Age-associated decreases in prostaglandin contents in human gastric mucosa

Gastro-protective effect of l-arginine against nitric oxide deficiency-related mucosal injury induced by indomethacin: Does age matter?

Gastric ulcer is a common disease with increased prevalence in the aged population. Aged gastric mucosa has increased susceptibility to injury along with nonsteroidal anti-inflammatory drugs use due to impaired mucosal defense and decreased vasodilator release. We investigated whether l-arginine could protect against age-related gastric ulceration induced by indomethacin. Aged and adult male Wistar rats were administered sole and combined treatment of  l-arginine and Nω -nitro-l-arginine methyl ester ( l-NAME) before induction of gastric ulceration by indomethacin. The gastroprotective effect of  l-arginine was displayed only in adult rats with indomethacin-induced gastric ulceration, as evidenced by a significant decrease in ulcer index, oxidative stress parameters, and mucosal myeloperoxidase activity along with increased mucosal PGE2 levels. Interestingly, the mucosal gene expressions of NF-кB, iNOS, and COX-2 were significantly suppressed by  l-arginine pretreatment and aggregated upon pretreatment with  l-NAME in both adult and aged rats treated with indomethacin. In conclusion,  l-arginine protected the rats' gastric mucosa against indomethacin-induced gastric ulceration, possibly, at least in part, by enhancement of mucosal nitric oxide/PGE2 content along with suppressing gastric inflammation and oxidative stress. This study supposed that the gastroprotective effect of  l-arginine depends on aging, and even so, the adoption of a new approach to gastric ulcer treatment for the aged population is warranted.

Increased susceptibility of aging gastric mucosa to injury: The mechanisms and clinical implications

This review updates the current views on aging gastric mucosa and the mechanisms of its increased susceptibility to injury. Experimental and clinical studies indicate that gastric mucosa of aging individuals-“aging gastropathy”-has prominent structural and functional abnormalities vs young gastric mucosa. Some of these abnormalities include a partial atrophy of gastric glands, impaired mucosal defense (reduced bicarbonate and prostaglandin generation, decreased sensory innervation), increased susceptibility to injury by a variety of damaging agents such as ethanol, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), impaired healing of injury and reduced therapeutic efficacy of ulcer-healing drugs. Detailed analysis of the above changes indicates that the following events occur in aging gastric mucosa: reduced mucosal blood flow and impaired oxygen delivery cause hypoxia, which leads to activation of the early growth response-1 (egr-1) transcription factor. Activation of egr-1, in turn, upregulates the dual specificity phosphatase, phosphatase and tensin homologue deleted on chromosome ten (PTEN) resulting in activation of pro-apoptotic caspase-3 and caspase-9 and reduced expression of the anti-apoptosis protein, survivin. The imbalance between pro- and anti-apoptosis mediators results in increased apoptosis and increased susceptibility to injury. This paradigm has human relevance since increased expression of PTEN and reduced expression of survivin were demonstrated in gastric mucosa of aging individuals. Other potential mechanisms operating in aging gastric mucosa include reduced telomerase activity, increase in replicative cellular senescence, and reduced expression of vascular endothelial growth factor and importin-α-a nuclear transport protein essential for transport of transcription factors to nucleus. Aging gastropathy is an important and clinically relevant issue because of: (1) an aging world population due to prolonged life span; (2) older patients have much greater risk of gastroduodenal ulcers and gastrointestinal complications (e.g., NSAIDs-induced gastric injury) than younger patients; and (3) increased susceptibility of aging gastric mucosa to injury can be potentially reduced or reversed pharmacologically.

An imbalance between VEGF and endostatin underlies impaired angiogenesis in gastric mucosa of aging rats

