The cyclic AMP effects and neuroprotective activities of PACAP and VIP in cultured astrocytes and neurons exposed to oxygen-glucose deprivation.

BACKGROUND: Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are endogenous peptides, widely expressed in the central and peripheral nervous system. The adenylyl cyclase (AC)/cyclic AMP (cAMP) is their main intracellular signal transduction pathway. Numerous data suggest that PACAP and VIP have considerable neuroprotective potential, indicating the possibility for their use as new therapeutic strategies in stroke treatment. The aim of this study was to evaluate the effect of oxygen-glucose deprivation (OGD) - an established in vitro model for ischemic cell stress - on PACAP and VIP-evoked receptor-mediated cAMP generation in glial and neuronal cells, and to determine whether PACAP and VIP have neuroprotective activity under these conditions. METHODS: The formation of [(3)H]cAMP by PACAP, VIP and forskolin (a direct activator of AC) was measured in [(3)H]adenine prelabeled primary rat glial and neuronal cells under normoxia and OGD conditions. The effects of PACAP and VIP on cell viability were measured using the MTT conversion method, and were compared to tacrolimus (FK506), a well known neuroprotective agent. RESULTS: The OGD model inhibited the PACAP and VIP-induced cAMP formation in rat astrocytes and neurons. Incubation of neuronal cells with PACAP prevented OGD-induced cell death, more efficiently than VIP and FK506. CONCLUSION: The obtained results showed that hypoxia/ischemia may trigger down-regulation of the brain AC-coupled PACAP/VIP receptors, with a consequent decrease of PACAP- and/or VIP-ergic-dependent cAMP-driven signaling. Moreover, our findings indicate that PACAP and VIP can prevent the deleterious effect of OGD on rat neuronal cells.

PUFAs: Structures, Metabolism and Functions.

Polyunsaturated fatty acids (PUFAs) include two series of fatty acids: omega-6 and omega-3 series. PUFAs have amphiphatic properties: hydrophilic head and hydrophobic tail. Such structure and other properties of unsaturated fatty acids are responsible for exerting the following biological action: maintaining cell-membrane fluidity, inhib- iting inflammatory processes, decreasing secretion of proinflammatory cytokines by monocytes/macrophages, decreasing susceptibility to ventricular rhythm disorders of the heart, improving functions of vascular endothe- lial cells, inhibiting blood platelet aggregation and decreasing triglyceride synthesis in the liver. In an organism, aracidonic acid (ARA) is converted to prostanoids series 2 (PGE2, PGI2, TXA2) and leukotrienes series 4 (LTB4, LTC4, LTD4) which are endowed with pro-inflammatory potential and are able to induce platelet aggregation and vasoconstriction. The metabolism of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) gives prostanoids series 3 (PGE3, PGI3, TXA3) and leukotrienes series 5 (LTB5, LTC5, LTD5); this group of eicosanoids shows anti-inflammatory, antiplatelet and antiarrhythmic properties.

Aspirin and age-related macular degeneration: positives versus negatives.

The anti-inflammatory, analgesic, antipyretic and antithrombotic activities of aspirin confer its wide therapeutic application. The three former activities require higher doses of aspirin, whereas the latter can be achieved through a lower, thus safer dose of the drug. Low-dose, long-term aspirin is used as an antithrombotic therapy to prevent cardiovascular disease. Such therapy is used by millions of people worldwide, including those suffering from age-related macular degeneration (AMD); thus, questions have arisen as to whether such treatment has any impact on the development and course of AMD. This editorial addresses the important issue of possible beneficial and adverse effects of long-term, low-dose aspirin treatment of AMD patients. Special emphasis is given to the ability of aspirin to acetylate cyclooxygenases (especially COX-2) and thus to initiate a biochemical pathway leading to the generation of anti-inflammatory pro-resolving mediators synthesized from both ω-3 and ω-6 long-chain polyunsaturated fatty acids. Such mediators (e.g., resolvins, lipoxins) may be of therapeutic value in retarding the development of dry form AMD.

