Microglia Depletion Attenuates the Pro-Resolving Activity of the Formyl Peptide Receptor 2 Agonist AMS21 Related to Inhibition of Inflammasome NLRP3 Signalling Pathway: A Study of Organotypic Hippocampal Cultures

Microglial cells have been demonstrated to be significant resident immune cells that maintain homeostasis under physiological conditions. However, prolonged or excessive microglial activation leads to disturbances in the resolution of inflammation (RoI). Formyl peptide receptor 2 (FPR2) is a crucial player in the RoI, interacting with various ligands to induce distinct conformational changes and, consequently, diverse biological effects. Due to the poor pharmacokinetic properties of endogenous FPR2 ligands, the aim of our study was to evaluate the pro-resolving effects of a new ureidopropanamide agonist, compound AMS21, in hippocampal organotypic cultures (OHCs) stimulated with lipopolysaccharide (LPS). Moreover, to assess whether AMS21 exerts its action via FPR2 specifically located on microglial cells, we conducted a set of experiments in OHCs depleted of microglial cells using clodronate. We demonstrated that the protective and anti-inflammatory activity of AMS21 manifested as decreased levels of lactate dehydrogenase (LDH), nitric oxide (NO), and proinflammatory cytokines IL-1β and IL-6 release evoked by LPS in OHCs. Moreover, in LPS-stimulated OHCs, AMS21 treatment downregulated NLRP3 inflammasome-related factors (CASP1, NLRP3, PYCARD) and this effect was mediated through FPR2 because it was blocked by the FPR2 antagonist WRW4 pre-treatment. Importantly this beneficial effect of AMS21 was only observed in the presence of microglial FPR2, and absent in OHCs depleted with microglial cells using clodronate. Our results strongly suggest that the compound AMS21 exerts, at nanomolar doses, protective and anti-inflammatory properties and an FPR2 receptor located specifically on microglial cells mediates the anti-inflammatory response of AMS21. Therefore, microglial FPR2 represents a promising target for the enhancement of RoI.

Stimulation of Formyl Peptide Receptor-2 by the New Agonist CMC23 Protects against Endotoxin-Induced Neuroinflammatory Response: A Study in Organotypic Hippocampal Cultures

A substantial body of evidence demonstrates an association between a malfunction in the resolution of acute inflammation and the development of chronic inflammation. Recently, in this context, the importance of formyl peptide receptor 2 (FPR2) has been underlined. FPR2 activity is modulated by a wide range of endogenous ligands, including specialized pro-resolving mediators (SPMs) (e.g., LXA4 and AT-LXA4) and synthetic ligands. Since SPMs have unfavorable pharmacokinetic properties, we aimed to evaluate the protective and pro-resolving effects of a new potent FPR2 agonist, compound CMC23, in organotypic hippocampal cultures (OHCs) stimulated with lipopolysaccharide (LPS). The protective activity of CMC23 limited the lactate dehydrogenase release in LPS-stimulated cultures. This activity was mediated by the interaction with FPR2 as pretreatment with the FPR2 selective antagonist WRW4 abolished CMC23-induced protection. Furthermore, decreased levels of pro-inflammatory IL-1β and IL-6 were observed after CMC23 administration in LPS-treated OHCs. CMC23 also diminished the LPS-induced increase in IL-17A and both IL-23 subunits p19 and p40 in OHCs. Finally, we demonstrated that CMC23 exerts its beneficial impact via the STAT3/SOCS3 signaling pathway since it attenuated the level of phospho-STAT3 and maintained the LPS-induced SOCS3 levels in OHCs. Collectively, our research implies that the new FPR2 agonist CMC23 has beneficial protective and anti-inflammatory properties in nanomolar doses and FPR2 represents a promising target for the enhancement of inflammation resolution.

Prenatal stress aggravates age-dependent cognitive decline, insulin signaling dysfunction, and the pro-inflammatory response in the APPNL-F/NL-F mouse model of Alzheimer's disease

Accumulating evidence indicates that early adverse life experiences may be involved in the pathogenesis of Alzheimer's disease (AD). Prenatal stress (PS) can affect brain maturation and neuroimmune and metabolic interactions, leading to age-dependent cognitive deficits in offspring. However, a multi-faceted cause-and-effect impact of PS on the development of cognitive deficits in the process of physiological ageing and in the APP^NL-F/NL-F mouse model of Alzheimer's disease has not yet been evaluated. We have identified age-dependent cognitive learning and memory deficits using male C57BL/6 J (wild type, WT) and the knock-in APP^NL-F/NL-F (KI) aged 12, 15, and 18 months. An increase in the Aβ42/Aβ40 ratio and mouse ApoE levels in the hippocampus and frontal cortex preceded the onset of cognitive deficits in the KI mice. Moreover, dysfunction in insulin signaling, including increased IRS-1 serine phosphorylation in both brain areas and the tyrosine phosphorylation deficit in the frontal cortex, suggested age-dependent insulin/IGF-1 resistance. Resistance was reflected by disturbances in mTOR or ERK1/2 kinase phosphorylation and excessive pro-inflammatory (TNF-α, IL-6, and IL-23) status in the KI mice. Importantly, our study has provided insights into the higher vulnerability to PS-induced exacerbation of age-dependent cognitive deficits and biochemical dysfunction in KI mice than in WT animals. We anticipate our study will lead to future investigation of a multi-faceted cause-and-effect relationship between stress during neurodevelopment and the onset of AD pathology, distinguishing it from changes in the course of dementia during normal ageing.

Oxygen-Glucose Deprivation in Organotypic Hippocampal Cultures Leads to Cytoskeleton Rearrangement and Immune Activation: Link to the Potential Pathomechanism of Ischaemic Stroke

