[Effect of synthetic tripeptides on hemopoietic stem cells in norm and after gamma-irradiation].

Our work was aimed at researching into the influence of dipeptide (gamma-dGlu-dTrp) "Timodepressin" and this dipeptide-based tripeptides on the colony-forming ability of the irradiated in vitro bone marrow and hemopoietic stem cells of the normal organism. Also studied was the effect of various doses (1-1000 microg/kg) of one oftripeptides (dAla-gammadGlu-dTrp) on the output of exogenous splenic colonies in the case of its introduction 48 hours before irradiation. It is shown that the mode of influence of the preparations produced on the basis ofdipeptides dGlu-dTrp and gamma-dGlu-dTrp on the initial stages ofa hemopoiesis in the normal and irradiated organism depends on the nature of the additional amino-acid residue and its optical orientation.

[Influence of peptide derivatives of diketopiperazines on hemopoietic stem cells of an intact organism and irradiated bone marrow cells in vitro].

We have performed structural and functional studies of the hemotropic activity for a number of novel 2,5-diketopiperazine peptidomimetic derivatives. We employed a mouse model of hemopoietic stem cells cloning in the spleen of lethally irradiated animals. Biologic activity of synthetic products was studied in two experimental models: 1) in vitro irradiated bone marrow SFU-S was used for studying the radio modifying activity; 2) the biological effect of peptidomimetics on the intact non-irradiated bone marrow was evaluated in vivo. Various ways of administration of the peptidomimetics studied were used in the in vivo experiments: intravenous, intraperitoneal or subcutaneous injections and oral administration in the dose range of 10-10000 microg/kg. As a result of our work, we have discovered 2,5-diketopiperazine peptidomimetic derivatives with the dual activity: stimulation of intact committed SFU-S and radiomodifying activity.

[The study of peptide stability during hydrolysis by rat gastroenteric tract fragments].

The hydrolytic stability of therapeutic peptides such as dalargin, stemokin and some others, including cyclic tripeptides modified by ibuprofen and aspirin, was studied. Two experimental systems were used, one containing purified enzymes pepsin, trypsin and chymotrypsin and other based on fragments of rat stomach and ileum. It was found that linear peptides without D-aminoacids are hydrolyzed by fragments of stomach and ileum but resistant to hydrolysis with purified enzymes. The peptides with D-aminoacids and cyclic peptides are stable in all experimental conditions used, however, peptides modified with aspirin lost acetyl moiety of aspirin residue in acidic medium, the process is accelerated in presence of pepsin.

Protective effect of dermorphin analogue sedatin on indomethacin-induced injury to the gastric mucosa.

Administration of indomethacin (250 mg/kg) to mice was followed by the formation of severe ulcerative and erosive injury to the gastric mucosa, inhibition of DNA synthesis, and development of oxidative stress. Fivefold pretreatment with sedatin (100 microg/kg) decreased the area of indomethacin-induced ulcers and erosions, stimulated DNA synthesis, and reduced the severity of oxidative stress. Non-arginine dermorphin analogue did not stimulate DNA synthesis and had no effect on the degree of oxidative stress. After pretreatment with L-NAME, sedatin did not modulate the synthesis of DNA under conditions of indomethacin-induced injury to the gastric mucosa.

Dipeptide gamma-d-Glu-d-Trp (thymodepressin) inhibits migration of CD34+ cells from the bone marrow into peripheral blood during tumor growth.

We studied the effect of dipeptide gamma-d-Glu-d-Trp (thymodepressin) on migration of CD34+ hemopoietic precursors and their direct adhesion to fibronectin in tumor-bearing mice on days 8, 11, 15, and 17 of tumor growth and on expression of CXCR-4 (CD184+) to SDF-1 and integrin beta1 (CD29+) by bone marrow cells. In tumor-bearing mice treated with gamma-d-Glu-d-Trp, the percent of CD34+ hemopoietic precursors in the peripheral blood considerably decreased throughout the observation period; the content of CD34+ hemopoietic precursors in the tumor tissue was 2-3-fold below the control against the background of increased content of CD34+ cells in the bone marrow. In animals treated with the peptide, the content of cells expressing CXCR-4 in the peripheral blood, bone marrow, and tumor tissue significantly decreased, while the percent of cells expressing integrin beta1 receptor (CD29+) in the bone marrow increased 2-fold, which was paralleled by an almost 2-fold increase in the percent of cells binding to fibronectin. We hypothesized that dipeptide gamma-d-Glu-d-Trp suppressed mobilization/migration of CD34+ hemopoietic precursor cells from the bone marrow to the peripheral blood of tumor-bearing mice.