Paracetamol: mechanism of action, applications and safety concern.

Paracetamol/acetaminophen is one of the most popular and most commonly used analgesic and antipyretic drugs around the world, available without a prescription, both in mono- and multi-component preparations. It is the drug of choice in patients that cannot be treated with non-steroidal anti-inflammatory drugs (NSAID), such as people with bronchial asthma, peptic ulcer disease, hemophilia, salicylate-sensitized people, children under 12 years of age, pregnant or breastfeeding women. It is recommended as a first-line treatment of pain associated with osteoarthritis. The mechanism of action is complex and includes the effects of both the peripheral (COX inhibition), and central (COX, serotonergic descending neuronal pathway, L-arginine/NO pathway, cannabinoid system) antinociception processes and "redox" mechanism. Paracetamol is well tolerated drug and produces few side effects from the gastrointestinal tract, however, despite that, every year, has seen a steadily increasing number of registered cases of paracetamol-induced liver intoxication all over the world. Given the growing problem of the safety of acetaminophen is questioned the validity of the sale of the drug without a prescription. This work, in conjunction with the latest reports on the mechanism of action of paracetamol, trying to point out that it is not a panacea devoid of side effects, and indeed, especially when is taken regularly and in large doses (> 4 g/day), there is a risk of serious side effects.

AMD--the retinal disease with an unprecised etiopathogenesis: in search of effective therapeutics.

AMD (age-related macular degeneration) is a progressive vision-threatening ocular disease, affecting central region of the retina--the macula--and manifesting in the elderly. AMD is a degenerative disease, and the degeneration affects primarily the retinal pigment epithelial (RPE) cells and secondarily the photoreceptors, leading consequently to disturbances or partial loss of central vision and legal blindness. Clinically, the disease is classified as: atrophic--dry AMD (in majority of cases), and neovascular--wet AMD (with choroidal neovascularization--CNV: 10-15% of all AMD cases). Pathogenesis of AMD is complex, multifactorial and only poorly recognized. Main risk factors include: advanced age, genetic predispositions, environmental determinants, history of exposure to intensive light and smoking. At least four molecular processes contribute to the development of AMD pathology: lipofuscinogenesis, drusogenesis, inflammation and choroidal neovascularization (in wet AMD). Since vascular endothelial growth factor (VEGF) is a predominant proangiogenic factor in CNV. the wet AMD can be treated with intravitreous application of "anti-VEGF" agents (Avastin, Lucentis, Eylea). Till now, there is no approved therapy for dry AMD, although several agents/treatments are currently in clinical trials. This paper briefly describes major molecular and cellular events leading to AMD, and presents currently used and new experimental therapeutic strategies against AMD.

Oxidative stress, polyunsaturated fatty acids-derived oxidation products and bisretinoids as potential inducers of CNS diseases: focus on age-related macular degeneration.

Many pathologies of the central nervous system (CNS) originate from excess of reactive free radicals, notably reactive oxygen species (ROS), and oxidative stress. A phenomenon which usually runs in parallel with oxidative stress is unsaturated lipid peroxidation, which, via a chain reaction, contributes to the progression of disbalanced redox homeostasis. Among long-chain (LC) polyunsaturated fatty acids (PUFAs) abundantly occurring in the CNS, docosahexaenoic acid (DHA), a member of ω-3 LC-PUFAs, deserves special attention, as it is avidly retained and uniquely concentrated in the nervous system, particularly in retinal photoreceptors and synaptic membranes; owing to the presence of the six double bonds between carbon atoms in its polyene chain (C=C), DHA is exquisitely sensitive to oxidative damage. In addition to oxidative stress and LC-PUFAs peroxidation, other stress-related mechanisms may also contribute to the development of various CNS malfunctions, and a good example of such mechanisms is the process of lipofuscin formation occurring particularly in the retina, an integral part of the CNS. The retinal lipofuscin is formed and accumulated by the retinal pigment epithelial (RPE) cells as a consequence of both visual process taking place in photoreceptor-RPE functional complex and metabolic insufficiency of RPE lysosomal compartment. Among various retinal lipofuscin constituents, bisretinoids, originating from all-trans retinal substrate--a photometabolite of visual pigment cofactor 11-cis-retinal (responsible for photon capturing), are endowed with cytotoxic and complement-activating potential which increases upon illumination and oxidation. This survey deals with oxidative stress, PUFAs (especially DHA) peroxidation products of carboxyalkylpyrrole type and bisretinoids as potential inducers of the CNS pathology. A focus is put on vision-threatening disease, i.e., age-related macular degeneration (AMD), as an example of the CNS disorder whose pathogenesis has strong background in both oxidative stress and lipid peroxidation products.

