Drugs and gastric damage

Cissus subtetragona Planch. Ameliorates Inflammatory Responses in LPS-induced Macrophages, HCl/EtOH-induced Gastritis, and LPS-induced Lung Injury via Attenuation of Src and TAK1

Several Cissus species have been used and reported to possess medicinal benefits. However, the anti-inflammatory mechanisms of Cissus subtetragona have not been described. In this study, we examined the potential anti-inflammatory effects of C. subtetragona ethanol extract (Cs-EE) in vitro and in vivo, and investigated its molecular mechanism as well as its flavonoid content. Lipopolysaccharide (LPS)-induced macrophage-like RAW264.7 cells and primary macrophages as well as LPS-induced acute lung injury (ALI) and HCl/EtOH-induced acute gastritis mouse models were utilized. Luciferase assays, immunoblotting analyses, overexpression strategies, and cellular thermal shift assay (CETSA) were performed to identify the molecular mechanisms and targets of Cs-EE. Cs-EE concentration-dependently reduced the secretion of NO and PGE₂, inhibited the expression of inflammation-related cytokines in LPS-induced RAW264.7 cells, and decreased NF-κB- and AP-1-luciferase activity. Subsequently, we determined that Cs-EE decreased the phosphorylation events of NF-κB and AP-1 pathways. Cs-EE treatment also significantly ameliorated the inflammatory symptoms of HCl/EtOH-induced acute gastritis and LPS-induced ALI mouse models. Overexpression of HA-Src and HA-TAK1 along with CETSA experiments validated that inhibited inflammatory responses are the outcome of attenuation of Src and TAK1 activation. Taken together, these findings suggest that Cs-EE could be utilized as an anti-inflammatory remedy especially targeting against gastritis and acute lung injury by attenuating the activities of Src and TAK1.

Case-control study on the association of upper gastrointestinal bleeding and nonsteroidal anti-inflammatory drugs in Japan

OBJECTIVE

Studies in Western populations have shown the association of nonsteroidal anti-inflammatory drugs (NSAIDs) and upper gastrointestinal bleeding (UGIB). The role of Helicobacter pylori infection in NSAIDs-related UGIB remains to be studied. We conducted a case-control study in Japan to investigate these related topics.

METHODS

Cases of UGIB due to duodenal or gastric ulcer, or gastritis were identified in 14 study hospitals in various areas of Japan. For each case, two controls were identified from population registries in the same district. Information on drugs and other risk factors was obtained from 175 cases and 347 controls by telephone interviews. Anti-H. pylori antibody in the urine was measured in a single laboratory for all the cases and 225 controls.

RESULTS

The odds ratio (OR) of UGIB was 5.5 for aspirin and 6.1 for other NSAIDs (NANSAIDs) (p<0.01). The OR for regular use was higher than for occasional use both for aspirin (7.7 vs 2.0) and NANSAIDs (7.3 vs 4.1). Loxoprofen (5.9), frequently used in Japan as a safe 'prodrug', was significantly associated with UGIB. The odds ratio for H. pylori infection was 4.9 and the relative excess risk due to the interaction between H. pylori and the use of NSAID was 1.2 (95% CI: -5.8-8.1).

CONCLUSION

NSAIDs including loxoprofen increase the risk of UGIB in Japan as in Western countries, with a similar magnitude of association. There was no evidence of biological interaction between NSAIDs and H. pylori infection.

Comparative effects of nabumetone, naproxen, piroxicam, and diclofenac on rat gastric irritancy following acute exposure to OTC non-steroidal anti-inflammatory agents and other gastric irritants

This study examined the relative effects of equally-effective anti-inflammatory doses of nabumetone, naproxen, piroxicam and diclofenac on gastric irritancy induced by over-the-counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs) aspirin and ibuprofen and a variety of necrotizing agents (0.6 N HCl, 0.2 N NaOH and 25% NaCl). Within one hour, aspirin 100 and 200 mg/kg and ibuprofen up to 15 mg/kg produced significant gastric mucosal injury. Aspirin 50 mg/kg produced only minimal damage that was enhanced by 5 x ID25 piroxicam and naproxen, but not by nabumetone or diclofenac. 5 x ID25 naproxen, piroxicam, and diclofenac significantly enhanced mucosal damage produced by ibuprofen 2.5 mg/kg. An equivalent anti-inflammatory dose of nabumetone failed to enhance the gastric irritancy produced by ibuprofen 2.5 mg/kg. Similarly, naproxen, piroxicam, and diclofenac enhanced the susceptibility of the gastric mucosa to the necrotizing actions of 0.6 N HCl, 0.2 N NaOH or 25% NaCl. Naproxen, piroxicam, or diclofenac are more likely than nabumetone to enhance gastric mucosal injury produced by OTC NSAIDs (aspirin and ibuprofen) or other gastric irritants.

