Strain-dependent interactions of Streptococcus gallolyticus subsp. gallolyticus with human blood cells

BACKGROUND

Streptococcus gallolyticus subsp. gallolyticus (S. gallolyticus) is the causative pathogen in up to 20% of streptococcal-induced infective endocarditis (IE) cases. However, the underlying mechanisms of pathogenesis in S. gallolyticus have not yet been solved. Pathogens causing IE need to employ virulent strategies to initiate and establish infections, such as escape the bloodstream, invade the host-cell, and persist intracellularly. In this study, we examined the induction of inflammation by different S. gallolyticus strains in relation to their survival in whole blood and cell culture models as well as their ability to induce platelet aggregation. Phagocytosis of these bacteria by macrophages, followed by intracellular survival, was also quantified.

METHODS

In whole blood and THP-1 cell culture assays bacterial growth kinetics was determined by plating, followed by colony counting. Induction of interleukin (IL)-6 expression in whole blood of three healthy volunteers, caused by different strains, was quantified by ELISA. Gene expression of cytokines (IL1B, IL6 and IL8) was quantified by real-time PCR after stimulating THP-1 monocytes with bacteria. Induction of platelet aggregation was analyzed by light transmission aggregometry using the BORN method. A macrophage model was used to analyze phagocytosis of strains and their survival in macrophages within 48 h.

RESULTS

Strains promoted IL-6 secretion in a time-dependent fashion. For example, DSM16831 induced IL-6 secretion in whole blood earlier than other isolates, and was eliminated in the whole blood of one volunteer, whereas UCN34 could grow. Platelet aggregation depended on the different isolates used and on the individual platelet donor. Two strains (AC1181 and 010672/01) induced cytokine gene expression in THP-1 monocytes only marginally, compared to other strains. The phagocytosis rate of S. gallolyticus isolates differed significantly, and the isolates UCN34 and BAA-2069 could persist for a considerable time in the phagocytes.

CONCLUSION

The strain-dependent differences of S. gallolyticus isolates, observed during interaction with human blood cells, support the hypotheses that divergences in individual virulence factors determine a distinct pathogenicity of the isolates. These data constitute an additional step towards the elucidation of mechanisms in the complex, multifactorial pathogenesis of this IE pathogen.

Case-control study: Determination of potential risk factors for the colonization of healthy volunteers with Streptococcus gallolyticus subsp. gallolyticus

Streptococcus gallolyticus subsp. gallolyticus was identified in humans and animals as commensal of the gut and can act as a causative agent of endocarditis and septicemia. A case-control study was performed to identify yet unknown risk factors for the transmission of this facultative pathogen. The prevalence in the gut of 99 healthy volunteers was determined using real-time polymerase chain reaction resulting in 62.5% S. gallolyticus subsp. gallolyticus positive excrements. Subsequent cultivation offered three isolates and epidemiological analysis based on MLST revealed sequence type (ST) 3 and ST 7, previously detected from bovine and endocarditis patients. These results support the hypotheses of the zoonotic potential of this bacterium. Participant questionnaires were evaluated concerning personal characteristics, nutritional habits and animal contact. Specifically, closer contact between participants and animals influenced the colonization of the human gut significantly and was further affected if volunteers used excrement for the fertilization of plants.

Hepatitis E in blood donors: investigation of the natural course of asymptomatic infection, Germany, 2011

Asymptomatic hepatitis E virus (HEV) infections have been found in blood donors from various European countries, but the natural course is rarely specified. Here, we compared the progression of HEV viraemia, serostatus and liver-specific enzymes in 10 blood donors with clinically asymptomatic genotype 3 HEV infection, measuring HEV RNA concentrations, plasma concentrations of alanine/aspartate aminotransferase, glutamate dehydrogenase and bilirubin and anti-HEV IgA, IgM and IgG antibodies. RNA concentrations ranged from 77.2 to 2.19×10⁵ IU/mL, with viraemia lasting from less than 10 to 52 days. Donors showed a typical progression of a recent HEV infection but differed in the first detection of anti-HEV IgA, IgM and IgG and seropositivity of the antibody classes. The diagnostic window between HEV RNA detection and first occurrence of anti-HEV antibodies ranged from eight to 48 days, depending on the serological assay used. The progression of laboratory parameters of asymptomatic HEV infection was largely comparable to the progression of symptomatic HEV infection, but only four of 10 donors showed elevated liver-specific parameters. Our results help elucidate the risk of transfusion-associated HEV infection and provide a basis for development of screening strategies. The diagnostic window illustrates that infectious blood donors can be efficiently identified only by RNA screening.

