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Chevalier CM, Krampert L, Schreckenbach M, Schubert CF, Reich J, Novak B, Schmidt MV, Rutten BPF, Schmidt U. MMP9 mRNA is a potential diagnostic and treatment monitoring marker for PTSD: Evidence from mice and humans. Eur Neuropsychopharmacol 2021; 51:20-32. [PMID: 34022747 DOI: 10.1016/j.euroneuro.2021.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 10/21/2022]
Abstract
Although matrix metalloproteinase 9 (MMP9) has been found associated with various psychiatric disorders and with threat memories in humans, its role in post-traumatic stress disorder (PTSD) and related animal models is understudied. Thus, we analyzed MMP9 mRNA expression kinetics during two different stress experiments, i.e., the Trier Social Stress Test and the dexamethasone suppression test (DST), in whole blood of two independent cohorts of PTSD patients vs. non-traumatized healthy controls (HC) and, moreover, in a mouse model of PTSD and in dexamethasone-treated mice. Besides MMP9, we quantified mRNA levels of four of its regulators, i.e., interleukin (IL)-1 receptor 1 and 2 (IL1R1, IL1R2), IL-6 receptor and tumor necrosis factor receptor 1 (TNFR1) in 10 patients exposed to the DST before vs. after successful PTSD psychotherapy vs. 13 HC and, except from Il6r, also in different brain regions of the PTSD mouse model. We are the first to show that blood MMP9 mRNA concentrations were elevated after acute dexamethasone in PTSD patients, improved upon partial remission of PTSD and were, furthermore, also elevated, together with its regulator Tnfr1, in the prefrontal cortex of PTSD-like mice. In contrast, blood TNFR1 and IL1R2 were markedly underexpressed in PTSD patients. In conclusion, we found translational evidence supporting that, I, TNFR1 and MMP9 mRNA expression might be involved in PTSD pathobiology, II, might constitute potential diagnostic blood biomarkers for PTSD and, importantly, III, post-dexamethasone blood MMP9 hyperexpression, which speculatively results from post-dexamethasone underexpression of IL1R2, might serve also as potential treatment monitoring biomarker for PTSD.
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Affiliation(s)
- Céleste M Chevalier
- Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Luka Krampert
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Monika Schreckenbach
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany; Verein zur Förderung der Klinischen Verhaltenstherapie (VFKV) - Ausbildungsinstitut München gGmbH, Lindwurmstr. 117, 80337 München, Germany
| | - Christine F Schubert
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany; Verein zur Förderung der Klinischen Verhaltenstherapie (VFKV) - Ausbildungsinstitut München gGmbH, Lindwurmstr. 117, 80337 München, Germany; Catholic University of Eichstätt-Ingolstadt, Ostenstraße 25, 85072 Eichstätt, Germany
| | - Johanna Reich
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany; Schön Klinik München Schwabing, Parzivalpl. 4, 80804 München, Germany
| | - Bozidar Novak
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Mathias V Schmidt
- Research Group Neurobiology of Stress Resilience, Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Bart P F Rutten
- Maastricht University Medical Centre, School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Universiteitssingel 50, 6229 ER, PO Box 616 6200 MD, Maastricht, The Netherlands
| | - Ulrike Schmidt
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany; Maastricht University Medical Centre, School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Universiteitssingel 50, 6229 ER, PO Box 616 6200 MD, Maastricht, The Netherlands; RG Molecular and Clinical Psychotraumatology, Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany; RG Traumatic Stress & Neurodegeneration & PTSD Treatment Unit, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Von-Siebold-Straße 5, 37075 Göttingen, Germany.