Hyaluronan: towards novel anti-cancer therapeutics.

The understanding of the role of hyaluronan in physiology and various pathological conditions has changed since the complex nature of its synthesis, degradation and interactions with diverse binding proteins was revealed. Initially perceived only as an inert component of connective tissue, it is now known to be involved in multiple signaling pathways, including those involved in cancer pathogenesis and progression. Hyaluronan presents a mixture of various length polymer molecules from finely fragmented oligosaccharides, polymers intermediate in size, to huge aggregates of high molecular weight hyaluronan. While large molecules promote tissue integrity and quiescence, the generation of breakdown products enhances signaling transduction, contributing to the pro-oncogenic behavior of cancer cells. Low molecular weight hyaluronan has well-established angiogenic properties, while the smallest hyaluronan oligomers may counteract tumor development. These equivocal properties make the role of hyaluronan in cancer biology very complex. This review surveys recent data on hyaluronan biosynthesis, metabolism, and interactions with its binding proteins called hyaladherins (CD44, RHAMM), providing themolecular background underlying its differentiated biological activity. In particular, the article critically presents current ideas on actual role of hyaluronan in cancer. The paper additionally maps a path towards promising novel anti-cancer therapeutics which target hyaluronan metabolic enzymes and hyaladherins, and constitute hyaluronan-based drug delivery systems.

[Antiinflammatory therapy in ostheoarthritis including omega 3 and omega 6 fatty acids]. / Leczenie przeciwzapalne w chorobie zwyrodnieniowej stawów z uwzglednieniem kwasów tluszczowych omega 3 i omega 6.

Osteoarthritis (ostheoarthrosis, OA) is characterized by progressive destruction of articular cartilage, remodeling of the periarticular bone and inflammation of the synovial membrane. In patients occur joints pain, impaired joints motion and disability. The results of many studies indicate an inflammation as foundation of this disease. The management of OA include a combination of pharmacological treatments and nonpharmacological interventions. Pharmacological treatments include used paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs) and chondroprotectives (glucosamine, chondroitin sulfate and so on). NSAIDs long-term use associated with serious adverse effects. OA symptoms are effectively reduced by nutrients such omega 3 and omega 6 fatty acids (PUFAs as EPA, DHA), which decrease the need for non-steroidal drugs and may less adverse events. They exerts, particularly EPA, anti-inflammatory effect, inhibit catabolic processes, stimulate the anabolic process in the cartilage in the joint. Many different evidence validate that omega 3 alleviate the progression of osteoarthritis and have exciting therapeutic potential for preventing cartilage degradation associated with chronic inflammatory in joints.

[Pathogenesis and prophylaxis of AMD: focus on oxidative stress and antioxidants]. / Patogeneza i profilaktyka AMD: rola stresu oksydacyjnego i antyoksydantów.

