Current concepts of immune dysregulation in cystic fibrosis

Cystic fibrosis (CF) lung disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene and is characterized by a perpetuated feedback loop of bacterial infection and inflammation. Both intrinsic (CFTR-dependent) and extrinsic (CFTR-independent) mechanisms contribute to the inflammatory phenotype of CF lung disease. Innate immune cells, initially recruited to combat bacterial pathogens, are acting in a dysregulated and non-resolving fashion in CF airways and cause harm to the host by releasing proteases and oxidants. Targeting harmful immune pathways, while preserving protective ones, remains the challenge for the future. This review highlights current concepts of innate immune dysregulation in CF lung disease.

Neutrophilic myeloid-derived suppressor cells in cord blood modulate innate and adaptive immune responses

Neonates show an impaired anti-microbial host defence, but the underlying immune mechanisms are not understood fully. Myeloid-derived suppressor cells (MDSCs) represent an innate immune cell subset characterized by their capacity to suppress T cell immunity. In this study we demonstrate that a distinct MDSC subset with a neutrophilic/granulocytic phenotype (Gr-MDSCs) is highly increased in cord blood compared to peripheral blood of children and adults. Functionally, cord blood isolated Gr-MDSCs suppressed T cell proliferation efficiently as well as T helper type 1 (Th1), Th2 and Th17 cytokine secretion. Beyond T cells, cord blood Gr-MDSCs controlled natural killer (NK) cell cytotoxicity in a cell contact-dependent manner. These studies establish neutrophilic Gr-MDSCs as a novel immunosuppressive cell subset that controls innate (NK) and adaptive (T cell) immune responses in neonates. Increased MDSC activity in cord blood might serve as key fetomaternal immunosuppressive mechanism impairing neonatal host defence. Gr-MDSCs in cord blood might therefore represent a therapeutic target in neonatal infections.

Effects of laparoscopic sleeve gastrectomy on attentional processing of food-related information: evidence from eye-tracking

BACKGROUND

Weight loss after laparoscopic sleeve gastrectomy (LSG) might be associated partially with changes in reward system functioning and altered appetitive responses to food cues. Food cue processing refers to motivational, affective, and cognitive responses to stimuli that are associated with food. We investigated if food cue processing is altered 6 months after weight loss that is induced by LSG. We expected patients after LSG to show reduced appetitive responses to food cues.

METHODS

In an experimental longitudinal exploratory study, 17 severely obese patients (body mass index [BMI]: 48.3 ± 6.5 kg/m²) were investigated presurgery and 6 months postsurgery. We used eye-tracking to assess attentional biases during free viewing of food versus nonfood cues, assessed pleasantness ratings of food cues, and self-reported food craving.

RESULTS

After LSG, the mean BMI of patients was 36.4 ± 6.0 kg/m², and the percentage of excess weight loss (%EWL) was 46.6% ± 14.0%. Six months after LSG, patients showed an attentional bias toward nonfood cues compared with presurgery, reported lower food craving, and rated presented food stimuli as less pleasant.

CONCLUSION

Evidence of altered food cue processing was found in patients after LSG, which may be interpreted as reduced food reward associated with increased cognitive control. Surgery-induced physiologic, cognitive-motivational, and behavioral changes may lead to a desensitization of the reward system and enhanced cognitive control.

Differences of IgG antibody avidity after an acellular pertussis (aP) booster in adolescents after a whole cell (wcP) or aP primary vaccination

Compared to whole cell pertussis (wcP) vaccines, acellular pertussis vaccines (aP) have a better safety profile with lower reactogenicity, although their short and long-term efficacy was found to be slightly lower. Up to now, no established serological parameter to predict long-term protection exists. IgG-anti-pertussis avidity possibly determines the effect of different pertussis vaccines and boosting intervals on long-term immunity. Thus, the avidity of a tetanus-diphtheria-aP booster at 10-14 years was tested in three groups of adolescents who had been previously immunized with either five doses of aP (5aP) at 2, 4, 6, 15-18 months and 5-6 years of age, four doses of aP (4aP) or four doses of wcP (4wcP) at 2, 4, 6 and 15-18 months of age. Relative avidity index (RAI) of IgG-anti-pertussis toxin (PT) and IgG-anti-filamentous-hemagglutinin (FHA) was assessed by an adapted ELISA. RAI of IgG-anti-PT and of IgG-anti-FHA correlated positively with antibody concentrations in the pre-vaccination and in the post-vaccination analysis and significantly increased after adolescent booster with aP in all groups. Pre- and post-vaccination, the proportion of participants with IgG-anti-PT RAI>40% (moderate to high avidity) was significantly lower in the 4wcP group (52.9% and 88.9%) compared to the 5aP group (89.5% and 100.0%). In conclusion, TdaP in adolescence induces an increase of antibody avidity and, thus, is able to enhance the binding-quality of antibodies against pertussis. The study suggests including antibody avidity into serological studies on the humoral response to provide information about the long-term efficacy of the vaccine.

