Attitudes and barriers to resistance exercise training for older adults living with multiple long-term conditions, frailty, and a recent deterioration in health: qualitative findings from the Lifestyle in Later Life - Older People's Medicine (LiLL-OPM) study

BACKGROUND

Many older adults live with the combination of multiple long-term conditions (MLTC) and frailty and are at increased risk of a deterioration in health requiring interaction with healthcare services. Low skeletal muscle strength is observed in individuals living with MLTC and is central to physical frailty. Resistance exercise (RE) is the best available treatment for improving muscle strength, but little is known about the attitudes and barriers to RE in this group of older adults. This study therefore aimed to explore the knowledge of and attitudes towards RE, as well as the barriers and enabling factors, in older adults living with MLTC, frailty and a recent deterioration in health.

METHODS

Fourteen participants aged 69-92 years (10 women) from the Lifestyle in Later Life - Older People's Medicine (LiLL-OPM) study were recruited from an Older People's Medicine Day Unit in Newcastle, UK. Participants were invited to take part in a semi-structured interview exploring their knowledge and attitudes as well as barriers and enabling factors to RE. Data were analysed using thematic analysis.

RESULTS

The analysis generated three themes (1) a lack of awareness and understanding of RE, (2) a self-perceived inability to perform RE; physical and psychological barriers and (3) willingness to perform RE under expert guidance. There was a general lack of awareness and understanding of RE, with most participants having never heard of the term and being unaware of its potential benefits. When RE was described, participants stated that they would be willing to try RE, but it was apparent that an individualised approach underpinned by expert guidance would be required to support engagement.

CONCLUSIONS

Older adults living with MLTC, frailty and a recent deterioration in health lack awareness and understanding of RE. Despite a range of barriers, this group appear willing to engage in RE if they are appropriately supported. There is a need to co-design and deliver effective strategies, including education, to raise awareness and understanding of RE, as well as promote engagement in RE, in this group of older adults.

Feasibility of engaging older adults living with multiple long-term conditions, frailty, and a recent deterioration in health in a study of lifestyle: protocol for the LiLL-OPM study

Community-dwelling older adults living with multiple long-term conditions (MLTC), frailty and a recent deterioration in health are underserved by research. This results in a limited evidence base for their care, including the potential benefits of lifestyle interventions such as structured exercise. The aims of the LiLL-OPM (Lifestyle in Later Life - Older People's Medicine) study are to determine if it is feasible to carry out a research project with these patients, describe their health and lifestyle, their attitudes to engaging in exercise and their experiences of taking part in the research. Older adults who are attending an Older People's Medicine Day Unit service in Newcastle, UK, and their informal carers will be invited to take part. The study will use mixed methods with semi-structured interviews and a health and lifestyle questionnaire, carried out in a way that is most convenient to participants, including in their own homes and with a flexible schedule of study visits. The findings from the feasibility study will provide invaluable data on how to design research, including the most suitable approaches to recruitment and data collection. This will improve the inclusion in research of older adults living with MLTC, frailty and a recent deterioration in health.

The assessment of sarcopenia and the frailty phenotype in the outpatient care of older people: implementation and typical values obtained from the Newcastle SarcScreen project

Aim

Is it possible to implement the Newcastle SarcScreen, an assessment of sarcopenia and physical frailty, as part of the outpatient care of older people?

Findings

Grip strength measurement was possible in 98.2% and gait speed in 82.1%, with the latter typically not measured due to mobility impairment. We found a high prevalence of probable sarcopenia and the frailty phenotype across all age groups studied.

Message

We successfully implemented the Newcastle SarcScreen. The proforma is available to download as part of this article.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-022-00641-5.

Purpose

Sarcopenia and the frailty phenotype both indicate older adults at risk of adverse health outcomes and yet are not widely assessed in practice. We developed the Newcastle SarcScreen to enable assessment of these two ageing syndromes during clinical care. In the setting of our Older People’s Medicine Day Unit, our aims were to describe the implementation of the SarcScreen and to examine the typical values obtained.

Methods

The SarcScreen comprised height, weight, questions (three on the Fried frailty phenotype and five on the SARC-F questionnaire), grip strength and gait speed. We analysed data from 552 patients completing the SarcScreen. We expressed grip strength as Z-scores (number of standard deviations above the mean expected for a patient’s age and sex).

Results

It was possible to implement the SarcScreen. In 552 patients (65.9% females) with mean age 80.1 (7.7) years, grip strength was feasible in 98.2% and gait speed in 82.1%. Gait speed was typically not assessed due to mobility impairment. Most patients had weak grip strength (present in 83.8%), slow gait speed (88.8%) and the frailty phenotype (66.2%). We found a high prevalence of probable sarcopenia and the frailty phenotype across all age groups studied. This was reflected by low grip strength Z-scores, especially at younger ages: those aged 60–69 had grip strength 2.7 standard deviations (95% CI 2.5–2.9) below that expected.