Age-related macular degeneration (AMD) is the leading cause of severe visual loss and blindness in people over 55. Its pathogenesis--likely multifactorial, involving a complex interaction of metabolic, functional, genetic and environmental factors--remains poorly understood. Among molecular links in pathogenesis of AMD is the oxidative stress in the retina, a structure that is particularly susceptible to damage by reactive oxygen species (ROS) since photoreceptor outer segment (POS) membranes are rich in polyunsaturated fatty acids which can be readily oxidized and can initiate a cytotoxic chain reaction. Occurring in the neighborhood of photoreceptors, the retinal pigment epithelial cells (RPE) actively contribute to both the retinoid cycle and catabolism of constantly shed and phagocytized parts of photoreceptor outer segments. Enzymatic degradation of photoreceptor fragments occurring in RPE phagolysosomes is not complete and undigested material in the form of insoluble aggregates, called lipofuscin, is deposited in lysosomes of RPE cells. Lipofuscin contains a mixture of diverse molecular components including retinoid-derived compounds, some of which displaying potent photoinducible properties, contributing to an enhancement and propagation of the oxidative stress. The retina possesses defense mechanisms against the oxidative stress that effectively neutralize the consequences of reactive oxygen species actions under normal conditions. A key role in the antioxidant defense plays an array of substances, including: xanthophylls (lutein and zeaxanthin), vitamin C and E, and glutathione. This paper surveys the current concepts on the role of the oxidative stress in pathophysiology of AMD, and describes major components of the antioxidant defense system, including their use in AMD prophylaxis and therapy.

[Anti-inflammatory pro-resolving derivatives of omega-3 and omega-6 polyunsaturated fatty acids]. / Przeciwzapalne "prowygaszeniowe" pochodne wielonienasyconych kwasów tluszczowych omega 3 i omega 6.

Inflammation is a physiological defense reaction of living tissues to injury or infection. An array of mediators, including those derived from omega-6 (omega6) polyunsaturated fatty acids (PUFAs), such as arachidonic acid (AA) e.g. prostaglandins and leukotrienes, promote the inflammatory response. Acute inflammation has several programmed fates, including complete resolution or progression to chronic inflammation, scarring, and eventual loss of tissue function. Studies on AA-derived proinflammatory mediators led to the discovery of AA-derived anti-inflammatory and pro-resolving compounds. These include lipoxins, originating from AA, and resolvins, originating from the omega-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as well as the omega-6 PUFA docosapentaenoic acid (DPA-omega6). DHA is also a substrate for other anti-inflammatory mediators, i.e. neuroprotectin and maresin. Because of their role in the final phase of acute inflammation, i.e. the resolution of inflammation, the above anti-inflammatory mediators were named pro-resolving mediators. They are formed in cooperating cells present in the region of inflammation in a process called transcellular biosynthesis with the aid of specific lipoxygenases (LOX) and cyclooxygenases (COX). Pro-resolving anti-inflammatory mediators exert their biological activities in a receptor-dependent manner in the resolution phase of inflammation. Of their various biological effects, the most important include inhibition of leukocyte mobilization and traffic through endothelial or epithelial layers, suppression of proinflammatory cytokine release by different cells present in inflamed tissue, and stimulation of the phagocytic activity of monocytes/macrophages. This article surveys the current knowledge on inflammation and the role of the pro-resolving and anti-inflammatory potential of lipid-derived agonistic mediators.

[The neuroprotective effect of PACAP, VIP, and derivatives in brain ischemia]. / Dzialanie neuroprotekcyjne PACAP, VIP oraz pochodnych w niedokrwieniu mózgu.

Nowadays, stroke is the most frequent cause of adult disability and death of the elderly. In most cases, the etiology of stroke involves cerebral ischemia. Ischemia-induced changes in the brain tissue lead not only to its degeneration, but also to significant activation of cellular mechanisms which protect the affected cells from damage. One such mechanism is the expression of endogenous neuroprotective substances, for example pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intenstinal peptide (VIP), whose properties were investigated recently. PACAP and VIP are neuropeptides widely distributed in both the central nervous system and peripheral organs of various vertebrates. They display pleiotropic biological activity. An extremely strong neuroprotective potential of these peptides has been observed and confirmed in numerous animal models. The protective mechanism of PACAP and VIP involves many intracellular pathways, which can be generally classified into four categories of action: antiapoptotic, anti-inflammatory, metabolic, and modulation of gene expression. Numerous data provided by many research centers suggest that endo- and exogenous PACAP and VIP, as well as their synthetic derivatives, reveal considerable neuroprotective and anti-inflammatory potential, suggesting a possibility of their use as new therapeutic strategies in stroke treatment.