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Hofmann J, Huber C, Novak B, Schreckenbach M, Schubert CF, Touma C, Rutten BP, Schmidt U. Oxytocin receptor is a potential biomarker of the hyporesponsive HPA axis subtype of PTSD and might be modulated by HPA axis reactivity traits in humans and mice. Psychoneuroendocrinology 2021; 129:105242. [PMID: 33975150 DOI: 10.1016/j.psyneuen.2021.105242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 01/01/2023]
Abstract
This study aimed to identify yet unavailable blood biomarkers for the responsive and the hyporesponsive hypothalamic-pituitary-adrenal (HPA) axis subtypes of posttraumatic stress disorder (PTSD). As, I, we recently discovered the intranasal neuropeptide oxytocin to reduce experimentally provoked PTSD symptoms, II, expression of its receptor (OXTR) has hitherto not been assessed in PTSD patients, and III, oxytocin and OXTR have previously been related to the HPA axis, we considered both as suitable candidates. During a Trier Social Stress Test (TSST), we compared serum oxytocin and blood OXTR mRNA concentrations between female PTSD patients, their HPA axis reactivity subtypes and sex and age-matched healthy controls (HC). At baseline, both candidates differentiated the hyporesponsive HPA axis subtype from HC, however, only baseline OXTR mRNA discriminated also between subtypes. Furthermore, in the hyporesponsive HPA axis subgroup, OXTR mRNA levels correlated with PTSD symptoms and changed markedly during the TSST. To assess the influence of (traumatic) stress on the cerebral expression of oxytocin and its receptor and to test their suitability as biomarkers for the mouse PTSD-like syndrome, we then analyzed oxytocin, its mRNA (Oxt) and Oxtr mRNA in three relevant brain regions and Oxt in blood of a PTSD mouse model. To further explore the HPA axis reactivity subtype dependency of OXTR, we compared cerebral OXTR protein expression between mice exhibiting two different HPA axis reactivity traits, i.e., FK506 binding protein 51 knockout vs. wildtype mice. In summary, blood OXTR mRNA emerged as a potential biomarker of the hyporesponsive HPA axis PTSD subtype and prefrontal cortical Oxtr and Oxt of the mouse PTSD-like syndrome. Moreover, we found first translational evidence for a HPA axis responsivity trait-dependent regulation of OXTR expression. The lack of a cohort of the (relatively rare) hyporesponsive HPA axis subtype of HC is a limitation of our study.
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Affiliation(s)
- Julia Hofmann
- kbo-Isar-Amper-Klinikum München Ost, Vockestraße 72, 85540 Haar, Germany
| | - Christine Huber
- Technical University of Munich, Department of Gynecology and Obstetrics, Schneckenburgerstrasse 6, 81675 Munich, Germany
| | - Bozidar Novak
- Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Monika Schreckenbach
- Verein zur Förderung der Klinischen Verhaltenstherapie (VFKV)-Ausbildungsinstitut München gGmbH, Lindwurmstr. 117, 80337 München, Germany
| | - Christine F Schubert
- Verein zur Förderung der Klinischen Verhaltenstherapie (VFKV)-Ausbildungsinstitut München gGmbH, Lindwurmstr. 117, 80337 München, Germany; Catholic University of Eichstätt-Ingolstadt, Ostenstraße 25, 85072 Eichstätt, Germany
| | - Chadi Touma
- Department of Behavioural Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Bart Pf Rutten
- Maastricht University Medical Centre, School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Universiteitssingel 50, 6229 ER, PO Box 616 6200 MD, Maastricht, The Netherlands
| | - Ulrike Schmidt
- Maastricht University Medical Centre, School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Universiteitssingel 50, 6229 ER, PO Box 616 6200 MD, Maastricht, The Netherlands; Rheinische Friedrich-Wilhelms University of Bonn, Department of Psychiatry and Psychotherapy, RG Molecular and Clinical Psychotraumatology & Psychotrauma Outpatient Unit, Venusberg-Campus-1, 53127 Bonn, Germany; University Medical Center Göttingen (UMG), Department of Psychiatry and Psychotherapy, RG Stress Modulation of Neurodegeneration & Psychotrauma Outpatient Unit, Von-Siebold-Strasse 5, 37075 Göttingen, Germany.