Gastric mucosa of aging individuals exhibits increased susceptibility to injury and delayed healing. Our previous studies in young rats showed that healing of mucosal injury depends on and is critically dependent on VEGF and angiogenesis. Since angiogenesis in aging gastric mucosa has not been examined before, in this study we examined the extent to which angiogenesis is impaired in gastric mucosa of aging vs. young rats and determined the underlying mechanisms with a focus on mucosal expression of VEGF (proangiogenic factor) and endostatin (antiangiogenic factor). Aging rats had significantly impaired gastric angiogenesis by ~12-fold, 5-fold, 4-fold, and 3-fold, respectively (vs. young rats; all P < 0.001) at 24, 48, 72, and 120 h following ethanol-induced gastric injury and reduced and delayed healing of mucosal erosions. In gastric mucosa of aging (vs. young) rats at baseline, VEGF expression was significantly reduced, whereas endostatin levels were significantly increased (P < 0.05 and P < 0.01, respectively). In contrast to young rats, gastric mucosal VEGF levels did not increase following ethanol-induced injury in aging rats. MMP-9 enzyme activity was significantly higher in gastric mucosa of aging vs. young rats both at baseline (2.7-fold) and 24 h (3.8-fold) after ethanol injury (both P < 0.001). Since endostatin is generated from collagen XVIII by MMP-9, this finding can explain the mechanism of increased endostatin expression in aging gastric mucosa. The above findings demonstrate that reduced VEGF and increased endostatin result in the impaired angiogenesis and delayed injury healing in gastric mucosa of aging rats.

Effect of aging on gastric mucosal defense mechanisms: ROS, apoptosis, angiogenesis, and sensory neurons

Aging changes in the stomach lead to a decreased capacity for tissue repair in response to gastric acid. The aim of this study was to determine the mechanism associated with the increased susceptibility to injury of aging mucosa including reactive oxygen species (5), apoptosis, angiogenesis, and sensory neuron activity. Fischer 344 rats at four different ages (6, 31, 74 wk, and 2 yr of age) were studied. The connective tissue indicators [salt-soluble collagen and sulfated glycosaminoglycan (sGAG)], lipid hydroperoxide (LPO), myeloperoxidase (MPO), and hexosamine were assessed. We also evaluated the expression of early growth response-1 (Egr-1), phosphatase and tension homologue deleted on chromosome 10 (PTEN), caspase-9 (index of apoptosis), VEGF (index of angiogenesis), calcitonin gene-related peptide (CGRP, index of sensory neurons), and neuronal nitric oxide synthase (nNOS). The histological connective tissue area in the lower part of rat gastric mucosa increased with aging, with increase of salt-soluble collagen and sGAG. LPO and MPO in old rats were significantly greater than in the young rats, whereas hexosamine was significantly reduced. The old gastric mucosa had increased expression of Egr-1, PTEN, and caspase-9, whereas the VEGF, CGRP, and nNOS expression were significantly reduced. These results indicate that the lower part of rat gastric mucosa was found to be replaced by connective tissue with accumulation of oxidative products with aging. In addition, impairment of apoptosis, angiogenesis, and sensory neuron activity via the activation of Egr-1 and PTEN might increase the susceptibility of gastric mucosa to injury during aging.

Oxidative stress, nitric oxide and prostaglandin E2 levels in the gastrointestinal tract of aging rats

Objectives

To evaluate the presence of oxidative stress and alterations in the levels of two cytoprotective agents, prostaglandin E2 and nitric oxide, in the gastrointestinal tract of aging rats.

Methods

The production of superoxide anion, lipid peroxides, levels of superoxide dismutase and catalase, and production of prostaglandin E2 and nitric oxide in the stomach and duodenum of rats were determined at 1.5, 3, 12, 18 and 24 months of age.

Key findings

Oxidative stress was present in the stomach of the old rats (24 months), whereas prostaglandin E2 and nitric oxide production remained stable at 18 and 24 months. In the duodenum, no oxidative stress was observed at 24 months, but at 18 months, an increase in superoxide anion levels was detected. Prostaglandin E2 remained constant in the aged rats but nitric oxide decreased significantly at 24 months.

Conclusions

The absence of macroscopic gastric injury throughout the gastrointestinal tract indicates that the oxidative stress in the stomach and the significant decrease of nitric oxide in the duodenum in the old rats are not sufficient to disrupt the mucosal defence network. The results support the notion that the disruption of the mucosal network is essentially regulated by the cytoprotective agents prostaglandin E2 and nitric oxide, and that injury appears only when both substances are concurrently reduced.

[Comparison of clinical characteristics and outcomes between geriatric and non-geriatric patients in peptic ulcer bleeding]

BACKGROUND/AIMS

In geriatric patients with peptic ulcer, the use of NSAID and prevalence of chronic illness have been increased, but the Helicobacter pylori (H. pylori) infected portion decreased. The aim of this study was to evaluate the clinical characteristics and outcomes of geriatric patients (aged 65 or older) with peptic ulcer bleeding and compare with non-geriatric patients (less than 65 years old).

