Characterization of myeloid leukocytes and soluble mediators in pancreatic cancer: importance of myeloid-derived suppressor cells

Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest cancers in the world. PDAC cells activate tumor-specific immune responses but simultaneously trigger a strong immunosuppression. We showed that PDAC cells produce high amount of chronic inflammatory mediators and PDAC tumors build an immunosuppressive cytokine milieu, which correlates with tumor progression. We observed a low frequency of dendritic cells (DC) and a pronounced accumulation of macrophages and myeloid-derived suppressor cells (MDSC) in murine PDAC tumors. A strong accumulation of MDSC has also been demonstrated in the peripheral blood of resected PDAC patients. While DC and macrophages seem not to play a significant role in this PDAC model in the context of immunosuppression, MDSC are highly suppressive, and their accumulation is associated with an increase in intratumoral VEGF concentration during the PDAC progression. Application of the phosphodiesterase-5 inhibitor sildenafil led to a prolonged survival of PDAC-bearing female mice, which was due to the decrease in MDSC frequencies and in the systemic VEGF level. This led to a restoration of anticancer immune responses, manifested in the recovery of T lymphocyte functions and in an increase in the frequency of conventional CD4⁺ T cells in tumors and IFNγ level in serum of PDAC-bearing mice. Thus, MDSC are strongly involved in the PDAC-associated immunosuppression and that their depletion could create new approaches for therapy of PDAC.

Immunological in vivo effects of B7-H1 deficiency

B7-H1 regulatory protein, a member of the B7-H family, plays a crucial role in the modulation of immune response in healthy steady-state conditions as well as in different pathologies. B7-H1 knockout mice represent an important model to elucidate further molecular and cellular mechanisms involved, among others, in autoimmunity development and cancer progression. However, a deep immunologic characterization of this model is not complete yet. This study examined the role of B7-H1 in vivo further by direct comparison of specifically phenotyped spleen immune-cell subpopulations and their activation and naïve/memory state as well as cytokine profile in wild-type and B7-H1 knockout mice. Our results demonstrated that B7-H1 deficiency in vivo modulates several immunological parameters, including the amount and composition of Gr1(+)CD11b(+) myeloid population, the composition and activation state of the DC compartment, the frequency and status of NK and NKT cells, B-cells, naïve/memory state of CD8 T-cells and production of IL-2 and IL-10 cytokines. Moreover, we observed an increase in the PD-1 expression in the immune cells in B7-H1 knockout mice compared to the wild-type animals. Valuing the importance of B7-H1 knockout mice for their use in disease models, these data underline the role of B7-H1 in vivo also in healthy state and should be taken into account in future studies on this immunosuppressive molecule.

[Life-threatening fentanyl and propofol addiction: interview with a survivor]

Anesthesiologists have a well-known increased risk of substance abuse including the intravenous administration of opioids and propofol. However, katamnestic reports from the point of view of propofol-addicted anesthesiologists themselves are missing which would aid a better understanding of the dynamics and progress of addiction. This article presents an interview with a formerly addicted female anesthesiologist who after long-term abuse with oral tilidine combined with naloxone switched to intravenous administration of fentanyl and later on propofol. Several life-threatening incidents occurred but after some severe setbacks occupational rehabilitation outside the field of anesthesiology was successful following inpatient treatment. This case shows exemplarily in accordance with the current literature that warning signs in addicted physicians are often ignored by colleagues and supervisors and rehabilitation is possible under professional therapy and continuous surveillance. Additionally, this case emphasizes the necessity of controlling the distribution of propofol to reduce the life-threatening professional risk to anesthesiologists.

[Social desirability in pain therapy. Response behavior of various professional groups on the implementation of multi-professional pain management]

BACKGROUND

Research on the quality of pain management is often based on self-reported data pertaining to internal regulations provided by employees. However, data examining the correctness of the information given are rare. The project "Pain-Free Hospital" facilitated such an analysis and compared the answers provided by staff members with currently existing regulations.

METHODS

In the course of the project (2004-2006) data on internal pain-related therapy plans, pain management-related regulations as well as the level of knowledge of 3421 nurses, 1757 physicians (825 conservative ward physicians, 728 surgeons and 526 anesthesiologists) from a total of 19 hospitals were collected and examined prior to and after the implementation of a specific training intervention. The congruence of the answers given was measured.

