Neutrophil oxidative metabolism in aged humans: a perspective

Risk factors for complications and mortality of percutaneous endoscopic gastrostomy insertion

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) is a relatively safe procedure; however, acute and chronic complications of PEG have been reported. We aimed to determine risk factors associated with complications and 30-day mortality after PEG, based on 11 years of experience at a single tertiary hospital.

METHODS

In total, 401 patients who underwent first PEG insertion at the Asan Medical Center, Seoul, Korea, between January 2005 and December 2015 were eligible. Medical records were retrospectively reviewed to determine clinical characteristics and outcomes of 139 and 262 patients who underwent pull-type and introducer-type PEG, respectively.

RESULTS

The median age of the overall population was 68 years, and the median body mass index was 19.5 kg/m2. Acute and chronic complications developed in 96 (23.9%) and 105 (26.2%) patients. Acute ileus and chronic tube obstruction were significantly more frequent in the introducer-type PEG group (p = 0.033 and 0.001, respectively). The 30-day mortality rate was 5.0% (median survival: 10.5 days). Multivariate analysis revealed that underlying malignancy was a predictor of acute complications; age ≥ 70 years and diabetes mellitus were predictors of chronic complications. The median follow-up was 354 days. Neurologic disease and malignancy were the most common indications for PEG. Neurologic diseases were classified into two groups: stroke and the other neurologic disease group (including dementia, Parkinson's disease, neuromuscular disease, and hypoxic brain damage). Multivariate analysis showed that 30-day mortality was significantly lower in the other neurologic disease group and higher in patients with platelet count < 100,000/μL, and C-reactive protein (CRP) ≥ 5 mg/dL.

CONCLUSIONS

PEG is a relatively safe and feasible procedure, but it was associated with significantly higher early mortality rate in patients with platelet count < 100,000/μL or CPR≥5mg/dL, and lower early mortality rate in neurologic disease group including dementia, Parkinson's disase, neuromuscular disease, and hypoxic brain damage. In addition, acute complications in patients with underlying malignancy, and chronic complications in patients aged ≥70 and those with diabetes mellitus should be considered during and after PEG.

Nanoparticles and Cell Longevity

The field of engineering has made substantial strides in nanotechnology, in the realm of materials science and construction of nanoscale devices. Nanomedicine encompasses application of cutting edge engineered nanostructures to biological systems and development of novel strategies for disease intervention. In the current review, we discuss the pharmacological application of nanoparticles as free radical scavengers and the capacity of nanoparticles to promote cell and organismal longevity.

Old age is associated with increased severity of complications in endoscopic biliary stone removal

BACKGROUND AND AIM

Various techniques are required in endoscopic biliary stone removal. Because the presence of biliary stones is a benign disease, it is essential to minimize procedure-related complications. Having a sound knowledge of the risk factors can help reduce the number and severity of complications. We determined the risk factors for complications in patients undergoing endoscopic biliary stone removal.

METHODS

This was a retrospective observational cohort study. We analyzed 743 consecutive patients with biliary stones who were treated with endoscopic retrograde cholangiopancreatography and identified the independent risk factors for complications.

RESULTS

Complications occurred in 66 patients (8.9%). Pancreatitis occurred in 26 patients (3.5%), cholangitis in 16 (2.2%), bleeding in 12 (1.6%) and other in 12 (1.6%). Independent risk factors for overall complications were multiple biliary stones (P = 0.0480) and anti-thrombotic drugs (P = 0.0186).Independent risk factors for moderate or severe complications were old age (P = 0.0201), multiple biliary stones (P = 0.0300), anti-thrombotic drugs (P = 0.0131), and cirrhosis of the liver (P = 0.0013). The respective risk factors for pancreatitis, cholangitis, and bleeding were precut technique (P = 0.0005), endoscopic mechanical lithotripsy (P = 0.0421), and both anti-thrombotic drugs (P = 0.0228) and cirrhosis of the liver (P = 0.0115).

CONCLUSIONS

Old age was associated with a similar complication rate to younger age but increased the severity of complications following endoscopic biliary stone removal. Improved awareness of the severity of complications may be of benefit during periprocedural management. Further studies are warranted.