Conclusion

It is possible to implement an assessment of sarcopenia and the frailty phenotype as part of the routine outpatient care of older people.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-022-00641-5.

Current assays overestimate 25-hydroxyvitamin D3 and underestimate 25-hydroxyvitamin D2 compared with HPLC: need for assay-specific decision limits and metabolite-specific assays

Background: Clinical demand for quick, cheap, precise and accurate 25-hydroxyvitamin D (25(OH)D) results has led to the development of a variety of assay methods. Lack of standardization of these methods has resulted in intermethod disagreement and challenged whether current assays recognize 25(OH)D2 and 25(OH)D3 equally.

Methods: We studied 172 patient samples from hip fracture cases using DiaSorin (DS) and IDS radioimmunoassays and the Nichols Advantage-automated protein binding assay (NA-CLPBA) in comparison to high-performance liquid chromatography (HPLC). 52 patient samples were analysed before and after three months treatment with 1000 IU of daily ergocalciferol (vitamin D2).

Results: Linear regression analysis in pre-treatment samples demonstrated a positive Y-intercept for each immunoassay compared with HPLC, and a slope that varied from 0.64 (IDS) to 0.97 (DS, NA-CLPBA). Bland Altman analysis demonstrated that all the three assays had a proportional positive bias relative to HPLC at values from 20 to 50 nmol/L. Regression analysis of post-treatment samples demonstrated a slope that was not significantly different from zero for the IDS and NA-CLPBA and 0.2 for the DS method, with a positive intercept for all assays of between 8 and 22, indicating less than 50% of 25(OH)D2 measured by HPLC was detected.

Conclusions: These results demonstrate the need for assay-specific decision limits for 25(OH)D3 in order to define appropriate thresholds for treatment institution. Treatment with vitamin D2 may not be accurately monitored with any of the three commercial assays studied. Clinicians and biochemists who continue to use 25(OH)D assays need to be urgently informed of these issues.

Periodontitis is associated with cognitive impairment among older adults: analysis of NHANES-III

BACKGROUND

Periodontitis is ubiquitous and associated with serological evidence of exposure to periodontal organisms, systemic inflammation and vascular disease. Dementia is a major public health problem likely related to a complex interaction between genetics and diseases associated with systemic inflammation, including diabetes, smoking and stroke.

METHODS

To assess relationships between systemic exposure to periodontal pathogens and cognitive test outcomes, data were analysed from the Third National Health and Nutrition Examination Survey (NHANES-III), a nationally representative cross sectional observational study among older adults. We included 2355 participants >or=60 years who completed measures of cognition and Poryphyromonas gingivalis IgG. Using SUDAAN, logistic regression models examined the association of P gingivalis IgG with cognitive test performance.

RESULTS

Poor immediate verbal memory (<5/9 points) was prevalent in 5.7% of patients, and 6.5% overall had impaired delayed recall (<4/9); 22.1% had difficulty with serial subtractions (<5/5 trials correct). Individuals with the highest P gingivalis IgG (>119 ELISA Units (EU)) were more likely to have poor delayed verbal recall (OR 2.89, 95% CI 1.14 to 7.29) and impaired subtraction (OR 1.95, 95% CI 1.22 to 3.11) than those with the lowest (<or=57 EU), with dose-response relationships for both (p trend, delayed memory = 0.045, subtraction = 0.04). After adjusting for socioeconomic and vascular variables, these relationships remained robust for the highest P gingivalis IgG group (delayed verbal memory OR 3.01 (95% CI 1.06 to 8.53); subtraction OR 2.00 (95% CI 1.19 to 3.36)). In contrast, immediate verbal memory was not significantly associated with P gingivalis.

CONCLUSION

A serological marker of periodontitis is associated with impaired delayed memory and calculation. Further exploration of relationships between oral health and cognition is warranted.

Eosinophilic vasculitis in an isolated central nervous system distribution

BACKGROUND

Eosinophilic vasculitis has been described as part of the Churg-Strauss syndrome, but affects the central nervous system (CNS) in <10% of cases; presentation in an isolated CNS distribution is rare. We present a case of eosinophilic vasculitis isolated to the CNS.