Calciotropic and Phosphaturic Hormones in End-Stage Heart Failure Patients Supported by a Left-Ventricular Assist Device

Background

Calcium and phosphate are central for myocardial contractility and energy metabolism, and low levels of the calciotropic hormone 1,25-dihydroxyvitamin D (1,25(OH)₂D), as well as high levels of the phosphaturic hormone fibroblast growth factor (FGF)-23, are independently associated with poor clinical outcome in heart failure (HF) patients. We therefore aimed to investigate the postoperative time course of the aforementioned hormones in HF patients supported with a left-ventricular assist device (LVAD) implant.

Methods

For the present study, stored biobank plasma samples of 69 patients, collected before LVAD implantation (t0) and 12 days (t1), 30 days (t2), 83 days (t3), and 300 days (t4) post-intervention, were used to measure circulating FGF-23, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), 1,25(OH)₂D, and kidney function.

Results

Most patients were male and had baseline INTERMACS levels and cardiac index values ≤ 3 and ≤ 2.7 L/min/m², respectively. There were significant time effects on estimated glomerular filtration rate (eGFR), FGF-23 and 1,25(OH)₂D, but not on PTH or 25OHD. Notably, eGFR values increased and FGF-23 levels decreased only transiently, whereas 1,25(OH)₂D increased continuously until t4. The rise in 1,25(OH)₂D was largely influenced by those patients who survived the first post-implant year, and was not seen in non-survivors. Variations in 1,25(OH)₂D levels could only partly be explained by eGFR values or FGF-23, 25OHD, and PTH levels (multiple R² = 0.305;P<0.001).

Conclusions

The present study indicates that LVAD implantation has only transient effects on circulating FGF-23 levels, but is associated with a continuous increase in circulating 1,25(OH)₂D levels, especially in survivors.

Establishment of a proficiency panel for an external quality assessment programme for the detection of bacterial contamination in platelet concentrates using rapid and cultural detection methods

BACKGROUND

Platelet concentrates (PCs) are the main focus regarding the residual risk of transfusion-transmitted bacterial infections. Rapid screening methods for bacterial detection in platelets have been optimized over the last decade, but their external evaluation represents a complicated process. We developed a new type of proficiency panel for bacterial detection in PCs using currently available screening methods (especially rapid methods) suitable for external quality assessment programmes (EQAP).

METHODS

PC samples were inoculated with different bacteria at two concentrations (10E+03 CFU/ml, 10E+05 CFU/ml) and stored under temperature-controlled conditions (1-5 days). Bacterial growth was further prevented by the addition of 0-20 μg/ml cotrimoxazole. Samples were analysed prior to and after storage using rapid detection methods (Bactiflow (BF), bacteria-generic NAT) and cultural methods to determine the influence of storage and antibiotic treatment on bacterial counts and the result outcome. A pilot EQAP was performed with four participants.

RESULTS

Testing under the evaluated conditions demonstrated that bacterial counts remained constant prior to and after storage. The supplementation of 10 μg/ml cotrimoxazole did not influence bacterial detection using the two rapid detection methods BF and NAT. Furthermore, the detection of bacteria using cultural methods is still possible despite of antibiotic supplementation. The pilot EQAP confirmed these results. A storage time of up to 3 days proved practicable, showing no considerable influence on bacterial count and outcome of test results.

