Low mechano-afferent fibers reduce thermal pain but not pain intensity in CRPS.

BACKGROUND: Human hairy (not glabrous skin) is equipped with a subgroup of C-fibers, the C-tactile (CT) fibers. Those do not mediate pain but affective aspects of touch. CT-fiber-activation reduces experimental pain if they are intact. In this pilot study we investigated pain modulating capacities of CT-afferents in CRPS. METHODS: 10 CRPS-patients (mean age 33 years, SEM 3.3) and 11 healthy controls (mean age 43.2 years, SEM 3.9) participated. CT-targeted-touch (brush stroking, velocity: 3 cm/s) was applied on hairy and glabrous skin on the affected and contralateral limb. Patients rated pleasantness of CT-targeted-touch (anchors: 1 "not pleasant"-4 "very pleasant") twice daily on 10 days. Pain intensity (NRS: 0 "no pain" - 10 "worst pain imaginable") was assessed before, 0, 30, 60 and 120 min after each CT-stimulation. To assess sensory changes, quantitative-sensory-testing was performed at the beginning and the end of the trial period. RESULTS: CT-targeted-touch was felt more pleasant on the healthy compared to the affected limb on hairy (p < 0.001) and glabrous skin (p 0.002), independent of allodynia. In contrast to healthy controls patients felt no difference between stimulating glabrous and hairy skin on the affected limb. Thermal pain thresholds increased after CT-stimulation on the affected limb (cold-pain-threshold: p 0.016; heat-pain-threshold: p 0.033). CONCLUSIONS: CT-stimulation normalizes thermal pain thresholds but has no effect on the overall pain in CRPS. Therefore, pain modulating properties of CT-fibers might be too weak to alter chronic pain in CRPS. Moreover, CT-fibers appear to lose their ability to mediate pleasant aspects of touch in CRPS.

Preoperative Elevated Levels for Depression, Anxiety, and Subjective Mental Stress Have No Influence on Outcome Measures of Peripheral Nerve Field Stimulation for Chronic Low Back Pain-A Prospective Study.

OBJECTIVE: Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. The treatment of low back pain strongly depends on psychological factors like anxiety, depression, and mental stress. The aim of this study was to evaluate the impact of such factors on outcome measures after lead- and implantable pulse generator-implantation. MATERIALS AND METHODS: Between 2014 and 2019, a prospective cohort study of 39 patients with chronic lumbar pain was conducted. Hospital Anxiety and Depression Scale (HADS) score was assessed at baseline to measure symptoms of anxiety and depression. Symptom checklist-90 (SCL-90) was used to measure subjective psychopathology. Pain intensity (numeric pain rating scale [NRS]), SF12v2 with Physical Component Summary and Mental Component Summary (MCS) scores, and Oswestry Disability Index (ODI) were assessed pre- and postoperatively as well as three and six months after PNFS implantation. Outcome values were compared to baseline data. Statistical analysis was performed using depending t-test and analysis of variance (ANOVA). A p value <0.05 was considered significant. RESULTS: The cohort consisted of 39 patients (18 females, 21 males) with a median age of 61 years (IQR25-75  = 52-67 years). NRS, ODI, and SF12v2 showed significant improvement in the whole follow-up period compared to baseline values (p < 0.05). Elevated HADS scores for anxiety were seen in 64.1%, for depression in 76.9% of the patients at baseline. SCL-90 was pathologic in 71.8% of the cases. A one-way ANOVA revealed no differences between elevated HADS- and SCL-90 values and all outcome measures after PNFS implantation in the whole follow-up period (p > 0.05). CONCLUSION: Chronic low back pain is often associated with psychological distress. Our study showed highly elevated levels for anxiety and depression as well as subjective mental stress in patients with chronic low back pain without negative impact on NRS, ODI, and SF12v2 in the whole follow-up after PNFS implantation.

The Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection in Peripheral Nerve Field Stimulation for Chronic Low Back Pain: A Prospective Study.

