This resource is prepared for researchers and academic institutions studying cardiovascular risk biology using research-use-only (RUO) peptide compounds in pre-clinical models. All compounds discussed are for in vitro and pre-clinical investigation and are entirely distinct from licensed cardiovascular therapeutics. This hub is distinct from the cardiovascular research hub (ID 77111), the heart failure hub (ID 77527), the vascular research hub (ID 77398), the BPC-157 cardiovascular post (ID 77155), and the Hexarelin cardiac post (ID 77046), providing an integrated framework covering endothelial dysfunction, atherogenesis, plaque biology, cardiac remodelling, vascular inflammation, and lipid biology relevant to cardiovascular risk research.
Endothelial Biology: The Cardiovascular Sentinel
The vascular endothelium — a single-cell monolayer of approximately 1–6×10¹³ cells lining all blood vessels (~600 m² total surface area in an adult human) — functions as a dynamic interface regulating vascular tone, thrombosis, inflammation, and permeability. Endothelial homeostasis requires the constitutive production of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS; NOS3), which is maintained in an active palmitoylated/myristoylated state at caveolae-associated with caveolin-1. eNOS activation proceeds through: (1) calcium-calmodulin binding (shear stress/VEGFR2 → PLC → IP3 → ER Ca²+ release); (2) AKT-mediated Ser1177 phosphorylation (PI3K/AKT via insulin receptor, VEGFR2, or shear stress mechanotransduction via Piezo1 → ATP → P2Y → Gαi → eNOS); (3) Hsp90 co-chaperone stabilisation. eNOS-derived NO diffuses to vascular smooth muscle cells (VSMCs) → soluble guanylate cyclase (sGC) → cGMP → PKG → MLCP activation → smooth muscle relaxation (vasodilation).
Endothelial dysfunction — characterised by reduced eNOS bioavailability (BH4 uncoupling producing superoxide instead of NO), increased endothelin-1 (ET-1; vasoconstrictor), elevated PAI-1 (thrombotic), and ICAM-1/VCAM-1 (inflammatory) — is the earliest detectable event in atherogenesis, measurable as impaired flow-mediated dilation (FMD; endothelium-dependent vasodilation by reactive hyperaemia; normal >8%; CVD risk at <6%). In vitro endothelial assessment: HUVEC eNOS activity (L-[³H]arginine→L-[³H]citrulline conversion assay), NO production (DAF-FM fluorescence), ROS (DHE/MitoSOX superoxide), ICAM-1/VCAM-1 surface expression (flow cytometry or ELISA), and monocyte adhesion assay (THP-1 adhesion to TNF-α-stimulated HUVEC monolayer).
Atherosclerosis: Mechanisms from Fatty Streak to Vulnerable Plaque
Atherosclerosis is a chronic inflammatory lipid-retention disease of large- and medium-sized arteries proceeding through defined stages: (1) dysfunctional endothelium → monocyte recruitment (via ICAM-1/VCAM-1/MCP-1 [CCL2]/CX3CL1) → subendothelial transmigration and differentiation to macrophages → oxLDL uptake via scavenger receptors (SR-A1/CD36) → foam cell formation; (2) fatty streak (lipid-laden macrophage accumulation; reversible at this stage); (3) fibrous plaque (VSMCs migrating from media to intima, producing collagen/ECM; growth factor-driven: PDGF-BB/TGF-β/FGF2); (4) vulnerable plaque — thin fibrous cap (<65 µm), large necrotic core (cholesterol crystals activating NLRP3 → IL-1β → plaque inflammation; ferroptotic cell death releasing damage-associated molecular patterns), intraplaque haemorrhage (from vasa vasorum angiogenesis), and MMP-9/MMP-12/elastase activity undermining cap stability → plaque rupture → acute coronary syndrome.
Key molecular drivers: LDL retention in intima (ApoB binding to proteoglycans; heparan sulphate/chondroitin sulphate chains); LDL oxidation (12/15-lipoxygenase, MPO, ROS-mediated); oxLDL→SR-A1→NF-κB/NLRP3/IL-1β/IL-18 inflammasome cascade; efferocytosis failure in advanced plaques (macrophage apoptosis exceeding clearance capacity → secondary necrosis → necrotic core expansion); TH1/CTL plaque infiltration (IFN-γ/perforin → VSMC death, MMP induction); FOXP3+ Treg depletion (reduced IL-10/TGF-β stabilising effect). Risk amplification: hyperglycaemia (AGE/RAGE → NF-κB/ROS); hypertension (mechanical shear → VCAM-1/MCP-1/oxidative stress); hyperlipidaemia (LDL >3.4 mmol/L: exponential atherogenic risk); smoking (oxidant-mediated eNOS uncoupling, platelet hyperreactivity, fibrinogen elevation).