Review article: aspirin and gastrointestinal bleeding

Many animal and human studies have shown aspirin to cause gastric mucosal erosions and enhanced spontaneous microbleeding. Chronic use is associated with uncomplicated gastric ulcer (but not clearly with uncomplicated duodenal ulcer) and with presentation with haematemesis and melaena. Sub-group analysis suggests that the risks of bleeding duodenal ulcer as well as bleeding gastric ulcer (and possibly non-ulcer bleeding) are increased. These data imply that an anti-haemostatic as well as an ulcerogenic effect contributes to such presentation and acute data support this proposition. A broken mucosa and inhibition of thromboxane synthesis both appear to be necessary for bleeding to occur. Aspirin enhances the bleeding associated with mucosal biopsy analogous to its prolongation of the skin bleeding time. Anti-haemostatic properties could account for the apparent increase in presentation with haematemesis and melaena in patients taking low doses of aspirin for cardiovascular prophylaxis. However, acute studies also show aspirin 300 mg to cause a level of mucosal injury which is substantial, though significantly less than with aspirin 600 mg q.d.s. The risk attached to aspirin consumption needs to be kept in perspective. It can be calculated that aspirin use is associated with approximately 700 bleeds per annum in the UK. The relative risk for upper gastrointestinal bleeding is roughly similar to that for non-aspirin non-steroidal anti-inflammatory drugs but those affected are generally younger, in an age group where death from upper gastrointestinal bleeding is very uncommon. In keeping with this and in contrast to non-aspirin non-steroidal anti-inflammatory drugs, no study has shown increased mortality from aspirin-related upper gastrointestinal complications.

The influence of acute or chronic nicotine treatment on ethanol-induced gastric mucosal damage in rats

The influences of acute or chronic nicotine pretreatment on ethanol-induced changes on gastric secretion, mucosal blood flow (GMBF), and glandular mucosal damage were studied in anesthetized rats. Ethanol administration decreased gastric acid secretion and GMBF, which were accompanied by a marked increase in gastric mucosal damage. Acute nicotine incubation 2 or 4 mg dose-dependently elevated both the titratable acid in the luminal solution and the gastric secretory volume; it also prevented the depressive action on GMBF and gastric mucosal damage in ethanol-treated animals. Chronic nicotine treatment for 10 days reduced the inhibitory action of ethanol on gastric acid secretion; the higher dose (25 micrograms/ml drinking water) potentiated the decrease of GMBF and the ulcerogenic property of ethanol. However, chronic treatment with the lower dose (5 micrograms/ml drinking water) had the opposite effects; it also markedly increased the gastric secretory volume. It is concluded that acute nicotine pretreatment elevates, whereas chronic nicotine pretreatment differentially affects GMBF. These effects could account for their protective or preventive actions on ethanol ulceration. The increase in nonacid gastric secretory volume by nicotine could partially explain its antiulcer effect. Furthermore, the acid secretory state of the stomach appears unrelated to the ulcerogenic property of ethanol.

Effect of nicotine and alcohol pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats

The effect of nicotine and alcohol pretreatment by feeding nicotine (2.5 mg/100 ml), alcohol (25%, v/v) and their combination (nicotine 2.5 mg/100 ml + alcohol 25%, v/v) in drinking water ad libitum for 21 days was studied on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats. When given alone, neither nicotine nor alcohol produced any visibly discernible gastric lesions. Their concurrent administration, however, produced minor injury to the gastric mucosa appearing as 5-7 circular ulcers of less than 1 mm in diameter. Pretreatment with nicotine, alcohol, and their combination resulted in the significant augmentation of gastric ulcers produced by aspirin, phenylbutazone, and reserpine. The augmentation of gastric lesions in the group pretreated with the combination of nicotine and alcohol was significantly greater than in the groups treated by either of them alone. The effect of nicotine on the mucus neck cell population of the gastric mucosa and pancreatic bicarbonate secretion, and the gastric mucosal damaging effect of chronic alcohol treatment may be responsible for the potentiation of ulcerogenic effects of aspirin, phenylbutazone, and reserpine.