OBJECTIVE: Peripheral nerve field stimulation (PNFS) is an effective alternative treatment for patients with chronic low back pain. Transcutaneous electrical nerve stimulation (TENS) is frequently used in pain therapy. Aim of this prospective study was to examine the predictive value of TENS for later PNFS treatment. MATERIALS AND METHODS: Between 2014 and 2019, a prospective cohort study of 41 patients with chronic lumbar pain was conducted. Pain intensity (NRS) was assessed before and after TENS use, preoperatively/postoperatively and in the follow-up after three and six months, SF12v2 questionnaires with physical (PCS) and mental component summary (MCS) scores, and Oswestry disability index (ODI) questionnaire at baseline as well as three and six months after PNFS implantation. Implantation of the PNFS-system with two percutaneous leads was performed after four to seven days of positive testing. Statistical analysis was performed using depending t-test, ANOVA, and Spearman correlation. RESULTS: The cohort consisted of 41 patients (19 females, 22 males) with a median age of 60.5 years (IQR25-75 52-67). Two patients were lost to follow-up. After positive PNFS testing a pulse generator (IPG) was implanted in 15 patients with positive TENS effect and 15 patients without TENS effect. Leads were explanted in nine patients after negative PNFS trial phase. TENS positive patients showed significant correlation to a positive effect in the PNFS trial phase in NRS reduction (p = 0.042) indicating that TENS responders will also respond to PNFS (94% patients). After three and six months follow-up median NRS and SF12v2 (PCS) improved significantly in both cohorts, SF12v2 (MCS) and ODI only in the TENS positive cohort, respectively. CONCLUSION: TENS can be predictive for patient selection in PNFS, as TENS positive patients showed significant correlation with a positive PNFS trial period. Therefore, TENS positive patients might be justifiable to be directly implanted with leads and IPG. TENS positive patients further tend to show a better improvement in the follow-up.

Spinal cord stimulation for the treatment of complex regional pain syndrome leads to improvement of quality of life, reduction of pain and psychological distress: a retrospective case series with 24 months follow up.

Background and aims Complex regional pain syndrome (CRPS) is a common pain condition which is characterized by pain, functional impairment, and trophic changes. Neurosurgical treatment is not widely offered. In this study the treatment with spinal cord stimulation (SCS) was evaluated over 24 months follow up. Methods A retrospective case analysis of six patients with severe CRPS was performed. Pain chronicity was recorded with the Mainz Pain Staging System (MPSS). Pain intensity (NRS), activity level and health-related quality of life (EQ-5D-5L), the actual mood state (ASTS), and treatment satisfaction (CSQ-8) were assessed. All patients received conventional pharmacological treatments including multimodal pain therapy through their local pain therapist or in specialized centers as well as physical therapy. A SCS electrode was implanted for trial stimulation. After successful trial a neurostimulator was implanted and connected to the electrode. Patients were retrospectively analyzed before implantation and 6, 12 and 24 months postoperatively. Statistical analysis was performed using Mann-Whitney U and Wilcoxon rank-sum test. Results Patients median age was 43 years (IQR25-75 37-43 years). The median MPSS Score was 3 of 3 indicating a high pain chronicity. Median NRS before implantation of the neurostimulator was 8.8 (IQR25-75 7.6-9.3). A reduction to 7.8 (IQR25-75 4.8-8.1; p = 0.14) after 6 months, 6.5 (IQR25-75 3.8-8.1; p = 0.08) after 1 year, and 6.8 (IQR25-75 3.8-8.5; p = 0.15) after 2 years was achieved. Median EQ-5D-5L index value before treatment was 0.27 (IQR25-75 0.25-0.41) indicating a severely lowered quality of life. A significant improvement to 0.53 (IQR25-75 0.26-0.65; p = 0.03) after 6 months, 0.58 (IQR25-75 0.26-0.84; p = 0.03) after 1 year as well as after 2 years was seen. ASTS scale showed an increase of values for positive mood, and a reduction in values for sorrow, fatigue, anger and desperation during the whole follow up period. The treatment satisfaction in the whole cohort with a median CSQ-8 value of 29.5 of 32 was very high. Conclusion The results of this small case series showed a significant improvement of the EQ-5D-5L after implantation of a neurostimulator. NRS reduction was not significant but a clear tendency towards reduced values was observed. We therefore conclude that SCS is an alternative option to relieve chronic pain and psychological distress originating from CRPS if non-invasive managements of severe CRPS failed. The preoperative selection plays a crucial role for good results. Implications CRPS is difficult to treat. SCS is an alternative option to improve the quality of life and relieve chronic pain originating from severe CRPS if conservative treatment modalities fail. Further psychological distress is reduced in long-term follow up. SCS should be kept in mind for therapy refractory cases.

