Atherosclerosis remains one of the leading contributors to cardiovascular morbidity and mortality worldwide. Although its clinical expression varies from silent plaque formation to advanced ischemic events, the underlying pathology involves a complex interplay of endothelial injury, lipid accumulation, oxidative stress, and chronic inflammation within the arterial wall. The gradual thickening and remodeling of the intima—hallmarks of atherosclerotic change often progress silently until they manifest as symptomatic vascular disease.

Among the numerous biochemical factors implicated in plaque initiation and progression, serum homocysteine has gaAtherosclerosis continues to be a major global cause of illness and death, driven by a complex sequence of endothelial injury, lipid deposition, oxidative stress, and chronic inflammatory responses within the arterial wall [1]. The disease often progresses silently, with gradual intimal thickening and structural remodeling that ultimately lead to symptomatic vascular compromise only in its advanced stages. Over the past several decades, research has increasingly focused on biochemical markers that may influence or accelerate these pathological events.

Among these factors, serum homocysteine has emerged as a key molecule of interest. Early experimental and clinical observations proposed its direct involvement in vascular damage and lipid dysregulation, suggesting a meaningful role in atherogenesis [1,2]. Elevated homocysteine has been shown to impair endothelial function, increase oxidative stress, and enhance smooth muscle proliferation, thereby creating a milieu favorable for plaque development [3,4]. Multiple epidemiological studies have also linked hyperhomocysteinemia with an increased risk of cardiovascular disease, although the extent of this association varies across populations [4,5].

Disturbances in the lipid profile remain equally fundamental to the pathology of atherosclerosis. High levels of LDL cholesterol promote foam-cell formation and intimal lipid accumulation, whereas low HDL cholesterol weakens reverse cholesterol transport and vascular protection. Triglyceride-rich lipoproteins add further inflammatory potential to the evolving lesion. These lipid abnormalities often coexist with hyperhomocysteinemia, and together they may intensify endothelial dysfunction and accelerate plaque progression [1,4].

Despite considerable research, relatively few studies have explored these biochemical parameters specifically in individuals with histologically proven atherosclerotic lesions, where microscopic confirmation provides the most reliable evidence of disease. Evaluating homocysteine and lipid alterations in this subset may offer deeper insight into their contribution to lesion severity.

The present study aims to assess serum homocysteine levels and lipid profile changes in patients with biopsy-confirmed atherosclerosis and to examine their relationship with the degree of histological involvement. By combining clinical, biochemical, and microscopic findings, this investigation seeks to clarify the relevance of these markers in characterizing atherosclerotic disease burden.

Study Design and Setting

This observational, cross-sectional study was conducted in the Department of Pathology at RVM Institute of Medical Sciences & Research Center, Mulugu, Siddipet, Telangana. All procedures and assessments were carried out within the institutional laboratory and affiliated clinical departments. The study was conducted over a six-month period, from May 2025 to August 2025.

Study Population

A total of 80 patients with histologically proven atherosclerotic vascular disease were included. Patients were referred from surgical, cardiology, and general medicine units for tissue evaluation following vascular interventions, amputations, endarterectomy specimens, or autopsy samples where atherosclerotic lesions were identified.

Inclusion Criteria

• Patients aged ≥18 years.

• Availability of vascular tissue showing atherosclerotic changes on histopathology.

• Complete biochemical records including fasting lipid profile and serum homocysteine levels.

Exclusion Criteria

• Patients with known congenital hyperhomocysteinemia or inborn errors of metabolism.

• Individuals on lipid-lowering agents, folate, or vitamin B-complex therapy within the past three months.

• Cases with severe systemic infections, chronic liver disease, renal failure, or malignancy influencing metabolic markers.

• Inadequate tissue samples or incomplete biochemical documentation.

Histopathological Assessment

Tissue samples were fixed in 10% buffered formalin, processed routinely, and stained with hematoxylin and eosin. Atherosclerotic lesions were categorized into mild–moderate or severe based on intimal thickening, lipid core size, calcification, and degree of luminal narrowing following standard histological criteria. All slides were reviewed independently by two experienced pathologists to minimize observer variation.

Biochemical Evaluation

Fasting venous blood samples were analyzed on the same day of collection.

Serum homocysteine was measured using an enzymatic immunoassay.

Lipid profile parameters total cholesterol, LDL-C, HDL-C, and triglycerides—were estimated using automated enzymatic colorimetric methods.
Quality control procedures and internal calibration standards were followed throughout testing.

Data Collection and Variables

Demographic features, comorbidities such as hypertension and diabetes, histological grading, serum homocysteine levels, and lipid profile components were recorded using a standardized proforma. Biochemical abnormalities were defined according to accepted clinical reference ranges.

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using descriptive and comparative statistics. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. Associations between homocysteine levels, lipid abnormalities, and histological severity were assessed using chi-square tests or independent t-tests as appropriate. A p-value <0.05 was considered statistically significant.

A total of 80 histologically proven atherosclerotic cases were included in the study. The mean age of the participants was 56.8 ± 9.4 years, and males constituted 62.5% of the sample. Hypertension and type 2 diabetes mellitus were the most frequent comorbidities, observed in 48% and 35% of patients, respectively (Table 1).

