Intracranial vascular stent with copper-containing platinum-chromium alloy to modulate macrophage polarization function

Abstract

The application aims to provide an intracranial blood vessel stent copper-containing platinum-chromium alloy for regulating macrophage polarization function and a preparation method thereof, and relates to the field of intracranial blood vessel interventional treatment instruments.The chemical composition of the alloy is as follows (wt. %): Pt: 21.5-32.5 wt. %, Cr: 17.5-18.5 wt. %, Ni: 8.5-9.5 wt. %, Mo: 2.5-3.5 wt. %, Cu: 0.5-6 wt. %, and the balance is Fe.The copper-containing platinum-chromium alloy can realize the transformation of macrophages from M1 pro-inflammatory phenotype to M2 anti-inflammatory phenotype, can play the functions of anti-inflammation and promoting the regeneration and repair of pathological blood vessel tissues, and the density of the alloy reaches 9.95-10.52 g / cm 3 , which guarantees high visibility and facilitates the accurate implantation of the stent into the intracranial blood vessel stenosis or pathological site, meanwhile, the addition of copper can reduce the content of noble metal platinum in the alloy, significantly reduces the preparation cost of the intracranial blood vessel stent, and has extremely high clinical application potential.

Description

Technical Field

[0001] This invention relates to the field of intracranial vascular interventional therapy devices, specifically a copper-platinum-chromium alloy for intracranial vascular stents used to regulate macrophage polarization. Background Technology

[0002] Stroke is a disease caused by narrowing, blockage, or rupture of arteries supplying blood to the brain, resulting in blood loss and brain tissue damage. It is the second leading cause of death worldwide. Intracranial vascular stenting has become the preferred treatment for intracranial vascular stenosis due to its minimally invasive nature, rapid effectiveness, and quick recovery, and has achieved excellent clinical results.

[0003] Macrophages play a crucial role in the development of intracranial vascular stenosis and in stent implantation therapy. Pro-inflammatory (M1) macrophages exhibit an imbalance in lipid metabolism, leading to excessive lipid accumulation within the macrophages and deposition in the vascular intima, forming fibrosis and atherosclerotic plaques. This results in vascular hardening, decreased medial elasticity, and narrowing of the vascular lumen. Anti-inflammatory (M2) macrophages promote endothelial cell differentiation by secreting platelet-derived growth factor. Simultaneously, M2 macrophages induce smooth muscle cell dedifferentiation through exosomes, promoting vascular repair after stent implantation and reducing in-stent restenosis. Therefore, stents that regulate macrophage polarization from M1 to M2 phenotypes can create a favorable microenvironment for endothelial cell regeneration, reducing the risk of complications such as stent restenosis and late-onset atherosclerosis.

[0004] To address in-stent restenosis, clinical intracranial vascular stents primarily work by using drug-eluting coatings to inhibit smooth muscle cell proliferation, thereby reducing neointimal hyperplasia after stent implantation. However, delayed neointimal formation leads to prolonged stent exposure to the bloodstream, significantly increasing the probability of late-stage thrombosis. Furthermore, insufficient stability and long-term effectiveness of the drug-eluting coating can reduce or even disable the stent's pro-repair function. Summary of the Invention

[0005] To provide a favorable regenerative microenvironment and promote vascular tissue repair after stent implantation, this invention provides a copper-platinum-chromium alloy for intracranial vascular stents that regulates macrophage polarization and its preparation method, which can be applied in the field of intracranial vascular interventional therapy devices.

[0006] The technical solution of this invention is as follows:

[0007] The application discloses a copper-containing platinum-chromium alloy for regulating macrophage polarization function of an intracranial blood vessel stent, and chemical components of the alloy are as follows in percentage by weight: Pt: 21.5-32.5 wt.%, Cr: 17.5-18.5 wt.%, Ni: 8.5-9.5 wt.%, Mo: 2.5-3.5 wt.%, Cu: 0.5-6 wt.%, and the balance is Fe. Further preferably, the chemical components of the alloy are as follows in percentage by weight: Pt: 21.5-32.5 wt.%, Cr: 17.5-18.5 wt.%, Ni: 8.5-9.5 wt.%, Mo: 2.5-3.5 wt.%, Cu: 0.5-6 wt.%, and the balance is Fe.

[0008] The alloy can regulate the transformation of macrophages from an M1 pro-inflammatory phenotype to an M2 anti-inflammatory phenotype, and innovatively plays the functions of anti-inflammation and promoting the regeneration and repair of pathological vascular tissues.

