOS inhibitor; 10 mg/kg), 1400 W (selective inducible NOS [iNOS] inhibitor; 10 mg/kg), or L-NIO (a selective endothelial NOS [eNOS] inhibitor; 30 mg/kg). After 1 h, the rats were treated with alendronate (30 mg/kg) by gavage for 4 days. SNP and L-Arg prevented alendronate-induced gastric damage in a dose-dependent manner. Alendronate reduced nitrite/nitrate levels, an effect that was reversed with SNP or L-Arg treatment. Pretreatment with ODQ or glibenclamide reversed the protective effects of SNP and L-Arg. L-NAME, 1400 W, or L-NIO aggravated the severity of alendronate-induced lesions. In addition, alendronate reduced the expression of iNOS and eNOS in the gastric mucosa. Gastric ulcerogenic responses induced by alendronate were mediated by a decrease in NO derived from both eNOS and iNOS. In addition, our findings support the hypothesis that activation of the NO/cGMP/KATP pathway is of primary importance for protection against alendronate-induced gastric damage.

The hydrogen sulfide donor, Lawesson's reagent, prevents alendronate-induced gastric damage in rats

Our objective was to investigate the protective effect of Lawesson's reagent, an H2S donor, against alendronate (ALD)-induced gastric damage in rats. Rats were pretreated with saline or Lawesson's reagent (3, 9, or 27 µmol/kg, po) once daily for 4 days. After 30 min, gastric damage was induced by ALD (30 mg/kg) administration by gavage. On the last day of treatment, the animals were killed 4 h after ALD administration. Gastric lesions were measured using a computer planimetry program, and gastric corpus pieces were assayed for malondialdehyde (MDA), glutathione (GSH), proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β], and myeloperoxidase (MPO). Other groups were pretreated with glibenclamide (5 mg/kg, ip) or with glibenclamide (5 mg/kg, ip)+diazoxide (3 mg/kg, ip). After 1 h, 27 µmol/kg Lawesson's reagent was administered. After 30 min, 30 mg/kg ALD was administered. ALD caused gastric damage (63.35 ± 9.8 mm(2)); increased levels of TNF-α, IL-1β, and MDA (2311 ± 302.3 pg/mL, 901.9 ± 106.2 pg/mL, 121.1 ± 4.3 nmol/g, respectively); increased MPO activity (26.1 ± 3.8 U/mg); and reduced GSH levels (180.3 ± 21.9 µg/g). ALD also increased cystathionine-γ-lyase immunoreactivity in the gastric mucosa. Pretreatment with Lawesson's reagent (27 µmol/kg) attenuated ALD-mediated gastric damage (15.77 ± 5.3 mm(2)); reduced TNF-α, IL-1β, and MDA formation (1502 ± 150.2 pg/mL, 632.3 ± 43.4 pg/mL, 78.4 ± 7.6 nmol/g, respectively); lowered MPO activity (11.7 ± 2.8 U/mg); and increased the level of GSH in the gastric tissue (397.9 ± 40.2 µg/g). Glibenclamide alone reversed the gastric protective effect of Lawesson's reagent. However, glibenclamide plus diazoxide did not alter the effects of Lawesson's reagent. Our results suggest that Lawesson's reagent plays a protective role against ALD-induced gastric damage through mechanisms that depend at least in part on activation of ATP-sensitive potassium (KATP) channels.

Evaluation of gastric ulcerogenic and healing impairment effects of bisphosphonates: adverse gastric reactions of bisphosphonate

Bisphosphonates (BPPs) were developed as antiresorptive drugs capable of treating diseases related to bone remodeling; however, they have untoward effects including ulceration in the upper gastrointestinal tract and worsen the healing-impairment action of nonsteroidal anti-inflammatory drugs, prescribed in patients with arthritis or osteoporosis. We produced ulcers in the antrum by administering BPPs to fasted rats, followed by refeeding, and confirmed their healing-impairment action on pre-existing gastric ulcers; the ulcerogenic effect is due to direct mucosal irritation and decrease in the mucosal anti-oxidative system, while the latter effect is due to dysregulation of growth factor expression, such as vascular endothelial growth factor and basic fibroblast growth factor, and angiogenesis in the ulcerated mucosa. In this article, we describe these two animal models for investigating BPP-related adverse reactions, including methods for the induction of antral ulcers and healing impairment of gastric ulcers, as well as measurement of pathogenic functional and biochemical changes.

