Regulation of anti-HIV-1 activity of RANTES by heparan sulfate proteoglycans

The role of cell surface proteoglycans in CC chemokine-mediated anti-HIV-1 activity in T cells and macrophages was investigated. Enzyme digestion of heparan sulfate (HS), but not chondroitin sulfate, from the surface of PM1(CD26H) cells (a human T cell line selected for high CD26 expression) rendered them resistant to the antiviral effects of RANTES and macrophage-inflammatory protein-1beta at otherwise inhibitory chemokine concentrations. HIV-1 infection of macrophages, however, was inhibited only partially, even at high concentrations of RANTES, and this inhibition was not prevented by HS removal. Flow cytometry revealed that digestion of cell surface proteoglycans, including HS, prevented the binding of RANTES at 10 to 100 nM concentrations to PM1(CD26H) cells. However, the binding of RANTES to activated macrophages occurred only at higher concentrations (100-300 nM) and was mostly chondroitin sulfate, and not HS, dependent. These results support a role for HS in facilitating the interaction of CC chemokines with the cell surface and the consequent inhibition of HIV-1 infection. The absence of HS-dependent binding of RANTES at lower concentrations to macrophages is consistent with the resistance of these cells to the antiviral effects of chemokines.     

Interaction of angiogenic basic fibroblast growth factor with endothelial cell heparan sulfate proteoglycans. Biological implications in neovascularization

Even if there were antiretrovirals developed that could completely eliminate HIV from the body, it is thought that immune-based therapy would still be necessary. Pervasive damage occurs in the immune system even in early stages of the disease, and this damage would not be corrected by antiretrovirals. Several different types of immune-based therapies are presented in this article; some have been successful, and some have not been successful. All have been important, however, in increasing the knowledge base of HIV pathogenesis and in narrowing the options that might rebuild the immune system and, thereby, reverse this pathology.     

Syndecans, heparan sulfate proteoglycans, maintain the proteolytic balance of acute wound fluids

An imbalance between proteases and antiproteases is thought to play a role in the inflammatory injury that regulates wound healing. The activities of some proteases and antiproteases found in inflammatory fluids can be modified in vitro by heparin, a mast cell-derived glycosaminoglycan. Because syndecans, a family of cell surface heparan sulfate proteoglycans, are the major cellular source of heparin-like glycosaminoglycan, we asked whether syndecans modify protease activities in vivo. Syndecan-1 and syndecan-4 ectodomains are shed into acute human dermal wound fluids (Subramanian, S. V., Fitzgerald, M. L., and Bernfield, M. (1997) J. Biol. Chem. 272, 14713-14720). Moreover, purified syndecan-1 ectodomain binds cathepsin G (Kd = 56 nM) and elastase (Kd = 35 nM) tightly and reduces the affinity of these proteases for their physiological inhibitors. Purified syndecan-1 ectodomain protects cathepsin G from inhibition by alpha1-antichymotrypsin and squamous cell carcinoma antigen 2 and elastase from inhibition by alpha1-proteinase inhibitor by decreasing second order rate constants for protease-antiprotease associations (kass) by 3700-, 32-, and 60-fold, respectively. Both enzymatic degradation of heparan sulfate and immunodepletion of the syndecan-1 and -4 in wound fluid reduce these proteolytic activities in the fluid, indicating that the proteases in the wound environment are regulated by interactions with syndecan ectodomains. Thus, syndecans are shed into acute wound fluids, where they can modify the proteolytic balance of the fluid. This suggests a novel physiological role for these soluble heparan sulfate proteoglycans.     

In vivo clearance of ternary complexes of vitronectin-thrombin-antithrombin is mediated by hepatic heparan sulfate proteoglycans