Reduced neutrophil superoxide production among healthy older adults in response to acute psychological stress

Ageing is associated with higher morbidity and mortality, and declining immune function, termed immunesenescence. The present study examined the effects of an acute laboratory psychological stress task on innate immunity, specifically neutrophil function, among older adults. The two functional assays used were phagocytosis of Escherichia coli and stimulated superoxide production. Participants were 17 (11 female) older adults (mean age 75.7, SD=7.06 years). Blood samples to determine neutrophil function by flow cytometry were taken at the end of resting baseline, during an acute stress task and during recovery. The stress task was an 8-minute time-pressured mental arithmetic challenge with social evaluation. There was a significant reduction in neutrophil superoxide production, p=.017, η(2)(p)=.240, associated with the stress task relative to baseline, but no effect on phagocytosis. The results of this study could contribute to explaining the increased risk of infection in older adults, particularly those subject to frequent stress exposures. Future research is needed to explore the underlying mechanisms of acute stress effects on human neutrophil function in older adults in greater detail.

A cerium oxide nanoparticle-based device for the detection of chronic inflammation via optical and magnetic resonance imaging

Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration, distinguishing physiological from abnormal levels. As a result under physiological and transient inflammatory conditions, the device's fluorescence and magnetic resonance signals, emanating from multimodal iron oxide nanoparticles, were similar. However, under chronic inflammatory conditions that are usually associated with high local concentrations of reactive oxygen species and pH decrease, the device's output was considerably different. Specifically, the device's fluorescence emission significantly decreased, while the magnetic resonance signal T2 increased. Further studies identified that the changes in the device's output are attributed to inactivation of the sensing component's nanoceria that prevents it from successfully scavenging the generated free radicals. Interestingly, the buildup of free radical excess led to polymerization of the iron oxide nanoparticle's coating, with concomitant formation of micron size aggregates. Our studies indicate that a nanoceria-based device can be utilized for the monitoring of pro-inflammatory biomarkers, having important applications in the management of numerous ailments while eliminating nanoparticle toxicity issues.

Effects of age, gender and time on receptor expression and anti-Aspergillus functions of human phagocytes

Phagocytes play a central role in immune defense. Their dysfunction predisposes to infections. This study determined the expression level of nine receptors involved in Aspergillus immune response as well as the values of phagocytosis and production of radical oxygen species after Aspergillus stimulation, in a healthy adult population. The expression values of the CD11b, CD11c, CD14, CD18, CD35, CD181, CD182, CD282 and CD284 receptors on peripheral human monocytes and granulocytes was established. A heterogenous expression of the CD282 on granulocytes was observed as CD181, CD182 and CD284 on monocytes. Similarly, we observed considerable variation in the expression of these receptors over time. Only CD282 on granulocytes varied with sex. No variation with age was observed. Adherence of Aspergillus conidia to phagocytes was dependent of individual, sex, age and time. A better characterization of these innate immunity parameters is necessary to develop in the future an immunologic surveillance strategy for transplant recipients.

Mean cell volume of neutrophils and monocytes compared with C-reactive protein, interleukin-6 and white blood cell count for prediction of sepsis and nonsystemic bacterial infections

Clinicians are in need of better diagnostic markers for rapid diagnosis of severe infections. Therefore, we studied the diagnostic significance of mean cell volume of neutrophils (MNV) and monocytes (MMV) compared with Interleukin-6 (IL-6), C-reactive protein (CRP) and white blood cell count for predicting systemic clinical infection (sepsis). MNV and MMV were obtained by volume conductivity scatter (VCS) technique of the Coulter LH 750 hematology analyzer during automated differential counts, and blood samples from patients with sepsis (n = 37), nonsystemic bacterial infections (n = 39) and controls (n = 48) were studied. We observed a significant increase in MNV and MMV in the sepsis group compared with limited infections and controls. However, at a designated cut-off point of 250 pg/ml, IL-6 seemed to be the best predictor for sepsis with a sensitivity of 93% and a specificity of 76%. Compared with CRP (cut-off point 60 mg/dl), MNV at a cut-off of 150 had a comparable sensitivity and specificity and was the most predictive VCS parameter. Taken together, MNV and MMV seemed to be potential parameters to discriminate between sepsis and nonsystemic infections.