Ischaemic stroke is characterized by a sudden loss of blood circulation to an area of the brain, resulting in a corresponding loss of neurologic function. As a result of this process, neurons in the ischaemic core are deprived of oxygen and trophic substances and are consequently destroyed. Tissue damage in brain ischaemia results from a complex pathophysiological cascade comprising various distinct pathological events. Ischaemia leads to brain damage by stimulating many processes, such as excitotoxicity, oxidative stress, inflammation, acidotoxicity, and apoptosis. Nevertheless, less attention has been given to biophysical factors, including the organization of the cytoskeleton and the mechanical properties of cells. Therefore, in the present study, we sought to evaluate whether the oxygen-glucose deprivation (OGD) procedure, which is a commonly accepted experimental model of ischaemia, could affect cytoskeleton organization and the paracrine immune response. The abovementioned aspects were examined ex vivo in organotypic hippocampal cultures (OHCs) subjected to the OGD procedure. We measured cell death/viability, nitric oxide (NO) release, and hypoxia-inducible factor 1α (HIF-1α) levels. Next, the impact of the OGD procedure on cytoskeletal organization was evaluated using combined confocal fluorescence microscopy (CFM) and atomic force microscopy (AFM). Concurrently, to find whether there is a correlation between biophysical properties and the immune response, we examined the impact of OGD on the levels of crucial ischaemia cytokines (IL-1β, IL-6, IL-18, TNF-α, IL-10, IL-4) and chemokines (CCL3, CCL5, CXCL10) in OHCs and calculated Pearsons' and Spearman's rank correlation coefficients. The results of the current study demonstrated that the OGD procedure intensified cell death and nitric oxide release and led to the potentiation of HIF-1α release in OHCs. Moreover, we presented significant disturbances in the organization of the cytoskeleton (actin fibers, microtubular network) and cytoskeleton-associated protein 2 (MAP-2), which is a neuronal marker. Simultaneously, our study provided new evidence that the OGD procedure leads to the stiffening of OHCs and a malfunction in immune homeostasis. A negative linear correlation between tissue stiffness and branched IBA1 positive cells after the OGD procedure suggests the pro-inflammatory polarization of microglia. Moreover, the negative correlation of pro- and positive anti-inflammatory factors with actin fibers density indicates an opposing effect of the immune mediators on the rearrangement of cytoskeleton induced by OGD procedure in OHCs. Our study constitutes a basis for further research and provides a rationale for integrating biomechanical and biochemical methods in studying the pathomechanism of stroke-related brain damage. Furthermore, presented data pointed out the interesting direction of proof-of-concept studies, in which follow-up may establish new targets for brain ischemia therapy.

Insights into the Potential Impact of Quetiapine on the Microglial Trajectory and Inflammatory Response in Organotypic Cortical Cultures Derived from Rat Offspring

Atypical antipsychotics currently constitute the first-line medication for schizophrenia, with quetiapine being one of the most commonly prescribed representatives of the group. Along with its specific affinity for multiple receptors, this compound exerts other biological characteristics, among which anti-inflammatory effects are strongly suggested. Simultaneously, published data indicated that inflammation and microglial activation could be diminished by stimulation of the CD200 receptor (CD200R), which takes place by binding to its ligand (CD200) or soluble CD200 fusion protein (CD200Fc). Therefore, in the present study, we sought to evaluate whether quetiapine could affect certain aspects of microglial activity, including the CD200-CD200R and CX3CL1-CX3CR1 axes, which are involved in the regulation of neuron-microglia interactions, as well as the expression of selected markers of the pro- and anti-inflammatory profile of microglia (Cd40, Il-1β, Il-6, Cebpb, Cd206, Arg1, Il-10 and Tgf-β). Concurrently, we examined the impact of quetiapine and CD200Fc on the IL-6 and IL-10 protein levels. The abovementioned aspects were investigated in organotypic cortical cultures (OCCs) prepared from the offspring of control rats (control OCCs) or those subjected to maternal immune activation (MIA OCCs), which is a widely implemented approach to explore schizophrenia-like disturbances in animals. The experiments were performed under basal conditions and after additional exposure to the bacterial endotoxin lipopolysaccharide (LPS), according to the "two-hit" hypothesis of schizophrenia. The results of our research revealed differences between control and MIA OCCs under basal conditions and in response to treatment with LPS in terms of lactate dehydrogenase and nitric oxide release as well as Cd200r, Il-1β, Il-6 and Cd206 expression. The additional stimulation with the bacterial endotoxin resulted in a notable change in the mRNA levels of pro- and anti-inflammatory microglial markers in both types of OCCs. Quetiapine diminished the influence of LPS on Il-1β, Il-6, Cebpb and Arg1 expression in control OCCs as well as on IL-6 and IL-10 levels in MIA OCCs. Moreover, CD200Fc reduced the impact of the bacterial endotoxin on IL-6 production in MIA OCCs. Thus, our results demonstrated that quetiapine, as well as the stimulation of CD200R by CD200Fc, beneficially affected LPS-induced neuroimmunological changes, including microglia-related activation.

Design, Synthesis, Biological Evaluation, and Computational Studies of Novel Ureidopropanamides as Formyl Peptide Receptor 2 (FPR2) Agonists to Target the Resolution of Inflammation in Central Nervous System Disorders

Formyl peptide receptor 2 (FPR2) agonists can boost the resolution of inflammation and can offer alternative approaches for the treatment of pathologies with underlying chronic neuroinflammation, including neurodegenerative disorders. Starting from the FPR2 agonist 2 previously identified in our laboratory and through fine-tuning of FPR2 potency and metabolic stability, we have identified a new series of ureidopropanamide derivatives endowed with a balanced combination of such properties. Computational studies provided insights into the key interactions of the new compounds for FPR2 activation. In mouse microglial N9 cells and in rat primary microglial cells stimulated with lipopolysaccharide, selected compounds inhibited the production of pro-inflammatory cytokines, counterbalanced the changes in mitochondrial function, and inhibited caspase-3 activity. Among the new agonists, (S)-11l stands out also for the ability to permeate the blood-brain barrier and to accumulate in the mouse brain in vivo, thus representing a valuable pharmacological tool for studies in vivo.

Time-Dependent Protective and Pro-Resolving Effects of FPR2 Agonists on Lipopolysaccharide-Exposed Microglia Cells Involve Inhibition of NF-κB and MAPKs Pathways

Prolonged or excessive microglial activation may lead to disturbances in the resolution of inflammation (RoI). The importance of specialized pro-resolving lipid mediators (SPMs) in RoI has been highlighted. Among them, lipoxins (LXA4) and aspirin-triggered lipoxin A4 (AT-LXA4) mediate beneficial responses through the activation of N-formyl peptide receptor-2 (FPR2). We aimed to shed more light on the time-dependent protective and anti-inflammatory impact of the endogenous SPMs, LXA4, and AT-LXA4, and of a new synthetic FPR2 agonist MR-39, in lipopolysaccharide (LPS)-exposed rat microglial cells. Our results showed that LXA4, AT-LXA4, and MR-39 exhibit a protective and pro-resolving potential in LPS-stimulated microglia, even if marked differences were apparent regarding the time dependency and efficacy of inhibiting particular biomarkers. The LXA4 action was found mainly after 3 h of LPS stimulation, and the AT-LXA4 effect was varied in time, while MR-39′s effect was mainly observed after 24 h of stimulation by endotoxin. MR-39 was the only FPR2 ligand that attenuated LPS-evoked changes in the mitochondrial membrane potential and diminished the ROS and NO release. Moreover, the LPS-induced alterations in the microglial phenotype were modulated by LXA4, AT-LXA4, and MR-39. The anti-inflammatory effect of MR-39 on the IL-1β release was mediated through FPR2. All tested ligands inhibited TNF-α production, while AT-LXA4 and MR-39 also diminished IL-6 levels in LPS-stimulated microglia. The favorable action of LXA4 and MR-39 was mediated through the inhibition of ERK1/2 phosphorylation. AT-LXA4 and MR39 diminished the phosphorylation of the transcription factor NF-κB, while AT-LXA4 also affected p38 kinase phosphorylation. Our results suggest that new pro-resolving synthetic mediators can represent an attractive treatment option for the enhancement of RoI, and that FPR2 can provide a perspective as a target in immune-related brain disorders.