Thrombin is inhibited by its cognate plasma inhibitor antithrombin, through the formation of covalent thrombin-antithrombin (TAT) complexes that are found as ternary complexes with vitronectin (VN-TAT). To determine whether the metabolism of VN-TAT ternary complexes is different from that previously reported for binary TAT complexes, plasma clearance studies were done in rabbits using human VN-TAT. 125I-VN-TAT was shown to be cleared rapidly from the circulation (t1/2alpha = 3.8 min) in a biphasic manner mainly by the liver. 125I-TAT had a similar initial clearance (t1/2alpha = 5.3 min) but had a significantly faster beta-phase clearance (t1/2beta = 42.8 min versus 85.4 min for VN-TAT; p = 0.005). Protamine sulfate and heparin abolished the rapid initial alpha-phase of 125I-VN-TAT clearance and reduced its liver-specific association and in vivo degradation. Heparin also reduced the alpha-phase clearance of 125I-TAT and was associated with the appearance of high molecular weight complexes, suggesting enhanced complex formation between VN and TAT. 125I-VN-TAT binding to HepG2 cells was reduced by competition with VN-TAT or heparin but to a much lesser extent in the presence of TAT. The binding of VN-TAT to HepG2 cells was not inhibited by competition with the low density lipoprotein receptor-related protein ligand, methylamine-alpha2-macroglobulin. 125I-VN-TAT binding was also inhibited by treating HepG2 cells with heparinase or by growing the cells in the presence of beta-D-xyloside. Finally, both heparin and chloroquine, but not methylamine-alpha2-macroglobulin, reduced the internalization and degradation of VN-TAT by HepG2 cells. Taken together, these data indicate the importance of VN in TAT metabolism and demonstrate that VN-TAT binds to liver-associated heparan sulfate proteoglycans, which mediate its internalization and subsequent intracellular degradation.     

Chemoenzymatic synthesis of classical and non-classical anticoagulant heparan sulfate polysaccharides

Heparan sulfate (HS) polysaccharides interact with numerous proteins at the cell surface and orchestrate many different biological functions. Though many functions of HS are well established, only a few specific structures can be attributed to HS functions. The extreme diversity of HS makes chemical synthesis of specific bioactive HS structures a cumbersome and tedious undertaking that requires laborious and careful functional group manipulations. Now that many of the enzymes involved in HS biosynthesis are characterized, we show in this study how one can rapidly and easily assemble bioactive HS structures with a set of cloned enzymes. We have demonstrated the feasibility of this new approach to rapidly assemble antithrombin III-binding classical and non-classical anticoagulant polysaccharide structures for the first time.     

Extracellular matrix heparan sulfate modulates endothelial cell susceptibility to Staphylococcus aureus

We have examined several types of tumor cell lines and shown that they invariably expressed little or no Egr-1, in contrast to their normal counterparts. We have previously shown that the expression of exogenous Egr-1 in human breast and other tumor cells markedly reduces transformed growth and tumorigenicity. We therefore hypothesized that the loss of Egr-1 expression plays a role in transformation. All human and mouse breast cancer cell lines and tumors examined had reduced Egr-1 expression compared with their normal counterparts. Reduced Egr-1 expression was also observed in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors, and this level increased to normal levels in tumors that regressed after tamoxifen treatment. We concluded, therefore, that loss of Egr-1 expression may play a role in the deregulation of normal growth in the tumorigenic process and that Egr-1 acts as a tumor suppressor gene.     

Secretion-capture role for apolipoprotein E in remnant lipoprotein metabolism involving cell surface heparan sulfate proteoglycans

To determine the impact of enhanced apolipoprotein (apo) E secretion on the mechanism of remnant lipoprotein uptake, rat hepatoma cells (McA-RH7777) were stably transfected with normal human apoE3 or receptor binding-defective apoE-Leiden. After a 2-h incubation, the human apoE secreted from the transfected hepatocytes was 10-12 times greater than the endogenous rat apoE. The apoE3-transfected cells bound and internalized rabbit beta-very low density lipoproteins (beta-VLDL) to a much greater degree than did apoE-Leiden-transfected cells and nontransfected cells. The apoE3-secreting cells displayed a 2-3.5-fold enhancement of cell-associated beta-VLDL compared to either the apoE-Leiden-transfected or nontransfected cells. Fluorescently labeled beta-VLDL were observed to concentrate within intracellular granules of the apoE3-transfected cells, presumably within endosomes and lysosomes. Furthermore, electron microscopy revealed that the apoE3-secreting cells displayed abundant beta-VLDL and chylomicron remnants on their cell surfaces and microvilli, in contrast to non-transfected or apoE-Leiden-secreting cells. Electron microscopy also revealed an abundance of chylomicron remnants within intracellular vesicles and multivesicular bodies of apoE3-transfected hepatocytes. Heparinase treatment (3 units/ml) completely abolished the increased association of beta-VLDL with apoE3-transfected cells but did not affect the limited association of beta-VLDL with apoE-Leiden-transfected or nontransfected cells. We established that the apoE3-enriched beta-VLDL were bound to cell surface heparan sulfate proteoglycans, as was the newly synthesized and secreted apoE3 (approximately 12% of the total secreted apoE3 was released by heparinase and suramin; 4% by heparin). In addition, reisolation of beta-VLDL by fast performance liquid chromatography after their incubation with exogenous apoE3, with medium from apoE3-secreting cells, or with the apoE3-secreting cells themselves revealed that the particles were enriched in apoE3 and displayed enhanced binding. These results suggest a secretion-capture role for apoE and indicate an important role for heparan sulfate proteoglycans on the cell surface for remnant lipoprotein metabolism.     