CASE REPORT

A 39-year-old woman with a history of migraine without aura presented to an institution (located in the borough of Queens, New York, USA; no academic affiliation) in an acute confusional state with concurrent headache and left-sided weakness and numbness. Laboratory evaluation showed increased cerebrospinal fluid (CSF) protein level, but an otherwise unremarkable serological investigation. Magnetic resonance imaging showed bifrontal polar gyral-enhancing brain lesions. Her symptoms resolved over 2 weeks without residual deficit. After 18 months, later the patient presented with similar symptoms and neuroradiological findings involving territories different from those in her first episode. Again, the CSF protein level was high. She had a raised C reactive protein level and erythrocyte sedimentation rate. Brain biopsy showed transmural, predominantly eosinophilic, inflammatory infiltrates of medium-sized leptomeningeal arteries without granulomas. She improved, without recurrence, when treated with a prolonged course of corticosteroids.

CONCLUSIONS

To our knowledge, this is the first case of non-granulomatous eosinophilic vasculitis isolated to the CNS. No aetiology for this patient's primary CNS eosinophilic vasculitis has yet been identified. Spontaneous resolution and recurrence of her syndrome is an unusual feature of the typical CNS vasculitis and may suggest an environmental epitope with immune reaction as the cause.

Issues of methodology, standardization and metabolite recognition for 25-hydroxyvitamin D when comparing the DiaSorin radioimmunoassay and the Nichols Advantage automated chemiluminescence protein-binding assay in hip fracture cases

BACKGROUND

Deficiency of vitamin D is commonly associated with hip fracture and treatment with vitamin D reduces hip fracture rates. Consequently, the demand for assays to measure 25-hydroxyvitamin D (25-OHD) has increased. The Nichols Advantage chemiluminescence protein-binding assay (CLPBA) for 25-OHD is a first-generation automated immunoassay with decreased turnaround time, reduced manual handling and non-radioactive label.

METHODS

We compared the CLPBA to the DiaSorin radioimmunoassay (RIA) and high-performance liquid chromatography (HPLC) for the measurement of 25-OHD using 161 samples from hip fracture patients and samples before and after institution of ergocalciferol (vitamin D(2)) therapy.

RESULTS

A negative bias for the CLPBA at concentrations below 30 nmol/L and a positive bias at 25-OHD values above 30 nmol/L compared with the RIA resulted in diagnostic discordance for one in three samples when using 30 and 50 nmol/L as decision limits. HPLC analysis confirmed the presence of a negative bias for the CLPBA at low values. Both immunoassays under-estimate 25-hydroxyvitamin D(2).

CONCLUSIONS

The discordance between 25-OHD values may be due to differences in standardization of each assay relative to HPLC. Our results emphasize the need for assay-specific clinical decision limits.

Interleukin-8 and anti-interleukin-8 autoantibodies in gingival crevicular fluid from patients with periodontitis

Interleukin-8 (IL-8) is believed to play an important role in the pathogenesis of various forms of periodontitis. In addition, the anti-IL-8 autoantibody has been recently recognized as a potent modulator of IL-8 function. In the current study, the concentrations of IL-8 and its autoantibody in gingival crevicular fluid from patients with chronic generalized periodontitis were compared to those in gingival crevicular fluid from patients with refractory chronic periodontitis. Gingival crevicular fluids were collected from patients treated in a private periodontal clinic. Nine patients who were identified as having chronic generalized periodontitis and four with refractory chronic periodontitis were selected for the study. Patients included in the latter group had undergone supportive periodontal therapy for more than 10 years, and during that time had experienced many episodes of periodontal destruction. The gingival crevicular fluid concentrations of total protein, IL-8, free anti-IL-8 autoantibody and IL-8 bound to the autoantibody (anti-IL-8:IL-8 complexes) were examined. There were no differences in concentration of total protein, but significantly higher levels of IL-8 were detected in patients with chronic generalized periodontitis in comparison to patients with refractory chronic periodontitis (P < 0.05). In addition, anti-IL-8:IL-8 complexes were present in 90% of patients with chronic generalized periodontitis, but in only 50% of patients with refractory chronic periodontitis. The results suggest that elevated concentrations of free and complexed IL-8 can differentiate patients with chronic generalized periodontitis from patients with refractory chronic periodontitis.

The relationship between field tests of anaerobic power and 10-km run performance

The purpose of this study was to investigate the relationship between several field tests of anaerobic power and distance running performance. Thirty-six trained runners (20 men and 16 women; mean +/- SD age, 27.9 +/- 5.7 years) participated in this study. Tests of anaerobic power consisted of a 50-m sprint, vertical jumps from a static take-off position and with a countermovement, a plyometric leap test, and a 300-m sprint. The results indicated that gender, height, weight, percent body fat, 50-m sprint time, the height and power of both types of vertical jumps, plyometric leap distance, and the 300-m sprint time were significantly correlated with 10-km run time (p < or = 0.05) in the total subject pool (N = 36). Stepwise multiple regression identified the plyometric leap distance to explain 73.9% of the variance in run time. When combined with 300-m sprint time, 77.9% of the variance (standard error of the estimate, 2.92 minutes) was explained. The regression equation developed is Y' (10-km time) = 57.22 - 5.15(plyometric leap distance in meters) + 0.27(300-m sprint time in seconds). The results indicate that anaerobic power is significantly related to distance running performance and may explain a meaningful percentage of variability in 10-km run time. Therefore, it may be beneficial for distance runners to supplement aerobic training with some power and speed development such as plyometrics and sprinting.