METHODS

We conducted a retrospective study of 88 patients with peptic ulcer bleeding treated with therapeutic endoscopy from January 2006 to December 2006. We compared the clinical characteristics and outcomes of geriatric patients (n=34, 38.6%) with those of non-geriatric patients (n=54, 61.4%).

RESULTS

Hypertension (52.9% vs. 24.1%), cardiovascular disease (35.3% vs. 13.0%), and chronic obstructive pulmonary disease (20.6% vs. 3.7%) were more prevalent in the geriatric group, compared with the non-geriatric group (p<0.05). The geriatric group had taken more ulcerogenic drugs than the non-geriatric group (64.7% vs. 33.3%, p<0.05); aspirin plus clopidogrel (23.6% vs. 13.0%) and aspirin (20.6% vs. 11.0%). Sixteen (21.1%) of the 76 cases had H. pylori-negative ulcer. Between the two groups, there was no difference in the prevalence of H. pylori-negative ulcer (25.9% vs. 18.4%, p>0.05). The amount of transfusion length of ICU stay, rebleeding rate, operation rate and mortality were not different between the two groups. The length of hospital stay in the geriatric patients was significantly longer than the non-geriatric group (12.3+/-10.6 vs. 7.2+/-5.9 days, p<0.05). In multiple regression analysis, old age was a significant risk factor for longer hospital stay (p<0.05).

CONCLUSIONS

The geriatric patients with bleeding peptic ulcer had longer hospital stay than the non-geriatric patients in our study. The important emerging etiologies such as ulcerogenic drug and associated chronic illness should be checked and treated in these patients.

Influence of aging on gastric ulcer healing activities of the antioxidants alpha-tocopherol and probucol

In the present study, we compared the effects of alpha-tocopherol and probucol, antioxidants, on the healing of acetic acid-induced gastric ulcers in 8-, 48- and 96-week-old rats. The repeated oral administration of alpha-tocopherol (16 mg/kg twice daily) and probucol (1000 mg/kg twice daily) for 14 consecutive days markedly accelerated the gastric ulcer healing in 48- and 96-week-old rats as well as 8-week-old ones. The ulcer healing effects of both drugs were not significantly different among the rats at three different ages. The superoxide dismutase (SOD) activity in the ulcerated region of 8-, 48- and 96-week-old rats was markedly lower than that in the unulcerated region. In contrast, the thiobarbituric acid (TBA)-reactive substance content, an index of lipid peroxidation, in the ulcerated region of rats at three different ages markedly increased, as compared to that in the unulcerated region. The SOD activity tended to decrease with aging, while the TBA-reactive substance content gradually increased. The repeated administration of alpha-tocopherol and probucol accelerated the ulcer healing and inhibited the increase in the TBA-reactive substance content in the ulcerated region. These results suggest that alpha-tocopherol and probucol promote the ulcer healing by their potent antioxidant activities in 48- and 96-week-old rats as well as 8-week-old rats.

Prevalence of peptic ulcer in dyspeptic patients and the influence of age, sex, and Helicobacter pylori infection

We investigated the prevalence of peptic ulcer in dyspeptic patients in China to analyze the influence of age, sex, and Helicobacter pylori (H. pylori) infection. The results showed that the prevalence of gastric and duodenal ulcer increased with age. In patients under 60 years old, the prevalence of duodenal and gastric ulcers in females was markedly lower than that in males, especially the prevalence of duodenal ulcer. The prevalence of duodenal ulcer and gastric ulcer in H. pylori-infected patients was markedly higher than in patients without H. pylori infection. In the patients under 60 years old, sex differences were still seen in both H. pylori-positive and H. pylori-negative patients. The prevalence of gastric and duodenal ulcers was markedly increased with age in both H. pylori-positive and H. pylori-negative patients. Multivariate logistic regression analysis showed that age, male sex, and H. pylori infection were three independent risk factors for gastric and duodenal ulcers.

