How can platelet proteomics best be used to interrogate disease?

Various modifications of proteins and the resulting proteoforms of a protein can associate with many diseases and are also significantly involved in the rapid regulation of hemostasis and thrombosis. For example, the release of prostacyclin from the intact endothelium and the consequent following phosphorylation of VASP in platelets is a post-translational regulation to keep them in a quiescent state. In Alzheimer's disease, proteoforms arise from the altered cleavage of the amyloid precursor protein, which finally causes amyloid plaques in the brain. This changed processing of the amyloid precursor protein can also be detected in platelets, making them an attractive source of biomarkers for this neurodegenerative disease. Age-related or prothrombotic disorders can have multiple origins, including genomic, transcriptional, and translational factors, which together can be mapped at the proteome level. Hence, recording these dynamic protein changes under physiological and pathophysiological conditions is paramount in platelet proteomics. To effectively study diseases through platelet proteomics, it is crucial to consider platelets' primary regulatory mechanism and thoroughly evaluate the disparities between the two leading proteomics technologies, top-down and bottom-up approaches. This commentary provides insights into the differences between these two technologies, which are particularly noticeable in detecting the different proteoforms of a protein.

A Practical and Analytical Comparative Study of Gel-Based Top-Down and Gel-Free Bottom-Up Proteomics Including Unbiased Proteoform Detection

Proteomics is an indispensable analytical technique to study the dynamic functioning of biological systems via different proteins and their proteoforms. In recent years, bottom-up shotgun has become more popular than gel-based top-down proteomics. The current study examined the qualitative and quantitative performance of these two fundamentally different methodologies by the parallel measurement of six technical and three biological replicates of the human prostate carcinoma cell line DU145 using its two most common standard techniques, label-free shotgun and two-dimensional differential gel electrophoresis (2D-DIGE). The analytical strengths and limitations were explored, finally focusing on the unbiased detection of proteoforms, exemplified by discovering a prostate cancer-related cleavage product of pyruvate kinase M2. Label-free shotgun proteomics quickly yields an annotated proteome but with reduced robustness, as determined by three times higher technical variation compared to 2D-DIGE. At a glance, only 2D-DIGE top-down analysis provided valuable, direct stoichiometric qualitative and quantitative information from proteins to their proteoforms, even with unexpected post-translational modifications, such as proteolytic cleavage and phosphorylation. However, the 2D-DIGE technology required almost 20 times as much time per protein/proteoform characterization with more manual work. Ultimately, this work should expose both techniques' orthogonality with their different contents of data output to elucidate biological questions.

[Occupational cancer of the urinary tract-incidence, reporting behavior, and administrative procedures]

Tumors of the urinary tract are among the most common types of occupational cancer. A significant proportion of about 5-15% may be of occupational etiology. Suspicion of an occupational genesis is subject to mandatory reporting. However, epidemiological analyses show that the number of reports received by accident insurance companies and employers' liability insurance associations is significantly lower than expected. Finally, the economic and administrative effort in surveying a patient's occupational history hinders adequate reporting. By routinely and systematically using a structured questionnaire as part of clinical routine in our hospital, a significantly improved detection of justified suspected cases (from about 4.8% to about 67% of the theoretically expected value) has been achieved since about 2006. In addition to improved medical care and adequate compensation for recognition as an occupational disease, disease-related care is subject to extra-budgetary remuneration in Germany (UV-GOÄ).

Platelet Phenotype Analysis of COVID-19 Patients Reveals Progressive Changes in the Activation of Integrin αIIbβ3, F13A1, the SARS-CoV-2 Target EIF4A1 and Annexin A5

Background: The fatal consequences of an infection with severe acute respiratory syndrome coronavirus 2 are not only caused by severe pneumonia, but also by thrombosis. Platelets are important regulators of thrombosis, but their involvement in the pathogenesis of COVID-19 is largely unknown. The aim of this study was to determine their functional and biochemical profile in patients with COVID-19 in dependence of mortality within 5-days after hospitalization. Methods: The COVID-19-related platelet phenotype was examined by analyzing their basal activation state via integrin αIIbβ3 activation using flow cytometry and the proteome by unbiased two-dimensional differential in-gel fluorescence electrophoresis. In total we monitored 98 surviving and 12 non-surviving COVID-19 patients over 5 days of hospital stay and compared them to healthy controls (n = 12). Results: Over the observation period the level of basal αIIbβ3 activation on platelets from non-surviving COVID-19 patients decreased compared to survivors. In line with this finding, proteomic analysis revealed a decrease in the total amount of integrin αIIb (ITGA2B), a subunit of αIIbβ3, in COVID-19 patients compared to healthy controls; the decline was even more pronounced for the non-survivors. Consumption of the fibrin-stabilizing factor coagulation factor XIIIA (F13A1) was higher in platelets from COVID-19 patients and tended to be higher in non-survivors; plasma concentrations of the latter also differed significantly. Depending on COVID-19 disease status and mortality, increased amounts of annexin A5 (ANXA5), eukaryotic initiation factor 4A-I (EIF4A1), and transaldolase (TALDO1) were found in the platelet proteome and also correlated with the nasopharyngeal viral load. Dysregulation of these proteins may play a role for virus replication. ANXA5 has also been identified as an autoantigen of the antiphospholipid syndrome, which is common in COVID-19 patients. Finally, the levels of two different protein disulfide isomerases, P4HB and PDIA6, which support thrombosis, were increased in the platelets of COVID-19 patients. Conclusion: Platelets from COVID-19 patients showed significant changes in the activation phenotype, in the processing of the final coagulation factor F13A1 and the phospholipid-binding protein ANXA5 compared to healthy subjects. Additionally, these results demonstrate specific alterations in platelets during COVID-19, which are significantly linked to fatal outcome.

[Urinary bladder cancer as a late sequela of spinal cord injury : Decision-making aids for assessment of this causal association]

BACKGROUND

There is to date no convincing literature that has assessed the association between traumatic spinal cord injury (SCI) and the later development of urinary bladder cancer. The aim of this work is to present medical experts as well as the national accident insurance and the social courts decision-making aids based on the latest medical scientific knowledge, for assessment of this causal association.

MATERIALS AND METHODS

A study conducted between April 1998 and March 2017 in the BG Trauma Hospital Hamburg forms the basis for the decision-making aids. Urinary bladder cancer was diagnosed in 32 out of 6432 treated outpatient and inpatient SCI patients. Furthermore, relevant published literature was taken into consideration for the decision-making aids.