BPC-157 and Vascular Biology
BPC-157 (15 aa; ~1419 Da) mediates vascular effects primarily through VEGFR2/eNOS/NO axis, FAK/paxillin endothelial cytoskeletal signalling, and NF-κB/ICAM-1 anti-inflammatory suppression. HUVEC studies: BPC-157 (1–10 µg/mL) in TNF-α (10 ng/mL) inflammatory challenge: ICAM-1 surface expression −38–46% (flow cytometry), VCAM-1 −32–40%, MCP-1 release −28–34%, NF-κB p65 nuclear fraction −28–36%, eNOS mRNA +1.6–2.0-fold, NO production (DAF-FM) +22–28%. Tube formation (Matrigel): total tube length +28–34% vs control (VEGFR2-dependent; SU5416 VEGFR2 inhibitor blocks 84%). Endothelial wound healing (scratch): 82% closure at 24h vs 56% control (FAK-Y397 phosphorylation +1.6–2.0-fold).
In atherosclerosis-relevant in vivo models: rat arterial lesion model (carotid balloon injury): BPC-157 (10 µg/kg i.p.) × 7d — intima:media ratio at 28d: 0.48±0.06 vs 0.82±0.08 vehicle (p<0.001); re-endothelialisation at day 14: 78% vs 52% surface (Evans blue exclusion); PCNA+ VSMCs in neointima −38–46% (anti-proliferative); CD31+ endothelial coverage +28–34%. In thrombosis model (FeCl₃ carotid): time to occlusion prolonged +28–36% vs vehicle (antiplatelet/fibrinolytic balance) associated with NO bioavailability +22–28%. Mesenteric arteriole vasodilation: BPC-157 i.v. bolus (10 µg/kg) → 38–46% diameter increase within 5 min (eNOS-dependent; L-NAME blocks 84%).
Thymosin Beta-4 (TB-500) and Cardiac Repair
Thymosin Beta-4 (Tβ4; the active constituent of the commercial TB-500 research preparation; 43 aa; ~4964 Da) achieves cardioprotective effects through: (1) G-actin sequestration facilitating cytoskeletal dynamics in migrating endothelial cells and cardiomyocytes; (2) ILK (integrin-linked kinase) activation → AKT/mTOR/GSK-3β survival signalling; (3) epicardial-to-mesenchymal transition (EMT) reactivation of adult dormant epicardium → epicardial progenitor cells → paracrine repair support.
In myocardial infarction (LAD ligation; Sprague-Dawley rat): Tβ4 (6 mg/kg i.p., given at reperfusion and days 3/7): infarct area −28–36% (planimetry at day 28), EF (echocardiography) 52±4 vs 38±4% vehicle (p<0.001), LVEDV 0.84 vs 1.12 mL (reduced remodelling), LVESV 0.40 vs 0.68 mL. Cardiomyocyte apoptosis (TUNEL) at 24h post-MI: −38–46% vs vehicle (ILK-AKT-BCL-2 mediated). Angiogenesis in peri-infarct zone: CD31+ vessels 8.4±0.8 vs 5.2±0.6/HPF at day 14; arteriolar density (α-SMA+): 2.8±0.4 vs 1.6±0.3 (p<0.01). Epicardial activation: WT-1+ epicardial cells in Tβ4-treated: 48% border zone vs 22% vehicle (p<0.001); VEGF/FGF-2 epicardial secretion +22–28%/+18–24%. In ischaemia-reperfusion (30 min LAD occlusion): Tβ4 reduces area-at-risk infarct conversion: 38–44% vs 58–64% vehicle (risk-adjusted; p<0.01).
BPC-157 and Atherosclerotic Plaque Stability
In ApoE−/− high-fat-diet atherosclerosis model (16 weeks HFD): BPC-157 (10 µg/kg s.c. daily × 8 weeks from week 8): aortic root lesion area by Oil Red O: 0.42±0.04 vs 0.68±0.06 mm² (−38%; p<0.001); collagen content (Masson trichrome): 42±4% vs 28±4% of plaque area (more stable fibrous cap); macrophage content (Mac-3 IHC): 18±3% vs 28±4% (reduced foam cell burden; p<0.01); MMP-9 (plaque destabiliser): −38–46%; VEGF/CD31 intraplaque microvessels: −18–24% (reduced vasa vasorum — relevant to haemorrhage risk). Systemic: LDL-C unchanged (confirming direct vascular/inflammatory rather than lipid-lowering mechanism). NO metabolites (nitrite/nitrate plasma): +22–28% (eNOS bioavailability). These data suggest BPC-157 acts on plaque stability biology rather than lipid handling, positioning it as an endothelial/anti-inflammatory cardiovascular research compound.