A Retrospective Analysis of 25 Cases With Peripheral Nerve Field Stimulation for Chronic Low Back Pain and the Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection.

OBJECTIVE: Transcutaneous electrical nerve stimulation (TENS) and peripheral nerve field stimulation (PNFS) may be proposed to patients with chronic lumbar pain refractory to conventional treatment. Aim of this study was to assess the importance of preoperatively treatment with TENS as a predictive value for later successful PNFS and impact of PNFS in follow-up of 12 months. METHODS: Between 2012 and 2016, a retrospective analysis of 25 patients with chronic lumbar pain and implantation of a PNFS-system was performed. Pain intensity (NRS), health-related quality of life (EQ-5D-5L), Oswestry disability index (ODI), actual mood state scale (ASTS), and treatment satisfaction (CSQ-8) were assessed pre/postoperatively, after 6 and 12 months. TENS use before surgery was assessed. RESULTS: The cohort consisted of 25 patients with a median age of 56 years (IQR25-75 51-63). In a subgroup analysis, 18 patients used TENS before surgery, 7 did not use TENS and were excluded. No pain relief was observed in 14 patients. Ten of these patients showed later positive effect in PNFS trial stimulation. In four patients, pain relief with TENS was seen. One patient later on had no benefit after PNFS trial, three had sufficient pain relief. In the whole cohort, five patients had no benefit after PNFS trial, in 20 patients a neurostimulator was implanted. NRS, EQ-5D-5L, and ODI measures showed significant improvement in the whole follow-up after PNFS implantation. ASTS scale showed an increase of values for positive mood and a reduction in values for sorrow, fatigue, and anger. In 55%, a sustained reduction in demand for analgesics was seen after 6 months, 50% after 12 months, respectively. CONCLUSION: In this retrospective analysis, TENS has no predictive value in the selection of patients with low back pain for the PFNS treatment. PNFS is effective and safe to relieve significantly symptoms of chronic low back pain.

Caspofungin Modulates Ryanodine Receptor-Mediated Calcium Release in Human Cardiac Myocytes.

Recent studies showed that critically ill patients might be at risk for hemodynamic impairment during caspofungin (CAS) therapy. The aim of our present study was to examine the mechanisms behind CAS-induced cardiac alterations. We revealed a dose-dependent increase in intracellular Ca2+ concentration ([Ca2+]i) after CAS treatment. Ca2+ ions were found to be released from intracellular caffeine-sensitive stores, most probably via the activation of ryanodine receptors.

Oxidative and cytotoxic stress induced by inorganic granular and fibrous particles.