The effects of the EW dipeptide optical and chemical isomers on the CFU-S population in intact and irradiated mice.

The influence of Glu-Trp (EW) synthetic dipeptide isomers on hemopoietic progenitor cells and certain immune response reactions is determined by their optical and chemical properties. Thus, the all L-amino acid containing dipeptides L-Glu-L-Trp and L-gammaGlu-L-Trp have no effect on proliferation of committed and pluripotent CFU-S in intact bone marrow. The optical isomers of the Glu residue are an essential determinant of the EW dipeptide biological activity. The inversion of the amino acid optical form imparts suppressor properties: D-Glu-D-Trp,D--gammaGlu-D-Trp, D-Glu-L-Trp and D-gammaGlu-L-Trp inhibit proliferation of hemopoietic progenitors in intact bone marrow. The type of the peptide bond between L-Glu and Trp is another important factor for the biological activity of the L-Glu-containing peptides. Unlike L-Glu-D-Trp with alpha-peptide bond, the dipeptide L-gammaGlu-D-Trp with gamma-peptide bond stimulates CFU-S-8 proliferation in intact bone marrow. The diverse effects of the EW optical isomers on hemopoietic progenitors underlie the radioprotective properties of the D-Glu-containing dipeptides and the radiotherapeutic ones of the L-Glu dipeptides. In animals, pre-irradiation injection of D-Glu-D-Trp, D-gammaGlu-D-Trp, D-Glu-L-Trp, D-gammaGlu-L-Trp, or post-irradiation injection of L-Glu-L-Trp, L-gammaGlu-L-Trp promoted regeneration of the hemopoietic progenitor population.

Mechanisms for the effect of arginine-containing dermorphin analogue on proliferative processes in the gastric mucosa of albino rats.

Treatment with synthetic arginine-containing dermorphin analogue sedatin (100 mg/kg, 5 intraperitoneal injections) stimulated DNA synthesis in the gastric mucosa and decreased spontaneous and induced chemiluminescence in homogenates of the stomach from albino rats. Non-arginine sedatin analogue in the same dose had little effect on DNA synthesis and free radical oxidation. Fivefold treatment with NO synthase inhibitor L-NAME (9.3 x 10(-5) mol/kg) suppressed DNA synthesis in the gastric mucosa. Sedatin did not modulate DNA synthesis against the background of L-NAME administration.

Effect of sedatin (synthetic dermorphin analog) on the development of Acipenser schrenckii young fish.

We studied delayed effects of sedatin (arginine-containing mu/delta-opioid receptor agonist) and its arginine-free analog on the ontogenetic development of fish. Fertilized eggs of the Amur sturgeon (Acipenser schrenckii) were treated with the peptides. The results indicate that sedatin increased activities of the antiradical and antioxidant defense systems, stimulated fry development by increasing body weight and length, and increased the number of nucleoli in the myocardium and liver of young fish.

Thymodepressin inhibits migration of CD34+ cells from bone marrow in normal and granulocyte CSF-stimulated hemopoiesis.

We studied the effect of thymodepressin on migration and adhesion of mouse hemopoietic CD34+ cells under normal conditions and under the effect of granulocytic CSF. It was found that the peptide reduced the absolute number of CD34+ hemopoietic cells in the peripheral blood, increased the percent of cells bound to fibronectin and expressing receptor for integrin beta1 (CD29+) in the bone marrow of mice under normal conditions and after stimulation with granulocytic CSF, and reduced the relative number of cells carrying CXCR4 receptor for stromal factor-1 (CD184+) in the bone marrow (CD34+CD184+) and blood (CD184+) of mice stimulated with granulocytic CSF. The results suggest that thymodepressin can inhibit migration of CD34+ cells from bone marrow into peripheral blood under conditions of normal and granulocytic CSF-stimulated hemopoiesis.

Effects of structural and "mixed" isomers of Glu-Trp dipeptide on normal hemopoietic stem cells.