The effect of azithromycin and clarithromycin on ex vivo interleukin-8 (IL-8) release from whole blood and IL-8 production by human alveolar macrophages

We investigated the effects of azithromycin and clarithromycin, two antibiotics that possess a broad spectrum of antimicrobial activity (including antimycobacterial activity), on interleukin-8 (IL-8) release from human whole blood leucocytes and lung macrophages. Ex vivo stimulation of leukocytes with either of the antibiotics (0.04-40 mg/L) significantly increased IL-8 secretion. Incubation of alveolar macrophages with different concentrations of azithromycin or clarithromycin modified IL-8 production: it increased at a drug concentration of 4 mg/L and decreased at concentration of 400 mg/L. Our findings suggest that azithromycin and clarithromycin may alter IL-8 production, thus enhancing the clinical effectiveness of these antibiotics.

Anti-interleukin 8 autoantibody: interleukin 8 complexes in the acute respiratory distress syndrome. Relationship between the complexes and clinical disease activity

Increased levels of interleukin 8 (IL-8) are found in bronchoalveolar lavage (BAL) fluids from patients with the acute respiratory distress syndrome (ARDS). However, IL-8 is not an efficient predictor of the course of ARDS. Our prior studies demonstrated that IL-8 present in lung fluids from patients with ARDS is associated with anti-IL-8 autoantibodies (anti-IL-8:IL-8 complexes). These data led us to hypothesize that the complexes might better predict the development of acute lung injury. Accordingly, we measured concentrations of free and complexed IL-8 in BAL fluids from 19 patients at risk and 45 with established ARDS on Days 1, 3, 7, 14, and 21 after the onset of ARDS. The concentrations of anti-IL-8:IL-8 complexes in patients with ARDS on Day 1 were significantly higher than in patients at risk (p < 0.05). There was a significant association between anti-IL-8:IL-8 complex concentrations and the onset of ARDS (p = 0.03). Similarly, anti-IL-8:IL-8 complex concentrations were significantly higher in patients on Day 1 of ARDS who later died (p < 0.05), and the association between high anti-IL-8: IL-8 complex concentrations and the probability of dying was significant (p = 0.03). The presence of anti-IL-8:IL-8 complexes in BAL fluids of patients with ARDS is an important prognostic indicator for the development and outcome of ARDS.

Specific binding of IL-8 to rabbit alpha-macroglobulin modulates IL-8 function in the lung

OBJECTIVE AND DESIGN

The purpose of this study was to compare chemotactic activity of IL-8 alone with that of IL-8 reacted with rabbit alpha-macroglobulins (alphaM) in vivo.

METHODS

Initially the binding of recombinant human IL-8 (rhIL-8) to rabbit alphaM was studied. 125I-labeled rhIL-8 was incubated with alphaM, and electrophoresed on native 5% gels or SDS-polyacrylamide 4-20% gradient gels. Next, rhIL-8 or rhIL-8 bound to alphaM was administered via an endotracheal tube to rabbit's lungs.

TREATMENT

An endotracheal tube was wedged into a segment of the lobe of each lung, and a sample instilled through the tube into this segment. After 4 h the lungs were lavaged.

RESULTS

rhIL-8 bound to alphaM retained its full chemotactic activity in vitro but exhibited a diminished ability to induce the influx of neutrophils into the rabbit lung.

CONCLUSIONS

The data suggest that alphaM may facilitate IL-8 clearance from the lung.

Involvement of alpha-2-macroglobulin receptor in clearance of interleukin 8-alpha-2-macroglobulin complexes by human alveolar macrophages