[0009] The density of the alloy reaches 9.95-10.52 g / cm 3 , and high visibility is ensured, so that the stent can be precisely implanted in a stenosis or pathological part of an intracranial blood vessel.

[0010] As a preferred technical scheme,

[0011] In the copper-containing platinum-chromium alloy, the content of Cu is 3-5 wt.%, and the content of Pt is 22.5-27.2 wt.%. The addition of Cu can reduce the content of the noble metal Pt in the alloy while ensuring the functions of regulating macrophage polarization and high visibility, and significantly reduces the preparation cost of the intracranial blood vessel stent.

[0012] The application further provides a preparation method of the copper-containing platinum-chromium alloy, and specifically comprises the following steps: obtaining an alloy ingot by using a vacuum thermal induction furnace, and then forging at 900-1200 DEG C, and then keeping at 900-1100 DEG C for 1-2 hours, and then water cooling; then keeping at 600-700 DEG C for 0.5-2 hours, and then performing hot deformation with a deformation amount of 70-80% under the condition that a strain rate is greater than or equal to 0.1 s -1 ; and then keeping at 500-600 DEG C for 0.5-2 hours, and then air cooling, and then performing cold deformation with a deformation amount greater than 10%.

[0013] The application has the following beneficial effects:

[0014] The copper-containing platinum-chromium alloy prepared by the method can regulate the transformation of macrophages from an M1 pro-inflammatory phenotype to an M2 anti-inflammatory phenotype, and innovatively plays the functions of anti-inflammation and promoting the regeneration and repair of pathological vascular tissues, and the density of the alloy reaches 9.95-10.52 g / cm 3, which can ensure high visibility and facilitate accurate implantation of the stent into the intracranial vascular stenosis or lesion site. Meanwhile, the addition of copper can reduce the content of precious metal platinum in the alloy, thereby significantly reducing the preparation cost of the intracranial vascular stent, and the alloy has extremely high clinical application potential. DETAILED DESCRIPTION

[0015] The present application is further described by the following examples, which are merely illustrative of the best mode of the application and do not limit the scope of the application.

[0016] Examples 1-8 are copper-containing platinum-chromium alloys having the function of regulating macrophage polarization, and the chemical compositions thereof are shown in Table 1. The chemical composition range according to the present application is controlled during smelting.

[0017] The preparation process is as follows: an alloy ingot is obtained by using a vacuum hot induction furnace, and is forged at 1100℃, followed by heat preservation at 1050℃ for 1 hour and water cooling; then heat preservation at 600-700℃ for 0.5h, and deformation at a strain rate greater than or equal to 0.1s -1 under the condition of a deformation amount of 70-80% heat deformation; and then heat preservation at 500-600℃ for 1h, air cooling, and cold deformation with a deformation amount greater than 10%.

[0018] Comparative Examples 1-9 are platinum-chromium alloys, and the chemical compositions thereof are shown in Table 1. The specific processing technology is the same as that of the examples.

[0019] Table 1 Chemical composition of the materials of examples and comparative examples (wt. %)

[0020] Material Pt Cr Ni Mo Cu Fe Example 1 32.5 18.5 9.5 3.5 0.5 Balance Example 2 30.4 17.6 9.4 3.4 1.0 Balance Example 3 27.2 18.1 8.5 2.5 1.5 Balance Example 4 26.8 17.5 9.2 3.2 2.0 Balance Example 5 25.7 18.3 9.1 3.1 3.0 Balance Example 6 24.3 17.9 8.9 2.9 4.0 Balance Example 7 22.5 17.7 8.8 3.0 5.0 Balance Example 8 21.5 18.0 9.0 3.3 6.0 Balance Comparative Example 1 33.3 17.7 9.1 2.8 - Balance Comparative Example 2 32.5 18.5 9.5 3.5 - Balance Comparative Example 3 30.4 17.6 9.4 3.4 - Balance Comparative Example 4 27.2 18.1 8.5 2.5 - Balance Comparative Example 5 26.8 17.5 9.2 3.2 - Balance Comparative Example 6 25.7 18.3 9.1 3.1 - Balance Comparative Example 7 24.3 17.9 8.9 2.9 - Balance Comparative Example 8 22.5 17.7 8.8 3.0 - Balance Comparative Example 9 21.5 18.0 9.0 3.3 - Balance

[0021] The performance detection method of the examples is shown as follows:

[0022] 1. Cell toxicity test

[0023] A CCK-8 kit is used to quantitatively detect the influence of the biological safety of the surface of different samples. This is a colorimetric method based on the principle that WST-8 is reduced to orange Formazan by mitochondrial enzymes of living cells, which indirectly measures the metabolic activity of living cells, while dead cells have no such function.