We studied the effects of optical (dd-, ll-, dl-, and ld-dipeptides with alpha-bond, EW) structural isomers and cyclic (dd-, ll-, dl-, and ld-dipeptides with gamma-bond, iEW) analogs of Glu-Trp synthetic dipeptide on the population of normal hemopoietic stem cells. Dipeptides containing lGlu (lGlu-lTrp, lGlu-dTrp) injected to mice were inert towards committed bone marrow CFU-S; dGlu-containing dipeptides (dGlu-dTrp, dGlu-lTrp) inhibited the growth of CFU-S-8; and LiGlu-dTrp stimulated these cells. Inhibitory or stimulatory effects of optical and chemical isomers of Glu-Trp dipeptide are determined by optical orientation and nature of peptide bond of Glu residue. The effects of cyclic and mixed peptides towards colony formation are similar to those of the corresponding linear dipeptides.

Effects of iEW synthetic peptide isomers on bone marrow colony-forming capacity in vivo.

Studies of cooperative effects of D- or L-isomers of iEW dipeptide and neuraminidase on the number of splenic CFU, comparison of the peptide effects on CD34+ cells and splenic CFU, and evaluation of the effects of iEW D- or L-isomers on parameters of T-cell activation showed that interactions of L-(iEW) and D-(iEW) with CD34+ surface receptors are realized through the same mechanism, while their different biological effects on hemopoietic precursor cells in vivo can be explained by their different influence on T-component of the microenvironment.

[Thymodepressin protects murine bone marrow CFU-S from the hyperthermic damage].

Was studied the influence of the Thymodepressin (dipeptide D-iEW--a new Russian immuno- and haemodepressant), on the hyperthermic sensitivity of haemopoietic precursors (CFU-S) and tumor model cells (EL-4 and Rauscher leukaemia). It was determined, that the injection of the Thymodepressin to donor mice, or the incubation with the preparation of the marrowy cells of normal mice provides the increasing of the CFU-S resistance to the following heating (43 degrees C). On the contrary, Thymodepressin-treated tumor cells became even more heat-sensitive. The data show that Thymodepressin can be useful for protection the haemopoietic precursors not only from radiation and chemotherapy, as it was shown earlier, but also from the hyperthermy.

[Carcinogen activity of the new drug thymodepressin studied in chronic tests on rats and mice]. / Izuchenie kantserogennoi aktivnosti novogo lekarstvennogo sredstva - timodepressina v chronicheskikh opytakh na krysakh i myshakh.

The new drug thymodepressin was subcutaneously injected in doses 0.0145 and 0.145 mg/kg in rats and mice over a period of 104 weeks. No statistically significant difference in the tumor frequencies between the test and control groups was observed during this period of time. It is concluded that thymodepressin is not carcinogenic.

Effect of the arginine-containing mu,delta-opiate receptor agonist sedatin on DNA synthesis in the epithelium of the gastric fundus in albino rats.

We studied the effect of arginine-containing mu,delta-opiate receptor agonist sedatin on DNA synthesis in the epithelium of the gastric fundus in albino rats. Fivefold intraperitoneal injection of sedatin in various doses increased the index of labeled nuclei. Similar changes were observed after intranasal and intraperitoneal treatment with sedatin in a dose of 10 microg/kg for 21 days. Administration of sedatin for 21 days prevented the decrease in weight gain induced by experimental stress. Our results suggest that arginine entering the composition of sedatin plays a role in its biological effects.

[Immunogenic peptide neogen stimulates postradiation recovery thrombopoiesis]. / Immunomoduliator neogen stimuliruet postradiatsionnoe vosstanovlenie trombotsitopoéza.

In experiments on mice F1 total exposed to gamma-irradiation at the 5.0 Gy, showed that a intraperitoneal injection neogen at the dose 10 micrograms/kg oue time at the day and night during the 8 days after irradiation results in recovery of the number blood platelets and time issue of blood from standard wound to normal level on the week by compare with irradiated control animals.

Proliferative processes in the epidermis of patients with atopic dermatitis treated with thymodepressin.

Proliferative activity of the epidermis in skin biopsy specimens from patients with atopic dermatitis before and during therapy with thymodepressin (immunosuppressant) was studied by immunohistochemical method (by expression of Ki-67 antigen). The number of Ki-67-positive keratinocyte nuclei in atopic dermatitis considerably surpassed the corresponding parameter in intact skin (32.46 +/- 3.06% vs. 8.73 +/- 1.28%, p<0.05). Two 10-day courses of thymodepressin (0.1% solution, 1 ml intramuscularly) for 30 days reduced the number of Ki-67-positive keratinocyte nuclei to 20.78 +/- 3.36%. Clinical improvement was also achieved (sleep became normal, itching decreased, erythema and desquamation also decreased or disappeared). These findings suggest that disorders in keratinocyte proliferation are an important component in the pathogenesis of atopic dermatitis and confirm high efficiency of thymodepressin in the treatment of this condition.