Assessment of Age-Related Changes in Abdominal Organ Structure and Function With Computed Tomography and Positron Emission Tomography

With the size of the aged population in the United States expected to grow considerably during the next several decades, the number of imaging studies performed on such aged individuals will similarly increase. Thus, it is important to understand normal age-related changes in the structural and functional imaging appearance of the abdominal organs. We therefore present preliminary data and a review of the literature relevant to structural and functional changes in the abdominal organs of children and older adults. In a retrospective study of both adult and pediatric populations, we used computed tomography (CT), positron emission tomography (PET), and PET/CT imaging to investigate age-associated changes in size, attenuation, and metabolic function of the abdominal organs. Organs of interest include the liver, spleen, pancreas, kidneys, adrenal glands, stomach, small bowel, colon, and rectum. Although volumes of adult liver, spleen, pancreas, and kidneys do not change significantly with age, adult left and right adrenal gland volumes do significantly increase with age (r = 0.2823, P = 0.0334, and r = 0.3676, P = 0.0049, respectively). Also, the attenuation of adult liver (r = -0.2122, P = 0.0412), spleen (r = -0.4508, P < 0.0001), pancreas (r = -0.5124, P = 0.0007), and left and right adrenal gland (r = -0.5835, P < 0.0001 and r = -0.6135, P < 0.0001, respectively) decrease significantly with increasing age. Every organ studied in the pediatric population demonstrates a positive association between organ volume and age. Significant age-related changes in organ function are noted in the adult liver and small bowel, with the liver demonstrating a positive association between metabolic activity and age (r = 0.4434, P = 0.0029) and the small bowel showing an inverse association between mean small bowel standardize uptake value and age (r = -0.2435, P = 0.0174). Also, the maximum overall small bowel and colon metabolic activity in children increases with age (r = 0.6478, P = 0.0008). None of the other organs studied (ie, spleen, pancreas, adrenal glands, stomach, colon, rectum) demonstrate significant changes in metabolism with advancing age. The metabolic volumetric product (calculated as the product of organ volume and mean organ SUV) of the liver and spleen does not change significantly with age. In conclusion, various abdominal organs demonstrate differential changes in volume, attenuation, and/or metabolism with increasing age in pediatric and adult populations.

Improving the gastrointestinal tolerability of aspirin in older people

Interventions to reduce mortality and disability in older people are vital. Aspirin is cheap and effective and known to prevent cardiovascular and cerebrovascular disease, many cancers, and Alzheimer dementia. The widespread use of aspirin in older people is limited by its gastrointestinal side effects. Understanding age-related changes in gastrointestinal physiology that could put older people at risk of the side effects of aspirin may direct strategies to improve tolerance and hence lead to greater numbers of older people being able to take this effective intervention.

Effect of age-related changes in gastric physiology on tolerability of medications for older people

Studies specifically examining the effect of age upon the stomach are limited and frequently uncontrolled for the high prevalence of Helicobacter pylori in this age group. Age-related changes in gastric physiology such as reduced mucosal protection, gastric blood flow and impaired repair mechanisms may all impact upon gastrointestinal adverse effects and how older people tolerate medicines. Understanding how the upper gastrointestinal tract changes with advancing age could allow interventions that lead to more appropriate prescribing for older people, potentially reduce adverse effects, increase compliance with treatment regimens, and may allow older people to take medications that they would not otherwise tolerate. This review emphasises how the stomach changes with age, and how understanding this will aid clinicians when prescribing medications with potential gastrointestinal adverse effects to older people.

Review article: the ageing bowel and intolerance to aspirin

Aspirin has a role in the prevention of cardiovascular and cerebrovascular disease, Alzheimer's dementia and several cancers. Encouraging all 50 year olds to take low-dose aspirin doubles their chances of living a healthy life into their nineties. The widespread use of aspirin, however, is limited as many older subjects are currently unable to take aspirin because of gastrointestinal side-effects. This review explores why gastrointestinal events occur with aspirin use and how a net benefit from prophylactic aspirin might be achieved in older subjects. It is suggested that, by understanding the age-related changes in upper gastrointestinal physiology and the mechanisms by which aspirin leads to the risk reductions associated with its use, it may be possible to direct interventions to improve tolerability in older subjects. This would allow greater numbers of older subjects to gain the benefits associated with aspirin use.

Influence of aging on gastric ulcer healing activities of cimetidine and omeprazole

In this study, we compared the effects of cimetidine and omeprazole on the healing of acetic acid-induced gastric ulcers in 8-, 48-, and 96-week-old rats. The repeated oral administration of cimetidine or omeprazole for 14 consecutive days markedly accelerated the ulcer healing in 8- and 48-week-old rats. However, both drugs were ineffective in 96-week-old rats. The basal gastric acid secretion of 8-, 48-, and 96-week-old rats decreased with aging. A single oral administration of cimetidine or omeprazole strongly decreased basal gastric acid secretion in the three different ages of rats. Cimetidine and omeprazole produced a potent and sustained serum gastrin-elevating action in 8- and 48-week-old rats. However, the gastrin-elevating actions of both drugs in 96-week-old rats were much weaker than in the 8- and 48-week-old rats. These results indicate that cimetidine and omeprazole have potent gastric ulcer healing actions in 8- and 48-week-old rats, as well as potent serum gastrin-elevating actions, but both drugs are ineffective in 96-week-old rats, which have lost their gastrin-elevating actions.