Herpes simplex virus infection and propagation in a mouse L cell mutant lacking heparan sulfate proteoglycans

We have isolated a variant line of mouse L cells, termed gro2C, which is partially resistant to infection by herpes simplex virus type 1 (HSV-1). Characterization of the genetic defect in gro2C cells revealed that this cell line harbors a specific defect in the heparan sulfate synthesis pathway. Specifically, anion-exchange high-performance liquid chromatography of metabolically radiolabeled glycosaminoglycans indicated that chondroitin sulfate moieties were synthesized normally in the mutant cells, whereas heparin-like chains were absent. Because of these properties, we have used these cells to investigate the role of heparan sulfate proteoglycans in the HSV-1 life cycle. In this report, we demonstrate that the partial block to HSV-1 infection in gro2C cells occurs in the virus entry pathway. Virus adsorption assays using radiolabeled HSV-1 (KOS) revealed that the gro2C cell surface is a relatively poor target for HSV-1 in that virus attachment was 85% lower in the mutant cells than in the parental L cell controls. A portion of the 15% residual virus adsorption was functional, however, insofar as gro2C cells were susceptible to HSV-1 infection in plaque assays and in single-step growth experiments. Moreover, although the number of HSV-1 plaques that formed in gro2C monolayers was reduced by 85%, the plaque morphology was normal, and the virus released from the mutant cells was infectious. Taken together, these results provide strong genetic evidence that heparan sulfate proteoglycans enhance the efficiency of HSV attachment to the cell surface but are otherwise not essential at any stage of the lytic cycle in culture. Moreover, in the absence of heparan sulfate, other cell surface molecules appear to confer susceptibility to HSV, leading to a productive viral infection.     

Role of the extracellular domain of human herpesvirus 7 glycoprotein B in virus binding to cell surface heparan sulfate proteoglycans

In an attempt to identify the human herpesvirus 7 (HHV-7) envelope protein(s) involved in cell surface binding, the extracellular domain of the HHV-7 glycoprotein B (gB) homolog protein was cloned and expressed as a fusion product with the Fc domain of human immunoglobulin G heavy chain gamma1 (gB-Fc) in an eukaryotic cell system. Indirect immunofluorescence followed by flow cytometric analysis revealed specific binding of gB-Fc to the membrane of SupT1 cells but not to other CD4+ T-lymphoblastoid cell lines, such as Jurkat or PM1, clearly indicating that gB-Fc did not bind to the CD4 molecule. This was also suggested by the ability of gB-Fc to bind to CD4-negative fibroblastoid Chinese hamster ovary (CHO) cells. The binding was abrogated by enzymatic removal of cell surface heparan sulfate proteoglycans by heparinase and heparitinase but not by treatment with condroitinase ABC. In addition, binding of the gB-Fc fusion protein to CHO cells was severely impaired in the presence of soluble heparin, as well as when heparan sulfate-deficient mutant CHO cells were used. Consistent with these findings, soluble heparin was found to block HHV-7 infection and syncytium formation in the SupT1 cell line. Although the CD4 antigen is a critical component of the receptor for the T-lymphotropic HHV-7, these findings suggest that heparin-like molecules also play an important role in HHV-7-cell surface interactions required for infection and that gB represents one of the HHV-7 envelope proteins involved in the adsorption of virus-to-cell surface proteoglycans.     