Effect of nicotine, alcohol and caffeine pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats

The effects of nicotine (2.5 mg/100 ml), alcohol (25% v/v) and caffeine (30 mg/100 ml base) and their combination (nicotine, 2.5 mg/100 ml; alcohol, 25% v/v; and caffeine, 30 mg/100 ml base) fed in drinking water ad libitum for 21 days were studied on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats. When given alone, none of them produced any visibly discernible gastric lesions. Their concurrent administration, however, produced some injury to the gastric mucosa which was far less severe than the lesions induced by any of the ulcerogenic drugs used in this study. Pretreatment with nicotine, alcohol and caffeine and their combination resulted in a significant augmentation of gastric lesions produced by aspirin, phenylbutazone and reserpine. These results establish an association between nicotine, alcohol and caffeine in the pathogenesis of gastric ulcers and also implicate them as modifying factors in the genesis of gastric lesions induced by aspirin, phenylbutazone and reserpine.

Effect of nicotine and caffeine pretreatment on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats

The effect of nicotine and caffeine pretreatment by feeding nicotine (2.5 mg %), caffeine (30 mg % base), and their combination (nicotine 2.5 mg % + caffeine 30 mg %) in drinking water ad libitum for 21 days was studied on the gastric mucosal damage induced by aspirin, phenylbutazone, and reserpine in rats. When given alone, neither nicotine nor caffeine produced any visibly discernible gastric lesions. Their concurrent administration too, did not produce any gastric mucosal injury. Pretreatment with nicotine, caffeine, and their combination resulted in significant augmentation of gastric ulcers produced by aspirin, phenylbutazone, and reserpine. However, caffeine administration produced a comparatively less profound augmentation of experimentally induced gastric lesions than that produced by nicotine pretreatment. The enhancement of gastric ulcers in the groups pretreated with the combination of nicotine and caffeine followed by one of the drugs was significantly greater than in the groups treated by either of them alone. The effect of nicotine on the mucus neck cell population of the gastric mucosa and on pancreatic bicarbonate secretion and the gastric secretory effect of caffeine may be responsible for the potentiation of the ulcerogenic effects of aspirin, phenylbutazone, and reserpine.

The effect of nicotine pretreatment on the gastric mucosal damage induced by aspirin and reserpine in rats

The effect of nicotine pretreatment by feeding nicotine (5mcg/ml) in drinking water ad libitum for 10 days was studied on the aspirin and reserpine induced gastric mucosal damage in rats. The administration of nicotine resulted in the significant augmentation of aspirin (P less than 0.01) and reserpine (P less than 0.05) induced gastric ulcers. The mechanism(s) involving the sensitization of gastric mucosa towards the ulcerogenic effect of aspirin and reserpine may be responsible for the increased intensity of gastric ulcers in both the groups. The study indicates the possibility of a similar interaction in heavy smokers who ingest these drugs.

The fate of fenclozic acid in the gut and its effect on some aspects of gut metabolism

In the rat [14C]fenclozic acid is not metabolized in the gut and passes into the portal blood unchanged. After intraduodenal administration of [14C]fenclozic acid, a small proportion of the dose binds to high molecular weight substances in the gut wall. The incorporation of L-[U-14C]leucine and N-[3H]acetyl-D-glucosamine into acid-precipitable materials by isolated mucosal cells and homogenates of gut mucosal cells was inhibited by fenclozic acid in a dose-dependent manner. Other non-steroidal anti-inflammatory drugs (indomethacin, phenylbutazone, prednisolone, salicylic acid and paracetamol) were tested for their potency as inhibitors of glycoprotein production by whole cell preparations and by homogenized gut cell preparations. Marked differences were observed in the inhibitory potency of indomethacin, paracetamol and salicylic acid in the two experimental systems. Fenclozic acid had no major effect on the rate of total glycoprotein production by the isolated perfused rat liver or by the duodenal mucosa in situ. Fenclozic acid displaces albumin-bound [3H]tryptophan and increases the level of hepatic tryptophan pyrrolase approx. threefold. The inhibition of gut glycoprotein production by fenclozic acid was not prevented by free tryptophan.