Geriatric neutrophils: implications for older adults

OBJECTIVES

To review the intersection of immunosenescence and neutropenia, focusing on innate immunity, and implications for research and practice for neutropenic older adults with cancer.

DATA SOURCES

Research studies, journal articles, and web sites.

CONCLUSION

Immunosenescence, age-related changes within the immune system renders older adults more vulnerable to infection. This vulnerability is magnified by cancer and its treatment. Unfortunately, there has been little consideration of immunosenescence as it relates to supportive care for this population.

IMPLICATIONS FOR NURSING PRACTICE

Studies detailing the impact of immunosenescence on neutropenia and outcomes for neutropenic older adults are necessary to advance clinical research and practice.

Interrelationship Among Neutrophil Efficiency, Inflammation, Antioxidant Activity and Zinc Pool in Very Old Age

Neutrophils are the first barrier against infections. Aged neutrophils display impaired oxidative burst and phagocytosis with subsequent less capability to destroy bacteria. In successful ageing (nonagenarians), neutrophil efficiency (phagocytosis) increases. After ingested microbes, aged neutrophils are less prone to undergo apoptosis favouring chronic inflammation. Moreover, the superoxide dismutase (SOD) activity, which is necessary in avoiding ROS produced by oxidative burst, is limited in ageing. The mechanisms of age-related changes in neutrophil function are not fully understood, taking also into account that nonagenarians escape infections in comparison with elderly. Zinc pool may be involved because it is pivotal for neutrophil efficiency and SOD activity. Since zinc also controls the inflammation, via IL-6 and soluble factor of gp130 (sgp130), we have assessed the possible interrelationship among oxidative burst, apoptosis, inflammation, SOD, adhesion molecule Mac-1 and zinc pool in elderly and in nonagenarians. The oxidative burst and the capacity to increase Mac-1 after PMA stimulation decrease both in elderly and nonagenarians, but the latter display a slight increased neutrophil induced apoptosis, decreased sgp130, increased SOD, and more neutrophil zinc content, as it occurs in young-adults. Significant correlation exists between sgp130 and zinc pool in very old age. These findings suggest lower chronic inflammation in nonagenarians, via more zinc available, with subsequent long-life survival. Therefore, a more correct interrelationship among neutrophil efficiency, inflammation, antioxidant activity and zinc pool exists in successful ageing with subsequent more effectiveness to control the inflammatory response to pathogens.

Role of defective ERK phosphorylation in the impaired GM-CSF-induced oxidative response of neutrophils in elderly humans

GM-CSF-induced oxidative responses are defective in neutrophils of elderly humans. In the present study we evaluated whether this phenomenon might be related to alterations in cytokine-dependent MAPK signalling. Neutrophils obtained from elderly humans and stimulated with GM-CSF showed a significant reduction in phosphorylated ERK1/2 levels and an even higher decrease in ERK1/2 activation with respect to baseline. No changes in GM-CSF-induced p38 MAPK phosphorylation were observed. Cell pretreatment with the MEK inhibitor PD98059 determined a marked suppression of GM-CSF-induced O2- release. Interestingly, under the above experimental condition, there was no longer any difference in O2- production observed between elderly and young subjects. Furthermore, despite the fact that the p38 MAPK pathway was activated less strongly by GM-CSF, the p38 MAPK inhibitor SB203580 reduced GM-CSF-induced O2- production in the neutrophils of the elderly to levels similar to those obtained with PD98059. TNF-alpha-triggered O2- production was not altered by ageing and in fact, a similar ERK1/2 or p38 MAPK activation was found in TNF-alpha-stimulated neutrophils from elderly and young individuals. In accordance with the different potency of TNF-alpha in activating ERK1/2 and p38 MAPK, the TNF-alpha-induced oxidative responses were more sensitive to the inhibitory effects of SB203580 than to those of PD98059 in young as well as elderly subjects. These results suggest that, along the GM-CSF-dependent ERK signalling pathway, a step proximal to MEK1/2 but distal to the connection with the p38 MAPK module likely becomes defective as a feature of age. The consequent decline in ERK1/2 activation could potentially account for the GM-CSF-dependent impairment of the neutrophil respiratory burst that occurs with ageing.