RESULTS

It was found that urinary bladder cancer in SCI patients occurs at a considerably younger age as compared to the general population, more frequently shows muscle invasive carcinoma with a higher grade at first diagnosis and a higher proportion of the more aggressive squamous cell carcinoma than that of the general population. Correspondingly, the survival time is extremely unfavorable. For medical experts a matrix was compiled where the various influencing factors, either for or against the recognition of an association between SCI and urinary bladder cancer, were weighted according to their relevance.

CONCLUSION

The results showed that urinary bladder cancer in SCI patients differs considerably from that of able-bodied patients. These differences drastically shorten the survival time. A study on patients with spina bifida, i.e., a congenital spinal cord disorder, corroborates these observations. They indicate histopathological differences that have so far been intangible.

Altered platelet proteome in lupus anticoagulant (LA)-positive patients-protein disulfide isomerase and NETosis as new players in LA-related thrombosis

Patients with antiphospholipid syndrome (APS) are at high risk of developing venous and arterial thromboembolism (TE). The role of platelets in the pathogenesis of these prothrombotic conditions is not yet fully understood. The aim of this study was to gain mechanistic insights into the role of platelets in APS by comparing the platelet proteome between lupus anticoagulant (LA)-positive patients with (LA+ TE+) and without a history of TE (LA+ TE-) and healthy controls. The platelet proteome of 47 patients with LA, 31 with a history of TE and 16 without thrombotic history, and 47 healthy controls was analyzed by two-dimensional differential in-gel electrophoresis and mass spectrometry to identify disease-related proteins. Afterward, selected LA-related platelet proteins were validated by western blot and ELISA. Alterations of 25 proteins were observed between the study groups. STRING pathway analysis showed that LA-related protein profiles were involved in platelet activation, aggregation, and degranulation. For example, protein disulfide isomerase family members, enzymes that promote thrombosis, were upregulated in platelets and plasma of LA+ TE+ patients. Leukocyte elastase inhibitor (SERPINB1), an antagonist of neutrophil extracellular trap (NET) formation, was decreased in platelets of LA+ TE+ patients compared to healthy controls. Additionally, citrullinated histone H3, a NET-specific marker, was increased in plasma of LA+ TE+ patients. These findings suggest that decreased platelet SERPINB1 levels favor prothrombotic NETosis, especially in LA+ TE+ patients. Our findings reveal protein abundance changes connected to altered platelet function in LA-positive patients, thus suggesting a pathogenic role of platelets in thrombotic complications in APS.

Platelet PI3K Modulates Innate Leukocyte Extravasation during Acid-Induced Acute Lung Inflammation

Introduction Blood platelets are increasingly recognized as modulators of leukocyte effector functions in various pathologies including acute lung injury (ALI). ALI is a life-threatening disease, caused by damage to the alveolar epi- and endothelium. Excessive accumulation of leukocytes leads to severe lung inflammation, resulting in impaired lung function and hypoxemia.

Objective Since leukocyte migration is modulated by activated platelets and phosphatidylinositol 3-kinase (PI3K) signaling is involved in platelet function, we aimed to elucidate the effect of PI3K on platelet-mediated immune responses.

Materials and Methods We generated a mouse model with a platelet-specific deletion of p85α, the most important regulatory subunit of the class IA PI3K, and evaluated platelet function and platelet–leukocyte interactions. Moreover, we analyzed the impact of platelet-specific p85α gene deficiency during sterile peritonitis and acid-induced ALI.

Results In vitro analyses of platelets revealed that lack of p85α led to decreased downstream signaling and diminished expression of surface activation markers, for example, CD62P and CD63, as well as reduced platelet aggregation. Moreover, platelet PI3K essentially mediated direct interactions of platelets with monocytes and neutrophils. In mice, platelet-specific p85α deficiency prevented leukocyte infiltration into the peritoneum and the bronchoalveolar compartment during sterile peritonitis and ALI, respectively. Additionally, the release of the inflammatory cytokine interleukin-12/23 was diminished in platelet p85α-deficient mice during ALI. In contrast to PI3K, neither overexpression nor depletion of platelet phosphatase and tensin homolog, the endogenous antagonist of PI3K, significantly modulated platelet function.

Conclusion Our data indicate a crucial role of platelet PI3K signaling for leukocyte extravasation upon inflammatory stimuli in various diseases models.

Development of a new biochip array for APOE4 classification from plasma samples using immunoassay-based methods

BACKGROUND

Apolipoprotein E (APOE) is a key player in lipid transport and metabolism and exists in three common isoforms: APOE2, APOE3 and APOE4. The presence of the E4 allelic variant is recognized as a major genetic risk factor for dementia and other chronic (neuro)degenerative diseases. The availability of a validated assay for rapid and reliable APOE4 classification is therefore advantageous.

METHODS

Biochip array technology (BAT) was successfully applied to identify directly the APOE4 status from plasma within 3 h, through simultaneous immunoassay-based detection of both specific APOE4 and total APOE levels.

RESULTS

Samples (n=432) were first genotyped by polymerase chain reaction (PCR), and thereafter, using BAT, the corresponding plasma was identified as null, heterozygous or homozygous for the E4 allele by calculating the ratio of APOE4 to total APOE protein. Two centers based in Austria and Ireland correctly classified 170 and 262 samples, respectively, and achieved 100% sensitivity and specificity.

CONCLUSIONS

This chemiluminescent biochip-based sandwich immunoarray provides a novel platform to detect rapidly and accurately an individual's APOE4 status directly from plasma. The E4 genotype of individuals has been shown previously to affect presymptomatic risk, prognosis and treatment response for a variety of diseases, including Alzheimer's disease. The biochip's potential for being incorporated in quantitative protein biomarker arrays capable of analyzing disease stages makes it a superior alternative to PCR-based APOE genotyping and may deliver additional protein-specific information on a variety of diseases in the future.

A prospective study with ten years follow-up of two-hundred patients with proximal femoral fracture

BACKGROUND

The proximal femoral fracture is one of the most common injuries in the elderly. Nevertheless, no results beyond the second year post surgery have been reported in the literature. Therefore, the purpose of this study was to evaluate any revision and mortality within 10 years follow-up as well as the walking ability of still alive patients.

METHODS

A total of 200 consecutive patients were included. A prospective database was first used to collect the demographic data. Exactly ten years after the surgery, a final evaluation was conducted by telephone for every patient. Any revision, any contralateral as well as other fractures and the date of death were recorded. For all patients who were still alive, the mobility score according to Parker was also surveyed.