Bisphosphonate-induced gastrointestinal mucosal injury is mediated by mitochondrial superoxide production and lipid peroxidation

Bisphosphonates such as alendronate and risedronate are commonly used for the treatment of postmenopausal osteoporosis. They have the gastrointestinal adverse effects such as erosions and ulcers in stomach and small intestine. However, the detailed biological mechanism remains to be elucidated. Since alendronate is suggested to increase the risk of non-steroidal anti-inflammatory drug-related gastropathy, we hypothesized that bisphosphonates and non-steroidal anti-inflammatory drugs have the same pathophysiological mechanisms in gastrointestinal mucosa: Bisphosphonates may induce cellular lipid peroxidation by inducing the production of mitochondrial superoxide. We also hypothesized that geranylgeranylacetone, an antiulcer drug, may prevent lipid peroxidation by reducing superoxide production. We treated gastric RGM1 cells and small intestinal IEC6 cells with alendronate or risedronate, and examined cellular injury, lipid peroxidation and superoxide production with specific fluorescent dyes, and underwent electron paramagnetic resonance spectroscopy to detect the production of superoxide in vitro. The results indicated that bisphosphonates indeed induced cellular injury, cellular lipid peroxidation, and superoxide production. We also demonstrated that the pretreatment of geranylgeranylacetone decreased superoxide production and prevented cellular lipid peroxidation. These results suggested that bisphosphonates, like non-steroidal anti-inflammatory drugs, induce lipid peroxidation by producing mitochondrial superoxide, which was prevented by geranylgeranylacetone.

Pharmacovigilance of oral bisphosphonates: adverse effects manifesting in the soft tissue of the oral cavity

PURPOSE

It is well known that oral bisphosphonates can induce necrosis of the osseous structures of the jaws. However, there seems to be a limited awareness that oral bisphosphonates can also induce adverse effects in the soft tissues of the oral cavity, as indicated by the paucity of reported cases in the literature. Because oral bisphosphonates are widely used drugs for several skeletal conditions, it is reasonable to assume that mucosal adverse effects are more common than the small number of published cases indicates. The purpose of this study was to investigate whether this adverse effect of bisphosphonates is represented as reports from health practitioners in an adverse drug reaction database, as well as to gain knowledge about which substances are being associated with adverse drug reactions affecting the oral mucosa.

MATERIALS AND METHODS

The database of the Medical Products Agency-Sweden was searched for adverse effects from oral bisphosphonates manifesting in the oral and maxillofacial region. Reports of reactions limited to the soft tissues of the oral cavity were selected and further analyzed. Only those reports showing recovery or improvement after the cessation of bisphosphonate use were included in the study.

RESULTS

A total of 83 cases of adverse reactions to oral bisphosphonates were retrieved from the search. Of these, 12 were included in the study. They were associated with the use of alendronate, etidronate and risedronate, in descending order. Sixteen percent of the reports comprising the oral and maxillofacial region were limited to the oral mucosa and reported recovery or improvement after discontinuation of the drug.

CONCLUSIONS

Adverse effects of oral bisphosphonates with manifestations in the soft tissue of the oral cavity seem to be more common than the small number of published cases indicates. However, considering that oral bisphosphonates are widely used drugs, the incidence is still low. These adverse drug reactions are not limited to alendronate and may also be induced by etidronate and risedronate. Still, a significant proportion of the cases are associated with alendronate. Regardless of the substance used, discontinuing the drug is an effective treatment for the mucosal lesions.

