Background/Objectives: Osteonecrosis of the femoral head (ONFH) is a common condition in hip surgery, which is characterized by the death of bone cells due to disruption of the blood supply and ultimately irreversible destruction of the hip joint. As a result of the COVID-19 pandemic, a significant increase in the incidence of ONFH has been identified. To better understand the pathogenesis of ONFH in the context of COVID-19, our research aimed to determine pathomorphological changes in articular tissues specific to post-COVID-19 ONFH. Methods: Using morphological, morphometric, and statistical methods, the femoral heads after hip arthroplasty were retrospectively studied in patients with post-COVID-19 ONFH (n = 41) compared to a non-COVID-19 group of patients (n = 47). Results: Our results revealed that the key morphofunctional biomarkers of post-COVID-19 ONFH were clusters of mast cells, extensive areas of fibrosis, numerous arterial and venous thrombi, and giant cell granulomas. The potential relationship of those morphological features with the action of the SARS-CoV-2 coronavirus was discussed. Conclusions: Mast cells have been proposed as the leading players that may trigger the main molecular and cellular mechanisms in the development of post-COVID-19 ONFH and can be considered a diagnostic sign of the disease.

ВИЧ-ассоциированные заболевания внутренних органов достаточно многообразны, среди них именно патология сердечно-сосудистой системы является одной из непосредственных причин гибели пациентов с ВИЧ-инфекцией. Наблюдательные исследования показали, что ВИЧ-инфицированные лица имеют высокий риск неблагоприятных сердечно-сосудистых событий по сравнению с остальной популяцией. Сердечно-сосудистые заболевания, обусловленные атеросклерозом, в том числе инфаркт миокарда и инсульт, представляют одну из основных причин смертности среди ВИЧ-положительных больных. Ряд исследований указывают на ускорение процессов атерогенеза вследствие ВИЧ-инфекции. В качестве возможных причин обсуждаются как прямое воздействие ВИЧ, так и другие факторы, которые имеют место у данной категории лиц: побочные эффекты антиретровирусной терапии, злоупотребление наркотическими средствами, сопутствующие заболевания, связанные с ВИЧ. Помимо специфических факторов риска у пациентов с ВИЧ-инфекцией могут присутствовать и традиционные — курение, гиподинамия, ожирение, гиперхолестеринемия. Результаты различных исследований показывают, что существует большой научный и практический интерес к проблеме атеросклероза у пациентов с ВИЧ-инфекцией.

Intra-articular hyaluronan injections represent a widely used and generally safe therapeutic approach for knee osteoarthritis (OA). However, the side effects of this treatment remain insufficiently studied. Acute post-injection reactions, particularly those arising from an improper technique resulting in the deposition of the therapeutic agent into joint tissues, are well-documented. In contrast, chronic hyaluronan-induced inflammatory responses have received scant attention in the scientific literature. The aim of this study is to characterize for the first time the morphological patterns of chronic granulomatous inflammation induced by exogenous hyaluronan (e-HA) in osteoarthritic knees, focusing on three distinct tissue reactions: synovitis, adipositis, and osteomyelitis. Using a three-case series approach and morphological analysis, we identified e-HA penetration pathways; described associated foreign body responses in the synovial, adipose, and bone tissues of the joints; and emphasized the clinical relevance of these underreported adverse effects. These observations highlight an understudied phenomenon—an active conflict between e-HA and joint tissues that recognize it as a foreign body. The prevalence, clinical significance, and prognostic implications of this phenomenon require further investigation.