RESULTS

The average age was 79.0 years (SD: 12.5); women were affected at higher numbers (73.5%). The total surgical revision rate was 17.5% (35/200), due in particular to hematoma (9×) or infection (7×). A surgical revision later than two years was only needed in three patients (1.5%). The risk of another fracture caused by a fall was 19% (38/200), most often a contralateral femoral fracture (22/200; 11%) that happened on average 51.9 months (1-97) after the initial surgery. The risk of a contralateral femoral fracture was 15.4% (22/143) in patients who survived the first year post surgery. The postoperative mortality was 1, 2, 5 and 10 years or 23.5%, 32.5%, 55% as well as 81.5%, respectively. An average Parker's mobility score of 6.3 points (0-9) was determined for the 37 patients (18.5%) who were still alive at the time of the follow-up.

CONCLUSION

The long-term study showed that revision surgery was only required in 3/200 patients (1.5%) beyond the second year of that surgery. On the other hand, more than half of all patients had already passed away five years after the initial surgery. The exact incidence of a contralateral femoral fracture was 11.9%, climbing to 15.4% if the patient survived at least one year. Nearly every fifth patient experienced another fall resulting in a severe fracture requiring treatment during the long-term course.

Careful neuropsychological testing reveals a novel genetic marker, GSTO1*C, linked to the pre-stage of Alzheimer's disease

Approximately 30 million people currently suffer from late-onset Alzheimer's disease (LOAD) worldwide. Twin studies demonstrated that 60 to 80% of LOAD is genetically determined, 20% of which remaining unassigned. This case-control study included 118 cognitively healthy controls, 52 patients with mild cognitive impairment (MCI; the pre-stage of LOAD) and 71 LOAD patients. The participants were genotyped for the genetic LOAD marker apolipoprotein E4 (APOE4) and the single-nucleotide polymorphism rs4925 in glutathione S-transferase omega-1 (GSTO1). Additive logistic regression showed a novel, statistically significant association of the major allele GSTO1*C with MCI (OR1.9; p = 0.032). However, identification of significant SNP-disease relations required well-defined study groups. When classifying participants solely by the short Mini Mental State examination (MMSE), the associations of GSTO1*C and the reference marker APOE4 with MCI were cancelled. Moreover, even identifying only the control group by MMSE nullified a statistically significant association (OR1.8; p = 0.045) between GSTO1*C and LOAD. In contrast, these statistical relations were retained when the detailed Consortium to Establish a Registry for Alzheimer's Disease (CERAD-Plus) test battery was used. Hence, besides proposing rs4925 as a genetic marker for cognitive impairment, this work also emphasized the importance of carefully characterized controls in addition to well-diagnosed patients in case-control studies.

Gender-related increase of tropomyosin-1 abundance in platelets of Alzheimer's disease and mild cognitive impairment patients

The incidence of Alzheimer's disease (AD) is higher in elderly women than in men. The molecular background of this gender-related risk, however, is largely unknown. In a previous proteomics study, we identified significantly elevated levels of monoamine oxidase-B and tropomyosin-1 in AD patients, together with significant changes of the genetic AD risk factors apolipoprotein E4 (APOE4) and glutathione S-transferase omega 1 (GSTO1), in platelets - a promising source for AD blood biomarkers. The present study aimed to investigate the gender-specificity as well as the disease-stage dependency of these biomarkers in AD patients and those with mild cognitive impairment (MCI). Tropomyosin-1 and monoamine oxidase-B protein levels were quantified by 2-D DIGE and 1-D Western blotting. Here, for the first time, we revealed a significant increase of 38&39kDa tropomyosin-1 protein levels in female but not male AD (+56%; p=0.008) and MCI patients (+46%; p=0.041) measured by 1-D WB. In contrast, levels of monoamine oxidase-B were, independently of gender, elevated in AD patients (+52%; p=0.009) but unaltered in MCI compared to control subjects. Moreover, we confirmed that APOE4-positive females are at a higher risk (OR=18.7; p=9.7E-09) of developing AD compared to APOE4-positive males (OR=6.5; p=5.9E-04). No gender-related effects were observed for GSTO1.

SIGNIFICANCE

Platelet tropomyosin-1 constitutes a gender-related and stage-dependent protein in cognitive impairment. In contrast, platelet monoamine oxidase-B, frequently described to be increased in platelets and brains of AD patients, shows a gender-independent but stage-related increase since it is unaltered in MCI subjects. A blood biomarker test for this preceding stage of AD that considers gender-specificity is not yet available. The newly described AD-related platelet protein profiles might refine and facilitate routine diagnosis and enable early as well as tailored interventions.

Peri-implant femoral fractures: The risk is more than three times higher within PFN compared with DHS

INTRODUCTION

Information is lacking regarding incidence rates, treatment regimens, and outcomes concerning peri-implant femoral fractures (PIF). Therefore, we performed a retrospective study to provide scientific data concerning incidence and outcome of PIF following osteosynthesis of proximal femoral fractures (PFF).

MATERIAL AND METHODS

We retrospectively included all patients who received osteosynthesis for PFF between 2006 and 2015 and in whom PIF was confirmed postoperatively. All available patients with PIF were contacted minimum one year post-surgery.

RESULTS

A total of 1314 osteosynthesis procedures were performed, of which 705 were proximal femoral nails (PFNs), 597 were dynamic hip screws (DHSs), and 12 were screws appliances only. During the same period, 18 PIFs (1.4%) were reported. However, PIF was 3.7 times higher within PFN when compared to DHS (15/705:2.1% versus 3/597:0.5%; odds ratio: 3.7). The following analysis also included 8 patients with PIF who were referred from other hospitals, resulting in a total of 26 patients. Mean patient age was 84.8 years (range, 57-95), with a predominance in female (23×) and in the left femur (19×). PIF occurred after an average of 23.6 months (range, 1-81) post-surgery. The fractures, most of which were spiral-shaped, were most commonly treated with locking plate osteosynthesis. The surgical revision rate was 7.7%, and the one-year mortality was 23.1%. At an average of 43.0 months (range, 12-100) post-surgery, it was possible to contact 18/26 patients (69.2%), and their mean Parker Mobility Score was 5.2 points (range 2-9).

CONCLUSIONS

Peri-implant femoral fracture is a rare incident within the old age traumatology of PFF. However, based on our small number of cases, it occurred within PFN much more frequently compared with DHS. Locking plate osteosynthesis has been shown to be effective and reliable. Surgical revision and mortality rates do not appear to be increased when compared to those with the initial treatment of proximal femoral fractures.