The purpose of this study was to determine if interleukin 8 (IL-8) in complex with alpha2-macroglobulin (alpha-2-M) can be taken up by human alveolar macrophages. First, we demonstrated that human alveolar macrophages have receptors for alpha-2-M but not IL-8. The binding of(125)I-labeled alpha-2-M to the cells was specific and saturable, whereas(125)I-labeled recombinant human IL-8 (rhIL-8) did not bind to macrophages. However,(125)I-rhIL-8-alpha-2-M complexes bound to macrophages, and unlabeled alpha-2-M competed for the binding. We then cultured the cells in the presence of(125)I-rhIL-8-alpha-2-M complexes,(125)I-rhIL-8 alone or buffer for 24 h. Macrophages were lysed, and the released radioactivity measured. IL-8 concentrations in supernatants and cells were also measured using an IL-8 ELISA. When the macrophages were incubated with(125)I-rhIL-8-alpha-2-M complexes there was a significant amount of IL-8 associated with the cells. However, this was not the case when the cells were incubated with(125)I- rhIL-8 alone suggesting that only these complexes were taken-up by human alveolar macrophages. Furthermore, the clearance of complexes was specifically inhibited by a monoclonal antibody against the 515-kDa subunit of the alpha-2-M receptor (alpha-2-MR) but not by an isotopic mouse IgG1. The study shows an important clearance mechanism for IL-8 in the lung.

Effect of age on plasma membrane asymmetry and membrane fluidity in human leukocytes and platelets

BACKGROUND

We determined whether ageing changes in plasma membrane phospholipid asymmetry were related to changes in membrane physical characteristics.

METHODS

Plasma membrane asymmetry was determined in polymorphonuclear leukocytes (PMN), lymphocytes, and platelets from 45 healthy young (mean 29 years, 26 male) and 28 healthy elderly (mean 70 years, 15 male) subjects by flow cytometric measurement of annexin V binding to cell surface phosphatidylserine. Membrane fluidity in lymphocytes and platelets from young and elderly subjects was determined by fluorescence polarization of 1,6-diphenyl- 1,3,5-hexatriene (DPH) and (4-trimethylammonium)-DPH (TMA).

RESULTS

In elderly subjects, a higher proportion of lymphocytes had specific annexin V binding to phosphatidylserine (PS) than in young subjects (young: median percentage of cells with specific annexin V binding to PS 5.3 [second to fourth quintiles range 3.8-8.7]; elderly: 8.5 [5.2-17.2]; p = .028). No ageing change in annexin V binding to PMN was observed (young: 35.0% [21.8-53.5]; elderly: 39.6% [27.4-69.8]; p = .42). Platelets had no specific annexin V binding (young: median molecules of annexin V specific binding 3.8 [0.4-11.3]; elderly: -1.4 [-4.8-1.7]; p = .23). Superficial membrane fluidity was increased in lymphocytes (TMA anisotropy, young: 0.271 [0.259-0.289]; elderly: 0.262 [0.242-0.279];p = .004), but not in platelets (young: 0.273 [0.259-0.293]; elderly: 0.269 [0.248-0.284]; p = .12). Lymphocyte annexin V binding correlated with TMA (r = -.65, p = .022), but not DPH anisotropy (r = -.39, p = .18).

CONCLUSIONS

Plasma membrane asymmetry is decreased with age in human lymphocytes, but not in human PMN or platelets. The increased proportion of lymphocytes with loss of plasma membrane asymmetry corresponds to the ageing changes in superficial membrane fluidity observed in lymphocytes. Such alterations in lymphocyte plasma membrane structure with age could account for changes in membrane-bound receptor function described with ageing, and may contribute to alterations in immune responsiveness and vascular thrombosis seen in older humans.

Effect of aging on CD11b and CD69 surface expression by vesicular insertion in human polymorphonuclear leucocytes

The exocytosis of intracellular vesicles is an important function of the plasma membrane, which is responsible for hormone secretion, cell surface expression of antigens, ion transporters and receptors, and intracellular and intercellular signalling. Human aging is associated with many physiological and cellular changes, many of which are due to alterations in plasma membrane functioning. Alterations in vesicle externalization with age could account for many of these changes. We investigated whether alterations in vesicle exocytosis occur with increasing age by flow-cytometric determination of CD11b and CD69 expression on the surface of human polymorphonuclear leucocytes (PMN) stimulated with phorbol myristate acetate (PMA), a tumour promoter which binds to and activates protein kinase C (PKC) directly, or with formyl-Met-Leu-Phe (fMLP), which activates PKC indirectly via interactions with a cell surface receptor and G-protein, and subsequent inositol phosphate hydrolysis. Following stimulation with PMA, a decrease in the proportion of PMN expressing CD69 at high levels was observed in elderly compared with young subjects (young, 55.3%; elderly, 43.9%; P=0.01). No aging-related differences in the proportion of PMN expressing CD11b (young, 73.7%; elderly, 68.4%; P=0.15), or in the number of molecules of CD69 or CD11b expressed per cell, were observed. Stimulation with fMLP or low PMA concentrations resulted in full CD11b expression but minimal CD69 expression in both young and elderly subjects. Cells which expressed CD69 had no CD11b expression, while those cells expressing CD11b had minimal CD69 expression. Thus the PMA-induced expression of CD11b and CD69 in human PMN represents two separate processes, only one of which is affected in aging. CD11b expression appears to require a lesser degree of PKC stimulation compared with that required for CD69 expression. The age-associated reduction in PMA-stimulated CD69 expression may occur either at or distal to PKC activation. Such a decrease may contribute to the age-associated impairments in PMN function that contribute, in turn, to immunosenescence.