The hazards of granular and fibrous particles have been associated with the generation of reactive oxygen species (ROS), which in turn is often associated with physicochemical properties exhibited by these particles. In the present study, the ability of various types of fibrous and granular dusts to generate oxidative stress, and their cytotoxicity, was investigated. Biopersistent granular dusts employed in the present study included micro­ and nanosized titanium dioxide with rutile or anatase crystal structure modifications. Additionally, glass fibres, chrysotile and crocidolite asbestos representative of fibrous dust were selected. Detailed characterisation of particles was performed using scanning electron microscopy, and the effect of exposure to these particles on cell viability and intracellular ROS generation was assessed by PrestoBlue and 2',7'­dichlorofluorescein assays, respectively. A549 human lung epithelial adenocarcinoma cells were exposed to increasing concentrations (0.1­10 µg/cm2) of particles and fibres for 24 h. Subsequently, the gene expression of X­linked inhibitor of apoptosis (XIAP), superoxide dismutase (SOD)1 and SOD2 were analysed by reverse transcription­quantitative polymerase chain reaction. All investigated granular particles induce ROS production in A549 lung carcinoma cells within 24 h. Hematite increased ROS production in a dose­dependent manner. A concentration of >1 µg/cm2 TiO2 na with its disordered surface, demonstrated the greatest ability to generate ROS. Therefore, the crystalline surface structure of the particle may be considered as a determinant of the extent of ROS induction by the particle. Fibrous particle compared with granular particles were associated with a lower ability to generate ROS. Glass fibres did not significantly increase ROS production in A549 cells, but elevated gene expression of SOD2 was observed. The results demonstrated that in general, the ability of particles to generate ROS depends on their number and crystal phase. Therefore, the present study helps to understand the cause of particle toxicity.

CYP1B1 mRNA inducibility due to benzo(a)pyrene is modified by the CYP1B1 L432V gene polymorphism.

Benzo(a)pyrene (BaP), a primary component of tobacco smoke, is activated by cytochrome P450 1B1 (CYP1B1). Smokers homozygous for the C-allele (*1/*1) at the CYP1B1 Leu432Val polymorphism have shown increased CYP1B1 expression, compared to smokers homozygous for the G-allele *3/*3. Since no difference has been shown in CYP1B1 expression between both genotypes in non-smokers, we assumed that the genetic impact is produced in combination with an exogenous induction (e.g. BaP). To confirm this theory and to quantify the effect, we induced human leucocytes with increasing BaP concentrations and determined CYP1B1 mRNA expression with real-time polymerase chain reaction (PCR). We incubated human leucocytes from 27 healthy donors with BaP concentrations ranging from 2.5 to 250 µM. We identified the CYP1B1 genotypes by melting curve analysis and assessed relative CYP1B1 mRNA expression using real-time PCR. Expression was related to ß-2-microglobulin with the 2(-ΔΔCT) method. Inducibility of CYP1B1 mRNA by BaP was higher in leucocytes carrying the CYP1B1*1/*1 genotype than in leucocytes carrying the CYP1B1*3/*3 genotype (P = 0.012). We revealed significant differences, with BaP concentrations of 2.5 µM (P = 0.0094), 5 µM (P = 0.027), 10 µM (P = 0.0006), 25 µM (P = 0.0007) and 50 µM (P = 0.017). Homozygous carriers of the C-allele (*1/*1) at the CYP1B1 Leu432Val polymorphism show a higher response to environmental factors, such as carcinogenic BaP, than homozygous carriers of the G-allele *3/*3.

Interleukin-6 contributes to the paracrine effects of cardiospheres cultured from human, murine and rat hearts.

Cardiosphere-derived cells (CDCs) were cultured from human, murine, and rat hearts. Diluted supernatant (conditioned-medium) of the cultures improved the contractile behavior of isolated rat cardiomyocytes (CMCs). This effect is mediated by the paracrine release of cytokines. The present study tested the hypothesis, that the cardiovascular state of the donor's heart influences this effect on CMCs and tries to identify the responsible factors. CDCs were cultured from human tissue samples of cardiac surgery and from murine and rat hearts. The supernatants of cultured CDCs from hypertensive humans and rats showed a higher improvement of the contractile behavior of CMCs compared to CDCs of normotensive origin. Subsequently, the cytokine profile of the supernatants was analyzed. Among the cytokines elevated in supernatants originating from hypertensive humans or rats was Interleukin-6. CDCs were also generated from Interleukin-6(-/-) -mice and their wildtype littermates. The supernatant of the cultured Interleukin-6(-/-) -CDCs had no effect on the contractile behavior, whereas the supernatant of the Interleukin-6(+/+) -CDCs showed a positive effect. To confirm the hypothesis that Interleukin-6 contributes to the paracrine effects, CMCs were incubated with Interleukin-6. It improved the contractile function in a concentration dependent way. Finally, the effect of the supernatant of cultured CDCs derived from a hypertensive human sample could be abolished by simultaneous incubation with a specific Interleukin-6 antibody. CDCs release cytokines that improve the contractile behavior of CMCs. This effect is more intense in CDCs from hypertensive donors. Interleukin-6 is involved in this phenomenon.