Autocrine secretion of 15d-PGJ2 mediates simvastatin-induced apoptotic burst in human metastatic melanoma cells

BACKGROUND AND PURPOSE

Despite new therapeutic approaches, metastatic melanomas still have a poor prognosis. Statins reduce low-density lipoprotein cholesterol and exert anti-inflammatory and anti-proliferative actions. We have recently shown that simvastatin triggers an apoptotic burst in human metastatic melanoma cells by the synthesis of an autocrine factor.

EXPERIMENTAL APPROACH

The current in vitro study was performed in human metastatic melanoma cell lines (A375, 518a2) and primary human melanocytes and melanoma cells. The secretome of simvastatin-stressed cells was analysed with two-dimensional difference gel electrophoresis and MS. The signalling pathways involved were analysed at the protein and mRNA level using pharmacological approaches and siRNA technology.

KEY RESULTS

Simvastatin was shown to activate a stress cascade, leading to the synthesis of 15-deoxy-12,14-PGJ2 (15d-PGJ2 ), in a p38- and COX-2-dependent manner. Significant concentrations of 15d-PGJ2 were reached in the medium of melanoma cells, which were sufficient to activate caspase 8 and the mitochondrial pathway of apoptosis. Inhibition of lipocalin-type PGD synthase, a key enzyme for 15d-PGJ2 synthesis, abolished the apoptotic effect of simvastatin. Moreover, 15d-PGJ2 was shown to bind to the fatty acid-binding protein 5 (FABP5), which was up-regulated and predominantly detected in the secretome of simvastatin-stressed cells. Knockdown of FABP5 abolished simvastatin-induced activation of PPAR-γ and amplified the apoptotic response.

CONCLUSIONS AND IMPLICATIONS

We characterized simvastatin-induced activation of the 15d-PGJ2 /FABP5 signalling cascades, which triggered an apoptotic burst in melanoma cells but did not affect primary human melanocytes. These data support the rationale for the pharmacological targeting of 15d-PGJ2 in metastatic melanoma.

Treatment and outcome of destructive tuberculosis of the talus

We describe a case of isolated destructive talar tuberculosis that is, to the best of our knowledge, the first reported case in Germany. Caseous talar necrosis was finally detected after repeated surgical debridements of an infection eight months after subtalar screw arthrodesis. Following the diagnosis of TB, we performed a total of three additional surgical revisions within a three-month period; these revisions included a talectomy and an induction of a septic tibiocalcaneal arthrodesis with an external fixator that was removed after solid fusion six months later. Following this treatment regime, which included pharmaceutical anti-tuberculosis therapy, the 50-year-old male patient was fitted with orthopaedic shoes. He resumed work as a professional farmer with a number of restrictions 12 months after the diagnosis and treatment of destructive talar tuberculosis.

Platelets, a reliable source for peripheral Alzheimer's disease biomarkers?

Peripheral biomarkers play an indispensable role in quick and reliable diagnoses of any kind of disease. With the population ageing, the number of people suffering from age-related diseases is expected to rise dramatically over the coming decades. In particular, all types of cognitive deficits, such as Alzheimer's disease, will increase. Alzheimer's disease is characterised mainly by coexistence of amyloid plaques and neurofibrillary tangles in brain. Reliable identification of such molecular characteristics antemortem, however, is problematic due to restricted availability of appropriate sample material and definitive diagnosis is only possible postmortem. Currently, the best molecular biomarkers available for antemortem diagnosis originate from cerebrospinal fluid. Though, this is not convenient for routine diagnosis because of the required invasive lumbar puncture. As a consequence, there is a growing demand for additional peripheral biomarkers in a more readily accessible sample material. Blood platelets, due to shared biochemical properties with neurons, can constitute an attractive alternative as discussed here. This review summarises potential platelet Alzheimer's disease biomarkers, their role, implication, and alteration in the disease. For easy comparison of their performance, the Hedge effect size was calculated whenever data were available.

[Physician's role in "medical drama" pitfall? Reflection of stereotypical images of doctors in context of contemporary doctor's series]

In contemporary U.S. doctor's series, the characters are usually represented by good-looking or typical character actors. The aim of our pilot study was to investigate whether the long-term impact of this format on German television viewers could have an influence on the choice of doctor in Germany. Two different groups of people anticipating TV consumption patterns were questioned: a first group of younger adults who knew theTV series was asked to judge their doctor choice using a web-based survey tool with respect to three criteria (sympathy, expertise and own treatment preference). The second group of adults beyond the 40th year of life who need not know theTV series were shown photos of the serial figures. Study participants should select the "doctor" of which they would most likely want to be treated and this based on two predetermined reasons (sympathy or expertise). Our results indicate that stereotypical images of doctors found high approval only in the first group of people, while the participants in the second group decided in majorityfora more realistic representation of average appearance.

A combined proteomic and genetic analysis of the highly variable platelet proteome: from plasmatic proteins and SNPs

High biological variation in protein expression represents a major challenge in clinical proteomics. In a study based on 2D-DIGE, we found that the standardised abundance of only a few proteins varied by more than 50%. While some of the highest variable proteins in platelets of 52 healthy elderly were of plasmatic origin, such as albumin or haptoglobin, absence of several other high-abundant plasma proteins strongly suggests that plasma-derived proteins represent an integral part of the platelet proteome. Amongst the highly variable platelet-derived proteins, two spots were both identified as GSTO1 and assigned to either the wild-type or mutant isoform of SNP A140D. Remarkably, when the spots were considered within the respective genotype groups, their CV decreased to about the median variation. Albeit 2D-DIGE allowed correct genotyping, two individuals seemed to be GSTO1*A140 deficient. Probing 2D-Western blots with novel mAb, however, detected A140 protein as additional spot at pH 8.1, caused by the SNPs E155del and E208K. In contrast to previous studies, we show that GSTO1 protein is expressed in vivo, despite the deletion E155. Our data indicate that incorporation of exogenous proteins and genetic polymorphisms of endogenous proteins represent the main source of extreme biological variation in the platelet proteome.

