Effects of CC-chemokine receptor 5 on ROCK2 and P-MLC2 expression after focal cerebral ischaemia-reperfusion injury in rats.

OBJECTIVE: CC-chemokine receptor 5 (CCR5) plays a pivotal role in reperfusion after stroke. This study assessed and confirmed the effects of CCR5 in experimental stroke via regulation of ROCK/P-MLC pathway. METHODS: Male Sprague Dawley (SD) rats were randomly divided into sham group, ischaemia-reperfusion group (I/R group) and DAPTA group (I/R + CCR5 antagonist group). The rats of the I/R group were subjected to transient middle cerebral artery occlusion (tMCAO) for 2 hours, followed by 24 hours of reperfusion. Animals were measured for neurologic deficit, cerebral infarct volume, TUNEL and hematoxylin-eosin (HE) staining. The protein expressions of ROCK2 and P-MLC2(Ser19) were determined by western blot. RESULTS: Pre-treatment with DAPTA displayed significantly improved neurological functional outcome and reduced cerebral lesion compared with the I/R group animals (p < 0.05); HE staining showed that the I/R group had severe neuronal damage in the ischaemia core and penumbral; Compared with the I/R group, ROCK2 and P-MLC2(Ser19) protein expression in the DAPTA group was reduced (p < 0.05). CONCLUSIONS: The data demonstrate that CCR5 is correlated with up-regulation of the expression of ROCK2 and P-MLC2(Ser19) in the ischaemia cortex. Treated with CCR5 antagonist protects the brain against focal cerebral ischaemia-reperfusion injury in rats.

The chemokine CCL5 induces CCR1-mediated hyperalgesia in mice inoculated with NCTC 2472 tumoral cells.

Although the expression of the chemokine receptor CCR1 has been demonstrated in several structures related to nociception, supporting the nociceptive role of chemokines able to activate it, the involvement of CCR1 in neoplastic pain has not been previously assessed. We have assayed the effects of a CCR1 antagonist, J113863, in two murine models of neoplastic hyperalgesia based on the intratibial injection of either NCTC 2472 fibrosarcoma cells, able to induce osteolytic bone injury, or B16-F10 melanoma cells, associated to mixed osteolytic/osteoblastic bone pathological features. The systemic administration of J113863 inhibited thermal and mechanical hyperalgesia but not mechanical allodynia in mice inoculated with NCTC 2472 cells. Moreover, in these mice, thermal hyperalgesia was counteracted following the peritumoral (10-30µg) but not spinal (3-5µg) administration of J113863. In contrast, hyperalgesia and allodynia measured in mice inoculated with B16-F10 cells remained unaffected after the administration of J113863. The inoculation of tumoral cells did not modify the levels of CCL3 at tumor or spinal cord. In contrast, although the concentration of CCL5 remained unmodified in mice inoculated with B16-F10 cells, increased levels of this chemokine were measured in tumor-bearing limbs, but not the spinal cord, of mice inoculated with NCTC 2472 cells. Increased levels of CCL5 were also found following the incubation of NCTC 2472, but not B16-F10, cells in the corresponding culture medium. The intraplantar injection of CCL5 (0.5ng) to naïve mice evoked thermal hyperalgesia prevented by the coadministration of J113863 or the CCR5 antagonist, d-Ala-peptide T-amide (DAPTA), demonstrating that CCL5 can induce thermal hyperalgesia in mice through the activation of CCR1 or CCR5. However, contrasting with the inhibitory effect evoked by J113863, the systemic administration of DAPTA did not prevent tumoral hyperalgesia. Finally, the peritumoral administration of an anti-CCL5 antibody completely inhibited thermal hyperalgesia evoked by the inoculation of NCTC 2472 cells.

Chemokine receptor-5 (CCR5) is a receptor for the HIV entry inhibitor peptide T (DAPTA).