CONCLUSION

The established proficiency panel provided PC matrix-conform samples with stabilized bacterial counts which can be analysed in parallel by rapid and cultural detection methods.

A prospective clinical trial to assess lapatinib effects on cutaneous squamous cell carcinoma and actinic keratosis

BACKGROUND

Antiepidermal growth factor receptor (EGFR)-targeted therapy is widely used in many epithelial cancer types. We investigated lapatinib effects on cutaneous squamous cell carcinoma (cSCC) scheduled for resection and in coexisting precursor lesions (actinic keratosis (AK) and Bowen's disease (BD)) in a phase 2 mode of action clinical trial including a histological workup of the cSCC.

PATIENTS AND METHODS

We initiated a prospective single-centre, open-label, non-controlled clinical study with translational intentions to investigate changes in size and histopathological features in cSCC after a 14-day period of neoadjuvant lapatinib therapy at a dose of 1500 mg/day prior to surgery, to quantify the impact on AK and BD in the same patient after 56 days and to evaluate the tolerability in patients with cSCC and precursor lesions.

RESULTS

10 immunocompetent male patients were included with a mean age of 73 years (range 59-87). 8 patients were treated with the study medication lapatinib 1500 mg/day for a total duration of 56 days according to the protocol and were available for full analysis, whereas 2 patients had to discontinue treatment during the first 2 weeks because of adverse events (diarrhoea, pancreatitis). Tolerability was acceptable with only 1 related grade III adverse event. A reduction in tumour size of cSCC was documented in 2 of 8 evaluable patients after 14 days of treatment. The mean regression of captured precursor lesions was 30% after 56 days of treatment and 36% 28 days after therapy cessation.

CONCLUSIONS

Short-term lapatinib resulted in a cSCC tumour reduction in 2 of 8 patients. In addition, there was a clinically documented reduction of AK in 7 of 8 patients encouraging larger clinical trials, especially in high-risk patients with cSCC such as organ transplant recipients.

TRIAL REGISTRATION NUMBER

NCT0166431.

Evaluation of the New Cyclosporine and Tacrolimus Automated Electrochemiluminescence Immunoassays under Field Conditions

BACKGROUND

Careful monitoring of the post-transplantation immunosuppressant drugs (ISDs) cyclosporine (CsA) and tacrolimus (TAC) in whole blood is essential to prevent adverse drug events. Immunoassays represent the most widely used methodology for therapeutic drug monitoring. In this study, the technical performance of the new automated electrochemiluminescence immunoassays (ECLIAs) for CsA and TAC measurement were assessed under field conditions.

METHODS

Residual whole blood samples from patients undergoing CsA or TAC therapy following organ transplant were used to evaluate the assays at six independent laboratories across four countries. Experiments included within-run imprecision using PreciControl ISD controls and recovery of commercial external quality assurance (EQA) scheme samples. Both assays were compared with liquid chromatography-tandem mass spectrometry (LC-MS/MS), using methods routinely employed at each investigational site, as well as with an equivalent commercial chemiluminescent microparticle immunoassay (CMIA) and enzyme multiplied immunoassay (EMIT).

RESULTS

Within-run imprecision testing gave coefficients of variation of ≤ 5% in the > 90.0 - 2000 ng/mL range for the CsA ECLIA and ≤ 4.2% in the 3.5 - 12 ng/mL range and ≤ 4.9% in the > 12 - 40 ng/mL range for the TAC ECLIA. EQA sample recovery by ECLIA gave a mean bias of 6.9% for CsA and 4.9% for TAC versus the spiked concentration or the mean LC-MS/MS value. Deming regression analysis of ECLIA method comparison to LC-MS/MS for all sites yielded a slope of 1.22, intercept 8.43 ng/mL and r = 0.97 for CsA and a slope of 1.22, intercept -0.51 ng/mL and r = 0.96 for TAC. Comparison with CMIA yielded a slope of 0.87, intercept 5.51 ng/mL and r = 0.97 for CsA and a slope of 0.98, intercept 0.12 ng/mL and r = 0.97 for TAC. Comparison with EMIT yielded a slope of 1.23, intercept -8.74 ng/mL and r = 0.96 for CsA.