Comparative platelet proteome analysis reveals an increase of monoamine oxidase-B protein expression in Alzheimer's disease but not in non-demented Parkinson's disease patients

Monoamine oxidase-B (Mao-B) catalysing the breakdown of the neurotransmitter dopamine, is known to be involved in the pathophysiology of Parkinson's (PD) and Alzheimer's disease (AD). Increased brain Mao-B activity is associated with AD. This alteration can also be seen in platelets, albeit the cause has hitherto remained elusive. To gain a deeper understanding of the etiology of AD, the platelet proteome was characterised, (2D DIGE pH6-9, including Mao-B) from 150 individuals: 34 AD, 13 vascular dementia, 15 non-demented PD patients, 49 matched controls, 18 oldest old and 21 young individuals. One significant change was noted after applying false discovery rate with the upregulation of the Mao-B expression (30% adjusted P value<0.001; effect size 1.31) in AD compared to age- and sex-matched controls. In contrast, Mao-B levels were unchanged in PD to matched controls. Western blot and mRNA analyses verified these findings. Moreover, Mao-B concentration correlated with age in the cognitive healthy individuals (r=0.53; P<0.001) and PD patients but not in those suffering from AD (r=-0.03; P=0.874). Mao-B activity correlated with the increased Mao-B protein expression in AD (r=0.81; P=0.016). We suggest that Mao-B platelet protein level may serve as a biomarker for age-related dementia, especially AD.

[Incontinence after radical prostatectomy and cystectomy: are combined training with mechanical devices and whole body vibration effective?]

In spite of improvements in nerve-sparing operation techniques in radical prostatectomies, a disturbance of (early) continence is subjectively perceived by a number of patients as burdensome, which can last for several months. Skilled physiotherapy is appreciated as causal therapy in the hands of the qualified therapist. In an open randomised controlled trial the efficacy of a standardised rehabilitation therapy with pelvic floor re-education instructed by a physiotherapist (n=25) as the control group in comparison to a group with additional combined electrostimulation and biofeedback device (Myo 420™; n=25) or whole body vibration therapy (FitVibe medical™; n=25). Pre- and post-therapeutic evaluation of the International Prostate Symptom Score (IPSS), the enclosed question about quality of life (IPSS-QL), pad test, pelvic floor strength, maximum uroflow, micturition volume, serum testosterone and blood glucose was done. Within the treatment duration of 3-4 weeks in all treatment groups a statistically significant improvement of IPSS and IPSS-QL was seen. Due to whole body vibration the reduction of urine loss (pad test), increase of voided volume and maximum uroflow were statistically significant. Whereas for isolated physiotherapy during the short therapy duration merely a trend for the improvement of pelvic floor muscle strength was seen, the difference was significant in the Myo 420 and the whole body vibration groups, respectively. It was shown that a continuous improvement in continence depends on the consistent continuation of the training also under domestic conditions. The controlled trial conditions also confirm the efficacy, acceptance and tolerance of a standardised pelvic floor re-education under the conditions of urological inpatient rehabilitation treatment. By additional use of a combined electro- and multichannel biofeedback device or a whole body vibration device, the treatment results could be further improved. Due to the different causal therapeutic approaches and effects, a further therapy optimisation by combination of all three components should be evaluated in an additional controlled trial.

[Clinical symptoms of hypogonadism after radical prostatectomy]

This study checked whether the prevalence of hypogonadal symptoms [measured using the Aging Males' Symptoms Scale (AMSS)] after radical prostatectomy can give information about the prevalence of hypogonadism in this group of patients. Distribution of the level of complaints (no, mild, moderate or severe) on the AMSS after radical prostatectomy (n=576) was analyzed in all patients (G) and stratified by the point in time of data collection [surgery to AMSS less (K1) and more than 1 year (K2)].The total score shows more patients with mild and moderate symptoms in G, K1, and K2 compared with the control (G 57.6 and 23.4%, K1 59.1 and 22.4%, K2 40 and 35.6% vs 36.5 and 11.2%). In the somatic score G and K1 show 2.4% (G) and 1.7% (K1) less patients with no and 1.5% (G) and 0.9% (K1) less patients with little complaints compared with the control; 2.6% (G) and 1.8% (K1) more patients state moderate and 1.2% (G) and 0.8% (K1) more severe complaints. K2 shows fewer patients with no and mild (22.2 and 31.1% vs 33.3 and 39.3%) and more with moderate and severe complaints (33.3 and 13.3% vs 21.0 and 6.4%) compared with the control. In the psychological score patients in G and K1 state less mild complaints (G 33.9%, K1 32.8% vs 41.8%), more patients state no complaints (G 45.8%, K1 47.3% vs 43.6%) as well as moderate and severe complaints (G 12.8%, K1 12.8% vs 10.9% and G 7.5%, K1 7.2% vs 3.7 %) compared with the control. K2 shows more complaints of all levels compared with the control (mild 46.7 vs 41.8%, moderate 13.3 vs 10.9%, and severe 11.1 vs 3.7%). In the sexual score all groups of patients show significantly more severe complaints (G 89.6%, K1 89.5%, K2 91.1% vs 6.1%).Multiple factors influenced by surgery and diagnosis of cancer which are independent of hormonal effects make distribution of hypogonadal symptoms on the AMSS not suitable to give information about the prevalence of hypogonadism after radical prostatectomy. An analysis of serum testosterone seems to be essential.

Effect of a high protein meat diet on muscle and cognitive functions: a randomised controlled dietary intervention trial in healthy men

BACKGROUND

Recommendations to use other criteria than N-balance for defining protein requirements have been proposed. However, little evidence to support other measures such as physiological functions is available.

OBJECTIVE

To investigate the effects of a usual (UP) versus a high protein (HP) diet on muscle function, cognitive function, quality of life and biochemical regulators of protein metabolism.

DESIGN

A randomised intervention study was conducted with 23 healthy males (aged 19-31 yrs). All subjects consumed a Usual Protein (UP) diet (1.5 g protein/kg BW) for a 1-wk run-in period before the intervention period where they were assigned to either a UP or a High Protein (HP) diet (3.0 g protein/kg BW) for 3-wks with controlled intake of food and beverages. Blood and urine samples were taken along with measurements of physiological functions at baseline and at the end of the intervention period.

RESULTS

The HP group improved their reaction time significantly compared with the UP group. Branched chain amino acids and phenylalanine in plasma were significantly increased following the HP diet, which may explain the improved reaction time.

CONCLUSION

Healthy young males fed a HP diet improved reaction time. No adverse effects of the HP diet were observed. This trial was registered at www.clinicaltrials.gov as NCT00621231.

Hypochlorite-oxidized LDL induces intraplatelet ROS formation and surface exposure of CD40L--a prominent role of CD36

OBJECTIVE

OxLDL represents a central player in atherogenesis and has been shown to activate human blood platelets. In light of the pivotal role of CD40L in inflammation, it was the aim of this work to clarify if platelet-activating effects of oxidized LDL result in surface exposure and liberation of CD40L and to explore the role of platelet scavenger receptor CD36 in this process.