Mucosal defense and repair. Role of prostaglandins in the stomach and duodenum

When considering the diseases of the stomach and duodenum, peptic ulcer disease has been the one of greatest clinical impact. Although there are several components that contribute mechanistically to ulcer disease, it is recognized that gastroduodenal mucosal prostaglandins play a central pathogenic role, especially in ulcers related to the use of NSAIDs. As a result of understanding the mechanisms of NSAID-induced ulceration, the crucial function that gastroduodenal mucosal prostaglandins have in mucosal defense and repair is appreciated. It now is held widely that mucosal prostaglandin deficiency increases susceptibility to ulcer formation and that exogenous administration of supplemental prostaglandins reduces ulcer risk. This article reviews the role that mucosal prostaglandins play in defense of the gastric and duodenal mucosa against injury and ulceration.

Physiology and organ-related pathology of the elderly: stomach ulcers

Peptic ulcer disease, particularly as a result of its complications, is a burden that is focused on the elderly through their higher Helicobacter pylori prevalence and use of non-steroidal anti-inflammatory drugs (NSAIDs). In these patients, senescence may further increase ulcer susceptibility, particularly in the stomach, by the loss of mucosal protection and repair mechanisms. Age is mainly a marker for the increased prevalence of other complicated ulcer risk factors such as previous ulcer history and use of anti-coagulants, steroids and aspirin. The development of selective cyclo-oxygenase inhibitors (coxibs) has reduced the specific risk of NSAID ulceration, but the residual incidence in high risk patients remains substantially higher than that in young patients without other risk factors. The argument for early surgery versus endoscopic therapy in high risk patients with bleeding ulcers has not been resolved, both having a high mortality. There is still potential for the development of new strategies to prevent primary and secondary ulcers, either by new drug development or by expanding existing co-prescription strategies.

Exacerbatory mechanism responsible for water immersion stress-induced gastric lesions in aged rats compared with young rats

1. The present study was designed to investigate whether or not ageing affects the development of water immersion stress-induced gastric lesions in rats. Effects of cetraxate, an anti-ulcer drug, were also examined. 2. Gastric lesions were induced by 6 h water immersion stress in rats. Gastric mucosal blood flow was determined by the hydrogen gas clearance technique and nitric oxide synthase (NOS) activity was measured enzymatically. 3. Early development of gastric lesions was observed in aged rats and exacerbation of gastric lesions was also found. Lowering of gastric mucosal blood flow and reduced NOS activity were observed in aged rats. 4. Cetraxate mitigated the development of gastric lesions in young rats and also increased gastric mucosal blood flow and NOS activity. However, these favourable effects were diminished in aged rats. 5. Decreased NOS activity may be an important exacerbatory factor to the development of gastric lesions in aged rats. 6. Effects of cetraxate differed between young rats and aged rats. 7. These results may explain the refractoriness and drug resistance in gastric ulcers encountered by elderly individuals.

Diagnosis and treatment of nonsteroidal anti-inflammatory drug-associated upper gastrointestinal toxicity

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed in the United States to treat pain and reduce inflammation from chronic inflammatory disorders such as rheumatoid arthritis and osteoarthritis. Approximately 40% of older Americans take NSAIDs. Chronic NSAID use carries a risk of peptic ulcer and other gastrointestinal disturbances. This article reviews the diagnosis of medication-induced ulcers based on clinical presentation, laboratory tests, and endoscopic findings to assist the clinician in early diagnosis and appropriate therapy. Risk factors for NSAID-induced ulcers include old age, poor medical status, prior ulcer, alcoholism, smoking, high NSAID dosage, prolonged NSAID use, and concomitant use of other drugs that are gastric irritants, such as alendronate, a bone resorption inhibitor prescribed for osteoporosis. Appropriate treatment options for patients with medication-induced ulcers include dosage reduction, medication substitution, medication withdrawal, antiulcer therapy, and discontinuation of other gastrotoxic drugs.