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Schubert CF, Schmidt U, Comtesse H, Gall-Kleebach D, Rosner R. Posttraumatic growth during cognitive behavioural therapy for posttraumatic stress disorder: Relationship to symptom change and introduction of significant other assessment. Stress Health 2019; 35:617-625. [PMID: 31430027 DOI: 10.1002/smi.2894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/26/2019] [Accepted: 08/16/2019] [Indexed: 11/11/2022]
Abstract
Posttraumatic growth (PTG) may play a role in the treatment of posttraumatic stress disorder (PTSD) as it is supposed to have either beneficial or dysfunctional effects on treatment-related PTS symptom (PTSS) changes. This study examined whether cognitive behavioral therapy (CBT) for PTSD patients can foster PTG assessed by self-reports and reports from significant others. Forty-eight PTSD patients participating in trauma-focused CBT were assessed twice: at the beginning of therapy (T1) and after 3 months of therapy (T2, N = 34). We used the Clinician Administered PTSD Scale and the Posttraumatic Growth Inventory (PTGI), and constructed a significant other version of the PTGI (PTGI-SOA). The PTSS severity declined during the course of treatment, whereas PTG levels remained stable. Both the PTGI and PTGI-SOA were associated with higher PTSS reduction at T2. The results suggest that PTG is associated with greater improvement in PTSS during trauma-focused CBT, even though treatment could not directly enhance PTG. Significant other assessments seem to be a promising approach to improve PTG measurement.
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Affiliation(s)
- Christine F Schubert
- Department of Psychology, Catholic University of Eichstaett-Ingolstadt, Eichstaett, Germany.,RG Molecular Psychotraumatology, Max Planck Institute of Psychiatry, Munich, Germany
| | - Ulrike Schmidt
- Department of Psychiatry and Psychotherapy, Psychotrauma Treatment Unit & RG Stress Modulation of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,RG Molecular Psychotraumatology, Max Planck Institute of Psychiatry, Munich, Germany.,Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University Medical Care, Maastricht, The Netherlands
| | - Hannah Comtesse
- Department of Psychology, Catholic University of Eichstaett-Ingolstadt, Eichstaett, Germany
| | - Dominique Gall-Kleebach
- RG Molecular Psychotraumatology, Max Planck Institute of Psychiatry, Munich, Germany.,Ausbildungsinstitut Muenchen gGmbH, Verein zur Foerderung der Klinischen Verhaltenstherapie (VFKV), Muenchen, Germany
| | - Rita Rosner
- Department of Psychology, Catholic University of Eichstaett-Ingolstadt, Eichstaett, Germany
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Schubert CF, Schreckenbach M, Kirmeier T, Gall-Kleebach DJ, Wollweber B, Buell DR, Uhr M, Rosner R, Schmidt U. PTSD psychotherapy improves blood pressure but leaves HPA axis feedback sensitivity stable and unaffected: First evidence from a pre-post treatment study. Psychoneuroendocrinology 2019; 100:254-263. [PMID: 30391833 DOI: 10.1016/j.psyneuen.2018.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 10/15/2018] [Accepted: 10/15/2018] [Indexed: 01/05/2023]
Abstract
Although key to development of tailored drugs for augmentation treatment of psychotherapy for posttraumatic stress disorder (PTSD), the biological correlates of PTSD remission are still unknown, probably because pre-post treatment studies searching for them are rare. Not even the feedback sensitivity of the otherwise well-studied hypothalamic-pituitary-adrenal (HPA) axis nor arterial blood pressure (BP), which was previously reported to be elevated in PTSD patients, have so far been analyzed during PTSD treatment. To narrow this knowledge gap, we first performed an overnight dexamethasone suppression test (DST) in a mixed-sex cohort of 25 patients with severe PTSD vs. 20 non-traumatized healthy controls (nt-HC). In addition to hormones, BP and heart rate (HR) were measured at each of the four assessment points (APs). Second, the same parameters were assessed again in 16 of these patients after 12 sessions of integrative trauma-focused cognitive behavioral therapy (iTF-CBT). In relation to nt-HC, PTSD patients showed a significant elevation in HR and diastolic BP while their systolic BP, DST outcomes and basal serum cortisol levels (BSCL) were not significantly altered. In response to iTF-CBT, PTSD symptoms and dysfunctional stress coping strategies improved significantly in PTSD patients. Most important, also their systolic and diastolic BP levels ameliorated at distinct APs while their DST outcomes and BSCL remained unchanged. To our knowledge, this is the first pre-post treatment study assessing the stability of the DST outcome and BP levels during PTSD treatment. Our results provide first evidence for a non-involvement of HPA axis feedback sensitivity in PTSD symptom improvement and, furthermore, suggest a possible role for BP-regulating pathways such as the sympathetic nervous system in PTSD remission. Limitations arise from the small sample size, the lack of an untreated patient group and drug treatment of patients.