The chemokine receptor CCR5 plays a crucial role in transmission of HIV isolates, which predominate in the early and middle stages of infection, as well as those, which populate the brain and cause neuro-AIDS. CCR5 is therefore an attractive therapeutic target for design of entry inhibitors. Specific rapid filtration binding assays have been useful for almost 30 years both for drug discovery and understanding molecular mechanisms of drug action. Reported in 1986, prior to discovery of chemokine co-receptors and so thought to act at CD4, peptide T (DAPTA) appears to greatly reduce cellular viral reservoirs in both HAART experienced and treatment naïve patients, without toxicities. We here report that DAPTA potently inhibits specific CD4-dependent binding of gp120 Bal (IC50=0.06 nM) and CM235 (IC50=0.32 nM) to CCR5. In co-immunoprecipitation studies, DAPTA (1 nM) blocks formation of the gp120/sCD4 complex with CCR5. Confocal microscopic studies of direct FITC-DAPTA binding to CCR5+, but not CCR5-, cells show that CCR5 is a DAPTA receptor. The capability of DAPTA to potently block gp120-CD4 binding to the major co-receptor CCR5 explains its molecular and therapeutic mechanism of action as a selective antiviral entry inhibitor for R5 tropic HIV-1 isolates.

Antiviral and immunological benefits in HIV patients receiving intranasal peptide T (DAPTA).

D-Ala-Peptide T-amide (DAPTA), the first viral entry inhibitor, blocks chemokine (CCR5) receptors, not CD4. Early investigators could not "replicate" DAPTAs potent in vitro antiviral effect using the lab-adapted, X4, peptide T-insensitive strain, IIIB, delaying clinical virological studies. We now report that DAPTA, administered to eleven long-term infected (mean=17 years) patients with stable persistent plasma "virus" for up to 32 weeks did not change this level. Infectious virus could not be isolated from their plasma suggesting HIV RNA was devoid of replicative capacity. Progressively less actual virus (P<0.01) could be isolated from white blood cells (PBMCs). DAPTA flushed the monocyte reservoir to undetectable viral levels in most patients. Five of eleven had a mean CD4 increase of 33%. Immune benefits also included a four-fold increase in gamma-interferon-secreting T-cells (antiviral cytotoxic T-cells) in the absence of drug-related toxicity. All five CD4 responders had increases in antiviral T cells and decreases in infected monocytes, an argument for initiating further studies promptly.

Update on D-ala-peptide T-amide (DAPTA): a viral entry inhibitor that blocks CCR5 chemokine receptors.

Peptide T, named for its high threonine content (ASTTTNYT), was derived by a database search which assumed that a relevant receptor binding epitope within env (gp120) would have sequence homology to a known signaling peptide. Binding of radiolabeled gp120 to brain membranes was displaced by peptide T and three octapeptide analogs (including "DAPTA", Dala1-peptide T-amide, the protease-resistant analog now in Phase II clinical trials) with the same potency that these four octapeptides blocked infectivity of an early passage patient isolate. This 1986 report was controversial due to a number of laboratories' failure to find peptide T antiviral effects; we now know that peptide T is a potent HIV entry inhibitor selectively targeting CCR5 receptors with minimal effects on the X4 tropic lab adapted virus exclusively in use at that time. Early clinical trials, which demonstrated lack of toxicity and focused on neurological and neurocognitive benefits, are reviewed and data from a small ongoing Phase II trial--the first to assess peptide T's antiviral effects--are presented. Studies using infectivity, receptor binding, chemotaxis, and blockade of gp120-induced neurotoxicity in vitro and in vivo are reviewed, discussed and presented here. Peptide T and analogs of its core pentapeptide, present near the V2 stem of numerous gp120 isolates, are potent ligands for CCR5. Clinical data showing peptide T's immunomodulation of plasma cytokine levels and increases in the percentage of IFNgamma secreting CD8+ T cells in patients with HIV disease are presented and suggests additional therapeutic mechanisms via regulation of specific immunity.

Biologic therapy for psoriasis: a brief history, I.