RESULTS

After training 16 surgical wards (previously 12) and 13 conservative wards (previously 2) had standardized therapy plans. Regulations existed in 13 conservative (previously 12) and 16 surgical wards (previously 12). In those hospitals with standardized therapy plans, a significantly higher level of knowledge was found among staff members after the intervention (p < 0.05), especially on surgical wards. In hospitals without therapy plans and regulations there were significantly more incongruent answers (p < 0.05). In comparison to colleagues from conservative wards, surgical nurses and physicians provided significantly more incongruent answers.

CONCLUSION

Therapy plans and pain management-related regulations are known in hospitals after a systematic training. Data suggest that hospitals without regulations show a trend towards social desirability.

Mechanism- and experience-based strategies to optimize treatment response to the capsaicin 8% cutaneous patch in patients with localized neuropathic pain

The capsaicin 8% cutaneous patch is an emergent new treatment option for patients with peripheral neuropathic pain. In randomized controlled clinical studies relevant pain relief for 12 weeks was achieved in about one third of patients following a single application. The first part of this paper is a review of the pathophysiology, pharmacology, and published clinical trials with the capsaicin 8% cutaneous patch. The second part reports on outcomes of an interdisciplinary expert workshop, where new treatment results of three major German pain centers were presented and reviewed with the objectives of obtaining responder rates for different pain syndromes, assessing maintenance of effect under real-life conditions, and giving recommendations for practical care. The 12 week responder rates with pain relief of ≥ 30% were comparable in patients with mononeuropathies (37.9%) and postherpetic neuralgia (38.8%). Similar responder rates were seen in a subgroup of patients with cervical spine radiculopathy and back pain (46.7%). In HIV-associated neuropathy the responder rates were high (47.8%) but lower in patients with other polyneuropathies (17.6%). Response rates were nearly identical after 1 week (46.6%) and 4 weeks (43.3) and dropped only slightly at 12 weeks (37.4%). In a subgroup of 54 patients who underwent a second treatment, efficacy was maintained. Response rates in patients with or without lidocaine pretreatment were comparable. Treatment with the capsaicin 8% cutaneous patch was generally safe and well tolerated. The workshop panel recommended further investigation of opportunities to improve the application procedure and to perform studies on the skin penetration and distribution of capsaicin. A modified quantitative sensory testing (QST) should be developed for clinical practice in order to better understand the correlation of sensory profiles and response to capsaicin treatment.

Childhood diabetic neuropathy: functional impairment and non-invasive screening assessment

AIM

Sensory diabetic neuropathy, determined by nerve conduction studies, is common in children with Type 1 diabetes. Diabetic neuropathy diagnoses are rarely made in paediatric daily care because they are asymptomatic, vibration detection is mostly normal and nerve-conduction testing is impractical. The present study aims to: (1) describe somatosensory dysfunction in children with diabetes, (2) test whether diabetes duration and HbA(1c) are related to somatosensory dysfunction and (3) identify the best screening test for large-fibre dysfunction, as indicated by nerve conduction studies.

METHODS

Forty-five children (age 13.2 ± 2.5 years) with Type 1 diabetes for 6.7 ± 2.5 years and matched control subjects were assessed by neurological examinations, nerve conduction tests and quantitative sensory testing on the feet using the protocol of the German Research Network on Neuropathic Pain. Abnormal nerve conduction was used as gold standard to define neuropathies.

RESULTS

We found a high prevalence of mechanical (38%) and thermal (24%) hypoesthesia often associated with hyperalgesia (47%). Tactile hypoesthesia (33%) was more frequent than pallhypaesthesia (11%). Only cold detection and mechanical pain thresholds were related to HbA(1c). Tactile hypoesthesia had the highest sensitivity (75%), specificity (89%) and positive (75%) and negative (89%) predictive values for neuropathies defined by nerve conduction tests (31% abnormal).

CONCLUSIONS

Almost half of the children with diabetes have subclinical large- and small-fibre neuropathies. Tactile detection was better than vibration for neuropathy assessment. Quantitative sensory testing is a valuable tool for assessment of neuropathy as well as a target of interventional studies in children with diabetes.

[Accidental levomethadone intoxication in a palliative patient]

Levomethadone is a strong opioid which is used rarely in the treatment of special pain syndromes in Germany. A main field for the usage of Levomethadone, which has be applied as a oral fluid, is the opioid replacement therapy of heroin-addicts. Due to the long plasma half life and its high inter-individual variability, the application implies a risk of cumulation leading to an overdosage. It is not recommended to use a fixed equianalgesic formula for the dosage conversion from other opioids. The conversion starts with a low start dose, an individual titration follows. In this case-report, the difficulty of cumulation, inaccurate drug dispensary and the characteristic of dosage calculation of levomethadone is discussed.