Effects of corticotropin-releasing hormone on proopiomelanocortin derivatives and monocytic HLA-DR expression in patients with septic shock.

Little is known about interactions between immune and neuro-endocrine systems in patients with septic shock. We therefore evaluated whether the corticotropin-releasing hormone (CRH) and/or proopiomelanocortin (POMC) derivatives [ACTH, ß-endorphin (ß-END), ß-lipotropin (ß-LPH), α-melanocyte stimulating hormone (α-MSH) or N-acetyl-ß-END (Nac-ß-END)] have any influences on monocyte deactivation as a major factor of immunosuppression under septic shock conditions. Sixteen patients with septic shock were enrolled in a double-blind, cross-over and placebo controlled clinical study; 0.5µg/(kgbodyweighth) CRH (or placebo) were intravenously administered for 24h. Using flow cytometry we investigated the immunosuppression in patients as far as related to the loss of leukocyte surface antigen-DR expression on circulating monocytes (mHLA-DR). ACTH, ß-END immunoreacive material (IRM), ß-LPH IRM, α-MSH and Nac-ß-END IRM as well as TNF-α and mHLA-DR expression were determined before, during and after treatment with CRH (or placebo). A significant correlation between plasma concentration of α-MSH and mHLA-DR expression and an inverse correlation between mHLA-DR expression and TNF-α plasma level were found. Additionally, a significant increase of mHLA-DR expression was observed 16h after starting the CRH infusion; 8h later, the mHLA-DR expression had decreased again. Our results indicate that the up-regulation of mHLA-DR expression after CRH infusion is not dependent on the release of POMC derivatives. From the correlation between plasma concentration of α-MSH and mHLA-DR expression, we conclude that in patients with septic shock the down-regulation of mHAL-DR expression is accompanied by the loss of monocytic release of α-MSH into the cardiovascular compartment.

Effects of cerivastatin on adrenergic pathways, hypertrophic growth and TGFbeta expression in adult ventricular cardiomyocytes.

The effects of statin treatment in the setting of heart failure have already been shown. Nevertheless, there is little knowledge about its influence on adrenergic pathways in cardiomyocytes. Therefore, this study investigated the impact of cerivastatin on adrenoceptor-mediated signalling pathways in isolated adult ventricular cardiomyocytes. It focused on two endpoints: hypertrophic growth and TGFbeta expression. Cultured cardiomyocytes were used to study rac activation (analysed by its translocation into the membrane fraction), ROS formation (H(2)DCF fluorescence) and hypertrophic growth ((14)C-phenylalanine incorporation). Alpha- and beta-adrenoceptor stimulation showed significant differences regarding rac activation, ROS formation, and p38 MAP kinase activation. Both alpha- and beta-adrenoceptor stimulation induced TGFbeta expression. Upon activation of alpha-adrenergic signalling - although ROS formation was not influenced by cerivastatin - TGFbeta expression decreased. Following beta stimulation, TGFbeta expression as well as rac and p38 MAP kinase activation were reduced after pre-treatment with cerivastatin. Statin treatment did not show any influence on hypertrophic growth. In summary, this study clearly demonstrates the ability of adrenoceptor stimulation to increase TGFbeta expression. One component of the beneficial effects of statin therapy on heart failure might therefore be due to a dominant reduction and inhibition of TGFbeta, which is involved in many pathophysiological processes in cardiomyocytes.

TGF-beta1 improves cardiac performance via up-regulation of laminin receptor 37/67 in adult ventricular cardiomyocytes.

