Multitargeted interventions to reduce dialysis-induced systemic stress

Hemodialysis (HD) is a life-sustaining therapy as well as an intermittent and repetitive stress condition for the patient. In ridding the blood of unwanted substances and excess fluid from the blood, the extracorporeal procedure simultaneously induces persistent physiological changes that adversely affect several organs. Dialysis patients experience this systemic stress condition usually thrice weekly and sometimes more frequently depending on the treatment schedule. Dialysis-induced systemic stress results from multifactorial components that include treatment schedule (i.e. modality, treatment time), hemodynamic management (i.e. ultrafiltration, weight loss), intensity of solute fluxes, osmotic and electrolytic shifts and interaction of blood with components of the extracorporeal circuit. Intradialytic morbidity (i.e. hypovolemia, intradialytic hypotension, hypoxia) is the clinical expression of this systemic stress that may act as a disease modifier, resulting in multiorgan injury and long-term morbidity. Thus, while lifesaving, HD exposes the patient to several systemic stressors, both hemodynamic and non-hemodynamic in origin. In addition, a combination of cardiocirculatory stress, greatly conditioned by the switch from hypervolemia to hypovolemia, hypoxemia and electrolyte changes may create pro-arrhythmogenic conditions. Moreover, contact of blood with components of the extracorporeal circuit directly activate circulating cells (i.e. macrophages-monocytes or platelets) and protein systems (i.e. coagulation, complement, contact phase kallikrein-kinin system), leading to induction of pro-inflammatory cytokines and resulting in chronic low-grade inflammation, further contributing to poor outcomes. The multifactorial, repetitive HD-induced stress that globally reduces tissue perfusion and oxygenation could have deleterious long-term consequences on the functionality of vital organs such as heart, brain, liver and kidney. In this article, we summarize the multisystemic pathophysiological consequences of the main circulatory stress factors. Strategies to mitigate their effects to provide more cardioprotective and personalized dialytic therapies are proposed to reduce the systemic burden of HD.

Osteoporosis in cirrhotics before and after liver transplantation: relation with malnutrition and inflammatory status

Background: Liver cirrhosis is associated with osteoporosis and liver transplantation (LT) with increased bone loss. This study aimed to in LT candidates investigate the potential relation between bone mineral density (BMD) and BMD loss in those who undergo LT, with malnutrition, systemic inflammation, and hormonal status.Methods: We included 102 consecutively recruited cirrhotic LT candidates between May 2004 and April 2007. BMD was assessed by means of dual energy X-ray absorptiometry (DXA). Malnutrition was defined by means of anthropometry and assessment of recent weight loss. In 75/102 patients, serum-thyroid stimulating hormone (TSH), free triiodthyronine (T3) and free thyroxine (T4) and growth hormone (GH), cortisol, free testosterone, dehydroepiandrosterone sulfate, estradiol, interleukin-6, and tumor necrosis factor (TNF)-α was assessed. Overall 57/102 patients received a LT and 47/102 were followed for one year post-LT. At follow-up, nutritional status and BMD were assessed in all patients (n = 47) while 34/47 had available blood samples for analysis.Results: Forty (40%) LT- candidates had osteopenia or osteoporosis and 34 (38%) were malnourished. Malnutrition was associated with osteopenia/osteoporosis (odds ratio: 3.5, 95% CI 1.4, 9.9). Hip BMD Z-score decreased -0.25 (95% CI -0.41, -0.09) from baseline to one year post-LT. High baseline TNF-α correlated with a more marked decline in BMD (Partial correlation (r) = -0.47, p < .05) as did high baseline cortisol levels (r = -0.49, p < .05).Conclusion: Malnutrition in liver cirrhosis seems to be associated with osteopenia/osteoporosis, and systemic inflammation (higher TNF-α) and systemic stress (higher cortisol) to bone loss in patients who undergo LT.