METHODS

Binding and functional studies were performed with hypochlorite-oxidized LDL in absence and presence of (potential) competitors in normal and CD36-deficient human platelets. To determine functional effects of hypochlorite-oxidized LDL on human platelets, formation of reactive oxygen species, intraplatelet calcium, CD40L and CD62P as well as platelet aggregation were quantified.

RESULTS

Addition of OxLDL to resting human platelets results in intracellular calcium flux, platelet aggregation and surface expression of CD62P. OxLDL triggers the formation of intracellular reactive oxygen species and surface exposure of CD40L, with both being sensitive to the NADPH oxidase inhibitor apocynin. In CD36-deficient human platelets, functional effects as well as high affinity binding of hypochlorite-oxidized LDL appears to be significantly reduced compared with platelets positive for CD36.

CONCLUSIONS

Our results prove a prominent--however, not exclusive--role of CD36 in platelet binding of hypochlorite-oxidized LDL. CD36 appears to be the major receptor responsible for hypochlorite-oxidized LDL-induced platelet activation that accumulates in the release of CD40L. As platelets represent the major source of CD40L, our findings emphasize an important pro-inflammatory role of platelets, especially in conditions of oxidative stress.

Specific binding of hypochlorite-oxidized HDL to platelet CD36 triggers proinflammatory and procoagulant effects

OBJECTIVE

Oxidative stress and systemic inflammation negatively affect several protective functions of high density lipoproteins (HDL) and oxidative modification of HDL by the inflammation-derived oxidant hypochlorite converts HDL into a potent platelet agonist. Therefore it was the aim of this work to clarify if these platelet-activating effects result from specific binding of hypochlorite-oxidized HDL (hyp-OxHDL) to the platelet surface and to identify responsible receptors.

METHODS

Binding and functional studies were performed with hyp-OxHDL in absence and presence of (potential) competitors in normal and CD36-deficient human platelets. Platelet aggregation was quantified by light transmission aggregometry. Surface expression of CD62P, phosphatidylserine and CD40L was quantified by flow cytometry.

RESULTS

Binding studies reveal that hyp-OxHDL show specific and saturable high-affinity binding to the platelet surface. Hyp-OxHDL trigger platelet aggregation and in a dose dependent way provoke the release of significant amounts of CD40L as well as phosphatidylserine on the platelet surface. Blocking specific binding of hyp-OxHDL to the platelet surface interferes with the ability of hyp-OxHDL to stimulate human platelets. CD36-deficient human platelets show markedly reduced binding of hyp-OxHDL. Upon addition of hypochlorite-oxidized HDL, CD36-deficient platelets do not aggregate and completely fail to release CD40L or phosphatidylserine.

CONCLUSIONS

From these results we conclude that specific binding of hyp-OxHDL to platelet CD36 is essential for the proinflammatory and procoagulant effects of hyp-OxHDL shown within this work. The contribution of other receptors besides CD36 to specific binding of hyp-OxHDL to the platelet membrane appears to be minimal, at best.

The role of proteomics in dementia and Alzheimer's disease

Proteomic analysis enables us to identify dementia-related protein profiles of both genetic and environmental origins. In this review, current proteomics technologies are described including many examples of clinical proteomics studies. Many of these studies present only results of the discovery phase. Progression to the validation phase was achieved by developing more advanced proteomics technologies such as fluorescence two-dimensional differential gel electrophoresis or isobaric tagging for relative and absolute protein quantification. These technologies will lead to the design of several new Alzheimer's disease-related protein panels for the analysis of CSF. On these new panels, established markers such as tau and Abeta42 will be used in combination with novel markers, for example beta-2-microglobulin, brain-derived neurotrophic factor 1 and fragments of cystatin C. However, there are still limitations to using proteomic assays. The preparation of homogeneous sample material is difficult due the complexity of brain tissue. Laser capture microdissection and recently developed more sensitive proteomics methods, for example fluorescence saturation labelling, will overcome these limitations. Combining proteomics with approaches at the level of the genome and transcriptome followed by interpretation by systems biology will soon shed further light on dementia-related pathogenesis.

[Procedures for determining occupational diseases in cases of urological disorders]

According to section sign 202 of the German Social Security Code VII, individuals diagnosed with bladder cancer or renal cell cancer who had been occupationally exposed to carcinogens known to induce cancer in these human tissues must be reported to the statutory accident insurance. In this paper, the course of the administrative procedure, particularly considering the reporting procedure and screening for occupational risk factors by a CD-based tool, developed by the authors, is described.

[Is rehabilitation of erectile function following pelvic surgery reasonable? Review of the literature: from sports to PDE5 inhibitors]

Increasingly, urologists are seeing patients with erectile dysfunction after pelvic operations. In most cases, radical prostatectomy is the cause. Even when a nerve-sparing procedure is performed, approximately 50% of the patients suffer from erectile dysfunction. This report discusses the causes and theoretical therapies, including lifestyle changes, strategies for neuroregeneration and the associated prevention of apoptosis of the smooth muscle of the corpus cavernosum and improvement of the corpora cavernosa by increased oxygenation. According to the international literature, many of these agents and lifestyle modifications display promise for treating impotence. Early treatment for patients recovering from pelvic operations seems to be reasonable. It is assumed that the natural recovery of erections may take as long as 18 to 24 months postsurgery or even longer; however, treatment modalities may reduce the time to erectile recovery.

Biological variation of the platelet proteome in the elderly population and its implication for biomarker research

Knowledge about the extent of total variation experienced between samples from different individuals is of great importance for the design of not only proteomics but every clinical study. This variation defines the smallest statistically significant detectable signal difference when comparing two groups of individuals. We isolated platelets from 20 healthy human volunteers aged 56-100 years because this age group is most commonly encountered in the clinics. We determined the technical and total variation experienced in a proteome analysis using two-dimensional DIGE with IPGs in the pI ranges 4-7 and 6-9. Only spots that were reproducibly detectable in at least 90% of all gels (n = 908) were included in the study. All spots had a similar technical variation with a median coefficient of variation (cv) of about 7%. In contrast, spots showed a more diverse total variation between individuals with a surprisingly low median cv of only 18%. Because most known biomarkers show an effect size in a 1-2-fold range of their cv, any future clinical proteomics study with platelets will require an analytical method that is able to detect such small quantitative differences. In addition, we calculated the minimal number of samples (sample size) needed to detect given protein expression differences with statistical significance.