Staphylococcal enterotoxin A-induced injury of human lung endothelial cells and IL-8 accumulation are mediated by TNF-alpha

Staphylococcal enterotoxin A (SEA), a superantigen produced by some strains of Staphylococcus aureus, causes a variety of clinical manifestations ranging from food poisoning to shock. S. aureus can also be associated with the development of acute respiratory distress syndrome, and SEA has been shown to cause an inflammatory reaction in the lung. Therefore, we examined possible interactions between SEA, PBMCs, polymorphonuclear cells (PMNs), and normal human lung microvascular endothelial cells (HMVEC-L), as well as the role of these interactions on the secretion of IL-8. Injury to HMVEC-L, as measured by the release of 51Cr, increased significantly when HMVEC-L were incubated with SEA and PBMCs. IL-8 was secreted by both PBMCs and HMVEC-L. The accumulation of IL-8 in the culture medium of HMVEC-L was increased by SEA in a dose-dependent manner and was directly related to the number of PBMCs present. Although neither anti-human IL-8 nor IL-1 mAb inhibited HMVEC-L cytotoxicity, anti-human TNF-alpha mAb inhibited both the cytotoxicity and IL-8 accumulation completely. When HMVEC-L were incubated with supernatants from SEA-treated PBMCs, HMVEC-L cytotoxicity was comparable with HMVEC-L incubated with SEA and PBMCs at the same time. Although high concentrations of purified PMNs induced HMVEC-L lysis in a dose-dependent manner, the effect of PMNs was not changed in the presence of SEA. These findings suggest that TNF-alpha secreted by SEA-stimulated PBMCs plays a leading role in HMVEC-L injury.

Anti-IL-8 autoantibodies in alveolar fluid from patients with the adult respiratory distress syndrome

IL-8 is a potent neutrophil attractant and activator. IL-8 has been reported to be involved in the pathogenesis of several diseases, including rheumatoid arthritis, sepsis, psoriasis, and the adult respiratory distress syndrome (ARDS). Our previous studies demonstrated that high concentrations of IL-8 were present in alveolar fluids from patients with ARDS and were associated with increased mortality. In this study we report that a major portion of IL-8 in bronchoalveolar fluids from patients with ARDS is associated with anti-IL-8 autoantibody (anti-IL-8:IL-8 complexes). Free autoantibodies that recognize IL-8 were also detected in these fluids. Next, we examined the properties of anti-IL-8 autoantibodies present in lung fluids from ARDS patients and compared them with autoantibodies from normal plasma and arthritic synovial fluids. The anti-IL-8 autoantibody was polyclonal, and IgG3 and IgG4 were the primary IgG subclasses. Anti-IL-8:IL-8 complexes consisted of one IgG and one IL-8 molecule. In addition, anti-IL-8 autoantibody bound IL-8 with a high affinity (approximately 10(-12) M) and inhibited IL-8 interaction with its specific receptors on neutrophils. The results suggest that anti-IL-8 autoantibodies may regulate IL-8 activity.

Anti-IL-8 autoantibodies in alveolar fluid from patients with the adult respiratory distress syndrome

IL-8 is a potent neutrophil attractant and activator. IL-8 has been reported to be involved in the pathogenesis of several diseases, including rheumatoid arthritis, sepsis, psoriasis, and the adult respiratory distress syndrome (ARDS). Our previous studies demonstrated that high concentrations of IL-8 were present in alveolar fluids from patients with ARDS and were associated with increased mortality. In this study we report that a major portion of IL-8 in bronchoalveolar fluids from patients with ARDS is associated with anti-IL-8 autoantibody (anti-IL-8:IL-8 complexes). Free autoantibodies that recognize IL-8 were also detected in these fluids. Next, we examined the properties of anti-IL-8 autoantibodies present in lung fluids from ARDS patients and compared them with autoantibodies from normal plasma and arthritic synovial fluids. The anti-IL-8 autoantibody was polyclonal, and IgG3 and IgG4 were the primary IgG subclasses. Anti-IL-8:IL-8 complexes consisted of one IgG and one IL-8 molecule. In addition, anti-IL-8 autoantibody bound IL-8 with a high affinity (approximately 10(-12) M) and inhibited IL-8 interaction with its specific receptors on neutrophils. The results suggest that anti-IL-8 autoantibodies may regulate IL-8 activity.