This article, the first in a 2-part series, reviews the treatment of psoriasis with biologic therapy. Although extensive research in this venue of treatment is currently being conducted, we review some of the pioneering clinical trials dealing with immunotherapy, including the use of peptide T, anti-CD4 antibody (OKTcdr4a and hIgG1-CD4), and anti-Tac. For each of these therapies, an extensive summation is given of the research, taking note of the investigators' procedural course, results, and side effects seen. Through the results of these studies, a foundation was laid for the further exploration of the use of biologic therapy to combat psoriasis.

Peptide T does not ameliorate experimental autoimmune encephalomyelitis (EAE) in Lewis rats.

Peptide T has been shown to inhibit T cell activation and cytokine production and function. Moreover, it has been reported to be a safe treatment in humans. We have studied the ability of peptide T to prevent or ameliorate EAE in Lewis rats. Peptide T was administered subcutaneously at different doses and phases of the disease according to several treatment protocols, but we could not observe a consistent effect of peptide T ameliorating the disease. Lymph node cell proliferation and IL-4 and interferon-gamma production were also studied. We conclude that peptide T neither prevents nor ameliorates EAE in Lewis rats.

Anti-chemotactic activities of peptide-T: a possible mechanism of actions for its therapeutic effects on psoriasis.

Peptide T is an octapeptide (ASTTTNYT) from the V2 region of gpl20 of HIV. D-[Ala]-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-amide (DAPTA) is one of its analogue. DAPTA has been shown to resolve the psoriatic lesions. The mechanisms of action of peptide T for its therapeutic effect is not clearly understood. Lymphomononuclear cells play an important roles in inflammatory disease processes. Intraepidermal collection of lymphocytes is a unique feature of the inflammatory processes of psoriasis. It is believed that chemokine such as RANTES (C-C class) plays an important role for intraepidermal localization of the inflammatory infiltrates in psoriasis. In order to study the mechanisms, we have analyzed the effects of DAPTA on monocyte and lymphocyte chemotaxis. Chemotaxis of cells was measured by using Boyden chamber. DAPTA inhibited significantly the monocyte and lymphocyte chemotactic activity of RANTES (p < 0.005, < 0.001). Antichemotactic activities of peptide T analogue could be a possible explanation for its therapeutic efficacy in psoriasis.

Randomized double-blind placebo-controlled trial of peptide T for HIV-associated cognitive impairment.

BACKGROUND: Cognitive impairment is a common consequence of human immunodeficiency virus (HIV) infection, and dementia is one of the diseases that defines the acquired immunodeficiency syndrome. Peptide T (d-ala-peptide-T-amide) has been reported to block the binding of gp120 to brain tissue and to protect neurons from the toxic effects of gp120 in vitro. In pilot studies, administration of peptide T to HIV-positive patients with cognitive impairment was associated with improvement in cognition and constitutional symptoms. OBJECTIVE: To determine whether the intranasal administration of peptide T would improve cognitive function of HIV-positive patients with cognitive impairment. PATIENTS AND METHODS: This was a 3-site, double-blind, placebo-controlled trial of peptide T given intranasally at a dosage of 2 mg 3 times a day for 6 months. Participants were HIV-seropositive persons with evidence of cognitive deficits on a screening test battery. Concomitant antiretroviral therapy was allowed. Randomization to the 2 study arms was balanced according to several stratification variables, such as CD4+ cell count, severity of cognitive impairment, and antiretroviral therapy at study entry. A comprehensive neuropsychological (NP) battery, which yielded 23 scores, was administered at baseline and the study end point. The primary outcome measure was a global NP score derived from the 23 standardized scores. The efficacy end point was the change in NP score at 6 months compared with baseline. Secondary efficacy measures were 7 cognitive domain scores and deficit scores of global and domain performance. The patients who completed the baseline and final NP evaluations (after at least 4 months in the randomized treatment arm) were included in the efficacy analyses. Additional analyses were conducted on subgroups of patients according to the CD4+ count and baseline NP deficit. The incidence of NP improvement in the 2 treatment arms was also compared. RESULTS: There was no statistically significant difference between the peptide T and placebo groups on the global NP change score, the individual domains, or the deficit scores. Because of an imbalance in the baseline CD4+ cell count between treatment arms, analyses were also adjusted for this variable. These CD4+-adjusted analyses suggested (P = .07; analysis of covariance [ANCOVA]) a greater improvement in the peptide T group. Subgroup analyses indicated a treatment effect for patients whose CD4 cell count was above 0.200 x 10(9)/L (200 cells/microL) at baseline. Moreover, peptide T treatment was associated with overall cognitive improvement in patients with baseline global deficit scores of at least 0.5, while overall deterioration was more common among the placebo group (P = .02; Mantel-Haenszel chi(2) test). CONCLUSIONS: Peptide T was not significantly different from placebo on the study primary end points. However, additional analyses indicated that peptide T may be associated with improved performance in the subgroup of patients with more evident cognitive impairment (ie, NP global deficit score > or = 0.5) or with relatively preserved immunological status (ie, CD4+ cell count > 0.200 x 10(9)/L).