CONCLUSIONS

The CsA and TAC ECLIA compare favorably with existing commercial immunoassays and with LC-MS/MS. They represent modern generation assays that meet the demands of monitoring drug concentrations in current immunosuppressive regimens. This study also highlights the importance of standardizing protocols and LC-MS/MS methods to give improved comparability between ISD assays.

Organic Turkey Flocks: A Reservoir of Streptococcus gallolyticus subspecies gallolyticus

Streptococcus gallolyticus subspecies gallolyticus (S. gallolyticus) can colonise the gastrointestinal tract of humans and animals and is known to cause similar infections in both humans and animals. Data about the spread or prevalence in farm animals are missing. In this study, Trypton Soya Agar was modified to a selective medium enabling the isolation and quantification of S. gallolyticus from faecal samples. The bacterium was observed in 82 out of 91 faecal samples obtained from 18 different organic turkey flocks. The prevalence of shedding birds was estimated by the number of positive fresh droppings and reached up to 100% on most farms. Furthermore, for the first time S. gallolyticus was quantified in faeces from poultry flocks. The median of colony forming units (CFU) per gramme faeces was 3.6 x 10⁵CFU/g. Typing of one isolate from each positive faecal sample by multilocus sequence typing delivered 24 sequence types (STs). Most of the isolates belonged to the clonal complex CC58. The same STs of this complex were detected in up to six different flocks. Partly, these flocks were located in various regions and stocked with varying breeding lines. Regarding the biochemical profiles of the same STs from different farms, the results did not contradict a spread of specific STs in the organic turkey production. Moreover, checking the pubMLST database revealed that STs found in this study were also found in other animal species and in humans. The high detection rate and the number of S. gallolyticus in turkey faeces indicate that this bacterium probably belongs to the common microbiota of the gastrointestinal tract of turkeys from organic flocks. Furthermore, the findings of this study support the suggestion of a possible interspecies transmission.

Implementation of NAT Screening for West Nile Virus and Experience with Seasonal Testing in Germany

BACKGROUND

West Nile virus (WNV) can be transmitted by transfusion through infected blood components. In Germany, a 28-day deferral for blood donors of therapeutic blood components who had spent at least 2 days in WNV-endemic areas from June 1 to November 30, 2014 was enforced. Otherwise, screening of blood donors for WNV RNA or the application of pathogen reduction techniques are appropriate alternatives.

METHODS

In the present study, we evaluated NAT screening for the detection of WNV in blood components. A total of 58 minipools consisting of 357 individual blood donors were screened for the presence of WNV RNA employing an automated high-volume extraction method using the RealStar WNV RT-PCR Kit. Additionally, different WNV reference reagents were quantified to prove the status quo of standardization. Four different WNV real-time NAT kits were compared using samples of an external quality assessment panel.

RESULTS

The 95% lower detection limit of the WNV MP-NAT was determined to 30.2 copies/ml (95% CI 24.2-45.4 copies/ml). No WNV RNA-positive minipool was detected. Quantification of WNV reference reagents revealed shortcomings in standardization. Comparison of several WNV NAT assays showed considerable differences in assay sensitivities and particularly a missing detection of WNV lineage 2. Implementation of seasonal WNV MP-NAT screening was demonstrated.

CONCLUSION

Actually, WNV infections in Germany are rare events introduced by returning travelers, but surveillance of these emerging infections is important for safety in blood supply. The validation study pointed out the need for standardization of WNV NAT because of current lack of an international standard for WNV RNA.

Bench Test for the Detection of Bacterial Contamination in Platelet Concentrates Using Rapid and Cultural Detection Methods with a Standardized Proficiency Panel

BACKGROUND

The most frequent infectious complication in transfusion therapy in developed countries is related to the bacterial contamination of platelet concentrates (PCs). Rapid and cultural screening methods for bacterial detection in platelets are available, but external performance evaluation, especially of rapid methods, has been difficult to realize so far. Here we summarize the results of three individual collaborative trials using an external quality assessment program (EQAP) for the application of current rapid and cultural screening methods.