Psychological dimensions after laparoscopic sleeve gastrectomy: reduced mental burden, improved eating behavior, and ongoing need for cognitive eating control

BACKGROUND

Obesity as a chronic disease has spread worldwide. Conservative treatment, especially with severe obesity, often fails. Obesity surgery has been shown to be an effective treatment. Laparoscopic sleeve gastrectomy (LSG), as a restrictive procedure, has low risks and results in good weight loss outcomes. However, to date, no studies have investigated the changes in psychological dimensions-especially concerning eating behavior and cognitive restraint-after LSG. The present study investigated, for the first time, eating behavior (cognitive restraint, disinhibition, hunger), depression, and perceived stress before and 1 year after LSG. The setting was a university hospital, comprehensive obesity center.

METHODS

Of 59 patients who had undergone LSG from 2008 to 2010, 40 patients were evaluated using questionnaires on eating behavior, depression, and stress, with measurements made before and 1 year after surgery.

RESULTS

The body mass index had decreased, on average, by 15.5 kg/m(2) 1 year after LSG (62.7% excess weight loss). The eating behaviors had changed, with patients experiencing less hunger, fewer food cravings, and decreased disinhibition. Depressive symptoms and perceived stress improved. However, the results showed high levels in the dimension of cognitive restraint of eating 1 year after LSG.

CONCLUSIONS

Most psychological dimensions improved as expected. The patients were less distracted by food, experienced less hunger, and were less disturbed by emotional distress. However, we found persistent cognitive restraint, reflecting an ongoing need for central eating control. Additional investigations are needed to describe the communication between the gut and brain after surgery.

[Psychotherapy and obesity: strategies, challenges and possibilities]

One fifth of the German population is obese with increasing prevalence. Psychotherapy plays an important role in weight loss programmes. Cognitive behaviour therapy, targeting lifestyle changes, including exercise and eating behaviour, is the evidence-based treatment of choice. Especially the lack of motivation or absence of weight loss, further weight gain or psychosocial burden makes psychotherapy essential. The treatment of a comorbid binge eating disorder should be initiated prior to focusing on weight loss. Remarkably difficult stages in the treatment of obesity are the initiation of changes as well as the maintenance of the achieved weight loss. Internet-based attempts will become increasingly important.

Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects

BACKGROUND

Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.

METHODS

Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.

KEY RESULTS

Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.

CONCLUSIONS & INFERENCES

Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.

Effects of medical training scenarios on heart rate variability and motivation in students and simulated patients

CONTEXT

Research regarding the experience of stress during medical training scenarios using standardised patients (SPs) has been primarily qualitative and has focused on the SPs. The purpose of this study was to quantitatively evaluate stress and motivation in both students and SPs during these scenarios by measuring heart rate variability (HRV) and administering the German version of the Questionnaire on Current Motivation (QCM).

METHODS

A total of 44 medical students (23 women, 21 men) participated in two medical history-taking training scenarios. In one scenario the SP role-played a patient with a somatic disease; in the other the SP played a patient with a psychosomatic disease, creating easy and difficult scenarios, respectively, for the student. Each student interviewed one of 11 SPs (five women, six men), using the same SP in both scenarios. Heart rate variability was measured during baseline periods and during the training scenarios in both students and SPs. Motivation was assessed before each training scenario.

RESULTS

Heart rate variability was lower in both students and SPs during the scenarios compared with baseline values, but did not differ by scenario type. For students, motivation increased when the first scenario involved psychosomatic illness, but decreased when the first condition was somatic. For SPs motivation was consistent over time for scenarios involving psychosomatic disease, but decreased for somatic disease-related scenarios.

CONCLUSIONS

The training scenarios induced stress in both students and SPs, as indicated by decreased HRV. Student motivation was high, indicating that SP scenarios represent a valid teaching method. Further studies in the natural setting of SP examinations are needed.