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Affiliation(s)
- Christine F Schubert
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany; Catholic University of Eichstätt-Ingolstadt, Ostenstraße 25, 85072 Eichstätt, Germany; Ludwig Maximilians University, Department of Psychology, Leopoldstraße 44, 80802 Munich, Germany
| | - Monika Schreckenbach
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany
| | | | - Dominique J Gall-Kleebach
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany; Verein für Klinische Verhaltenstherapie (VFKV) - Ausbildungsinstitut München gGmbH, Lindwurmstr. 117, 80337 München, Germany
| | - Bastian Wollweber
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Dominik R Buell
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Manfred Uhr
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 Munich, Germany
| | - Rita Rosner
- Catholic University of Eichstätt-Ingolstadt, Ostenstraße 25, 85072 Eichstätt, Germany
| | - Ulrike Schmidt
- Max Planck Institute of Psychiatry, Department of Translational Psychiatry, RG Molecular Psychotraumatology, Kraepelinstrasse 10, 80804 Munich, Germany; University Medical Center Göttingen (UMG), Department of Psychiatry and Psychotherapy, Psychotrauma Treatment Unit & RG Stress Modulation of Neurodegeneration, Göttingen, Germany; Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University Medical Centre, Maastricht, the Netherlands.
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Schubert CF, Schmidt U, Rosner R. Posttraumatic Growth in Populations with Posttraumatic Stress Disorder-A Systematic Review on Growth-Related Psychological Constructs and Biological Variables. Clin Psychol Psychother 2015; 23:469-486. [DOI: 10.1002/cpp.1985] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Christine F. Schubert
- RG Molecular Psychotraumatology; Max Planck Institute of Psychiatry; Munich Germany
- Department of Clinical and Biological Psychology; Catholic University of Eichstaett-Ingolstadt; Eichstaett Germany
| | - Ulrike Schmidt
- RG Molecular Psychotraumatology; Max Planck Institute of Psychiatry; Munich Germany
| | - Rita Rosner
- Department of Clinical and Biological Psychology; Catholic University of Eichstaett-Ingolstadt; Eichstaett Germany
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Zaba M, Kirmeier T, Ionescu IA, Wollweber B, Buell DR, Gall-Kleebach DJ, Schubert CF, Novak B, Huber C, Köhler K, Holsboer F, Pütz B, Müller-Myhsok B, Höhne N, Uhr M, Ising M, Herrmann L, Schmidt U. Identification and characterization of HPA-axis reactivity endophenotypes in a cohort of female PTSD patients. Psychoneuroendocrinology 2015; 55:102-15. [PMID: 25745955 DOI: 10.1016/j.psyneuen.2015.02.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 02/08/2015] [Accepted: 02/09/2015] [Indexed: 01/15/2023]
Abstract
Analysis of the function of the hypothalamic-pituitary-adrenal (HPA)-axis in patients suffering from posttraumatic stress disorder (PTSD) has hitherto produced inconsistent findings, inter alia in the Trier Social Stress Test (TSST). To address these inconsistencies, we compared a sample of 23 female PTSD patients with either early life trauma (ELT) or adult trauma (AT) or combined ELT and AT to 18 age-matched non-traumatized female healthy controls in the TSST which was preceded by intensive baseline assessments. During the TSST, we determined a variety of clinical, psychological, endocrine and cardiovascular parameters as well as expression levels of four HPA-axis related genes. Using a previously reported definition of HPA-axis responsive versus non-responsive phenotypes, we identified for the first time two clinically and biologically distinct HPA-axis reactivity subgroups of PTSD. One subgroup ("non-responders") showed a blunted HPA-axis response and distinct clinical and biological characteristics such as a higher prevalence of trauma-related dissociative symptoms and of combined AT and ELT as well as alterations in the expression kinetics of the genes encoding for the mineralocorticoid receptor (MR) and for FK506 binding protein 51 (FKBP51). Interestingly, this non-responder subgroup largely drove the relatively diminished HPA axis response of the total cohort of PTSD patients. These findings are limited by the facts that the majority of patients was medicated, by the lack of traumatized controls and by the relatively small sample size. The here for the first time identified and characterized HPA-axis reactivity endophenotypes offer an explanation for the inconsistent reports on HPA-axis function in PTSD and, moreover, suggest that most likely other factors than HPA-axis reactivity play a decisive role in determination of PTSD core symptom severity.