[Age-related macular degeneration--a complex genetic disease]. / Zwyrodnienie plamki zwiazane z wiekiem (AMD)--choroba o wieloczynnikowym podlozu genetycznym.

Age-related macular degeneration (AMD,) is the most common cause of severe visual loss and blindness in the population over 60 years old, especially in the developed world. Two types of AMD are distinguished: the dry (non-exudative or atrophic) and the wet (exudative or neovascular) form. Family and twins studies have shown that the susceptibility for this disease is genetically influenced and the heritability has been estimated to be up to 75%. Until now, many of the candidate-genes associated with AMD have been discovered using studies on genetically engineered and naturally mutated animals, linkage studies, studies of monogenic degenerative retinal diseases and association studies. Recently genes have been described that significantly contribute to the etiopathogenesis of AMD: CFH, PLEKHA1/LOC387715/HTRA1 and C2/BF genes. AMD is considered to be a genetic complex disease in which multiple genes and environmental factors play a role in pathogenesis. Identification of other genes involved in development of AMD will improve our knowledge about new pathways and pathological mechanisms of the disease, as well as avenues for novel more effective treatments. The aim of this article is to survey published data on genetic aspect of AMD, with emphasis of several recently discovered genes described to be particularly important in the pathogenesis of AMD, and /or somehow associated with the occurrence of the disease.

Effects of PACAP and VIP on cAMP-generating system and proliferation of C6 glioma cells.

An identification of PAC1- and VPAC-type receptors in a great number of neoplastic cells gave rise to intensive studies on the biochemical and physiological role of the mentioned peptides in cancers. Our earlier studies focused on effects of pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP) in C6 glioma cells have shown their stimulatory receptor-mediated action on the cyclic adenosine monophosphate (cAMP)-generating system. In the present study, we demonstrated that truncated peptides, i.e., PACAP6-38 and VIP6-28, both produced a significant inhibition of the VIP-induced increase in cAMP production, whereas only PACAP6-38 did antagonize the PACAP-38 effect. In contrast to the well-expressed PACAP-38 and VIP effects on cAMP production in C6 cells, helodermin and secretin were poorly active as cAMP stimulators in this cell line, displaying some activity only at a high 5-microM dose. PACAP-38 and, to a lesser extent VIP stimulated the proliferation of C6 glioma cells, which was shown by an increased incorporation of 3H-thymidine into the cells, and the effects of these two peptides were antagonized by PACAP6-38. The truncated PACAP (10 microM) by itself significantly inhibited C6 cell proliferation. The study with the use of forskolin and dibutyryl-cAMP revealed that the growth effects of PACAP were cAMP independent. Our findings suggest that glioma C6 cells possess PAC1- and VPAC-type receptors, but the density of PAC1 seems to be much larger than VPAC receptors. Although the proliferative activity of PACAP and VIP is mediated via the PAC1-type receptor, the signaling cascade underlying this phenomenon does not seem to involve cAMP.

Characteristics of adrenaline-driven receptor-mediated signals in human microvessel-derived endothelial cells.