The N-Formyl Peptide Receptor 2 (FPR2) Agonist MR-39 Improves Ex Vivo and In Vivo Amyloid Beta (1-42)-Induced Neuroinflammation in Mouse Models of Alzheimer's Disease

The major histopathological hallmarks of Alzheimer's disease (AD) include β-amyloid (Aβ) plaques, neurofibrillary tangles, and neuronal loss. Aβ 1-42 (Aβ_1-42) has been shown to induce neurotoxicity and secretion of proinflammatory mediators that potentiate neurotoxicity. Proinflammatory and neurotoxic activities of Aβ_1-42 were shown to be mediated by interactions with several cell surface receptors, including the chemotactic G protein-coupled N-formyl peptide receptor 2 (FPR2). The present study investigated the impact of a new FPR2 agonist, MR-39, on the neuroinflammatory response in ex vivo and in vivo models of AD. To address this question, organotypic hippocampal cultures from wild-type (WT) and FPR2-deficient mice (knockout, KO, FPR2^-/-) were treated with fibrillary Aβ_1-42, and the effect of the new FPR2 agonist MR-39 on the release of pro- and anti-inflammatory cytokines was assessed. Similarly, APP/PS1 double-transgenic AD mice were treated for 20 weeks with MR-39, and immunohistological staining was performed to assess neuronal loss, gliosis, and Aβ load in the hippocampus and cortex. The data indicated that MR-39 was able to reduce the Aβ_1-42-induced release of proinflammatory cytokines and to improve the release of anti-inflammatory cytokines in mouse hippocampal organotypic cultures. The observed effect was apparently related to the inhibition of the MyD88/TRAF6/NFкB signaling pathway and a decrease in NLRP3 inflammasome activation. Administration of MR-39 to APP/PS1 mice improved neuronal survival and decreased microglial cell density and plaque load.These results suggest that FPR2 may be a promising target for alleviating the inflammatory process associated with AD and that MR-39 may be a useful therapeutic agent for AD.

Role of Polyinosinic:Polycytidylic Acid-Induced Maternal Immune Activation and Subsequent Immune Challenge in the Behaviour and Microglial Cell Trajectory in Adult Offspring: A Study of the Neurodevelopmental Model of Schizophrenia

Multiple lines of evidence support the pathogenic role of maternal immune activation (MIA) in the occurrence of the schizophrenia-like disturbances in offspring. While in the brain the homeostatic role of neuron-microglia protein systems is well documented, the participation of the CX3CL1-CX3CR1 and CD200-CD200R dyads in the adverse impact of MIA often goes under-recognized. Therefore, in the present study, we examined the effect of MIA induced by polyinosinic:polycytidylic acid (Poly I:C) on the CX3CL1-CX3CR1 and CD200-CD200R axes, microglial trajectory (MhcII, Cd40, iNos, Il-1β, Tnf-α, Il-6, Arg1, Igf-1, Tgf-β and Il-4), and schizophrenia-like behaviour in adult male offspring of Sprague-Dawley rats. Additionally, according to the “two-hit” hypothesis of schizophrenia, we evaluated the influence of acute challenge with Poly I:C in adult prenatally MIA-exposed animals on the above parameters. In the present study, MIA evoked by Poly I:C injection in the late period of gestation led to the appearance of schizophrenia-like disturbances in adult offspring. Our results revealed the deficits manifested as a diminished number of aggressive interactions, presence of depressive-like episodes, and increase of exploratory activity, as well as a dichotomy in the sensorimotor gating in the prepulse inhibition (PPI) test expressed as two behavioural phenotypes (MIA_PPI-low and MIA_PPI-high). Furthermore, in the offspring rats subjected to a prenatal challenge (i.e., MIA) we noticed the lack of modulation of behavioural changes after the additional acute immune stimulus (Poly I:C) in adulthood. The important finding reported in this article is that MIA affects the expression and levels of the neuron-microglia proteins in the frontal cortex and hippocampus of adult offspring. We found that the changes in the CX3CL1-CX3CR1 axis could affect microglial trajectory, including decreased hippocampal mRNA level of MhcII and elevated cortical expression of Igf-1 in the MIA_PPI-high animals and/or could cause the up-regulation of an inflammatory response (Il-6, Tnf-α, iNos) after the “second hit” in both examined brain regions and, at least in part, might differentiate behavioural disturbances in adult offspring. Consequently, the future effort to identify the biological background of these interactions in the Poly I:C-induced MIA model in Sprague-Dawley rats is desirable to unequivocally clarify this issue.

The Emerging Role of the Double-Edged Impact of Arachidonic Acid- Derived Eicosanoids in the Neuroinflammatory Background of Depression

Eicosanoids are arachidonic acid (AA) derivatives belonging to a family of lipid signalling mediators that are engaged in both physiological and pathological processes in the brain. Recently, their implication in the prolonged inflammatory response has become a focus of particular interest because, in contrast to acute inflammation, chronic inflammatory processes within the central nervous system (CNS) are crucial for the development of brain pathologies including depression. The synthesis of eicosanoids is catalysed primarily by cyclooxygenases (COX), which are involved in the production of pro-inflammatory AA metabolites, including prostaglandins and thromboxanes. Moreover, eicosanoid synthesis is catalysed by lipoxygenases (LOXs), which generate both leukotrienes and anti-inflammatory derivatives such as lipoxins. Thus, AA metabolites have double- edged pro-inflammatory and anti-inflammatory, pro-resolving properties, and an imbalance between these metabolites has been proposed as a contributor or even the basis for chronic neuroinflammatory effects. This review focuses on important evidence regarding eicosanoid-related pathways (with special emphasis on prostaglandins and lipoxins) that has added a new layer of complexity to the idea of targeting the double-edged AA-derivative pathways for therapeutic benefits in depression. We also sought to explore future research directions that can support a pro-resolving response to control the balance between eicosanoids and thus to reduce the chronic neuroinflammation that underlies at least a portion of depressive disorders.

The Contribution of Formyl Peptide Receptor Dysfunction to the Course of Neuroinflammation: A Potential Role in the Brain Pathology

Chronic inflammatory processes within the central nervous system (CNS) are in part responsible for the development of neurodegenerative and psychiatric diseases. These processes are associated with, among other things, the increased and disturbed activation of microglia and the elevated production of proinflammatory factors. Recent studies indicated that the disruption of the process of resolution of inflammation (RoI) may be the cause of CNS disorders. It is shown that the RoI is regulated by endogenous molecules called specialized pro-resolving mediators (SPMs), which interact with specific membrane receptors. Some SPMs activate formyl peptide receptors (FPRs), which belong to the family of seven-transmembrane G protein-coupled receptors. These receptors take part not only in the proinflammatory response but also in the resolution of the inflammation process. Therefore, the activation of FPRs might have complex consequences.