Anti-inflammatory/anti-pyretic salicylic acid esters with low gastric ulcerogenic activity

The methyl and some other esters of acetylsalicylic and salicylic acids and their derivatives were found to have much lower gastric ulcerogenic activity (when assayed in the stress-sensitized rat) compared with their corresponding acids. There was little or no loss in therapeutic potencies of these salicylate esters as determined by assessment of anti-inflammatory activity (against the carrageenan-induced oedema) and antipyretic activity (against yeast-induced fever in rats. The methyl ester of acetylsalicylic acid (=AME) was almost devoid of gastric irritancy/ulcerogenicity (as observed with acetylsalicylic acid) when given orally to pigs for 10 days. AME had appreciable anti-inflammatory activity in the adjuvant-arthritis model and at high doses (200 mg/kg t.i.d.) was without the lethal effects seen with acetylsalicylic acid. Moreover, no toxic effects were seen after long-term administration of 100-1000 mg/kg/day AME for 3-4 months. The results provide further evidence for the hypothesis that the carboxylic acid moiety of salicylates is a major factor in the gastric ulcerogenic activity of these drugs. The methyl esters of these salicylates may be considered as models for the development of pro-drugs and in some cases may be therapeutic alternatives to acetylsalicylic acid or salicylate.

Acetylsalicylic acid-induced gastrointestinal bleeding determined by a 51Cr method on a day-to-day basis

The daily gastrointestinal blood loss caused by plain and microencapsulated acetylsalicylic acid (ASA) tablets was compared. Fourteen healthy, male volunteers participated in a double-blind, cross-over study, lasting 38 days. Before drug administration a median gastrointestinal bleeding of 0.9 ml/24 h was observed. During oral intake of 1.5 g ASA twice a day for 5 days, an increased faecal blood loss was seen in all volunteers. The increase was significant for both plain and microencapsulated ASA (p less than 0.01). Plain ASA tablets, however, caused a greater faecal blood loss than the microencapsulated tablets (p = 0.05), maximum median levels being 6.2 ml/24 h and 3.9 ml/24 h, respectively. An optimal design of radiochromium studies for determination of drug-induced gastrointestinal blood loss is discussed.

Effects of phenacetin, paracetamol and caffeine on the erosive activity of acetylsalicylic acid in the rat stomach: dose-response relationships, time course of erosion development and effects on acid secretion

Adult male and female Wistar rats were equally susceptible to gastric injury induced with acetylsalicylic acid (aspirin). Both in male and in female rats simultaneous administration of caffeine and aspirin caused significantly more gastric erosions than the same dose of aspirin alone; likewise addition of paracetamol to aspirin decreased the incidence of gastric lesions in either sex, and addition of phenacetin to aspirin had no effect. The potentiation by caffeine and the inhibition by paracetamol were both dose-dependent and only markedly influenced the development of erosions after 3–4 h. Pretreatment with phenacetin or paracetamol 1 h before administration of aspirin did not affect its erosive activity. Administration of benorylate caused no more gastric erosions than the vehicle or than equivalent mixtures of aspirin and paracetamol. The histamine-stimulated acid output of the stomach during gastric perfusion with aspirin was rapidly diminished. Neither paracetamol nor caffeine initially affected this decrease in acid output. However, 30 min after perfusion with aspirin and caffeine, acid secretion increased approximately as strongly as after caffeine alone. Caffeine potentiates aspirin-induced erosions by its stimulatory effect on acid secretion whereas paracetamol inhibits these erosions by preventing their growth.

A review of upper-gastrointestinal effects of the newer nonsteroidal antiinflammatory agents

Newer nonsteroidal antiinflammatory agents (NSAI's) such as ibuprofen, neproxen, fenoprofen, and tolmetin have broadened the therapeutic choice and increased the chances of providing optimum arthritis control, but require careful assessment of the possibilities for unwanted drug effects when long-term therapy is required. A review of the literature on the gastrointestinal effects of the promising newer NSAIs, as compared with the older agents, aspirin, indomethacin, and phenylbutazone, is presented, highlighting animal toxicology and human adverse reaction surveillance data and the evidence for various suggested pathophysiological mechanisms.

A single dose study comparing the analgesic effects of diflunisal, acetylsalicylic acid, and placebo in pain following meniscectomy

A single dose experiment was used to evaluate the analgesic effect of diflunisal, a new salicylic acid derivative. Three dose levels of diflunisal (125 mg, 250 mg, and 500 mg) were compared to one dose level of acetylsalicylic acid (ASA) (600 mg) and placebo. The maximal analgesis induced by 500 mg diflunisal was comparable to that of 600 mg ASA. The onset of action was slightly more rapid with ASA but the duration of the analgesic effect was far longer for diflunisal, extending beyond 8 hours after administration. Diflunisal is a promising drug for the treatment of post-operative pain because of its long-lasting effect.