Cardiovascular disease is a serious problem of modern healthcare, which is one of the leading causes of general mortality, reduction and loss of ability to work, as well as disability. The search and the study of new cardiovascular biological markers can allow the optimization of the diagnosis of cardiovascular diseases, development of laboratory tools for assessing the effectiveness of a treatment, and improving the prediction of possible adverse clinical outcomes. The purpose of this review was to promote the consideration of interleukin-18 (IL-18) as a diagnostic and prognostic marker in cardiovascular pathology. For the first time, K. Nakamura et al. in 1989, described IL-18 and interferon-gamma (IFN--inducing factor, IFN--inducing factor, IGIF) as a new, previously unknown factor that induces the production of IFN-. Data obtained from rodent models and clinical studies have demonstrated that IL-18 is involved in the pathogenesis of several diseases, immune-inflammatory rheumatic conditions, systemic vasculitis, cardiovascular diseases, malignancy, central nervous system pathologies, inflammatory bowel disease, psoriasis, and diseases of the kidneys and lungs. In animal models of acute myocardial infarction, pressure overload, and left ventricular dysfunction, IL-18 has been demonstrated to increase cardiomyocyte hypertrophy, induce cardiac contractile dysfunction, and extracellular matrix remodeling. It is therefore expected that further scientific and clinical studies can demonstrate the possibility of using IL-18 as an additional laboratory tool for the diagnosis, risk stratification, and prediction of cardiovascular events in patients with a cardiac profile. The effect of blockade of this cytokine on reducing morbidity and mortality in patients with cardiovascular diseases remains to be assessed for more detail, while considering reasonable economic costs and the side effects of drugs.

Osteophytes (OPs) are a diagnostic hallmark of osteoarthritis (OA). However, the mechanisms underlying their initiation and their relationship with early subchondral bone changes remain poorly understood. Existing research primarily relies on animal models and late-stage OA tissue, leaving the initial morphological events leading to OP formation unclear. Background/Objectives: This study aimed to identify early changes in the subchondral bone as a key trigger for OP initiation in human OA through a comprehensive histological analysis of the subchondral area, including its peripheral regions. Methods: We conducted an extensive histological examination of full-section human tibial plateaus, including load-bearing and non-load-bearing compartments, obtained from patients with early and late stages of OA. Results: Our data demonstrate that subchondral bone changes, including osteoporosis, osteosclerosis, and microcracks, begin at the pre-chondropathic stage alongside microscopically intact cartilage. We identified a previously undescribed zone on the vertical wall of the tibial condyle (the VEPLS zone), characterized by reduced calcium content in the cortical plate and the persistence of embryonic cartilage, making it morphologically vulnerable. The first event in OP formation is microcracks in the cortical angle and the adjacent subchondral trabecula. These injuries initiate reparative osteogenesis, which, under continuous traumatic load (presumably shear forces due to joint instability), becomes insufficient, leading to cortical angle protrusion and OP formation. OP growth is accompanied by the deformation of the VEPLS zone cortical plate, causing vascular impairment and exacerbating bone weakness. Conclusions: Based on our findings, we propose the concept of tissue micro-instability. This concept posits that osteophytosis results from chronic microcracks and failed bone regeneration in vulnerable subchondral structures, induced by joint instability. We define an OP as a pathological outgrowth arising from this tissue micro-instability. Our study highlights the critical role of the peripheral subchondral area, particularly the VEPLS zone, in OA pathogenesis.

Background: Osteoarthritis (OA) of the knee joint is one of the most dangerous diseases, the most significant manifestation of which is chronic pain syndrome. There is a low correlation between the radiographic stage of OA and pain progression. First of all, this is a variety of pain syndromes, among which is the pathology of periarticular structures (AS). To date, the contribution of this type to the clinical picture of OA has been sufficiently studied, primarily due to the fact that the list and frequency of these lesions have not yet been described.Aim: to describe the basis of the main periarticular structures in patients with different radiographic stages of knee OA according to ultrasound data.Materials and methods: The observational study has currently included 88 patients who had an outpatient appointment with a rheumatologist for knee osteoarthritis between 2021 and 2023. The study assessed 110 knee joints using clinical and ultrasound techniques.Results: The most common periarticular ultrasound changes, regardless of radiographic stage, were pes anserine tendinopathy (57.3 %), Baker’s cyst (45.5 %), fibrosis of the severe Hoffa body (40 %) and ligamentopathy of the medial collateral ligament (36). ,4). %). A significant correlation was found between the number of changes according to ultrasound and the radiological stage (ρ=0.45 [95 % CI: 0.28, 0.59], p <0.001) as well as between the VAS and the definition of identified ultrasound changes (ρ= 0.29 [95 % CI: 0.11, p=0.002); In addition, it was shown that late stages of OA are associated with a greater content of changes (p <0.001).Conclusion: Changes in periarticular structures are present in most patients with knee osteoarthritis; their number correlates with the VAS value and radiographic stage of OA. Details of these changes, their clinical significance and pathogenetic contribution to the progression of knee OA require further study.