This review discusses the potential role of FPRs, and in particular the role of FPR2 subtype, in the brain under physiological and pathological conditions and their involvement in processes underlying neurodegenerative and psychiatric disorders as well as ischemia, the pathogenesis of which involves the dysfunction of inflammatory processes.

The prenatal challenge with lipopolysaccharide and polyinosinic:polycytidylic acid disrupts CX3CL1-CX3CR1 and CD200-CD200R signalling in the brains of male rat offspring: a link to schizophrenia-like behaviours

BACKGROUND

The bidirectional communication between neurons and microglia is fundamental for the homeostasis and biological function of the central nervous system. Maternal immune activation (MIA) is considered to be one of the factors affecting these interactions. Accordingly, MIA has been suggested to be involved in several neuropsychiatric diseases, including schizophrenia. The crucial regulatory systems for neuron-microglia crosstalk are the CX3CL1-CX3CR1 and CD200-CD200R axes.

METHODS

We aimed to clarify the impact of MIA on CX3CL1-CX3CR1 and CD200-CD200R signalling pathways in the brains of male Wistar rats in early and adult life by employing two neurodevelopmental models of schizophrenia based on the prenatal challenge with lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (Poly I:C). We also examined the effect of MIA on the expression of microglial markers and the profile of cytokines released in the brains of young offspring, as well as the behaviour of adult animals. Moreover, we visualized the localization of ligand-receptor systems in the hippocampal regions (CA1, CA3 and DG) and the frontal cortex of young rats exposed to MIA. The differences between groups were analysed using Student's t test.

RESULTS

We observed that MIA altered developmental trajectories in neuron-microglia communication in the brains of young offspring, as evidenced by the disruption of CX3CL1-CX3CR1 and/or CD200-CD200R axes. Our data demonstrated the presence of abnormalities after LPS-induced MIA in levels of Cd40, Il-1β, Tnf-α, Arg1, Tgf-β and Il-10, as well as IBA1, IL-1β and IL-4, while after Poly I:C-generated MIA in levels of Cd40, iNos, Il-6, Tgf-β, Il-10, and IBA1, IL-1β, TNF-α, IL-6, TGF-β and IL-4 early in the life of male animals. In adult male rats that experienced prenatal exposure to MIA, we observed behavioural changes resembling a schizophrenia-like phenotype.

CONCLUSIONS

Our study provides evidence that altered CX3CL1-CX3CR1 and/or CD200-CD200R pathways, emerging after prenatal immune challenge with LPS and Poly I:C, might be involved in the aetiology of schizophrenia.

The Potential Role of Dysfunctions in Neuron-Microglia Communication in the Pathogenesis of Brain Disorders

The bidirectional communication between neurons and microglia is fundamental for the proper functioning of the central nervous system (CNS). Chemokines and clusters of differentiation (CD) along with their receptors represent ligand-receptor signalling that is uniquely important for neuron - microglia communication. Among these molecules, CX3CL1 (fractalkine) and CD200 (OX-2 membrane glycoprotein) come to the fore because of their cell-type-specific localization. They are principally expressed by neurons when their receptors, CX3CR1 and CD200R, respectively, are predominantly present on the microglia, resulting in the specific axis which maintains the CNS homeostasis. Disruptions to this balance are suggested as contributors or even the basis for many neurological diseases. In this review, we discuss the roles of CX3CL1, CD200 and their receptors in both physiological and pathological processes within the CNS. We want to underline the critical involvement of these molecules in controlling neuron - microglia communication, noting that dysfunctions in their interactions constitute a key factor in severe neurological diseases, such as schizophrenia, depression and neurodegeneration-based conditions.

Inflammatory Consequences of Maternal Diabetes on the Offspring Brain: a Hippocampal Organotypic Culture Study

Gestational diabetes is a disorder associated with abnormal chronic inflammation that poses a risk to the developing fetus. We investigated the effects of experimentally induced diabetes (streptozotocin model) in Wistar female rats on the inflammatory status of the hippocampi of their offspring. Additionally, the impact of antidiabetic drugs (metformin and glyburide) on inflammatory processes was evaluated. Organotypic hippocampal cultures (OHCs) were prepared from the brains of the 7-day-old rat offspring of control and diabetic mother rats. On the 7th day in vitro, the cultures were pretreated with metformin (3 μM) or glyburide (1 μM) and then stimulated for 24 h with lipopolysaccharide (LPS, 1 μg/ml). The OHCs obtained from the offspring of diabetic mothers were characterized by the increased mortality of cells and an enhanced susceptibility to damage caused by LPS. Although we showed that LPS stimulated the secretion of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in the control and diabetic cultures, the levels of IL-1β and IL-6 in the OHC medium obtained from the offspring of diabetic mothers were more pronounced. In the diabetic cultures, enhanced levels of TLR-4 and the overactivation of the NLRP3 inflammasome were demonstrated. Metformin and glyburide pretreatment normalized the LPS-induced IL-1β secretion in the control and diabetic cultures. Furthermore, glyburide diminished both: LPS-induced IL-6 and TNF-α secretion in the control and diabetic cultures and increased NF-κB p65 subunit phosphorylation. Glyburide also diminished the levels of the NLRP3 subunit and caspase-1, but only in the diabetic cultures. The results showed that maternal diabetes affected inflammatory processes in the offspring brain and increased hippocampal sensitivity to the LPS-induced inflammatory response. The use of antidiabetic agents, especially glyburide, had a beneficial impact on the changes caused by maternal diabetes.

Role of Chronic Administration of Antidepressant Drugs in the Prenatal Stress-Evoked Inflammatory Response in the Brain of Adult Offspring Rats: Involvement of the NLRP3 Inflammasome-Related Pathway

Evidence indicates that adverse experiences in early life may be a factor for immune disturbances leading to the depression in adulthood. Recently, a pivotal role in the pathogenesis of depression has been assigned to the activation of the brain Nod-like receptor pyrin-containing 3 (NLRP3) inflammasome. We investigated the impact of chronic treatment with antidepressant drugs on the behavioral disturbances and the levels of proinflammatory factors in the hippocampus and frontal cortex of adult male rats after prenatal stress exposure. Next, we explored the involvement of the NLRP3 inflammasome-related pathways in the mechanism of antidepressant action. Our study confirmed that chronic antidepressant treatment attenuated depression-like disturbances and exerted an anxiolytic action. All antidepressants diminished the prenatal stress-induced increase in IL-1β in both brain areas, while IL-18 only in the hippocampus. Moreover, tianeptine administration diminished the increase in CCR2 levels in both brain areas, while in the hippocampus, tianeptine, along with venlafaxine CCL2 and iNOS levels. Next, we observed that in the hippocampus, tianeptine and fluoxetine suppressed upregulation of TLR4. Furthermore, venlafaxine suppressed NFкB p65-subunit phosphorylation, while fluoxetine enhanced the IкB level. Importantly, in the hippocampus, all antidepressants normalized evoked by stress changes in caspase-1 level, while tianeptine and venlafaxine also affect the levels of ASC and NLRP3 subunits. Our results provide new evidence that chronic administration of antidepressants exerts anti-inflammatory effects more pronounced in the hippocampus, through suppression of the NLRP3 inflammasome activation. These effects are accompanied by an improvement in the behavioral dysfunctions evoked by prenatal stress.