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Affiliation(s)
- Monika Zaba
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Thomas Kirmeier
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Irina A Ionescu
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Bastian Wollweber
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Dominik R Buell
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Dominique J Gall-Kleebach
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Christine F Schubert
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Bozidar Novak
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Christine Huber
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Katharina Köhler
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Florian Holsboer
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Benno Pütz
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Bertram Müller-Myhsok
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Nina Höhne
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Manfred Uhr
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Marcus Ising
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Leonie Herrmann
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany
| | - Ulrike Schmidt
- Max Planck Institute of Psychiatry, Clinical Department, Kraepelinstrasse 10, 80804 München, Germany.
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Abstract
Cryoimmunoglobulins are associated with numerous clinical problems ranging from collagen vascular disorders (rheumatoid arthritis and systemic lupus erythematosus) to infectious processes including HIV infection. The precise role of cryoglobulins in the pathophysiology of these disorders remains unresolved. Although cold insolubility may account for some of the observed processes, it cannot explain the entire array of findings in cryoglobulinemia. An alternative hypothesis suggests that the subtle differences responsible for cold precipitation of these proteins renders them intrinsically more sticky, resulting in deposition of cryoimmunoglobulins on vascular surfaces. We have explored this hypothesis by characterizing the binding of monoclonal cold soluble and cryoimmunoglobulins to silica beads as a model biological surface. It is found that monoclonal, type I, IgM and IgG cryoglobulins have only a slight tendency to bind to a greater extent to this surface than cold soluble immunoglobulins. Physical studies utilizing front surface fluorescence measurements and differential scanning calorimetry show surface interaction leads to partial thermal destabilization of the proteins. To a limited extent, this destabilization is more pronounced with the cryoglobulins compared to cold-soluble control homologues. Surface bound IgM cryoimmunoglobulin was also found to fix complement less efficiently than their cold soluble surface bound counterparts. These studies do not strongly support the hypothesis that pathological mechanisms of cryoimmunoglobulins primarily involve abnormal surface interactions, although surface effects could play a limited role in some situations.
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Affiliation(s)
- D T Brandau
- University of Iowa Hospital, Department of Radiology, Iowa City 52242
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Lawson EQ, Schubert CF, Lewis RV, Middaugh CR. The solubility of bovine lens crystallins. J Biol Chem 1981; 256:6523-5. [PMID: 7240223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Apparent thermodynamic parameters for the process of solubilization of the five major classes of bovine lens crystallins have been determined by the polyethylene glycol solubility method. Although each purified crystallin fraction displays significant structural heterogeneity as analyzed by high performance liquid chromatography, they behave as homogeneous proteins by the criteria of solubility. Using experimentally determined values for the apparent enthalpy and entropy of solution and the effects of a variety of low molecular weight solutes on crystallin solubility, the five classes can be arranged in order of the polarity of their solid phase intermolecular contacts as follows: gamma, high molecular weight beta greater than low molecular weight beta greater than high molecular weight alpha greater than alpha. Since alpha-crystallin is the major component of the insoluble material in bovine cataract, we suggest that cataract formation may be related to the intrinsic solubility and polarity of the lens crystallins.
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