[0024] Specific operation: the frozen tube of human brain microvascular endothelial cells HBMEC was taken out from -150℃, quickly melted in 37℃ water bath, centrifuged and discarded the supernatant, added to the fresh prepared D-MEM (dulbecco's modified eagle medium, high glucose medium) culture medium containing 10% fetal bovine serum, repeatedly blew and beat into cell suspension and then moved into the culture bottle, placed in 37℃, saturated humidity, 5% CO2 constant temperature incubator, and cultured for 3-4 days. The cell morphology was observed under an inverted phase contrast microscope. The growing HBMEC cells were digested with 2.5g / L trypsin, prepared into a cell suspension with a cell density of 2×10 4 / mL using D-MEM culture medium containing 10% fetal bovine serum, and inoculated on the surface of different samples. At least 3 parallel samples were set for each material, and cultured in the culture medium for 1, 3 and 7 days. At the time point, the original culture medium was aspirated, the samples were washed with phosphate buffer solution (PBS, Hyclone, USA), 300μL of cell culture medium containing 10% (v / v) CCK-8 reagent was added to each well, and incubated in a 37℃ incubator for 3 hours. Then, 100μL of supernatant was taken from each well and transferred to a 96-well plate, and the OD value (optical density) of each well was detected at 450nm using an enzyme-labeled instrument. The experiment was repeated three times to obtain the average value. The RGR (relative growth rate) was calculated, the calculation formula was: RGR=(experimental group OD value / culture medium group OD value)×100%, and the results of each group were evaluated. The results are shown in Table 2.

[0025] 2. Detection of macrophage polarization state

[0026] The frozen tube of mouse macrophage cell line RAW 246.7 cells was taken out from -150℃, quickly melted in 37℃ water bath, centrifuged and discarded the supernatant, added to the fresh prepared DMEM high glucose culture medium containing 10% fetal bovine serum, repeatedly blew and beat into cell suspension after moving into the culture bottle, placed in 37℃, saturated humidity, 5% CO2 constant temperature incubator, and cultured for 3-4 days. The growing THP-1 cells were digested with 2.5g / L trypsin, prepared into a cell suspension with a cell density of 2×10 4Cell suspensions of 1 μg / mL were seeded onto different sample surfaces, and lipopolysaccharide (LPS, 1 μg / mL) was added to the culture medium and cultured for 4 h to induce the M1 macrophage phenotype. Subsequently, the medium was replaced with normal medium and cultured for another 24 h to evaluate the effect of different materials on the macrophage phenotype. The culture medium was discarded, and the cells were gently washed with PBS. Total RNA was extracted using Trizol solution, and the RNA concentration was measured using a Nanodrop 1000 micro-UV spectrophotometer and adjusted to 150 ng / μL. Reverse transcription was then performed using a TaKaRa PrimeScript system. TM cDNA was synthesized by reverse transcription of RNA using an RT reagent kit. Real-time quantitative polymerase chain reaction (qRT-PCR) was then performed using the TaKaRa SYBR Premix Ex Taq™ II. CD86 was used as a marker for M1 macrophages, and CD206 as a marker for M2 macrophages. GAPDH was used as an internal control. The relative expression ratio of CD86 / CD206 genes was calculated to infer the phenotypic ratio of M1 / M2 macrophages, and the regulatory effect of different materials on macrophage polarization was analyzed. The results are shown in Table 2.

[0027] 3. The effect of regulating the angiogenesis microenvironment on HBMEC cell differentiation

[0028] The above RAW 246.7 cells were used at a rate of 2 × 10⁻⁶. 4 Cell suspensions of 1 μg / mL were seeded onto different sample surfaces, followed by inoculation with lipopolysaccharide (LPS, 1 μg / mL) for 4 h to induce macrophage activation. The culture medium was then discarded and replaced with serum-free D-MEM medium for another 6 h. Upon reaching the target time point, the culture medium was collected and HBMEC cells were cultured for another 24 h. Total RNA was then extracted using Trizol solution, and the RNA concentration was measured using a Nanodrop 1000 micro-UV spectrophotometer and adjusted to 150 ng / μL. Reverse transcription was then performed using a TaKaRa PrimeScript system. TM cDNA was synthesized by reverse transcription of RNA using an RT reagent kit. Real-time quantitative polymerase chain reaction (qRT-PCR) was then performed using the TaKaRa SYBR Premix Ex Taq™ II kit. VEGF mRNA expression levels in HBMEC cells were calculated to assess the effects of different alloys on endothelial cell differentiation by modulating the angiogenesis microenvironment. The results are shown in Table 2.