Interaction of the immune-inflammatory and the kynurenine pathways in rats resistant to antidepressant treatment in model of depression

The kynurenine pathway (KP), a major route of tryptophan catabolism, may be associated with the pathophysiology of depressive disorders. KP is responsible for ca. 99% of brain tryptophan metabolism via its degradation to kynurenine (KYN) catalyzed by indoleamine 2,3-dioxygenase (IDO). Some cytokines, such as interferon-γ (IFN-γ) and interleukin (IL)-6 are potent inducers of IDO. KYN is further converted by kynurenine aminotransferase (KAT) to the more neuroprotective kynurenic acid or by kynurenine 3-monooxygenase (KMO) to neurotoxic 3-hydroxykynurenine. The aim of the present study was to delineate whether the administration of imipramine (IMI) to rats subjected to chronic mild stress (CMS) may reverse behavioral changes induced by CMS in association with changes in immune-inflammatory markers and KP. We confirmed that the CMS procedure modeled one of the main symptoms of depression, i.e. anhedonia, and administration of IMI for 5 weeks resulted in a significant reduction in anhedonia in a majority of animals (CMS IMI-R animals), whereas 20% of animals did not respond to IMI treatment (CMS IMI-NR animals). We established that CMS procedure increased IFN-γ and IDO mRNA and decreased KAT II mRNA expression in the rat cortex. In the cortex and hippocampus, IMI treatment and non-responsiveness to IMI (in CMS IMI-NR animals) were associated with increased IL-6 mRNA expression. In the spleen, CMS increased production of IFN-γ and IL-6 proteins, while these cytokines were decreased by IMI in CMS IMI-R animals. Chronic IMI administration to CMS rats decreased IDO and KMO mRNA and protein expression and increased KAT II/KMO mRNA and protein ratio in IMI responders (CMS IMI-R) in comparison to CMS rats. In CMS IMI-NR rats, a significant increase in IDO mRNA expression and protein level in comparison with IMI responders was observed. Our findings indicate that resistance to therapeutic action of IMI could be explained by a deficiency of the inhibitory properties of IMI on IDO, KMO and KYN synthesis in the cortex. We conclude that the antidepressant activity of IMI may, at least in part, be explained by modulatory activities on the KAT II/KMO ratio in brain areas.

Protective effects of polydatin in free and nanocapsulated form on changes caused by lipopolysaccharide in hippocampal organotypic cultures

BACKGROUND

Polydatin (PD) is a compound, originally isolated from the root and rhizome of the Chinese herb Polygonum cuspidatum. To date, various biological properties of this compound, such as analgesic, anti-pyretic or diuretic effects, have been shown. Recently, anti-oxidant and anti-inflammatory properties have been widely postulated, yet PD instability and low bioavailability limit its beneficial actions. Therefore, it has been suggested that an encapsulation process may be a promising strategy for overcoming these limitations and increasing the therapeutic efficacy of PD.

METHODS

We examined the effects of PD in two forms, including free and in PD-loaded polymeric nanocapsules, on lipopolysaccharide (LPS)-induced changes in hippocampal organotypic cultures.

RESULTS

Our results indicated that free and encapsulated PD diminished cell death processes and attenuated the secretion of pro-inflammatory cytokines induced by LPS administration. Additionally, PD in both forms strongly inhibited the production of nitric oxide and down-regulated the level of iNOS enzyme in LPS-stimulated hippocampal cultures.

CONCLUSION

Taken together, our study showed that PD exerts anti-inflammatory and anti-oxidant properties in LPS-treated hippocampal organotypic cultures. Furthermore, we show that the encapsulation procedure preserved the features of the free form of this compound, and therefore, the polymeric nanocapsules containing PD may be used as a novel and promising delivery system in therapeutic strategies.

The effects of pessimism on cell-mediated immunity in rats

We used a recently developed ambiguous-cue interpretation (ACI) paradigm to investigate whether 'optimism' and 'pessimism' as behavioural traits may be interrelated with immune functions in rodents. To this aim, in a series of ACI tests (cognitive bias screening, CBS), we identified rats that displayed 'pessimistic' and 'optimistic' traits. We found significant differences in immune biomarkers between 'optimistic' and 'pessimistic' animals. Moreover 'pessimism' was associated with significantly lower relative weight of the spleen and thymus, significantly decreased proliferative activity of splenocytes. Pessimism was associated with an increased production of interleukin-(IL)1β and IL-4, activin A, l-selectin, interferon (IFN)-γ and some chemokines and receptors for advanced glycation endproducts. The findings indicate an inflammatory profile in "pessimistic" animals.

The Modulatory Properties of Chronic Antidepressant Drugs Treatment on the Brain Chemokine - Chemokine Receptor Network: A Molecular Study in an Animal Model of Depression

An increasing number of studies indicate that the chemokine system may be the third major communication system of the brain. Therefore, the role of the chemokine system in the development of brain disorders, including depression, has been recently proposed. However, little is known about the impact of the administration of various antidepressant drugs on the brain chemokine - chemokine receptor axis. In the present study, we used an animal model of depression based on the prenatal stress procedure. We determined whether chronic treatment with tianeptine, venlafaxine, or fluoxetine influenced the evoked by prenatal stress procedure changes in the mRNA and protein levels of the homeostatic chemokines, CXCL12 (SDF-1α), CX3CL1 (fractalkine) and their receptors, in the hippocampus and frontal cortex. Moreover, the impact of mentioned antidepressants on the TGF-β, a molecular pathway related to fractalkine receptor (CX3CR1), was explored. We found that prenatal stress caused anxiety and depressive-like disturbances in adult offspring rats, which were normalized by chronic antidepressant treatment. Furthermore, we showed the stress-evoked CXCL12 upregulation while CXCR4 downregulation in hippocampus and frontal cortex. CXCR7 expression was enhanced in frontal cortex but not hippocampus. Furthermore, the levels of CX3CL1 and CX3CR1 were diminished by prenatal stress in the both examined brain areas. The mentioned changes were normalized with various potency by chronic administration of tested antidepressants. All drugs in hippocampus, while tianeptine and venlafaxine in frontal cortex normalized the CXCL12 level in prenatally stressed offspring. Moreover, in hippocampus only fluoxetine enhanced CXCR4 level, while fluoxetine and tianeptine diminished CXCR7 level in frontal cortex. Additionally, the diminished by prenatal stress levels of CX3CL1 and CX3CR1 in the both examined brain areas were normalized by chronic tianeptine and partially fluoxetine administration. Tianeptine modulate also brain TGF-β signaling in the prenatal stress-induced animal model of depression. Our results provide new evidence that not only prenatal stress-induced behavioral disturbances but also changes of CXCL12 and their receptor and at less extend in CX3CL1-CX3CR1 expression may be normalized by chronic antidepressant drug treatment. In particular, the effect on the CXCL12 and their CXCR4 and CXCR7 receptors requires additional studies to elucidate the possible biological consequences.