Adrenaline (0.001-1,000 muM) strongly stimulated adenosine-3',5'cyclic monophosphate (cAMP) generation in cultured human microvascular-derived endothelial cells (HMEC-1). Isoprenaline mimicked the action of adrenaline, whereas noradrenaline appeared to be decisively less potent. Experiments carried out with an array of compounds acting selectively on different types/subtypes of adrenergic receptors revealed that the adrenaline cAMP effect in HMEC-1 cells did not possess either an alpha(1) or alpha(2) component. However, the effect may have been mediated through a receptor that did not fit beta(1)-, beta(2)-, or beta(3)-receptor classification. Supporting this assertion, various double and triple beta-subtype selective drug combinations maximally inhibited the adrenaline effect by 50-60%, whereas the non-selective antagonist propranolol totally prevented the hormone-evoked cAMP effect. Based on results utilizing the phosphodiesterase (PDE)-isoform nonselective inhibitor 3-isobutyl-1-methylxanthine (IBMX) and the PDE-4-selective inhibitor rolipram, the adrenaline-driven cAMP signal appeared to be regulated by PDE-4. In addition, the present study demonstrated that phenylephrine, a presumed selective alpha(1)-adrenoceptor agonist, was capable of stimulating cAMP generation in HMEC-1 cells in a prazosin-insensitive and propranolol-sensitive manner. This result indicated that in at least this cell model system, phenylephrine may act nonspecifically. Microvessel-derived endothelial cells such as HMEC-1 exhibit functional differences when compared with macrovessel-derived endothelial cells (e.g. HUVEC sensitivity to adrenaline). Accordingly, these cell cultures represent a useful model system to study the biological effects of endogenous catecholamines, including adrenaline, as well as potential therapeutics targeting adrenergic receptors.

Effects of PEDF and VEGF on PACAP-/VIP-induced cAMP formation in rat brain derived astrocyte cultures.

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are two structurally related peptides acting on their specific receptors. Both were shown to concentration-dependently (0.001 nM - 1 muM) stimulate cyclic 3',5' adenosinomonophosphate (cAMP) formation in rat primary glial cell (astrocyte) cultures, with PACAP being distinctly more potent than VIP. The acute effects of the peptides were significantly suppressed (25% and 36% for PACAP and VIP, respectively) when tested in cell cultures preincubated for 24 h (but not 2 h) in the presence of pigment epithelium-derived factor (PEDF, 50 ng/ml). Both 24 h and 2 h preincubation of cells with vascular endothelial growth factor (VEGF, 50 ng/ml) had no influence on PACAP or VIP actions. The addition of PEDF and VEGF together for 24 h preincubation, produced suppression of the PACAP- or VIP-evoked cAMP responses similar to that seen with PEDF alone. Neither PEDF nor VEGF significantly affected cAMP generation in an assay with a 15-min incubation, which is a standard incubation period for PACAP and VIP. The findings show that PEDF, displaying by itself no effect on cAMP generating system in rat astrocytes, significantly affected biological activity of both PACAP and VIP. The reported observation may be of significance, considering the neurotrophic and/or neuroprotective activity of the tested polypeptides.

Effects of PACAP, VIP and related peptides on cyclic AMP formation in rat neuronal and astrocyte cultures and cerebral cortical slices.

The effects of pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP), peptide histidine-isoleucine (PHI) and peptide histidine-methionine (PHM) on cyclic AMP formation were studied in parallel on rat cerebral cortical slices, primary neuronal cultures and primary glial (astrocyte) cultures. PACAPappeared to be the most potent agent in all biological systems. The rank order of the peptides' potency was as follows: PACAP > VIP > PHI = PHM for cortical slices and neuronal cell cultures, and PACAP >> PHM approximately VIP > PHI for glial cell cultures. The cyclic AMP responses to the tested peptides, especially to PACAP, were distinctly larger in glial cell cultures than in neuronal cell cultures or brain slices. In an additional study, the cyclic AMP response to helodermin and secretin, as well as isoprenaline, histamine and forskolin, were tested in parallel on glial and neuronal cell cultures, and directly compared with the actions of PACAP. Helodermin and isoprenaline showed clearly stronger activity in glial cell cultures, yet their activity was much weaker than that of PACAP, whereas the effect of forskolin was only 2 times larger in glial cells than in neuronal cultures; histamine had no effect in any cell culture, while secretin produced a small but significant effect only in glial cells. The obtained results suggest that the astrocyte compartment of the rat brain may be the main target for such peptides as PACAP, VIP, or structurally related PHI/PHM or helodermin.

[Bevacizumab: progress in the treatment of metastatic cancer and hope for patients with proliferative retinopathy]. / Bewacizumab--postep w leczeniu nowotworówz przerzutami i nadzieja pacjentów z retinopatiaproliferacyjna.