Oral ulcers, a little known adverse effect of alendronate: review of the literature

PURPOSE

To review the published data on a hitherto not widely known adverse effect of alendronate manifesting as mucosal ulcers in the oral cavity.

MATERIALS AND METHODS

The electronic database PubMed was searched for reports of this adverse effect. Publications published up to August 2010 were included. This electronic search was combined with a manual search of the reference lists of the selected publications.

RESULTS

A total of 47 publications were retrieved from the electronic and manual searches. Of these, 12 were selected for the review. Mostly, the ulcers were preceded by misuse of alendronate, but they also appeared after correct administration. The appearance of the ulcers varied from a few days to several months after the start of alendronate use. Effective treatment was withdrawal of the drug or revision of the dosing and administration instructions.

CONCLUSIONS

Alendronate can cause mucosal ulcerations in the oral cavity, affecting patients with intense pain and causing severe morbidity. Successful treatment of this oral pathosis is achieved by aborting the use of alendronate. This adverse effect of alendronate is a rare entity in published reports but careful monitoring of patients at risk is recommended.

Oral ulcer associated with alendronate: a case report

Irritation of the mucosa of the aerodigestive tract is a well-known adverse effect of alendronate, whereas oral ulceration has been reported in only 14 articles in both the English and non-English literature. All of these have been associated with misuse of the drug. We here present the first case of severe oral ulceration attributable to use of alendronate without inappropriate therapeutic administration of the medication.

Impairment of gastric ulcer healing by alendronate, a nitrogen-containing bisphosphonate, in rats

Bisphosphonates such as alendronate have been developed as antiresorptive agents capable of treating diseases related to bone remodeling. In the present study, we examined the effect of alendronate on the healing of acetic acid-induced gastric ulcers in rats and investigated the mechanism involved in this action both in vivo and in vitro using the rat gastric epithelial cell line (RGM1). Acetic acid-induced gastric ulcers healed spontaneously, with up-regulation of COX-2/prostaglandin E2 production as well as expression of vascular endothelium-derived growth factor (VEGF) and basic fibroblast growth factor (bFGF) in ulcerated mucosa. The healing of ulcers was impaired by indomethacin (2 mg/kg, s.c.) or alendronate (60 mg/kg, p.o.) given once daily for 7 days, starting 3 days after acid application. Indomethacin, but not alendronate, inhibited mucosal prostaglandin E2 production. Alendronate as well as indomethacin decreased the protein expression of both VEGF and bFGF in ulcerated mucosa, resulting in a reduction of angiogenesis in the ulcer base. Supplementation of recombinant bFGF significantly reverted the delay in ulcer healing caused by alendronate. On the other hand, the size of cell-free areas in RGM1 cells in vitro decreased with time after wound induction, and this process was promoted by epidermal growth factor (EGF; 10 ng/ml). Co-incubation with alendronate (1 mM) did not affect the spontaneous healing but significantly suppressed the accelerated wound healing caused by EGF. These results suggest that alendronate impairs the healing of gastric ulcers in rats, and this effect may be related to down-regulation of VEGF and bFGF, the important growth factors for vascularization/granulation, as well as suppression of the stimulatory action of EGF on epithelial proliferation/migration.

Drug injury in the upper gastrointestinal tract: effects of alendronate

Osteoporosis is a disease characterized by an increase in bone resorption and a decline in bone density, which leads to increased susceptibility to bone fractures. Long-term therapy is needed to increase bone mineral density and maintain bone strength. Safe and well-tolerated medical therapies are required for long-term maintenance. Alendronate, an oral bisphosphonate, has been used for treatment of osteoporosis since the mid 1990s; however, recent studies have suggested alendronate can have significant gastrointestinal side effects. Most data suggest that the risk of these effects is low and not significantly higher than with placebo but there are limited reports that suggest otherwise, in both clinical trials and animal studies. Alendronate continues to remain an important mainstay of osteoporosis therapy.