Evaluation of the effectiveness of chronic antidepressant drug treatments in the hippocampal mitochondria - A proteomic study in an animal model of depression

Several lines of evidence indicate that adverse experience in early life may be a triggering factor for disturbances in the brain mitochondrial proteins and lead to the development of depression in adulthood. On the other hand, little is known about the impact of chronic administration of various antidepressant drugs on the brain mitochondria, as a target for the pharmacotherapy of depression. The purpose of our study was to compare the impact of chronic treatment with two antidepressant drugs with different mechanisms of action, a tricyclic antidepressant (TCA), imipramine, and an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class, fluoxetine, on the mitochondria-enriched subproteome profile in the hippocampus of 3-month-old male rats following a prenatal stress procedure (an animal model of depression). We clearly confirmed that chronic imipramine and fluoxetine administration not only normalized depression-like disturbances evoked by the prenatal stress procedure but also modulated the mitochondria-enriched subproteome profile in the hippocampus of adult offspring rats. In line with this, two-dimensional electrophoresis coupled with mass spectrometry showed a statistically significant down-regulation of 14-3-3 and cytochrome bc1 proteins and an up-regulation of COP9 signalosome expression after chronic imipramine treatment in the hippocampus of prenatally stressed offspring. Fluoxetine administration strongly up-regulated the expression of cathepsin D, one of the key proteins involved in the prevention of the development of neurodegenerative processes. Furthermore, this antidepressant treatment enhanced expression of proteins engaged in the improvement of learning and memory processes (STMN1, Dnm-1) as well as in mitochondrial biogenesis and defense against oxidative stress (DJ-1). These findings provide new evidence that chronic administration of antidepressants exerts a varied impact on the mitochondria-enriched subproteome in the hippocampus of adult rats following a prenatal stress procedure. In particular, the effect of fluoxetine requires additional experiments to elucidate the possible beneficial biological consequences underlying the effects mediated by this antidepressant.

The effect of chronic tianeptine administration on the brain mitochondria: direct links with an animal model of depression

A growing body of evidence has focused on the impact of mitochondrial disturbances in the development of depression, but little data exist regarding the effects of chronic administration of antidepressant drugs on the brain's mitochondrial protein profile. The aim of this study was to investigate the impact of chronic treatment with an atypical antidepressant drug-tianeptine-on the mitochondria-enriched subproteome profile in the hippocampus and the frontal cortex of 3-month-old male rats following a prenatal stress procedure. Rats that were exposed to a prenatal stress procedure displayed depressive- and anxiety-like disturbances based on the elevated plus-maze and Porsolt tests. Moreover, two-dimensional electrophoresis coupled with mass spectrometry showed structure-dependent mitoproteome changes in brains of prenatally stressed rats after chronic tianeptine administration. A component of 2-oxoglutarate and succinate flavoprotein subunit dehydrogenases, isocitrate subunit alpha, was upregulated in the hippocampus. In the frontal cortex, there was a striking increase in the expression of glutamate dehydrogenase and cytochrome bc1 complex subunit 2. These findings suggest that mitochondria are underappreciated targets for therapeutic interventions, and mitochondrial function may be crucial for the effective treatment of stress-related diseases.

Anti-inflammatory properties of tianeptine on lipopolysaccharide-induced changes in microglial cells involve toll-like receptor-related pathways

Accumulating evidence suggests that activation of microglia plays a key role in the pathogenesis of depression. Activated microglia produce a wide range of factors whose prolonged or excessive release may lead to brain disorders. Thus, the inhibition of microglial cells may be beneficial in the treatment of depressive diseases. Tianeptine is an atypical antidepressant drug with proven clinical efficacy, but its mechanism of action remains still not fully understood. In the present study, using microglial cultures we investigated whether tianeptine modifies microglial activation after lipopolysaccharide (LPS) stimulation and which intracellular pathways are involved in the activity of this antidepressant. Our study shows that tianeptine attenuated the LPS-evoked inflammatory activation of microglia by decreasing the expression of proinflammatory cytokines such as IL-1β, IL-18, IL-6 and tumor necrosis factor α (TNF-α), the release of nitric oxide (NO) and reactive oxygen species (ROS) as well as the expression of inducible nitric oxide synthase. Analyses of signaling pathways demonstrate that tianeptine led to the suppression of LPS-induced TLR4 expression and ERK1/2 phosphorylation. Furthermore, our study reveals the inhibitory impact of tianeptine on caspase-3-induced PKCδ degradation and consequently on the activation of NF-κB factor in microglial cells. Taken together, present results show anti-inflammatory properties of tianeptine in microglial cultures stimulated by LPS. This study provides evidence that the inhibition of microglial activation may underlie the therapeutic activity of tianeptine. Our findings show the anti-inflammatory effect of tianeptine (TIA) in lipopolisaccharide (LPS)-stimulated microglial cells. The beneficial tianeptine action is mediated through the inhibition of Toll-like receptor 4 (TLR4) expression as well as the TLR4-related pathways: extracellular signal-regulated kinase 1/2 (ERK1/2), caspase-3-dependent protein kinase δ (PKCδ) cleavage and the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). These findings may provide a new therapeutic strategy for treatment of disorders based on neuroinflammation, including depression.