[Use of thymodepressin for treating autoimmune cytopenia]. / Primenenie timodepressinoa dlia lecheniia autoimmunnykh tsitopenii.

AIM: To study influence of thymodepressin on the course of autoimmune cytopenia. MATERIAL AND METHODS: Thymodepressin is a new synthetic hemoregulatory dipeptide (gamma-D-Glu-D-Trp). It was used for the treatment of 22 patients with autoimmune cytopenia. RESULTS: Hemoglobin levels were elevated in autoimmune hemolytic anemia and platelet levels were high in idiopathic thrombocytopenic purpura. A thymodepressin course resulted in a fall of total lymphocyte count and activated CD3+CD69+ lymphocytes. CONCLUSION: The above results, safety, absence of toxicity and allergenicity, parenteral and intranasal useability open perspectives for further studies of therapeutic action of thymodepressin as an immunodepressant in autoimmune processes.

[Postradiation recovery of hematopoiesis in mice affected by Neogen (IEW)]. / Postradiatsionnoe vosstanovlenie krovetvoreniia u myshei pod vliianiem neogena (IEW).

The effect of the synthetic peptide IEW (Neogen) with immunomodulating properties on postradiation recovery of haemopoiesis was investigated. We have shown that Neogen is a potential stimulator of haemopoiesis. The administration of Neogen after irradiation shortened duration of period of the recovery of the compartment of CFU-S-8 and the amount of bone marrow cells. The comparision of the effects of Neogen and GM-CSF (Leucomax) and G-CSF (Granocyte 34) have shown that the targets for these agents are probably different: polypotent CFU-S-for Neogen, and CFU-GM-for GM-CFS. Based on the results, we suggested the mechanism of Neogen effects on heamopoiesis.

[Effect of thymic peptides on the functional activity of phagocytic cells of donor peripheral blood]. / Vliianie timicheskikh peptidov na funktsional'nuiu aktivnost' fagotsitarnykh kletok perifericheskoi krovi donorov.

The direct action of synthetic peptide preparations, analogous to thymic hormones, on the functions of phagocytic cells was studied. The preparations Thymogen, Neogen and Thymodepressin in a dose of 10 mM produced a stimulating effect on the ingestive activity of the neutrophil, but not monocytic, population. All three preparations also enhanced the formation of oxygen metabolites registered in the luminol-dependent chemiluminescent analysis. The characteristics of spontaneous chemiluminescence (CL) reflecting the basal level of the synthesis of the active forms of oxygen and CL induced by opsomized zymosan significantly increased also in those cases when the preparations were used in a dose of 10 mM. The level of the synthesis of hydrogen peroxide in individual cells could be appraised by the intensity of the luminescence of dichlorofluorescein diacetate (DCF-DA), evaluated with the use of flow cytometry. All preparations produced a stimulating effect on the formation of hydrogen peroxide in monocytes. The reaction of neutrophils was even more active: Neogen (10 mM) produced the twofold change in the intensity of the luminescence of DCF-DA) in neutrophils, Thymogen and Thynodepressin increased the average intensity of the luminescence of DCF-DA by 80% and 60%, respectively.

Synthetic peptide thymodepressin promoted take of transplanted hemopoietic precursor cells in the bone marrow of irradiated mice.

We studied the possibility of using a new synthetic heme-inhibiting peptide thymodepressin for improving the efficiency of transplantations of syngeneic and allogeneic bone marrow. Thymodepressin was injected to recipients 3 times (48, 24, and 2 h) before irradiation and transplantation of bone marrow suspension. The yield of 9- and 12-day colonies increased, the number of proliferating CFU-S-12 and pre-CFU-S in recipient bone marrow increased in comparison with the control. In case of an allogeneic donor-recipient combination, the number of 9-day splenic colonies in thymodepressin-treated animals increased 5-fold compared to the control. We hypothesized that thymodepressin therapy and irradiation form an adaptive response of the recipient hemopoietic microenvironment in the bone marrow, which provides conditions for optimal functioning of donor hemopoietic precursors.