Interaction of hepatocyte growth factor with heparan sulfate. Elucidation of the major heparan sulfate structural determinants

We have demonstrated by affinity chromatography that hepatocyte growth factor (HGF) binds strongly to heparan sulfate (HS). This substantiates previous suggestions that cell-surface heparan sulfate proteoglycans constitute the so-called low affinity cellular binding sites for HGF. Using a recombinant human HGF affinity column, we have analyzed the effects of various specific chemical and enzymatic modifications/depolymerizations of HS on its affinity in order to elucidate the polysaccharide structural determinants. Interaction is shown to be only slightly affected by digestion with heparinase I or III or by replacement of N-sulfates with N-acetyl groups. This suggests a specific role for sulfated domains containing nonsulfated IdceA residues, with only a small contribution from N-sulfates and IdceA(2-OSO3) residues. In addition, disaccharide analyses of various HGF-binding oligosaccharides indicate that affinity is more closely associated with 6-O-sulfation of GlcNSO3 residues than with sulfation at any other position. Although interaction can be demonstrated with heparinase III-resistant oligosaccharides as small as hexasaccharides, the highest affinity was found with oligosaccharides containing a minimum of 10-12 monosaccharides. The structural specificity of the HGF-HS interaction is thus shown to be radically different from that previously described for the basic fibroblast growth factor-HS interaction.     

The heparan sulfate binding sequence of interferon-gamma increased the on rate of the interferon-gamma-interferon-gamma receptor complex formation

Interferon-gamma (IFNgamma), in common with a number of growth factors, binds both to heparan sulfate or heparin-related molecules and to a specific high affinity receptor (IFNgammaR). Using surface plasmon resonance technology, kinetic analysis of the IFNgamma. IFNgammaR complex formation was performed with the extracellular part of IFNgammaR immobilized on a sensor chip. At the sensor chip surface, IFNgamma was bound by two IFNgammaR molecules with an affinity in the nanomolar range (0.68 nM). This binding was characterized by an important on rate, kon = 7.3 x 10(6) M-1.s-1, and an off rate, koff = 5 x 10(-3).s-1. This binding assay was used to investigate a possible role of heparin in the IFNgamma.IFNgammaR complex formation. In contrast to growth factors for which binding to heparin is usually required for high affinity receptor interaction, we found in this study that IFNgamma bound to heparin displayed a strongly reduced affinity for its receptor. This is consistent with the fact that a cluster of basic amino acids (KTGKRKR, called the C1 domain) in the carboxyl-terminal sequence of the cytokine was involved both in heparin and receptor recognition. To understand how a single domain of IFNgamma could be implicated in two discrete functions (i.e. binding to heparin and to IFNgammaR), we also analyzed in a detailed manner the role of the IFNgamma carboxyl-terminal sequence in receptor binding. Using forms of IFNgamma, with carboxyl terminus truncations of defined regions of the heparin binding sequence, we found that the C1 domain functioned by increasing the on rate of the IFNgamma.IFNgammaR binding reaction but was not otherwise required for the stability of the complex. Interactions between the IFNgamma carboxyl-terminal domain and IFNgammaR could increased the association rate of the reaction either by increasing the number of encounters between the two molecules or by favoring productive collisions. The mechanisms by which heparan sulfate regulates IFNgamma activity may thus include both control of selective protease cleavage events, which directly affect the cytokine activity, and also an ability to modulate the interaction of IFNgamma with the IFNgammaR via competitive binding to the C1 domain.     

Arterial heparan sulfate proteoglycans inhibit vascular smooth muscle cell proliferation and phenotype change in vitro and neointimal formation in vivo

PURPOSE: The aim of this study was to determine whether heparan sulfate proteoglycans (HSPGs) from the normal arterial wall inhibit neointimal formation after injury in vivo and smooth muscle cell (SMC) phenotype change and proliferation in vitro. METHODS: Arterial HSPGs were extracted from rabbit aortae and separated by anion-exchange chromatography. The effect of HSPGs, applied in a periadventitial gel, on neointimal formation was assessed 14 days after balloon catheter injury of rabbit carotid arteries. Their effect on SMC phenotype and proliferation was measured by point-counting morphometry of the cytoplasmic volume fraction of myofilaments (Vvmyo) and 3H-thymidine incorporation in SMCs in culture. RESULTS: Arterial HSPGs (680 microg) reduced neointimal formation by 35% at 14 days after injury (P=.029), whereas 2000 microg of the low-molecular-weight heparin Enoxaparin was ineffective. HSPGs at 34 microg/mL maintained subconfluent primary cultured SMCs with the same high Vvmyo (52.1%+/-13.8%) after 5 days in culture as did cells freshly isolated from the arterial wall (52.1%+/-15.1%). In contrast, 100 microg/mL Enoxaparin was ineffective in preventing phenotypic change over this time period (Vvmyo 38.9%+/-14.6%, controls 35.9%+/-12.8%). HSPGs also inhibited 3H-thymidine incorporation into primary cultured SMCs with an ID50 value of 0.4 microg/mL compared with a value of 14 microg/mL for Enoxaparin (P< .01). CONCLUSION: When used periadventitially in the rabbit arterial injury model, natural arterial HSPGs are effective inhibitors of neointimal formation. In vitro, the HSPGs maintain SMCs in a quiescent state by inhibiting phenotypic change and DNA synthesis. This study suggests that HSPGs may be a natural agent for the treatment of clinical restenosis.     