Beneficial impact of intracerebroventricular fractalkine administration on behavioral and biochemical changes induced by prenatal stress in adult rats: Possible role of NLRP3 inflammasome pathway

Several lines of evidence indicate that adverse experience in early life may be a triggering factor for pathological inflammatory processes and lead to the development of depression. Fractalkine (CX3CL1), a chemokine, plays an important role not only in the migration, differentiation and proliferation of neuronal and glial cells but also in the regulation of neuronal-microglial signaling and the production of pro-inflammatory factors. In the present study, we examined the impact of a prenatal stress procedure on the expression of fractalkine in the hippocampus and frontal cortex of young and adult male rats. Furthermore, we measured the age-dependent effect of stress during pregnancy on the expression of pro-inflammatory factors IL-1β, IL-18, TNF-α, IL-6, and CCL2 in both brain structures. Next, to illustrate the link between fractalkine signaling and the behavioral and biochemical changes induced by prenatal stress, adult prenatally stressed offspring were injected intracerebroventricularly (icv) with exogenous fractalkine. We reported that prenatal stress leads to long-lasting deficits in fractalkine signaling and enhanced inflammatory activation. The study demonstrates that icv administration of fractalkine attenuates the behavioural changes evoked by prenatal stress procedure in adult animals. Moreover, fractalkine administration, exhibits anti-inflammatory action, mainly in the frontal cortex of adult prenatally stressed rats. The effect of fractalkine is related to inhibition of NLRP3 inflammasome. However, its action on the other members of NOD-like receptor family (NLR) cannot be excluded. These findings provide new in vivo evidence that the behavioral and inflammatory disturbances observed in adult prenatally stressed rats may be related to long-lasting malfunctions in fractalkine signaling.

Beneficial properties of maraviroc on neuropathic pain development and opioid effectiveness in rats

Targeting chemokine signaling pathways is crucial in neuropathy development. In this study, we investigated the influence of chronic administration of maraviroc (CCR5 antagonist) on nociception and opioid effectiveness during neuropathy, which develops as a result of chronic constriction injury (CCI) of the sciatic nerve. To investigate the mechanism of action of maraviroc, we measured the expression of glial cell markers, CCR5 and certain CCR5 ligands (CCL3, CCL4, CCL5, CCL7, CCL11), in the spinal cord and dorsal root ganglia (DRG) of vehicle- and maraviroc-treated, CCI-exposed rats. Our results demonstrate that chronic intrathecal administration of maraviroc diminished neuropathic pain symptoms on day 7 post-CCI. Western blot analysis showed that maraviroc diminished protein level of Iba-1 and GFAP and reversed the up-regulated CCR5 expression observed in spinal cord and DRG after CCI. Additionally, using qRT-PCR, we demonstrated that CCR5 and some of its pronociceptive ligands (CCL3, CCL4, CCL5) increased in the spinal cord after nerve injury, and maraviroc effectively diminished those changes. However, CCL11 spinal expression was undetectable, even after injury. In vitro primary culture studies showed that CCL3, CCL4, CCL5 and CCL7 (but not CCL11) were of microglial and astroglial origin and were up-regulated after LPS stimulation. Our results indicate that maraviroc not only attenuated the development of neuropathic pain symptoms due to significant modulation of neuroimmune interactions but also intensified the analgesic properties of morphine and buprenorphine. In sum, our results suggest the pharmacological modulation of CCR5 by maraviroc as a novel therapeutic approach for co-treatment of patients receiving opioid therapy for neuropathy.

A Potential Contribution of Chemokine Network Dysfunction to the Depressive Disorders

In spite of many years of research, the pathomechanism of depression has not yet been elucidated. Among many hypotheses, the immune theory has generated a substantial interest. Up till now, it has been thought that depression is accompanied by the activation of inflammatory response and increase in pro-inflammatory cytokine levels. However, recently this view has become controversial, mainly due to the family of small proteins called chemokines. They play a key role in the modulation of peripheral function of the immune system by controlling immune reactions, mediating immune cell communication, and regulating chemotaxis and cell adhesion. Last studies underline significance of chemokines in the central nervous system, not only in the neuromodulation but also in the regulation of neurodevelopmental processes, neuroendocrine functions and in mediating the action of classical neurotransmitters. Moreover, it was demonstrated that these proteins are responsible for maintaining interactions between neuronal and glial cells both in the developing and adult brain also in the course of diseases. This review outlines the role of chemokine in the central nervous system under physiological and pathological conditions and their involvement in processes underlying depressive disorder. It summarizes the most important data from experimental and clinical studies.

Immune malfunction in the GPR39 zinc receptor of knockout mice: Its relationship to depressive disorder

Depression is a serious psychiatric disorder affecting not only the monaminergic, glutamatergic, and GABAergic neurosystems, but also the immune system. Patients suffering from depression show disturbance in the immune parameters as well as increased susceptibility to infections. Zinc is well known as an anti-inflammatory agent, and its link with depression has been proved, zinc deficiency causing depression- and anxiety-like behavior with immune malfunction. It has been discovered that trace-element zinc acts as a neurotransmitter in the central nervous system via zinc receptor GPR39. In this study we investigated whether GPR39 knockout would cause depressive-like behavior as measured by the forced swim test, and whether these changes would coexist with immune malfunction. In GPR39 knockout mice versus a wild-type control we found: i) depressive-like behavior; ii) significantly reduced thymus weight; (iii) reduced cell viability of splenocytes; iv) reduced proliferative response of splenocytes; and v) increased IL-6 production of splenocytes after ConA stimulation and decreased IL-1b and IL-6 release after LPS stimulation. The results indicate depressive-like behavior in GPR39 KO animals with an immune response similar to that observed in depressive disorder. Here for the first time we show immunological changes under GPR39-deficient conditions.

Prenatal stress is a vulnerability factor for altered morphology and biological activity of microglia cells

Several lines of evidence suggest that the dysregulation of the immune system is an important factor in the development of depression. Microglia are the resident macrophages of the central nervous system and a key player in innate immunity of the brain. We hypothesized that prenatal stress (an animal model of depression) as a priming factor could affect microglial cells and might lead to depressive-like disturbances in adult male rat offspring. We investigated the behavioral changes (sucrose preference test, Porsolt test), the expression of C1q and CD40 mRNA and the level of microglia (Iba1 positive) in 3-month-old control and prenatally stressed male offspring rats. In addition, we characterized the morphological and biochemical parameters of potentially harmful (NO, iNOS, IL-1β, IL-18, IL-6, TNF-α, CCL2, CXCL12, CCR2, CXCR4) and beneficial (insulin-like growth factor-1 (IGF-1), brain derived neurotrophic factor (BDNF)) phenotypes in cultures of microglia obtained from the cortices of 1–2 days old control and prenatally stressed pups. The adult prenatally stressed rats showed behavioral (anhedonic- and depression-like) disturbances, enhanced expression of microglial activation markers and an increased number of Iba1-immunopositive cells in the hippocampus and frontal cortex. The morphology of glia was altered in cultures from prenatally stressed rats, as demonstrated by immunofluorescence microscopy. Moreover, in these cultures, we observed enhanced expression of CD40 and MHC II and release of pro-inflammatory cytokines, including IL-1β, IL-18, TNF-α and IL-6. Prenatal stress significantly up-regulated levels of the chemokines CCL2, CXCL12 and altered expression of their receptors, CCR2 and CXCR4 while IGF-1 production was suppressed in cultures of microglia from prenatally stressed rats. Our results suggest that prenatal stress may lead to excessive microglia activation and contribute to the behavioral changes observed in depression in adulthood.