[0029] 4. Material density test

[0030] Density of the alloy was measured based on Archimedes principle. The weight of each sample in air and deionized water was measured by using a high-precision balance (accuracy 0.01 g) respectively, and the density of the material was calculated by using formula (1):

[0031] ρ = M1·ρ w / (M1-M2) (1)

[0032] wherein M1 refers to the mass of the sample in air, M2 represents the mass in deionized water, ρ w represents the density of deionized water (ρ w = 1 x 10 3 g / cm 3 ). For each sample, the average density was determined by three independent density values. The test results are shown in Table 2.

[0033] Table 2 Test results of the properties of the materials of the examples and the comparative examples

[0034]

[0035]

[0036] As can be seen from the results in Table 2, the cytotoxicity level of the copper-containing platinum-chromium alloy described in Examples 1-7 is less than or equal to level 2, which meets the cytotoxicity requirement of biomedical materials. When the copper content is high and the platinum content is low (Example 8), the toxicity of the copper-containing platinum-chromium alloy is high, which cannot be applied to the human body. In the experiment, LPS was added to induce the activation of macrophages to M1 phenotype, so the M1 / M2 value of the macrophages after culture of the platinum-chromium alloys of Comparative Examples 1-9 is greater than 1, indicating that the macrophages are mainly in the M1 pro-inflammatory phenotype. In comparison, the M1 / M2 ratio of the macrophages after culture of the copper-containing platinum-chromium alloys described in Examples 1-7 is 0.29-0.52, which is less than 1, indicating that the copper-containing platinum-chromium alloys of Examples 1-7 can adjust the macrophage phenotype from M1 phenotype to M2 anti-inflammatory phenotype. At the same time, the vascular regeneration microenvironment formed by Examples 1-7 can significantly promote the expression of VEGF gene of HBMEC cells and promote the differentiation of vascular endothelial cells. However, due to the high copper content of Example 8, the cytotoxicity problem leads to a large number of deaths of macrophages and endothelial cells adhered to its surface, which cannot adjust the macrophage phenotype and establish the pro-vascular regeneration environment, so the expression amount of VEGF gene of the HBMEC cells cultured on its surface is low. In addition, the density value of the copper-containing platinum-chromium alloy described in Examples 1-7 is higher than that of the ordinary platinum-chromium alloy, and the density value is as high as 9.95-10.41 g / cm 3 , which is beneficial to improve the visibility during the stent surgery process and facilitate the precise implantation of the stent into the intracranial vascular stenosis or lesion site.

[0037] When the copper content is 3-5 wt.%, and the platinum content is 22.5-25.7 wt.%, the synergistic effect of the two elements is the most obvious, and the alloy provided by the application has the most excellent anti-inflammatory and promoting function of regenerating and repairing the lesion vascular tissue. At the same time, the density value of the alloy is still higher than that of the comparative example, which guarantees the visibility and significantly reduces the preparation cost of the intracranial vascular stent, and can be applied to the field of intracranial vascular stent interventional therapy instruments.

[0038] The remaining matters of the application are known technologies.

[0039] The above examples are only for illustrating the technical concept and characteristics of the application, and the purpose is to enable the person skilled in the art to understand the content of the application and implement it, and cannot limit the protection scope of the application. Any equivalent changes or modifications made according to the spirit and essence of the application shall be covered within the protection scope of the application.

Claims

1. A copper-containing platinum-chromium alloy for an intracranial blood vessel stent for regulating macrophage polarization function, characterized by, The chemical composition of the alloy is: Cr: 17.5~18.5wt.%, Ni: 8.5~9.5wt.%, Mo: 2.5~3.5wt.%, the content of Cu element is 3~5wt.%; the content of Pt element is 22.5~27.2wt.%; the balance is Fe; the density of the alloy is 9.95~10.52g / cm 3 ; the alloy can adjust the transformation of macrophages from M1 pro-inflammatory phenotype to M2 anti-inflammatory phenotype.

2. A method of preparing a copper-containing platinum-chromium alloy for use in an intracranial stent to modulate the polarization function of macrophages as claimed in claim 1, characterized by: The alloy ingot is obtained by using a vacuum heat induction furnace, forged at 900-1200℃, then heat treated at 900-1100℃ for 1-2h, water cooled, then heat treated at 600-700℃ for 0.5-2h, and deformed at a strain rate greater than or equal to 0.1s -1 -1, a deformation amount of 70-80%, and then cold deformed by more than 10% at 500-600℃ for 0.5-2h and air cooled.

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