Age-dependent modulation of heparan sulfate structure and function

Heparan sulfate interacts with growth factors, matrix components, effectors and modulators of enzymatic catalysis as well as with microbial proteins via sulfated oligosaccharide domains. Although a number of such domains have been characterized, little is known about the regulation of their formation in vivo. Here we show that the structure of human aorta heparan sulfate is gradually modulated during aging in a manner that gives rise to markedly enhanced binding to isoforms of platelet-derived growth factor A and B chains containing polybasic cell retention sequences. By contrast, the binding to fibroblast growth factor 2 is affected to a much lesser extent. The enhanced binding of aorta heparan sulfate to platelet-derived growth factor is suggested to be due to an age-dependent increase of GlcN 6-O-sulfation, resulting in increased abundance of the trisulfated L-iduronic acid (2-OSO3)-GlcNSO3(6-OSO3) disaccharide unit. Such units have been shown to hallmark the platelet-derived growth factor A chain-binding site in heparan sulfate.     

Isoaspartate in chrondroitin sulfate proteoglycans of mammalian brain

Mammalian brain contains a high mass protein (HMAP) that is unusually rich in atypical L-isoaspartyl (isoAsp) linkages. HMAP has now been purified from bovine brain by anion exchange, hydroxylapatite, and size exclusion chromatography. It is self-aggregating, acidic, and soluble in 5% trichloroacetic acid. Treatment with chondroitinase ABC eliminates the self-aggregation of HMAP and generates several distinct core proteins with estimated masses of 350-450 (doublet), 180, and 100 kDa, indicating that it is composed mainly of chondroitin sulfate proteoglycans (CSPGs). Most of the isoAsp resides in the 350-450-kDa core protein, which was identified by immunoblotting as phosphacan, a CSPG abundant in adult brain. The regional distribution and developmental profile of HMAP in rat brain support this identification. The 180-kDa core protein contains a tenascin-R-related molecule, consistent with recent observations that phosphacan forms a tight complex with tenascin-R. The average phosphacan molecule in adult brain contains at least seven isoAsp sites. Molecular heterogeneity due to isoAsp may explain some of the complex binding properties phosphacan exhibits with its natural ligands. Formation of isoAsp may be important in the roles that phosphacan and other CSPGs play in development of the nervous system.     

Characterization of the heparan sulfate and chondroitin sulfate assembly sites in CD44

Isoforms of CD44 are differentially modified by the glycosaminoglycans (GAGs) chondroitin sulfate (CS), heparan sulfate (HS), and keratan sulfate. GAG assembly occurs at serines followed by glycines (SG), but not all SG are utilized. Seven SG motifs are distributed in five CD44 exons, and in this paper we identify the HS and CS assembly sites that are utilized in CD44. Not all the CD44 SG sites are modified. The SGSG motif in CD44 exon V3 is the only HS assembly site; this site is also modified with CS. HS and CS attachment at that site was eliminated by mutation of the serines in the V3 motif to alanine (AGAG). Exon E5 is the only other CD44 exon that supports GAG assembly and is modified with CS. Using a number of recombinant CD44 protein fragments we show herein that the eight amino acids located downstream of the SGSG site in V3 are responsible for the specific addition of HS to this site. If the eight amino acids located downstream from the first SG site in CD44 exon E5 are exchanged with those located downstream of the SGSG site in exon V3, the SG site in E5 becomes modified with HS and CS. Likewise if the eight amino acids found downstream from the first SG in E5 are placed downstream from the SGSG in V3, this site is modified with CS but not HS. We also show that these sequences cannot direct the modification of CD44 with HS from a distance. Constructs containing CD44 exon V3 in which the SGSG motif was mutated to AGAG were not modified with HS even though they contained other SG motifs. Thus, a number of sequence and structural requirements that dictate GAG synthesis on CD44 have been identified.     