The impact of prenatal stress on insulin-like growth factor-1 and pro-inflammatory cytokine expression in the brains of adult male rats: the possible role of suppressors of cytokine signaling proteins

Stress, inflammation and the reduced expression of neurotrophic factors are risk factors for depression. The objective of this study was to determine if prenatal stress affects IGF-1 - cytokine interactions by influencing suppressors of cytokine signaling (SOCS) in the brains of adult rats, in basal conditions and after acute lipopolysaccharide (LPS) treatment. We demonstrated that prenatal stress leads to depression-like behavior, decreased IGF-1, increased IL-1β, TNF-α and IFN-γ release and disturbed SOCS-1, SOCS-2 and SOCS-3 expression in the hippocampus and frontal cortex of adult offspring. Furthermore, prenatal stress enhances the brain response to LPS-evoked inflammatory challenges.

Prenatal stress leads to changes in IGF-1 binding proteins network in the hippocampus and frontal cortex of adult male rat

Depression is a mental disorder of still unknown origin. Currently, much attention is paid to the potential influence of disturbances in the functioning of neurotrophic factors on the onset of this disease. Insulin-like growth factor 1 (IGF-1) is one of the most important growth agents affecting processes that are crucial for brain development. To date, there are no data showing the impact of prenatal stress on the family of six IGF binding proteins (IGFBP 1-6) that regulate IGF-1 bioactivity. The goal of this study was to investigate whether the decreased expression of IGF-1 in the frontal cortex (FCx) and hippocampus (Hp) of adult male rats following a prenatal stress procedure is related to changes in the IGFBP family. Our results show that rats exposed prenatally to stressful stimuli displayed depression-like behavior based on sucrose preference and elevated plus maze tests. In both cases, in the adult rat brain structures that were examined after the prenatal stress procedure, the IGF-1 protein level was reduced. Moreover, we observed changes of varying degrees in the levels of IGFBPs in stressed animals. A decrease in IGFBP-2 and IGFBP-3 accompanied by an increase in the IGFBP-4 concentration in the Hp and the FCx was detected. There were no differences in IGFBP-1 and IGFBP-6 brain levels between the stressed and control animals, whereas IGFBP-5 concentration was decreased in the Hp of prenatally stressed animals. This study demonstrated that stress during pregnancy may lead not only to behavioral disturbances but also to a decrease in IGF-1 level and the dysregulation of the IGF-1 binding protein network in adult rat offspring.

[Surgical management of pertrochanteric fractures with the dynamic hip screw of the AO type]

Since 1981 we have been using the dynamic hip screw (DHS) for surgical treatment of pertrochanteric fractures. After presentation of the implant and the operative technique the postoperative treatment is discussed. Immediate mobilization of the injured leg with weight-bearing is extremely important. Up to the end of 1986 we had used the DHS in 509 patients, whose average age was 75 years. During the hospital stay 31 patients died. Complications in the form of an infection occurred in 11 cases. Technical mistakes during surgery and breakage of the implant were each observed in two cases. After a period of 11 months patients were observed for assessment of the described technique. This examination was possible in 193 patients, showing excellent results presented in this paper. With full weight-bearing DHS ensures constant bony contact of the fracture fragments by means of the sliding mechanism. The advantages of the DHS are (1) relatively simple surgical technique; (2) low rate of complications; and (3) early mobilization without danger of complications resulting from the implant.

[Follow-up management of recently operated capsule and ligament injuries of the knee joint]

The guidelines for the treatment of ligament injuries of the knee joint are subject to continuous changes due to new experiences in the field of functional anatomy and pathophysiology, as well as to the progressive changes in surgical treatment. The authors suggest answers to the questions of immobilisation, appropriate support, mobilisation, etc., questions which as yet have no final and binding solutions. They also discuss the problems of muscle atrophy and the time at which sportive activities of varying strains may be taken up again.

[Differentiated procedure in fractures of the coxal femur end in adults]

After own clinical observations a choice of surgical treatment in coxofemoral fractures is pointed out: Femoral neck fractures of stage Garden I will be stabilized by lag screws. For the rest of subcapital fractures we use lag screws or Smith-Peterson nailing for stabilization; only old patients without the possibility of mobilisation without weight-bearing after operation are treated by endoprosthesis of the hip. In Garden-IV-fractures and fracture-type Pauwels III indication for endoprosthesis is conditioned in most elderly patients. In basocervical and pertrochanteric fractures of younger patients a dynamic hip screw will be performed; in older patients we use elastic nails described by Simon-Weidner and Ender with good success. For stabilization of subtrochanteric fractures different operations dependent on type of fracture, bone-structure and general condition are used: elastic nails with or without wire-loops, interlocking nailing, Y-nail, dynamic hip screw, angled plate and compound internal fixation.

[Fractures of the acetabulum (author's transl)]

The results of conservative and operative treatment of dislocated fractures of the acetabulum are compared. The types of fracture are described where surgical stabilisation is indicated. Depending of the type of fracture, the causes of unsatisfactory results following operative treatment are: primary lesions of the cartilage, difficulties with reduction and retention, septic complications. The aim of surgery is first of all the anatomic reconstruction of the supporting area of the acetabulum. 2/3 of our patients were operated between the 2nd and the 14th day. The lateral position with the extremity freely movable is recommended for dorsal and lateral approach. A trochanter traction screw with extension facilitates the operative reduction. It was possible to re-examine 45 of 64 cases after a period of between 2 and 13 years. Results were evaluated according to the scheme by Merle d'Aubigné. 35 patients had very good or good results, in 3 cases secondary arthrodesis was necessary and in one case a total hip prosthesis was implanted. Dislocated acetabular fractures should be be operated as soon as possible if conservative methods fail. Late reconstruction may also be successful. The lesion of the sciatic nerve is an absolute indication for operation. Satisfactory results can be achieved by anatomic reconstruction even in cases with multiple fragmentation.

[Delayed union and pseudarthrosis of the carpal navicular: diagnosis and treatment (author's transl)]

Knowledge of the pathophysiological ways and the changes by roentgenogram after fracture of the carpal navicular makes it possible to get an exact diagnosis of the stage of the fracture. The diagnosis will show the way to the correct treatment. The results in 31 cases with an average follow-up of 15 years are presented. In our series it is pointed out that the real pseudarthrosis can only be healed by operative treatment. All 13 operatively treated pseudarthroses had healed by way of ossification and 11 patients without treatment still suffer from pseudarthroses. 10 of these 11 cases show later arthritic or degenerative changes. In cases of traumatic cysts primary operative treatment is preferred. Severe pre-existing arthritis with sclerosis requires a palliative operation in all cases.

Grafting of ununited fractures of the scaphoid

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