Gastrointestinal bleeding in older people

Aging is associated with an increased rate of comorbidity, greater medication use, and atypical clinical presentations. The aging of the population makes the evaluation and management of gastrointestinal bleeding in older people a special and increasingly common clinical challenge. The unique features and common causes of upper and lower gastrointestinal bleeding in older people are reviewed. Important management issues considered include hemodynamic resuscitation, anticoagulation, and endoscopic and surgical therapy.

Dietary modulation of prostanoid synthesis in the aging process: role of cyclooxygenase-2

To investigate the role of cyclooxygenase (COX) as a mediator for prostaglandin synthesis in relation to generation of reactive oxidant species (ROS), we quantitated the COX-derived ROS generation and the gene expression of COX-2, an inducible form of COX in aged kidney. In addition, the modulation by dietary restriction was investigated. COX-derived ROS generation increased with age in ad libitum (AL) rats, but dietary restriction (DR) suppressed the level. The amounts of COX-2 protein and mRNA increased with age in AL rats but maintained at low levels in DR group. It was found that the binding characteristics of a nuclear transcription factor, NF-kappaB were altered by aging. The binding activity of NF-kappaB in aged kidney was significantly enhanced with the corresponding increase in mRNA and protein levels. These increases were closely in parallel to the increased ROS generation and gene expression of COX-2. The COX activity shown by NF-kappaB activation and the ROS generation by COX-mediated process were all modulated by DR. Our results suggest that the upregulation of COX-2 during aging may play an important role in many age-related diseases associated with aging process. And this upregulation was attenuated by DR. We propose that the modulation of the redox-sensitive transcription factor may well be a part of the mechanisms underpinning the anti-oxidative action of DR.

In vivo determination of ultratrace amounts of prostaglandin in plasma by high-performance liquid chromatography/laser-induced fluorometry/ultrasensitive laser spectrometry under severe conditions

We succeeded in determining ultratrace prostaglandin amounts in plasma, at the femtomolar level, using laser-induced fluorometry through a complete redesign of the analytical procedures. Practical samples, especially plasma, contain large amounts of admixtures, and prostaglandin in plasma (pg/mL) has been considered to be difficult to detect because the samples and reagents supplied by conventional procedures are neither pure nor stable enough to get good results by ultrasensitive laser spectrometry. We completely redesigned the analytical procedures after careful investigations of the reagent purification and the column separation conditions based on a newly found behavior of the reagent and derivatized prostaglandin in a small quantity of ethanol in the mobile phase. A lower determination limit of 23 pg/mL (65 fmol) was achieved, the variance was 12% at 25 pg/mL, and the recovery rate was 88-89%. This method was applied to in vivo analysis of the concentration of prostaglandin E1 administered as a prodrug of prostaglandin E1 (delta(8)-9-O-butyryl prostaglandin F1 butyl ester, AS-013) by intravenous infusion to beagle dogs. A clear correlation between the change of blood pressure and the prostaglandin E1 concentration was confirmed.

Toxicity of nonsteroidal anti-inflammatory drugs in the elderly: is advanced age a risk factor?

We reviewed the pharmacokinetic, physiologic and epidemiologic data concerning nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy and renal insufficiency in the elderly through a structured critical reading of the literature. References were collected through a search of MEDLINE and consultation with experts in the field. While there is an abundance of pharmacokinetic data comparing relevant parameters in young and old subjects, methods are not uniform and findings are inconsistent. Prostaglandin physiology appears to be altered in older versus younger subjects. Most surprisingly, there is a scarcity of epidemiologic data examining the contribution of age as a risk factor for NSAID-induced ulcers and/or renal insufficiency. The data that do exist do not clearly support age as an independent risk factor; and we believe that comorbidities, comedications and past history are more important predictors of NSAID-induced toxicity than age and more relevant in regard to therapeutic decision-making for this patient population.

Tissue concentrations and correlations of prostaglandins in healthy and inflamed human esophageal and jejunal mucosa

The PGE2, PGF2 alpha, PGI2, and TXB2 content in biopsies of healthy esophageal mucosa and inflamed mucosa and from subjects with chronic esophagitis was measured and statistically analyzed. No significant differences were found between the tissue concentrations of prostaglandins in the inflamed and the healthy mucosa, except for elevated PGI2 content in the inflamed esophageal mucosa in comparison to healthy mucosa. The prostaglandin content of jejunal mucosa was unchanged in jejunitis and in atrophy compared to findings in healthy subjects. Regression analysis revealed a significant negative correlation between the PGF2 alpha and PGI2 content in both inflamed esophageal and inflamed jejunal mucosa. In healthy mucosa, no correlation was found between the tissue concentrations of these two prostaglandins, either in the esophagus or in the jejunum. These results suggest the redistribution of cyclic endoperoxide metabolism under certain pathological conditions.