Treatment of early AIDS dementia in intravenous drug users: high versus low dose peptide T.

This placebo-controlled, double blind, cross-over study tested the efficacy of two different doses of Peptide T in the treatment of nine intravenous drug users with early AIDS dementia who were also receiving methadone and AZT. Subjects received Peptide T doses of either 15 or 1.5 mg daily for four weeks. Neuropsychological performance improved in four of five patients treated with the high dose, but at the lower dose, three of four patients showed no improvement on Peptide T when compared with placebo. When subjects who received the high dose were compared with those who received the low dose, a significant dose effect was found only during the active phase of the trial even after correction for differences in level of functioning at baseline.

[Neuropeptides in dermatologic therapy]. / Los neuropéptidos en la terapéutica dermatológica.

The presence of neuropeptides and their specific receptors has been detected in the skin and the epithelial tissues. They are involved in innervation, immunomodulation, glandular secretion, control of cellular proliferation and regulation of blood flow. The fact that they act in so many different ways means that neuropeptides and their agonists and antagonists are now being regarded as potential therapeutic agents in dermatologic diseases. Among the substances which act as antagonists, particular attention should be paid to capsaicin, which has therapeutic potential for three types of indication: peripheral neurologic pain, affections with a neurogenic inflammatory component and pruriginous dermatosis; peptide T with therapeutic potential for psoriasis; and spantide, which might prove useful in dermatoses related to substance P. The influence of topical corticosteroids on the mechanism of action of neuropeptides can explain its efficacy in the treatment of many dermatoses. Among the agonists, the possibility of taking advantage of the vasodilatory activity of the calcitonin gene-related peptide is being considered in Raynaud's disease and erectile disfunction of the penis; and the immunomodulatory and anti-inflammatory action of the alpha-melanocyte stimulating hormone is being studied as a potential means of controlling inflammatory dermatoses of immunological origin.

Peptide T in the treatment of painful distal neuropathy associated with AIDS: results of a placebo-controlled trial. The Peptide T Neuropathy Study Group.

OBJECTIVE: To assess the safety and efficacy of Peptide T in the treatment of painful distal symmetrical polyneuropathy (DSP) associated with human immunodeficiency virus (HIV) infection. BACKGROUND: Painful DSP is a frequent complication of HIV infection, although its etiology and optimal treatment are unknown. Peptide T (D-(alpha 1)-Peptide T-amide) has been found in phase I trials and anecdotal reports to relieve neuropathic pain in AIDS patients. DESIGN/METHODS: In this multicentered, double-blind, randomized study, subjects received intranasal Peptide T 6 mg/day or placebo for 12 weeks. The primary outcome measure was change in the modified Gracely pain score. Secondary efficacy variables were results of neurologic examination, neuropsychological and electrophysiologic studies, global evaluation, and CD4 lymphocyte counts. RESULTS: Of 81 evaluable subjects, 40 received Peptide T and 41 received placebo. The change in pain scores was not significantly different (p = 0.32) in the Peptide T group (-0.24) as compared to placebo (-0.39). Group comparisons were not significantly different for change in any clinical examination or neuropsychologic measure, sural nerve amplitude or conduction velocity, or CD4 lymphocyte count. No significant drug-related adverse effects occurred in either group. CONCLUSION: Intranasal Peptide T is safe but ineffective in the treatment of painful DSP associated with AIDS.