Selective cytotoxic actions of aspirin on parietal cells: a principal factor in the early stages of aspirin-induced gastric damage

Electronmicroscopic observations are reported on the effects of orally administered aspirin on the rat gastric mucosa to establish the cytotoxic events that occur during the early stages of the development of gastric damage induced by this drug. The results show that aspirin, apart from damaging superficial mucous cells, causes selective damage to the acid-secreting parietal cells located deep in the fundic mucosa. It is suggested that the selective accumulation of salicylates in the parietal cells may account for the specific cytotoxic actions of aspirin on these cells.

Gastric erosions induced by analgesic drug mixtures in the rat

Gastric erosions after oral administration of analgesics separately and in admixture have been examined in adult rats. After administration of acetylsalicylic acid (aspirin), phenacetin, paracetamol and caffeine as single drugs, gastric erosions were only observed with aspirin. The combination of aspirin with phenacetin did not change, that of aspirin with caffeine significantly increased, and aspirin with paracetamol significantly decreased the incidence of gastric lesions compared with aspirin alone. The results for aspirin with paracetamol did not differ from those for the vehicle. Addition of caffeine to the combination of aspirin and phenacetin caused a significant increase in erosions, but when given with aspirin and paracetamol no erosions occurred. The mechanisms underlying the effects of these drugs on aspirin-induced erosions are discussed.

The use of diflunisal in post-operative pain: a report of double-blind comparative trials in patients after meniscectomy

A series of double-blind randomized trials was carried out in patients suffering from moderate to severe pain after meniscectomy to assess the analgesic effectiveness of diflunisal. In a single-dose study, 150 patients received either diflunisal (125 mg, 250 mg or 500 mg), aspirin (600 mg), or placebo, and hourly assessments were made of pain severity over an 8-hour period. The results showed that 500 mg diflunisal produced comparable relief to aspirin within 3 to 4 hours, but the analgesic effect continued for longer and was still very marked after 8 hours. A multi-dose study in 120 patients receiving doses of diflunisal (375 mg or 500 mg) or placebo confirmed the overall effectiveness of twice daily treatment with diflunisal. In a comparative study against oxyphenbutazone (200 mg t.i.d.), hourly pain scores made on the first post-operative day showed that a single dose of 500 mg diflunisal produced comparable relief over a 12-hour period to that with 2 doses of 200 mg oxyphenbutazone. Overall response to multiple doses was assessed as excellent or good by all the patients receiving diflunisal. Preliminary results are reported on the use of diflunisal in other painful conditions.

Drug-induced gastrointestinal disease

The gastrointestinal tract is a common target for adverse drug reactions. The resultant changes are often nonspecific (e.g., mucosal ulceration, intestinal infarction, motility disturbance) and in many cases no radiographically detectable lesion may occur. A comprehensive review of the reported drug-induced disorders of the digestive organs is herein presented and their radiographic manifestations are described.

The comparative gastric ulcerogenic activities of non-steroid anti-inflammatory drugs

A new gastric assay was employed to screen for the ulcerogenic activity of non-steroid anti-inflammatory (NSAI) analgesic drugs. The technique involves exposing rats to brief periods of cold stress, which is not itself sufficient to cause mucosal damage, but does specifically sensitize the stomach to irritant or ulcerogenic actions of NSAI drugs. The assessment of gastric ulcerogenicity of some well-known anti-inflammatory/analgesic drugs using this new assay was shown to agree well with clinical reports of the occurrence of gastric ulceration and haemorrhage. This assay was employed to screen for the ulcrogenicity of some new anti-inflammatory drugs and for potential drug interactions resulting from administration of certain frequently used combinations of these drugs.

Gastric mucosal damage caused by plain and microencapsulated acetylsalicylic acid tablets in healthy subjects: a gastrocamera study

In a randomized, cross-over study plain acetylsalicylic acid (ASA) tablet and microencapsulated ASA tablets were given in doses of 1 gram 3 times a day for 3 days to 8 healthy subjects with no previous gastrointestinal disturbances. Gastrocamera examinations were performed before the ASA treatment and 1--2 hours after the last dose of ASA. The gastric mucosa appeared macroscopically normal at all the control examinations; whereas musocal bleeding was evident in all the subjects after the ASA treatment. There was no statistically significant difference between the plain ASA and the microencapsulated ASA preparations. No correlation could be found between the ASA concentration in plasma and the gastric mucosal damage.