Parallel telomere shortening in multiple body tissues owing to malaria infection

Several studies have shown associations between shorter telomere length in blood and weakened immune function, susceptibility to infections, and increased risk of morbidity and mortality. Recently, we have shown that malaria accelerates telomere attrition in blood cells and shortens lifespan in birds. However, the impact of infections on telomere attrition in different body tissues within an individual is unknown. Here, we tested whether malarial infection leads to parallel telomere shortening in blood and tissue samples from different organs. We experimentally infected siskins (Spinus spinus) with the avian malaria parasite Plasmodium ashfordi, and used real-time quantitative polymerase chain reaction (PCR) to measure telomere length in control and experimentally infected siskins. We found that experimentally infected birds showed faster telomere attrition in blood over the course of infection compared with control individuals (repeatedly measured over 105 days post-infection (DPI)). Shorter telomeres were also found in the tissue of all six major organs investigated (liver, lungs, spleen, heart, kidney, and brain) in infected birds compared with controls at 105 DPI. To the best of our knowledge, this is the first study showing that an infectious disease results in synchronous telomere shortening in the blood and tissue cells of internal organs within individuals, implying that the infection induces systemic stress. Our results have far-reaching implications for understanding how the short-term effects of an infection can translate into long-term costs, such as organ dysfunction, degenerative diseases, and ageing.

Assessing Systemic Stress in Otolaryngology: Methodology and Feasibility of Hair and Salivary Cortisol Testing

OBJECTIVE

Elevated systemic stress is a predictor of adverse health outcomes, and stress can be objectively quantified by cortisol concentration. Despite its utility, such testing is rarely performed in otolaryngology. This manuscript provides details on the principles, methodology, and feasibility of performing laboratory assessments of hair and salivary cortisol to inform researchers wishing to incorporate these novel tests in future otolaryngologic studies.

METHODS

Participants were older adults with hearing impairment. One hair sample and eight saliva samples were collected. Feasibility of study design was assessed through rates of participation in hair and saliva sampling and protocol adherence for saliva collection. Area under the curve (AUC) was used to evaluate overall secretion, and cortisol awakening response (CAR) was used to evaluate the dynamic secretion response.

RESULTS

From 9/1/2013 to 12/31/2013, 26/30 (86.7%) eligible participants agreed to hair sampling. All 30 subjects agreed to collect saliva, with 29 (96.7%) adhering to the collection protocol. Mean AUC was 401.2 nmol/L per hour, and CAR was 4.5 nmol/L.

CONCLUSIONS

Evaluating systemic stress in an otolaryngologic population using hair and saliva is feasible with acceptable participation and adherence. Repeat measurements over time will allow for evaluation of changes in systemic stress in relation to treatment.

A comparative study of stress episode prevalence and duration among Jomon period foragers from Hokkaido

This study reconstructs linear enamel hypoplasia (LEH) prevalence and stress episode duration among Jomon period foragers from Hokkaido, Japan (HKJ). Results are compared to Jomon period samples from coastal Honshu, Japan (HSJ) and Tigara Inupiat from Point Hope, Alaska (PHT) to provide a more comprehensive perspective on the manifestation of stress among circum-Pacific foragers. LEH were identified macro- and microscopically by enamel surface depressions and increased perikymata spacing within defects. Individuals with more than one anterior tooth affected by LEH were labeled as LEH positive. Stress episode durations were estimated by counting the number of perikymata within the occlusal wall of each LEH and multiplying that number by constants reflecting modal periodicities for modern human teeth. LEH prevalence and stress episode duration did not differ significantly between the two Jomon samples. Significantly greater frequencies of LEH were found in HKJ as compared to PHT foragers. However, HKJ foragers had significantly shorter stress episode durations as compared to PHT. This suggests that a greater proportion of HKJ individuals experienced stress episodes than did PHT individuals, but these stress events ended sooner. Similarity in stress experiences between the two Jomon samples and differences between the HKJ and PHT are found. These findings are important for two reasons. First, stress experiences of foraging populations differ markedly and cannot be generalized by subsistence strategy alone. Second, due to significant differences in episode duration, stress experiences cannot be understood using prevalence comparisons alone.