METHODS

Three different modules were available for the detection of bacterial contamination: module 1: rapid methods, module 2: culture methods, module 3: bacterial identification methods. The sample set-up included up to six different bacterial strains, 1-2 negative samples and 4-6 positive samples with stabilized bacterial cell counts (approximately 10(3)/10(4)/10(5) CFU/ml). Time schedule for testing was limited (module 1: 6 h, module 2 and 3: 7 days).

RESULTS

Samples of module 1 were analyzed with two different rapid methods (BactiFlow, NAT). The results of the three individual collaborative trials showed that all participants detected the negative samples with both assays correctly. Samples spiked with 10(4) to 10(5) CFU/ml of bacteria obtained positive results with both rapid screening methods, whereas samples spiked with only 10(3) CFU/ml disclosed a lower number of correctly identified positive results by NAT (86.6-93.8% sensitivity) compared to BactiFlow (100% sensitivity). The results for modules 2 and 3 revealed a 100% diagnostic sensitivity and specificity in all three collaborative trials.

CONCLUSION

This proficiency panel facilitates the verification of the analytical sensitivity of rapid and cultural bacterial detection systems under controlled routine conditions. The concept of samples provided in this EQAP has three main advantages: i) samples can be examined by both rapid and culture methods, ii) the provided material is matrix-equivalent, and iii) the sample material is ready-to-use.

Look-back study on recipients of Parvovirus B19 (B19V) DNA-positive blood components

BACKGROUND AND OBJECTIVES

To assess the relevance of Parvovirus B19 (B19V) DNA at low to intermediate concentrations in blood donors for the recipients of their blood components.

MATERIAL AND METHODS

We studied recipients of B19V DNA-positive blood components [red blood cell concentrates (RBCs), pooled platelet concentrates and fresh frozen plasma]. This included archived pretransfusion samples as well as follow-up samples investigated by ELISA or NAT and genome sequence analysis.

RESULTS

In 132 out of 424 recipients, we could detect no anti-B19V IgG before transfusion. In 67 out of 132 sero-negative recipients, a follow-up sample was available. Sixty-five of these received blood components from donors with <10(4) IU B19V DNA/ml plasma and had no evidence of transfusion-transmitted (TT)-B19V infection. Homology in genome sequences in donor and recipient provided evidence for a TT-B19V infection in two recipients. Both patients received RBC containing 3.4 × 10(6) and 1.8 × 10(4) IU B19V DNA/ml plasma, respectively. The anti-B19V IgG titres in the donors were 2 and 76 IU/ml plasma, respectively. The antibodies in the second donor were directed against capsid proteins and are thus considered as potential neutralizing antibodies.

CONCLUSIONS

TT-B19V infections through blood components with low (<10(4) IU/ml plasma) B19V DNA concentrations did not occur in our study. One of the TT-B19V infections occurred from RBC with intermediate B19V DNA concentration despite the presence of potential neutralizing antibodies in the donor, but its clinical significance was low.

Potential Transmission Pathways of Streptococcus gallolyticus subsp. gallolyticus

Streptococcus gallolyticus subsp. gallolyticus (S. gallolyticus subsp. gallolyticus), a member of group D streptococci, is an inhabitant of the animal and human gastrointestinal tract. Furthermore, it is a facultative pathogen which causes e.g. endocarditis, septicemia and mastitis. S. gallolyticus subsp. gallolyticus may be transmitted either directly or indirectly between animals and humans. However, the transmission routes are an unsolved issue. In this study, we present systematic analyses of an S. gallolyticus subsp. gallolyticus isolate of an infective endocarditis patient in relation to isolates of his laying hen flock. Isolates from pooled droppings of laying hens, pooled dust samples and human blood culture were characterized by using multilocus sequence typing (MLST) and DNA fingerprinting. MLST revealed the same allelic profile of isolates from the human blood culture and from the droppings of laying hens. In addition, these isolates showed clonal identity regarding a similar DNA fingerprinting pattern. For the first time, we received a hint that transmission of S. gallolyticus subsp. gallolyticus between poultry and humans may occur. This raises the question about the zoonotic potential of isolates from poultry and should be considered in future studies.