Peptide T and glucose metabolism in AIDS dementia complex.

AIDS dementia complex (ADC) is the most common presenting neurologic manifestation of human immunodeficiency virus (HIV)-1 infection. We report FDG-PET studies in a 39-year-old man who had ADC and completed a 12-wk treatment protocol with 1.2 mg/day of intranasal peptide T, one before and one after 12 wk of treatment with peptide T. Peptide T is an octapeptide under investigation for treatment of ADC patients. Values of rCMRglc were converted to Z scores using the mean and standard deviation of values of rCMRglc in three HIV-seronegative matched controls, each of which was studied twice, at the beginning and end of a 12-wk interval. Thirty-five of 60 regions assayed showed Z scores with absolute values > or = 3 (considered abnormal) in the baseline study. Regions with high absolute values of Z scores were located in subcortical areas and in the limbic system, and to a lesser degree in the frontal, temporal and parietal lobes. Thirty-four of these 35 regions showed remission (decrease in the absolute values of Z scores) after treatment. Only one region showed no improvement in the second study. Three regions with absolute values of Z scores < 3 in the baseline study manifested Z scores with magnitudes > or = 3 in the second study. These preliminary observations suggest that functional neuroimaging techniques provide a useful tool in the evaluation of the response to treatment in ADC patients.

Peptide T not effective for cognitive impairment.

AIDS: In a study conducted by the National Institutes of Health (NIH), open-label peptide T, a synthetic compound of eight amino acids, was found to be ineffective for the treatment of cognitive impairment in HIV-positive participants. Half of the 215 patients received 6 mg of peptide T intranasally for 6 months, the other half were given a placebo. All were placed on the drug for the following 6 months. Researchers measured overall neurological functions and seven cognitive functions, including memory and attention.^ieng

Peptide T.

AIDS: A 215-person trial sponsored by the National Institute of Mental Health (NIMH) has found that peptide T offers no benefit for people with HIV-related cognitive impairments. Peptide Technologies, of Australia, will discontinue all further studies of peptide T in the United States. Peptech, the American subsidiary, still claims to have confidence in the drug.^ieng

Peptide T: negative trial result.

AIDS: A placebo-controlled clinical trial studied the effects of peptide T on people with AIDS-related cognitive impairment. Results from 215 volunteers found no proof that peptide T was helpful for treating this condition, and that there was no toxicity from peptide T.^ieng

Peptide T for cognitive impairment.

AIDS: A nationwide, eleven-site study has begun that uses injectable peptide T for HIV-associated cognitive impairment. The twelve-week, placebo-controlled study will measure peptide T's ability to help neurocognitive impairment by reducing brain levels of TNF-alpha, an immune system stimulant present in high levels during HIV infection.^ieng

Histopathological and immunohistochemical changes in psoriatic skin during peptide T treatment.

Ten patients with plaque-type psoriasis were treated with 2 mg peptide T i.v. for 28 days. Six patients responded with a substantial clinical improvement. Sequential biopsies from skin lesions were taken before, during and after treatment. The histological score (defining the activity of the psoriasis), the epidermal thickness and the number of infiltrating dermal lymphocytes were all reduced in the six patients who responded to the treatment. An increase in the number of CD1+ dendritic cells was detected immunohistochemically in the epidermis of the responders. The nonresponders did not display any pronounced changes.