Die Therapie der Blasenüberaktivität bei älteren und alten Menschen

Overactive bladder syndrome is a widespread disorder that leads to considerable impairment of quality of life. Besides behavioural therapy (bladder training), methods used in physiotherapy, electrotherapy and instrumental biofeedback have also proved to be successful approaches to treatment. With their good clinical and urodynamic efficacy, substances with antimuscarinic action at M3 receptors in particular and possibly also at M2 receptors have proved successful as first-line agents for the treatment of overactive bladder (OAB). Despite the frequently high level of suffering and severe impairment of quality of life, however, compliance is poor. Muscarine receptors do have a significant effect on detrusor function, but numerous other mechanisms and receptor entities also play a role. Whether patient acceptance can be significantly increased by the development of selective M-receptor antagonists, improved bladder selectivity or formulating innovations remains to be proven by broad-based clinical testing and independent, comparative, scientific studies. At present, it is not possible to estimate with absolute certainty the risk of an anticholinergic-induced deterioration in cognitive abilities, in particular in elderly individuals. Initial data suggest that primarily M3-selective receptor blockage with darifenacin could be beneficial.

Reduced stress tolerance of glutamine-deprived human monocytic cells is associated with selective down-regulation of Hsp70 by decreased mRNA stability

In critically ill patients, clinicians observe a reverse correlation of survival and a decreased plasma concentration of the most abundant free amino acid, glutamine (Gln). However, in this context, the role of Gln remains largely elusive. Gln is used as an energy substrate by monocytes. Gln deprivation of these cells results in an increased susceptibility to cell stress and apoptosis, as well as in a reduced responsiveness to pro-inflammatory stimuli. We performed a systematic study to elucidate the molecular mechanism by which Gln depletion affects the heat stress response of the monocytic cell line U937. Proteomic analysis revealed that Gln depletion was associated with specific changes in the protein expression pattern. However, the overall level of tRNA-bound Gln remained unaffected. The stress protein heat shock protein (Hsp) 70 showed the highest reduction in protein synthesis. This was due to enhanced mRNA decay during Gln starvation while the transcriptional and the translational control of Hsp70 expression remained unchanged. A physiological Gln concentration and above was found to be necessary for maximum Hsp70 accumulation upon heat shock. Thus, the study shows a specific link between Gln metabolism and the regulation of heat shock proteins.

[Urinary diversion after cystectomy: aspects of quality of life and options for rehabilitation]

Radical cystectomy in combination with different types of continent and incontinent urinary diversion is an integral part of the treatment concept for bladder tumors. Although in principle this operation does not cause disability in general, it represents a potentially massive encroachment on the physical and psychological integrity of the individual. The term "quality of life" appears with increasing frequency in modern concepts of evidence-based medicine. Also recognition of the subjective assessment of treatment by those affected in comparison to the "objective" view of qualified doctors and functionaries has become more relevant.Nevertheless, few studies have analyzed the "quality of life" after cystectomy. In addition, methodological factors hinder comparability. Only a few authors have used validated measuring instruments that allow comparison of the data. Low case numbers limit the statistical significance. Besides typical postoperative consequences and their effect on quality of life, potential influences on the pre- and postoperative assessment in the intraindividual course are discussed. The authors argue in favor of postoperative urological rehabilitation in qualified urological centers to optimize physical and psychological coping with the new life situation of "cystectomy with urinary diversion."

Quantitative validation of different protein precipitation methods in proteome analysis of blood platelets

For the preparation of proteins for proteome analysis, precipitation is frequently used to concentrate proteins and to remove interfering compounds. Various methods for protein precipitation are applied, which rely on different chemical principles. This study compares the changes in the protein composition of human blood platelet extracts after precipitation with ethanol (EtOH) or trichloroacetic acid (TCA). Both methods yielded the same amount of proteins from the platelet preparations. However, the EtOH-precipitated samples had to be dialyzed because of the considerable salt content. To characterize single platelet proteins, samples were analyzed by two-dimensional fluorescence differential gel electrophoresis. More than 90% of all the spots were equally present in the EtOH- and TCA-precipitated samples. However, both precipitation methods showed a smaller correlation with nonprecipitated samples (EtOH 74.9%, TCA 79.2%). Several proteins were either reduced or relatively enriched in the precipitated samples. The proteins varied randomly in molecular weight and isoelectric point. This study shows that protein precipitation leads to specific changes in the protein composition of proteomics samples. This depends more on the specific structure of the protein than on the precipitating agent used in the experiment.

Increased susceptibility of glutamine-depleted monocytes to fever-range hyperthermia: the role of 70-kDa heat shock protein

OBJECTIVE

This study investigates the effect of fever-range hyperthermia on Gln-starving monocytes and the role of the 70-kDa heat shock protein Hsp70.

SUMMARY BACKGROUND DATA

Fever is a protective acute-phase response to infection. However, in critically ill patients, the harmful effects of fever seem to be predominant. Critical illness is frequently associated with reduced plasma glutamine (Gln) levels, which contribute to the immune suppression in these patients due to impaired monocyte function.

METHODS

Isolated monocytes were suspended in Gln-depleted medium and exposed to 41 degrees C. Cell survival was determined by an MTT-based assay, and phagocytosis of Escherichia coli was measured by flow cytometry. Expression of Hsp70 was determined by Western blot.

RESULTS

Hyperthermia for 300 minutes strongly decreased the viability of Gln-depleted monocytes (85%), whereas it had only a moderate effect on Gln-supplied cells (45%, P < 0.05). Shorter treatments (45 minutes) of Gln-starving monocytes had almost no effects on viability but decreased the phagocytosis activity by 30.8%. In addition, the expression of Hsp70 was inhibited almost completely.

CONCLUSION

These data show that Gln-starving monocytes have a reduced thermoresistance. This suggests that elevated body temperature damages monocytes in critically ill patients with reduced plasma Gln-levels possibly via an inhibition of the cytoprotective protein Hsp70.

Struktur- und Prozessqualität der stationären urologischen Rehabilitation

Inpatient rehabilitation and "Anschlussheilbehandlung" (rehabilitation soon after operation or acute intervention) are effective and economic for long-term improvement of urologic patients. Only therapy guided by urologic specialists during rehabilitation and afterwards guarantees the possibility of excellent results. Especially QOL and functional deficits are improved markedly by urologic rehabilitation. Therefore, inpatient urologic rehabilitation should be initiated more often in the future.