Table 1. Baseline Characteristics of the Study Population (N = 80)

Serum Homocysteine Profile

Elevated serum homocysteine was documented in 58 patients (72.5%). The mean homocysteine concentration for the entire cohort was 19.6 ± 6.3 µmol/L. Individuals with severe atherosclerotic plaques demonstrated markedly higher values (22.4 ± 5.8 µmol/L) compared to those with mild-to-moderate lesions (17.2 ± 4.9 µmol/L) (Table 2).

Table 2. Serum Homocysteine Levels in Atherosclerotic Patients

Lipid Profile Characteristics

Dyslipidemia was prevalent in 83.7% of the study population. The mean lipid parameters were as follows: total cholesterol 216.4 ± 38.2 mg/dL, LDL-C 142.7 ± 32.5 mg/dL, HDL-C 38.6 ± 6.4 mg/dL, and triglycerides 186.2 ± 41.7 mg/dL. Low HDL-C was the most frequent abnormality, identified in 72.5% of participants, followed by elevated LDL-C (61.2%) and raised triglycerides (55.0%) (Table 3).

Table 3. Lipid Profile Distribution in the Study Group (N = 80)

Association of Homocysteine With Lipid Abnormalities

A strong clustering of lipid abnormalities was observed among patients with elevated homocysteine. In this subgroup (n = 58), 84.5% had raised LDL-C, 75.9% had elevated triglycerides, and 69.0% exhibited low HDL-C. Patients with normal homocysteine levels showed fewer deviations across lipid parameters (Table 4).

Table 4. Association of Elevated Homocysteine With Lipid Abnormalities (n = 58)

Figure 1:Association of Elevated Homocysteine With Lipid Abnormalities

Biochemical Trends and Histological Severity

Patients with severe atherosclerotic lesions (n = 30) consistently showed higher homocysteine and LDL-C concentrations along with notably lower HDL-C values compared with those having mild-to-moderate changes, indicating a closer biochemical–histological correlation.

The present study evaluated serum homocysteine concentrations and lipid profile disturbances in patients with histologically confirmed atherosclerotic vascular disease. A large proportion of individuals demonstrated elevated homocysteine, and this abnormality frequently coincided with atherogenic lipid patterns, suggesting a synergistic metabolic influence on vascular injury. Similar interactions between hyperhomocysteinemia and lipid fractions have been highlighted in recent work, where homocysteine showed independent associations with LDL-C, triglycerides, and remnant cholesterol, reinforcing its contribution to dyslipidemic states [6].

In this study, 72.5% of participants exhibited raised homocysteine levels. Previous investigations also recognize hyperhomocysteinemia as an important vascular risk marker, with studies demonstrating its link to endothelial dysfunction, oxidative stress, and plaque vulnerability. Findings from retrospective cohorts show that higher homocysteine levels significantly alter lipid ratios and may exert differential effects depending on underlying cardiovascular status, further supporting its pathogenic relevance [7].

Dyslipidemia was similarly prevalent in our cohort, affecting 83.7% of patients. Low HDL-C emerged as the most common disturbance, followed by elevated LDL-C and triglycerides. This pattern aligns with community-based studies demonstrating that homocysteine tends to correlate with higher LDL-C and lower HDL-C levels, thereby promoting a more atherogenic lipid milieu [8]. HDL plays an essential role in reverse cholesterol transport and provides antioxidant and anti-inflammatory benefits; reductions in this fraction thus intensify susceptibility to plaque progression.

A striking observation in the current study was the clustering of lipid abnormalities among individuals with elevated homocysteine. Experimental data suggest that homocysteine-induced oxidative stress may enhance LDL oxidation and impair endothelial integrity, creating a highly permissive environment for lipid deposition. Although unrelated to atherosclerosis directly, studies from other biomedical fields demonstrate how biochemical stressors such as chemical agents, nanoparticles, or microbial toxins can alter tissue responses and cellular pathways in ways that parallel metabolic injury observed in vascular disease [9–11]. These analogies underscore how cumulative biochemical insults may accelerate structural pathology.

Histological grading provided additional insight, as severe lesions consistently displayed higher homocysteine and LDL-C levels, with markedly reduced HDL-C. This close biochemical-morphological relationship reflects the established concept that metabolic derangements shape plaque architecture and influence its advancement. Clinical observations in neurovascular compression disorders also show that the severity of structural pathology often parallels underlying physiological dysregulation, reinforcing the value of integrated biochemical assessment in disease characterization [12].

Overall, the findings of this study emphasize the importance of evaluating homocysteine alongside conventional lipid parameters. While dyslipidemia remains a central driver of atherosclerosis, the frequent coexistence of hyperhomocysteinemia highlights an additional metabolic burden that may accelerate plaque development. Timely identification and correction of these abnormalities could help reduce the progression of advanced vascular pathology.

This study demonstrates that elevated serum homocysteine and significant lipid abnormalities are highly prevalent in patients with histologically proven atherosclerotic vascular disease. Raised homocysteine levels were closely linked with atherogenic lipid patterns, particularly elevated LDL-C, higher triglycerides, and reduced HDL-C, indicating a combined metabolic burden that may intensify vascular injury. Patients with severe plaques showed the most pronounced biochemical disturbances, highlighting a strong association between metabolic derangement and histological severity. These findings suggest that evaluating both homocysteine and lipid fractions provides meaningful insight into disease progression and may help identify individuals at greater risk for advanced atherosclerotic changes.

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