Binding of Sindbis virus to cell surface heparan sulfate

Alphaviruses are arthropod-borne viruses with wide species ranges and diverse tissue tropisms. The cell surface receptors which allow infection of so many different species and cell types are still incompletely characterized. We show here that the widely expressed glycosaminoglycan heparan sulfate can participate in the binding of Sindbis virus to cells. Enzymatic removal of heparan sulfate or the use of heparan sulfate-deficient cells led to a large reduction in virus binding. Sindbis virus bound to immobilized heparin, and this interaction was blocked by neutralizing antibodies against the viral E2 glycoprotein. Further experiments showed that a high degree of sulfation was critical for the ability of heparin to bind Sindbis virus. However, Sindbis virus was still able to infect and replicate on cells which were completely deficient in heparan sulfate, indicating that additional receptors must be involved. Cell surface binding of another alphavirus, Ross River virus, was found to be independent of heparan sulfate.     

Defining the interleukin-8-binding domain of heparan sulfate

Interleukin-8, a member of the CXC chemokine family, has been shown to bind to glycosaminoglycans. It has been suggested that heparan sulfate on cell surfaces could provide specific ligand sites on endothelial cells to retain the highly diffusible inflammatory chemokine for presentation to leukocytes. By using selectively modified heparin and heparan sulfate fragments in a nitrocellulose filter trapping system, we have analyzed sequence requirements for interleukin-8 binding to heparin/heparan sulfate. We demonstrate that the affinity of a monomeric interleukin-8 molecule for heparin/heparan sulfate is too weak to allow binding at physiological ionic strength, whereas the dimeric form of the protein mediates binding to two sulfated domains of heparan sulfate. These domains, each an N-sulfated block of approximately 6 monosaccharide units, are contained within an approximately 22-24-mer sequence and are separated by a region of 相似文献   

Functional analysis of conserved cysteines in heparan sulfate N-deacetylase-N-sulfotransferases

N-Deacetylase-N-sulfotransferases (NDANST) catalyze the two initial modifications of the polysaccharide precursor in the biosynthesis of heparin and heparan sulfate. These modifications are the gating steps in establishing growth factor protein-binding domains of these glycosaminoglycans. We have undertaken a structure-activity analysis of the 841-amino acid Golgi-luminal portion of the rat liver NDANST to localize the two enzymatic functions. Each activity can be assayed in vitro independently of the other when provided with the appropriate substrate, and N-ethylmaleimide treatment selectively inactivates the deacetylase activity. In this study, dithiothreitol treatment of the rat liver NDANST was shown to inactivate the sulfotransferase function, while stimulating deacetylase activity 2-3-fold over the native protein. Site-directed mutagenesis of the eight cysteine (Cys) residues in the rat liver NDANST that are conserved in the mouse mastocytoma protein produced three important findings regarding the localization of each enzymatic function: 1) derivatization of Cys486 with N-ethylmaleimide resulted in total inactivation of the deacetylase activity based on steric hindrance of the active site (this residue was shown not to be involved in enzymatic catalysis), 2) substitution of either Cys159 or Cys486 with alanine resulted in enhanced activity of the deacetylase to the level obtained by dithiothreitol treatment, and 3) alanine substitution of Cys818 or Cys828 completely inactivated the sulfotransferase activity, while substitution of Cys586 or Cys601 resulted in a 90% loss in activity. These findings suggest that the two enzymatic domains within the NDANST localize to different portions of the protein, with two disulfide pairs toward the COOH-terminal half of the protein necessary for the sulfotransferase activity, and Cys residues within the NH2-terminal half influencing or located near the active site of the deacetylase functionality.     

Stimulation of heparan sulfate proteoglycan synthesis and secretion during G1 phase induced by growth factors and PMA

Pulsatile tinnitus is a disorder that can be extremely disabling. Nonetheless, it has not been well-researched in the fields of psychology or behavioral therapy. This article describes the evaluation and behavioral treatment of a gentleman with pulsatile tinnitus. The evaluation included polygraphic assessment of vasomotor and electromyographic function both before and after treatment. The results show that the combination of lifestyle modifications and specific behavioral interventions were successful in modifying not only self-report indices of functioning, but also the underlying physiology related to the disorder. The potential role of the various treatment components and the value of including polygraphic assessment for informing treatment and evaluating outcome are discussed.