Interleukin-8 (IL-8) is a major neutrophil chemotaxin from human alveolar macrophages stimulated with staphylococcal enterotoxin A (SEA)

Since Staphylococcus aureus is an important human pathogen, and infection of the lungs is characterized by neutrophil infiltration we studied the role of a staphylococcal toxin, enterotoxin A (SEA) on the synthesis and secretion of IL-8 by human alveolar macrophages. As SEA concentration was increased, the IL-8 accumulation in the macrophage conditioned medium increased. The concentration of mRNA encoding IL-8 was also elevated in the macrophage in response to increases in SEA concentration. Although the monocytic cell line U937 was able to respond to SEA and secrete IL-8, treatment with PMA prior to SEA stimulation increased the IL-8 accumulation around fifty fold indicating that maturation of the undifferentiated cell to a more macrophage-like cell facilitated IL-8 accumulation. Stimulating human alveolar macrophages with high concentrations of SEA caused an increase in IL-1 accumulation. However, when the cells were incubated with SEA in the presence of IL-1 receptor antagonist, there was no decrease in IL-8 accumulation. Addition of a neutralizing anti-IL-8 monoclonal antibody to the culture medium of SEA-stimulated macrophages significantly reduced the neutrophil chemotactic activity of the medium. These studies showed that IL-8 is a major neutrophil chemotaxin from human alveolar macrophages stimulated with SEA.

Glucocorticoids regulate hippocampal 11 beta-hydroxysteroid dehydrogenase activity and gene expression in vivo in the rat

Chronic glucocorticoid excess or deficiency is associated with hippocampal dysfunction and neuronal death. 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD), which catalyses the reversible conversion of corticosterone to inactive 11-dehydrocorticosterone, regulates glucocorticoid access to receptors in the kidney and liver in vivo. The enzyme is also present in the hippocampus where it might modulate glucocorticoid action. We examined the effects of corticosteroid manipulations on hippocampal and peripheral 11 beta-OHSD. In the hippocampus, chronic adrenalectomy (10 days) had no effect on 11 beta-OHSD activity, compared to sham-operated controls. Treatment of adrenalectomized animals with dexamethasone (200 micrograms/kg.day-1), but not aldosterone (20 micrograms/kg.day-1), for 10 days significantly increased hippocampal 11 beta-OHSD activity compared with sham or adrenalectomized rats (22% and 23% rise respectively, P < 0.05). These effects reflect changes in transcription of the liver-type 11 beta-OHSD gene, with dexamethasone significantly increasing 11 beta-OHSD mRNA expression in the hippocampus compared with sham or adrenalectomized animals (32% and 70% higher respectively, P < 0.05). In the liver, adrenalectomy significantly reduced 11 beta-OHSD activity (16% lower), which was restored to sham levels by dexamethasone, but not aldosterone. Similar trends were seen in 11 beta-OHSD mRNA expression, although these did not reach significance. None of the manipulations altered 11 beta-OHSD activity or mRNA expression in the kidney. The hippocampal effects of dexamethasone were similar to those of chronic stress (arthritis) which increased 11 beta-OHSD activity (20% rise, P < 0.05), although this was not reflected at the level of mRNA. Thus, hippocampal (and hepatic, but not renal) 11 beta-OHSD appears to be regulated by chronic glucocorticoid manipulations and stress. Hippocampal 11 beta-OHSD may thus ensure optimal long-term corticosterone exposure of glucocorticoid-sensitive neurons.

Atriopeptin: an endogenous corticotropin-release inhibiting hormone

Activation of the hypothalamic-pituitary-adrenocortical axis is a major component of the body's response to stress. Current theories on the pathophysiology of disorders associated with hyperfunction of the axis, such as depression and Cushing's stress, are based on the concept that anterior pituitary adrenocorticotropin (ACTH) secretion is stimulated by hypothalamic corticotropin-releasing hormones and inhibited by adrenal corticosteroids. Hypothalamic inhibitory control of pituitary ACTH secretion has been also postulated, but has not gained general acceptance because of the lack of definitive evidence for a corticotropin-release inhibiting hormone. It is shown here that in conscious rats stress-induced secretion of ACTH and corticosterone is markedly enhanced by the immunoneutralisation of atriopeptin. Therefore, we propose that atriopeptin is a physiologically relevant corticotropin-release inhibiting hormone.