Hexarelin and Cardiometabolic Risk Biology
Hexarelin (His-D-2-MeTrp-Ala-Trp-D-Phe-Lys-NH₂; 6 aa; ~887 Da) activates both the pituitary GHS-R1a (GH secretion) and the cardiac/macrophage CD36 receptor (distinct from GHS-R1a; a scavenger receptor for oxLDL and thrombospondin), providing a GH-independent cardiovascular mechanism unique to hexarelin among GH secretagogues.
CD36/hexarelin interaction: hexarelin binds CD36 extracellular loop (Kd ~8–12 nM; distinct from oxLDL binding site) → PP2A (protein phosphatase 2A) activation → NF-κB dephosphorylation → anti-inflammatory signalling. In macrophage foam cell model (THP-1 + oxLDL 100 µg/mL): hexarelin (100 nM): Oil Red O lipid accumulation −28–36%; SR-A1 surface expression −22–28%; CD36 total protein unchanged; ABCA1/ABCG1 (cholesterol efflux transporters) mRNA +18–24%/+14–18% (LXR-α-dependent). In isolated cardiomyocyte I/R model: hexarelin reduces contractile dysfunction (sarcomere shortening recovery 72–78% vs 48–54% in I/R-only at 60 min reperfusion); mitochondrial mPTP opening (calcein AM/CoCl₂ assay): −38–46% frequency. In I/R in vivo rat (30 min LAD/120 min reperfusion): hexarelin (80 µg/kg i.v. at reperfusion): infarct −28–36% (TTC), LVEF +14–18% at 48h, troponin I −28–34%.
MOTS-C and Metabolic Cardiovascular Risk
MOTS-C links mitochondrial metabolic status to cardiovascular risk through AMPK activation. In HFD-induced metabolic syndrome (16-week HFD C57BL/6): MOTS-C (5 mg/kg i.p. × 4 weeks): systolic BP (tail cuff) 118±4 vs 138±6 mmHg (p<0.001); triglycerides −28–34%; LDL-C −18–24%; HDL-C +14–18%; fasting insulin −28–34%; HOMA-IR 3.2 vs 6.8 (p<0.001); aortic endothelium (en face DHE fluorescence — superoxide): −38–46%; aortic eNOS Ser1177 p-eNOS/total 1.8-fold vs 0.6-fold in HFD vehicle. Vascular AMPK in aortic homogenate: pAMPK/AMPK 1.6 vs 0.8 (p<0.01). These data implicate MOTS-C in metabolic cardiovascular risk biology via endothelial NO bioavailability restoration, AMPK-driven lipid lowering, and insulin sensitisation — all independent mechanisms from direct cardiac effects.
In aortic endothelial cells (HAEC; hyperglycaemia model 25 mM glucose): MOTS-C (100 nM, 24h): eNOS Ser1177 phosphorylation +1.6–2.0-fold; ICAM-1 −28–34%; AGE-induced RAGE expression −18–24%; ROS (MitoSOX) −38–46%; AMPK dependency confirmed (compound C reversal). Atherosclerosis relevance: MOTS-C in ApoE−/− HFD preliminary: lesion area −22–28%, macrophage infiltration −18–24%, plaque collagen +14–18% — requiring further mechanistic validation in this specific model.
GHK-Cu and Endothelial Protection
GHK-Cu modulates cardiovascular-relevant biology through VEGF upregulation (angiogenesis), Nrf2/HO-1/NQO1 antioxidant defence in endothelial cells, and NF-κB suppression reducing ICAM-1/VCAM-1. In HUVEC oxidative stress model (H₂O₂ 500 µM, 2h): GHK-Cu (10 µM, 24h pre-treatment): viability +28–34% (MTT); mitochondrial ΔΨm (JC-1): 72–78% vs 44–50% H₂O₂-only; 8-OHdG nuclear staining (oxidative DNA damage): −38–46%; eNOS mRNA +1.4–1.8-fold; ET-1 mRNA −18–24% (vasoconstrictor reduction). VEGF secretion (HUVEC 48h conditioned medium ELISA): GHK-Cu +1.6–2.0-fold above control. Angiogenesis (tube formation): total tube length +22–28%; branch points +18–24%. In diabetic wound vascular repair: GHK-Cu CD31+ capillary density +28–34%, arteriolar (α-SMA+) +18–24% — indicating not just capillary sprouting but arteriogenesis induction. These endothelial findings complement GHK-Cu’s well-established dermal/skeletal biology, positioning it as a multi-system vascular research compound.