Association between circulating 25-hydroxyvitamin D levels and medication use in patients scheduled for cardiac surgery

BACKGROUND AND AIM

Low vitamin D status, i.e. circulating 25-hydroxyvitamin D (25OHD) levels <50 nmol/l, is independently associated with increased CVD risk. Medication use may influence 25OHD levels. We therefore investigated the association of circulating 25OHD with medication use in patients scheduled for cardiac surgery.

METHODS AND RESULTS

A total of 11,256 patients were included in this cross-sectional study. We compared 25OHD levels of medication users (18 groups of continuously used and 5 groups of intermittently used medications) with levels of non-users. Moreover, we assessed variables (medications, demographic and clinical parameters) that were independently associated with 25OHD levels <50 nmol/l. The prevalence of 25OHD levels <50 nmol/l was 65.7%. The use of statins and immunosuppressive agents was significantly associated with higher 25OHD levels and lower odds ratios of 25OHD levels <50 nmol/l. The use of ACE-inhibitors, catecholamines and antibiotics was associated with lower 25OHD levels and higher odds ratios of 25OHD levels <50 nmol/l. However, only use of antibiotics, immunosuppressive agents and catecholamines showed clinically relevant differences in 25OHD levels, i.e. differences of more than +4 nmol/l or -4 nmol/l, compared with respective non-users. These medications were prescribed either intermittently (antibiotics, catecholamines) and/or infrequently (<2%; immunosuppressive agents, catecholamines) and/or its causal relationship with circulating 25OHD is questionable (antibiotics). Female sex and blood drawing during wintertime were associated with the highest odds ratios of 25OHD levels <50 nmol/l.

CONCLUSION

Data indicate that in patients with high cardiovascular risk profile medication use does not substantially contribute to 25OHD levels <50 nmol/l.

Vitamin D metabolites and fibroblast growth factor-23 in patients with left ventricular assist device implants: association with stroke and mortality risk

PURPOSE

Stroke and mortality risk in patients with left ventricular assist device (LVAD) implants continue to be high. Whether nonclassical cardiovascular risk markers such as vitamin D metabolites and fibroblast growth factor (FGF)-23 contribute to this risk remains to be studied, and this was the objective of our work.

METHODS

In 154 LVAD patients (91 HeartWare and 63 HeartMate II implants), we measured circulating 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D3 (1,25[OH]2D3), parathyroid hormone (PTH) and FGF-23 shortly before LVAD implantation and investigated their association with stroke and mortality risk during 1-year follow-up.

RESULTS

Of the study cohort, 34.4 and 92.2%, respectively, had deficient 25OHD (<25 nmol/l) and 1,25(OH)2D3 (<41 pmol/l) values, whereas 42.6 and 98.7%, respectively, had elevated PTH levels (>6.7 pmol/l) and FGF-23 values above the reference range (100 RU/ml). One-year freedom from stroke was 80.9 %, and 1-year survival was 64.3%. The multivariable-adjusted hazard ratio of stroke was 2.44 (95% CI: 1.09-5.45; P = 0.03) for the subgroup of 25OHD levels <25 nmol/l (reference group: 25OHD levels ≥25 nmol/l). The multivariable-adjusted hazard ratio of 1-year mortality was 2.78 (95% CI: 1.52-5.09; P = 0.001) for patients with 25OHD levels <25 nmol/l compared with patients with 25OHD levels ≥25 nmol/l. PTH, FGF-23 and 1,25(OH)2D3 were not associated with stroke or mortality risk.