The formation of new blood vessels from pre-existing vasculature (neoangiogenesis) accompanies many diseases, including cancer and proliferative retinopathy. Knowledge of the molecular mechanisms of angiogenesis and angiogeneic factors, especially vascular endothelial growth factor (VEGF), enables the design of drugs more potent and specific in their action and less cytotoxic. Among angiogenesis inhibitors are drugs made by means of genetic engineering, i.e. monoclonal antibodies, devoid of unwanted actions that occur during chemotherapy. One of monoclonal antibodies successfully used in clinical trials in patients with metastatic colorectal cancer is bevacizumab. Because of its inhibitory potential regarding angiogenesis it may be useful in the treatment of age-related macular degeneration (AMD). Although anti-VEGF agents have already been used in AMD therapy, there are several arguments, primarily financial, favoring bevacizumab's applicability in ophthalmology.

Effects of PACAP and VIP on cyclic AMP formation in rat neuronal and astrocyte cultures under normoxic and hypoxic condition.

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) concentration (0.001-1000 nM)-dependently stimulated cyclic AMP production in rat primary neuronal and glial cell (astrocyte) cultures. The actions of both peptides were much more pronounced in astrocytes than in neuronal cultures. Stimulatory effects of PACAP and VIP on cyclic AMP formation were significantly smaller in cell cultures subjected to 24h lasting hypoxic conditions, induced either chemically (100 microM cobalt chloride) or by low 3% oxygen hypoxia, compared to the normoxic condition (95% air and 5% CO(2)). This picture contrasted with the effects of forskolin that were similar under normoxic and hypoxic conditions. It is suggested that hypoxia leads to changes in PACAP- and VIP-driven cyclic AMP-dependent signaling in the rat brain by influencing molecular processes likely occurring at the level of receptor protein or receptor-Gs protein coupling.

[The role of complement in physiology and pathology]. / Rola ukladu dopelniacza w fizjologii i patologii.

The complement system was discovered over one hundred years ago. It is an essential part of the innate immune system. A group of about 40 proteins assists in phagocytosis and stimulates inflammation. The complement system participates in the defense of an organism against different factors, e.g. microorganisms. There are three pathways of complement activation: the classical, lectin, and alternative. Activation of the complement system leads to the formation of a lytic macromolecule known as the membrane attack complex (MAC). The MAC may damage target cells in a process called bacteriolysis. The host organism is protected against the negative impact of autoimmunity by complement factor H (CFH). Recent experimental studies dealing with the regulation of the complement system suggest that this control process can be genetically determined. Mutations in genes encoding CFH (CFH polymorphism), factor B, and C2, can be crucial for a defective or insufficient regulation of the complement system. This paper surveys recent achievements on the structure and mechanisms of the complement system and shortly reviews the correlation between the complement function and pathogenesis of many diseases, including atypical hemolytic uremic syndrome (aHUS), membranoproliferative glomerulonephritis II (MPGN II), and age-related macular degeneration (AMD).

[Age-related macular degeneration (AMD): etiopathogenesis and therapeutic strategies]. / Zwyrodnienie plamki zwiazane z wiekiem (AMD): etiopatogeneza i strategie terapeutyczne.

Age-related macular degeneration (AMD) is a disease leading to severe visual loss and legal blindness in the population over 60 years of age. Its pathogenesis is likely multifactorial, involving a complex interaction of metabolic, functional, genetic, and environmental factors, and remains poorly understood. For these reasons, currently used therapeutic approaches are insufficiently effective. Although major abnormalities are seen in four functionally interrelated tissues, i.e. photoreceptors, retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaries, the impairment of RPE cell functions is an early and crucial event in the molecular pathways leading to clinical relevant AMD changes. The RPE progressively degenerates, which results in an irreversible degeneration of photoreceptors. Four processes: lipofuscinogenesis, drusogenesis, inflammation, and neovascularization, specifically contribute to the development of the disease. Two types of AMD are distinguished: the dry and the wet form. This paper briefly describes major molecular and cellular events leading to AMD, and presents currently used and new, forthcoming therapeutic strategies.