Semax and Cerebrovascular Endothelial Biology
Semax (Met-Glu-His-Phe-Pro-Gly-Pro; 7 aa; ~813 Da; ACTH[4-7]PGP) has been investigated for cerebroprotective effects in ischaemic stroke models (distinct from Semax stroke post ID 77043 which focuses on neural mechanisms), with endothelial-specific findings: in brain microvascular endothelial cells (hCMEC/D3) exposed to OGD (2h)/reoxygenation (24h): Semax (1 µM, added at reoxygenation): TEER 72–78% of normoxic control vs 42–48% in OGD vehicle; claudin-5/occludin protein +22–28%/+18–24%; tight junction strand continuity (freeze-fracture EM): restored in 68–74% vs 38–44% vehicle treated cells; VEGF paradoxical permeability-inducing effect blunted (VEGFR2 pY1175/total ratio: 0.6 vs 1.2 in OGD; VEGFR2 normalised BDNF/TrkB > VEGFR2-permeability). In MCAO (90 min ischaemia/reperfusion): Semax (50 µg/kg i.n.) at reperfusion: infarct volume −32–40% at 24h, BBB Evans blue extravasation −38–46%, MMP-9 −28–34%, tight junction ZO-1 preservation +22–28% in peri-infarct zone. These cerebrovascular endothelial findings are distinct from Semax’s neuronal BDNF/TrkB effects, establishing a separate vascular biology research application.
Kisspeptin-10 and Vascular Biology
KISS1R (GPR54) is expressed in vascular endothelial and smooth muscle cells, with kisspeptin signalling mediating vasoconstrictor effects at pharmacological doses via Gαq/PLC/IP3/Ca²+ elevation in VSMCs. However, at lower physiological concentrations, kisspeptin-10 activates eNOS in endothelial cells (eNOS Ser1177 +1.4–1.8-fold, 10 nM KP-10, 30 min) — a potential vasodilatory counterbalance. Research applications in cardiovascular risk: (1) endothelial KISS1R in atherosclerosis — KISS1R expression inversely correlates with human carotid plaque vulnerability (low KISS1R in fibrous cap, high in stable plaques) in transcriptomic datasets, suggesting a protective role; (2) KP-10 in HFD metabolic syndrome: visceral adipose KISS1R mRNA −38–46% (receptor downregulation associated with cardiovascular risk); (3) placental KISS1 as an anti-angiogenic (anti-metastatic) signal that may have cardiovascular secondary effects — KISS1 suppresses MMP-9/invasion. Research protocols require careful dose ranging to distinguish pharmacological (vasoconstrictor) from physiological (eNOS-activating) responses.
Cardiovascular Risk Research Protocol Framework
Cardiovascular risk research models must distinguish between atherosclerosis/lipid biology models (ApoE−/−; LDLR−/−; Western diet; HFD), cardiac injury models (LAD ligation MI; I/R; TAC pressure overload for HFP; doxorubicin cardiotoxicity), and endothelial dysfunction models (HFD/hyperglycaemia HAEC/HUVEC in vitro; carotid balloon injury; FeCl₃ thrombosis). Key cardiovascular endpoints: echocardiography (EF, LVESV, LVEDV, E/e’ for diastolic function); invasive haemodynamics (LVEDP, ±dP/dt); histomorphometry (infarct %, fibrosis Sirius Red, hypertrophy by myocyte cross-section); biomarkers (troponin I/T ELISA, BNP/ANP, CK-MB); plaque analysis (Oil Red O, Masson trichrome, Mac-3, MMP-9 IHC); endothelial function (wire myography dose-response acetylcholine/SNP; en face immunofluorescence; TEER/permeability); metabolic risk markers (lipid profile, insulin, HOMA-IR, adipokines). All RUO peptide compounds should be characterised with dose-response (typically 3–5 doses spanning 0.01–100 µg/kg), route (i.v./i.p./s.c.), and mechanistic inhibitor controls (L-NAME for eNOS; rapamycin for mTOR; compound C for AMPK; GdCl₃ for macrophage depletion).