CONCLUSIONS

In LVAD patients, deficient 25OHD levels are independently associated with high stroke and mortality risk. If confirmed in randomized controlled trials, preoperative correction of deficient vitamin D status could be a promising measure to reduce stroke and mortality risk in LVAD patients.

Abstract W MP91: Supply-demand Mismatch Transients Trigger Peri-infarct Depolarizations In Ischemic Penumbra

Background: Peri-infarct depolarizations (PIDs) worsen the outcome of ischemic stroke. Unlike their impact on metabolism and perfusion, triggering factors are virtually unknown. We hypothesized that transient worsening of O2 supply-demand mismatch precipitates a PID in critically hypoperfused penumbra.

Methods: We optically imaged cortical blood flow and oxygenation during distal middle cerebral artery occlusion in mice under full systemic physiological monitoring, and tested whether a transient (5 min) drop in O2 supply (hypotension or hypoxia) or increase in O2 demand (somatosensory cortical activation) can trigger PIDs during acute focal cerebral ischemia.

Results: Transient hypotension (<70 mmHg) or hypoxia (<90 mmHg) triggered a PID 90% of the time (p<0.01). Increasing the O2 demand by functional activation (tactile stimulation) of moderately ischemic cortex (contralesional forepaw or shoulder S1) increased the 5-min incidence of PIDs by approximately five-fold (p=0.001). Cortical oxyhemoglobin levels dropped by 35-40% in the activated S1 immediately before a PID (p=0.004) confirming increased O2 demand. Cortical foci from which PIDs originated during tactile stimulation had 27-32% residual CBF, indicating the presence of a critical range of ischemia vulnerable to PID initiation upon increased demand. Consistently, activation of non-ischemic cortex (hindpaw S1) or severely ischemic cortex (whisker S1) did not significantly increase the PID rate. Both tetrodotoxin (1 μM topical) and normobaric hyperoxia prevented somatosensory triggering of PIDs.

Conclusion: PIDs are triggered upon O2 supply-demand mismatch transients in metastable peri-infarct hot zones due to increased demand or reduced supply. We propose that minimizing sensory stimulation and hypoxic or hypotensive transients in the early stages of stroke and brain injury would reduce PID incidence and their adverse impact on outcome.

25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and postoperative outcome in cardiac surgery

CONTEXT

Several cohort studies have reported U-shaped or inverse J-shaped associations between circulating 25-hydroxyvitamin D [25OHD] and clinical outcomes.

OBJECTIVE

We aimed to investigate in cardiac surgical patients the association of preoperative 25OHD and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] levels with the risk of major adverse cardiac and cerebrovascular events (MACCE).

DESIGN

A prospective cohort study of adult cardiac surgical patients in 2012-2013 was used.

SETTING

The study was conducted at the Heart and Diabetes Center North Rhine-Westphalia, Germany.

PATIENTS

A total of 3371 adult patients participated in the study.

INTERVENTION

None Measurements: The main outcome measure was MACCE until discharge. We categorized vitamin D metabolite levels into subgroups and performed multivariable-adjusted logistic regression analysis to estimate odds ratios (ORs) of MACCE. Moreover, we performed multiple regression analysis to assess the association of 25OHD and circulating 1,25(OH)2D3 with preoperative parameters.

RESULTS

As compared with patients in the 25OHD reference category (75-100 nmol/L), the multivariable-adjusted odds ratios (OR) of MACCE was significantly higher in patients with deficient 25OHD levels (< 30 nmol/L) (OR = 2.06 [95%CI: 1.24-3.43]), but was comparable in patients with 25OHD levels > 100 nmol/L (OR = 1.16 [95% CI: 0.56-2.37]). Poor kidney function was an important predictor of high 25OHD (>100 nmol/L) and low 1,25(OH)2D3 levels. 1,25(OH)2D3 was not independently associated with the incidence of MACCE.

CONCLUSIONS

In cardiac surgical patients, deficient but not high 25OHD levels are independently associated with the risk of MACCE. Cohort studies should consider potential interrelationships between kidney function, circulating vitamin D metabolite levels, and clinical outcome.