Multiple mitochondrial DNA deletions in a patient with mitochondrial myopathy and cardiomyopathy but no ophthalmoplegia

Deletions of muscle mitochondrial DNA are known in mitochondrial myopathy patients who have chronic progressive external ophthalmoplegia (CPEO). A 41-year-old patient with no apparent family history of this condition suffers from hypertrophic cardiomyopathy, slight muscle atrophy, and weakness of the extremities, but not from CPEO. A muscle biopsy showed the presence of ragged-red fibers, and Southern blot analysis disclosed multiple deletions of muscle mitochondrial DNA. This combination of clinical features in our patient is atypical in mitochondrial myopathy with demonstrable deleted muscle mitochondrial DNA. Pleomorphic clinical expression is suggested.

Aspirin, age, and proximity to lymphoid nodules influence cell proliferation parameters in rat colonic crypts

Recent epidemiological studies have demonstrated a correlation between regular aspirin (acetylsalicylic acid) use and decrease risk for the development of fatal colorectal cancer. An increase in the size of the cell proliferation compartment in colorectal crypts has been correlated with an increased risk for the development of colon cancer in animals and in humans. To determine if acetylsalicylic acid acts to decrease the size of the cell proliferation compartment, young (3 month) and old (22 month) rats were treated intragastrically with: 1 the vehicle for acetylsalicylic acid delivery (0.25% wt/vol carboxymetylcellulose in 0.15 N (HCl), 2 a single dose of acetylsalicylic acid (100 mg/kg), or 3 acetylsalicylic acid (30 mg/kg) given daily for 30 days. One day after the last treatment, colons were resected, fixed, sectioned and mounted on slides for immunohistochemical staining with a monoclonal antibody to proliferating cell nuclear antigen to assess cell proliferation parameters in the colonic crypts. The results were subjected to three way analysis of variance to assess the effects of: 1 rat age, 2 acute or chronic acetylsalicylic acid treatment, and 3 location of crypts over and away from aggregates of lymphoid nodules on the crypt proliferative parameters. Results demonstrated that: 1 acetylsalicylic acid treatment caused on overall decrease in the proliferative zone height, as measured in number of cells in the crypt column, 2 that crypts located over aggregates of lymphoid nodules had significantly higher proliferative activity than crypts located away from aggregates of lymphoid nodules, and 3 after chronic acetylsalicylic acid treatment there was a greater suppression of proliferative zone height in the crypts of old rats than in the crypts of young rats. In conclusion, acute and chronic intragastric delivery of acetylsalicylic acid caused an overall downward shift in the cell proliferation compartment of colonic crypts of young and of old rats. Whether or not acetylsalicylic acid administration will cause the same proliferative zone height response in carcinogen-treated rats is not yet established.

Age-related reductions in gastric mucosal prostaglandin levels increase susceptibility to aspirin-induced injury in rats

BACKGROUND/AIMS

Aspirin and other nonsteroidal anti-inflammatory drugs are known to cause gastrointestinal mucosal injury in humans and animals. The present study was designed to determine the effect of aging on gastric mucosal eicosanoid formation and aspirin-induced injury in Fischer 344 rats.

METHODS

In part 1 of the study, rats of three different age groups (3, 12, and 21 months) were killed after an overnight fast, and gastric mucosal formation of prostaglandins and leukotrienes was determined. In part 2, rats of various ages were killed 3 hours after receiving aspirin (100 mg/kg intragastrically) or vehicle (for controls). Gastric mucosal eicosanoid formation and gross mucosal injury were assessed.

RESULTS

Gastric mucosal prostaglandin formation decreased with aging, whereas no significant changes in mucosal leukotriene formation were noted in any age groups. No gastric mucosal lesions were present in any rats treated with vehicle alone. In contrast, aspirin caused significant mucosal injury in all age groups, but significantly more mucosal lesions were noted in the older rats.

CONCLUSIONS

These observations indicate that gastric mucosal prostaglandin synthesis decreases with aging in rats and that aged animals are more susceptible to aspirin-induced acute gastric mucosal injury.