TGF-beta1 plays an important role in cardiac fibrosis, apoptosis, induction of hypertrophy and contractile dysfunction. This study investigates whether TGF-beta1 plays a role in laminin receptor 37/67 (37/67 LR)-dependent regulation of cardiac performance. Therefore, isolated adult cardiomyocytes were stimulated with TGF-beta1, the expression of the 37/67 LR was determined and cell shortening was investigated on cells attached to a non-specific, serum-based attachment substrate or to specific, laminin-coated dishes. The role of the MAP kinases in TGF-beta1-dependent induction of the 37/67 LR was examined by addition of PD98059, SB202190 and SP600125. Finally, the expression of receptor mRNA was investigated in transgenic mice constitutively over-expressing TGF-beta1 and the relationship to distress score and lung wet weight-to-body weight was analysed. TGF-beta1 induced a significant increase of the 37/67 LR mRNA and protein expression. The cytokine induced p38 MAP kinase and JNK, but not ERK. Inhibition of either p38 MAP kinase or JNK attenuated the TGF-beta1-dependent increase in 37/67 LR expression. TGF-beta1 induced a loss of cell shortening in cells attached to a non-specific substrate, but not in cells on a pre-coated laminin matrix. Inhibition of JNK attenuated the protective effect of laminin receptor up-regulation on cardiac performance. Inhibition of p38 MAP kinase attenuated the depressive effect of TGF-beta1 on basal cell shortening. In transgenic mice over-expressing TGF-beta1 a strong induction of laminin receptor expression attenuated the severeness of the mice' symptoms. This study shows a new and protective role of TGF-beta1-dependent up-regulation of the 37/67 LR in cardiomyocytes in cardiac remodelling with increased laminin expression.

New insights into paracrine mechanisms of human cardiac progenitor cells.

AIMS: Cardiac progenitor cells (CPCs) have been shown to promote cardiac regeneration in vivo. Understanding the function of CPCs is essential for further implementation of these cells in the treatment of cardiac diseases. The present study tested the hypothesis that adult CPC exert paracrine effects that lead to an improvement in the functional characteristics of cardiomyocytes. This study also investigated whether aging (we included patients aged between 4 months and 81 years) has any effect on the paracrine mechanisms of CPC. METHODS AND RESULTS: The supernatant of CPC generated both from human and rat hearts-so called 'conditioned cardiosphere medium' improved the contractile behaviour of isolated adult cardiomyocytes in a concentration-dependent manner after incubation for 24 h and increased the SERCA/NCX ratio. The observed positive effects on contractile behaviour were independent of the CPC donors' age. Conditioned cardiosphere media also normalized angiotensin II-induced contractile dysfunction. Cytokines released by CPC into the media were detected by cytokine arrays. CONCLUSION: The observed diversity of cytokines released by CPC needs to be further elucidated in detail. Nevertheless, CPC are a promising therapeutic approach in the field of cardiac disease. The methods described allow investigation of the underlying paracrine mechanisms in a standardized in vitro situation.

Role of protein phosphatases in hypoxic preconditioning.

To find a protein kinase C (PKC)-independent preconditioning mechanism, hypoxic preconditioning (HP; i.e., 10-min anoxia and 10-min reoxygenation) was applied to isolated rat hearts before 60-min global ischemia. HP led to improved recovery of developed pressure and reduced end-diastolic pressure in the left ventricle during reperfusion. Protection was unaffected by the PKC inhibitor bisindolylmaleimide (BIM; 1 micromol/l). It was abolished by the inhibitor of protein phosphatases 1 and 2A cantharidin (20 or 5 micromol/l) and partially enhanced by the inhibitor of protein phosphatase 2A okadaic acid (5 nmol/l). In adult rat cardiomyocytes treated with BIM and exposed to 60-min simulated ischemia (anoxia, extracellular pH 6.4), HP led to attenuation of anoxic Na(+)/Ca(2+) overload and of hypercontracture, which developed on reoxygenation. This protection was prevented by treatment with cantharidin but not with okadaic acid. In conclusion, HP exerts PKC-independent protection on ischemic-reperfused rat hearts and cardiomyocytes. Protein phosphatase 1 seems a mediator of this protective mechanism.