Platelet function in mitochondriopathy with stroke and stroke-like episodes

Stroke and stroke-like episodes are frequent complications in mitochondriopathy, particularly in MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes) which is a disorder of the mitochondrial oxidative metabolism in diverse cell types. To clarify a possible pathological aspect of stroke in these patients, we investigated platelet function before and after physical exercise. Ten patients with mitochondriopathy and stroke and ten healthy sex and age matched controls were investigated in an analyst blinded, prospective cross-sectional trial. Exercise decreased intraplatelet adenosine triphosphate (ATP) concentrations by -22% from baseline in patients with mitochondriopathy (p<0.01 between groups) while exercise increased ATP-levels by 28% healthy controls (p=0.01 vs baseline). Thrombin receptor activating peptide (TRAP) stimulated P-selectin expression increased up to 50% (p<0.05) in healthy subjects following exercise compared to 39% (p>0.05) in patients with mitochondriopathy. Exercise trendwise decreased platelet plug formation under shear stress by 24% in patients as measured by the platelet function analyzer PFA-100(R). Tromboelastography showed firm thrombus formation and delayed lysis in patients following exercise. In conclusion, this trial has shown that ATP depletion during and after exercise probably accounts for a defective oxidative metabolism in platelets of patients with mitochondriopathy and stroke. This might induce decreased platelet function in these patients but fails to explain the increased stroke rate. Therefore other mechanisms seem to be etiologically involved in the pathogenesis of stroke in patients with mitochondriopathy.

Glutamine starvation of monocytes inhibits the ubiquitin-proteasome proteolytic pathway

Peripheral blood monocytes utilize free glutamine (Gln) in addition to glucose as an important energy substrate. Although this demand increases upon activation, monocytes are commonly confronted with decreased plasma Gln during critical illness and thus suffer from Gln-starvation. Here we investigate the influence of Gln-starvation on protein stability and its effects on the monocyte proteome. Gln-starvation caused a reduction of protein degradation which was accompanied by an accumulation of ubiquitin-protein conjugates and a reduction of intracellular ATP. Similar effects were observed under ATP-reducing conditions and in the presence of a proteasome inhibitor. Using two-dimensional gel electrophoresis we identified the IL-1beta precursor protein (pIL-1beta) as the, by far, most induced protein in endotoxin-treated monocytes. The degradation of the short-lived pIL-1beta was strongly reduced during Gln-starvation, while the degradation of the long-lived, constitutively expressed beta-actin was less affected. This indicates that although Gln-starvation reduces protein breakdown on the overall proteasome level, it leads to differential changes in the stability of specific proteins. This selective effect is likely to contribute to the immunocompromised state of monocytes commonly observed during critical illness.

Human monocyte stimulation by experimental whole body hyperthermia

The thermal effect of fever, an evolutionarily conserved acute-phase response, has been associated with better survival and a shorter duration of disease in cases of infection. The molecular consequence of this beneficial fever response is poorly understood. To determine the influence of hyperthermia on human monocytes, which are important for the recognition and elimination of pathogens, twelve healthy volunteers were immersed in a 39.5 degrees C hot water bath to increase their body temperature. The expression of the endotoxin receptor CD14 and the complement receptor CD11b increased after the hot water bath (P < 0.05), whereas the expression of the selectin CD62L, which mediates the initial attachment of leukocytes at the endothelium during inflammation, was downregulated after hyperthermia (P < 0.05). Comparable changes in monocyte receptor expression were observed after in vitro hyperthermia. Furthermore, 3 hours after in vivo hyperthermia, the response of monocytes to endotoxin was enhanced in an ex vivo lipopolysaccharide stimulation assay, as expressed by a greater TNF-alpha release (P < 0.05). We conclude that the thermal effect of fever directly activates monocytes, which increases their ability to respond to bacterial challenge.

Glutamine depletion impairs cellular stress response in human leucocytes

During sepsis and major trauma the blood glutamine (Gln) level is reduced. The administration of Gln can improve the outcome of these patients. However, the mechanism of this beneficial effect of Gln is poorly understood. In the course of critical illness leucocytes are confronted with cytotoxic inflammatory mediators. To protect themselves against these factors, cells express heat shock proteins (HSP). Previous studies have shown that the expression of the major inducible HSP (HSP70) is improved by high Gln concentrations above 4 mM. In this study we investigated whether Gln depletion, such as observed during critical illness, has an effect on HSP70 expression. Human lymphocytes exposed for 2 h to 42 degrees C showed a 3-fold increase in HSP70 expression (P<0.01). A preceding Gln starvation period over 3 days had no influence on this increase. However, when Gln is reduced during the stress response, HSP70 expression is impaired. A reduction of Gln from 0.5 mM (physiological) to 0.125 mM (pathological) led to a 40% lower HSP70 level (P<0.002). In contrast, increasing Gln concentrations (up to 2 mM) had only minor stimulatory effects (about 15%). This Gln-dependency of heat mediated HSP70 expression was observed in resting as well as proliferating lymphocytes. Our data indicate that during periods of reduced plasma Gln levels the stress response of human lymphocytes is impaired. Thus, Gln may be essential to minimize the susceptibility of leucocytes to cytotoxic inflammatory mediators. This is a new aspect of the protective effect of Gln supplementation in critically ill patients.

Cell type-specific variations in the induction of hsp70 in human leukocytes by feverlike whole body hyperthermia

Fever has been associated with shortened duration and improved survival in infectious disease. The mechanism of this beneficial response is still poorly understood. The heat-inducible 70-kDa heat shock protein (Hsp70) has been associated with protection of leukocytes against the cytotoxicity of inflammatory mediators and with improved survival of severe infections. This study characterizes the induction of Hsp70 by feverlike temperatures in human leukocytes in vitro and in vivo. Using flow cytometry, Hsp70 expression was determined in whole blood samples. This approach eliminated cell isolation procedures that would greatly affect the results. Heat treatment of whole blood in vitro for 2 hours at different temperatures revealed that Hsp70 expression depends on temperature and cell type; up to 41 degrees C, Hsp70 increased only slightly in lymphocytes and polymorphonuclear leukocytes. However, in monocytes a strong induction was already seen at 39 degrees C, and Hsp70 levels at 41 degrees C were 10-fold higher than in the 37 degrees C control. To be as close as possible to the physiological situation during fever, we immersed healthy volunteers in a hot water bath, inducing whole body hyperthermia (39 degrees C), and measured leukocyte Hsp70 expression. Hsp70 was induced in all leukocytes with comparable but less pronounced cell type-specific variations as observed in vitro. Thus, a systemic increase of body temperature as triggered by fever stimulates Hsp70 expression in peripheral leukocytes, especially in monocytes. This fever-induced Hsp70 expression may protect monocytes when confronted with cytotoxic inflammatory mediators, thereby improving the course of the disease.