Acceptance of quantity recipes with zero added salt by a military population

The average civilian young man consumes approximately 5.5 g sodium daily in food plus an additional 20% as added salt. The average intake of military personnel may exceed this civilian level. The Surgeons General of the Military Services established 1,700 mg sodium per 1,000 kcal as the goal for sodium content in menus served in military dining facilities. We tested the acceptability of quantity recipes with zero added salt and control recipes with added salt in military dining facilities. Twenty-eight test recipes with zero added salt were prepared and offered on the regular serving line. Military personnel selecting the test items rated them for acceptability on a nine-point hedonic scale. Only 6 of the 28 recipes with zero added salt were rated significantly less acceptable than the control recipes. Chemical analysis of the test recipes showed an 11% to 87% reduction in sodium and a 28% to 80% reduction in chloride. Our results indicate that dietitians and/or foodservice managers can produce quantity food recipes that are reduced in sodium and acceptable to customers.

The secretory action of barium chloride in rat colon

BaCl2, applied serosally, caused a rise in the p.d. and short-circuit current (s.c.c), and a decrease in tissue resistance in stripped sheets of rat colon. This response was dose dependent. Mucosal application of BaCl2 was without effect. The BaCl2-induced rise in s.c.c. was inhibited by reducing the serosal Na+ concentration to 25 mM. Lowering the mucosal Na+ concentration was without effect. Ouabain (10(-3) M in serosal fluid) and furosemide (10(-3) M in serosal fluid) both reduced the rise in s.c.c. induced by BaCl2. Flux determinations indicated that BaCl2 inhibited Na+ absorption and stimulated Cl- secretion by the colon. In vivo, BaCl2 increased fluid accumulation within the colonic lumen, an effect that was associated with a rise in the transcolonic p.d. Increasing the serosal K+ concentration to 20 mM reduced the responses to BaCl2, acetylcholine and theophylline, and this could not be entirely accounted for by the concomitant reduction in the serosal Na+ concentration. As high serosal K+ did not mimic the secretory response it would appear that BaCl2 does not act by blocking K+ channels. The rise in s.c.c. induced by BaCl2 was not reduced by Ca2+-free conditions, but it was inhibited by 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8) and trifluoperazine. BaCl2 did not alter cyclic AMP production by colonic scrapes. It is concluded that BaCl2 induces colonic secretion by the release of intracellular Ca2+, which then combines with calmodulin to activate the secretory process.

The involvement of calcium in the intestinal response to secretagogues in the rat

The involvement of Ca2+ in the regulation of intestinal secretion was investigated in stripped sheets of rat mid-intestine. Removal of serosal Ca2+ together with the addition of EGTA at concentrations of 0.5 and 1 mM inhibited the rise in short-circuit current (s.c.c.) induced by both acetylcholine and theophylline, a similar degree of inhibition being observed with both secretagogues. Ca2+-free serosal fluid with 0.5 mM-EGTA added reduced significantly the rises in s.c.c. induced by A23187, acetylcholine, 5-hydroxytryptamine, theophylline, dibutyryl cyclic AMP and prostaglandin E2, but not the increased s.c.c. associated with glucose absorption. The Ca2+ channel blocker verapamil produced similar results. The calmodulin antagonist trifluoperazine inhibited secretagogue action while its sulphoxide derivative was without effect at the same concentration. The intracellular Ca2+ antagonist TMB-8 reduced the increased s.c.c. observed with acetylcholine and dibutyryl cyclic AMP. The net Cl- secretion, but not the decreased mucosal-to-serosal Na+ flux, induced by acetylcholine was abolished in Ca2+-free conditions. There was no consistent effect on the reduction in the residual ion flux caused by acetylcholine. Absence of Ca2+ converted the stimulation of Cl- secretion induced by dibutyryl cyclic AMP observed under control conditions to an enhancement of net Na+ and Cl- absorption. It is concluded that intestinal secretagogues, whether they act through cyclic AMP or not, require both internal and external sources of Ca2+ if they are to produce their full effects. Moreover, it appears that the nature of the response to dibutyryl cyclic AMP depends on the prevailing Ca2+ concentration.

The effect of barium chloride on intestinal secretion in the rat

The addition of BaCl2 to the serosal solution, at concentrations from 0 X 25 mM to 10 mM, caused increases in potential difference, short-circuit current and resistance across stripped sheets of rat mid-intestine, although mucosal application had little effect. The response to BaCl2 was significantly greater than that obtained with the same concentration of CaCl2. An increase in net Cl- secretion entirely accounted for the rise in short-circuit current induced by BaCl2. BaCl2 inhibited net fluid uptake by everted sacs. It also enhanced the accumulation of fluid by intestinal loops in vivo and this was associated with an increased potential difference. The response to BaCl2 in vitro was not reduced in the absence of serosal Ca2+ ions. The effect of BaCl2 was abolished by trifluoperazine and also by TMB-8 (8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride). BaCl2 did not alter cyclic AMP production by isolated enterocytes. It is concluded that BaCl2 induces intestinal secretion by releasing Ca2+ from intracellular stores which then combines with calmodulin to stimulate the secretory process.