Agnieszka Mikulska

Osteoblast dysfunction and altered Wnt/β-catenin-dependent responses accompany bone-remodeling imbalance in rheumatic and degenerative joint disease. Rosavin and salidroside are constituents of Rhodiola rosea preparations used without prescription, and are always encountered together rather than separately. This exploratory in vitro study asked whether the two compounds and their combination differentially affect total β-catenin concentration and cell-covered area in human osteoblasts (HOBs). HOBs from one commercial preparation (passage 7) were cultured in growth medium (GM) or mineralization medium (MM) and exposed to rosavin 50 µM (R50), salidroside 50 µM (Sal50) or both (R50/Sal50). Total β-catenin was quantified by ELISA in four independently cultured, treated, harvested and lysed wells per condition at days 7, 14 and 21. Cell-covered area was estimated from 79 phase-contrast fields. Welch ANOVA with Games–Howell post-hoc testing was pre-specified. Total β-catenin differed between conditions at day 14 (Welch ANOVA p = 0.003, Holm-adjusted p = 0.009; η² = 0.43): 8.9 ± 3.8 ng/mL in R50 versus 28.5 ± 3.8 in Sal50, 26.5 ± 16.9 in R50/Sal50, 23.5 ± 7.9 in MM and 27.4 ± 8.6 in GM. Sal50 versus R50 was the only contrast surviving correction (difference 19.6 ng/mL, 95% CI 13.1–26.1; p = 0.002). No difference was detected at day 7 ( p = 0.87) or day 21 ( p = 0.23). Cell-covered area differed at days 7 and 21, with R50/Sal50 lowest and most variable (54.5 ± 23.4% versus 98.1 ± 1.8% in GM at day 7). Cell-covered area explained 12% of the variance in group-mean β-catenin ( r = − 0.35). Rosavin alone was associated with a marked reduction in total β-catenin at day 14; its combination with salidroside was not. The two constituents therefore do not act interchangeably on human osteoblasts. These observations derive from a single experimental series and require replication before mechanistic or clinical interpretation.

Background: Rosavin, a bioactive compound derived from Rhodiola rosea , has been proposed to modulate osteoblast-associated signaling pathways. Emerging evidence highlights the role of CX3CL1 (fractalkine) in bone–immune interactions. This study aimed to investigate whether rosavin modulates CX3CL1 secretion and osteoblast morphology and confluence in human osteoblasts (HOB) in vitro, thereby providing descriptive cellular evidence relevant to CX3CL1-associated osteoblast responses under mineralizing conditions. Methods: Prior to biological testing, the chemical identity of rosavin was verified by high-resolution electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS). HOB were cultured in growth medium (DMEM-g), mineralization medium (DMEM-m), or DMEM-m supplemented with rosavin at 50 µM (R50) or 100 µM (R100). Cell morphology and confluence were assessed by phase-contrast microscopy, supported by semi-quantitative image-based estimation of cell-covered area using Fiji/ImageJ. Sirius Red staining was performed only in the DMEM-m mineralization control group and was evaluated qualitatively as a supportive assessment of extracellular matrix maturation. Results: Rosavin was associated with dose- and time-dependent changes in CX3CL1 secretion and morphology-related observations in HOB cultures. The 50 µM rosavin condition showed significantly increased CX3CL1 secretion at days 14 and 21 compared with DMEM-m alone and was associated with higher cell confluence and predominance of cuboidal cell morphology. In contrast, the 100 µM condition was associated with lower apparent confluence, mixed cellular morphology, and reduced CX3CL1 secretion at later time points. Conclusions: These observations are descriptive, preliminary, and hypothesis-generating. Rosavin was associated with concentration-dependent modulation of CX3CL1 secretion and osteoblast morphological characteristics in vitro; however, the biological significance of CX3CL1 modulation in this monoculture model remains uncertain. Further mechanistic and functional studies are required.

β-catenin is a key regulator of osteoblast differentiation, proliferation, and bone homeostasis. Through its interaction with transcription factors such as TCF/LEF, Runx2, and Osx, it coordinates gene expression essential for osteogenesis. The aim of this review is to demonstrate how β-catenin signaling is modulated by various physiological and pathological factors, including mechanical loading, oxidative stress, HIV-1 gp120, fluoride, implant topography, and microRNAs. These factors influence Wnt/β-catenin signaling through different mechanisms, often exerting opposing effects on osteoblast function. By integrating these modulators, we provide a comprehensive view of the dynamic regulation of β-catenin in bone biology. Understanding this complexity may provide insight into novel therapeutic strategies targeting β-catenin in bone regeneration, metabolic bone diseases, and pathologies such as HIV-associated bone loss or osteosarcoma.

Rosavin, a glycoside isolated from Rhodiola rosea, exhibits various biological activities, including potential modulation of metabolic pathways. Despite promising findings in animal models, its effects on many human bone cells remain unexplored. This study aimed to investigate, for the first time, the in vitro effects of rosavin on human osteoblasts (HOBs), focusing on BMP-2 expression, cell morphology, and culture confluence as indicators of osteogenic activity. HOB cultures were treated with 50 µM or 100 µM rosavin for 21 days. BMP-2 expression was measured by ELISA, collagen production was assessed via Sirius Red staining, and cell morphology and confluence were evaluated using phase-contrast microscopy. A significant increase in BMP-2 expression was observed in the 100 µM rosavin group compared to the mineralization control (p < 0.05), particularly on days 14 and 21. Both rosavin-treated groups exhibited higher confluence than controls, with the 50 µM group showing unexpectedly greater confluence than the 100 µM group. Rosavin at 50 µM also promoted a cuboidal morphology characteristic of active HOBs. The presence of collagen validated both the successful progression of the mineralization process and the correct implementation of the experimental protocol. Rosavin enhances BMP-2 expression and supports HOB proliferation and morphological maturation in vitro. These findings suggest its potential as a supportive agent in the prevention or treatment of metabolic bone diseases. Further research is necessary to determine its bioavailability, safety profile, and therapeutic relevance in clinical settings.

Rhodiola rosea, a long-lived herbaceous plant from the Crassulaceae group, contains the active compound salidroside, recognized as an adaptogen with significant therapeutic potential for bone metabolism. Salidroside promotes osteoblast proliferation and differentiation by activating critical signaling pathways, including bone morphogenetic protein-2 and adenosine monophosphate-activated protein kinase, essential for bone formation and growth. It enhances osteogenic activity by increasing alkaline phosphatase activity and mineralization markers, while upregulating key regulatory proteins including runt-related transcription factor 2 and osterix. Additionally, salidroside facilitates angiogenesis via the hypoxia-inducible factor 1-alpha and vascular endothelial growth factor pathway, crucial for coupling bone development with vascular support. Its antioxidant properties offer protection against bone loss by reducing oxidative stress and promoting osteogenic differentiation through the nuclear factor erythroid 2-related factor 2 pathway. Salidroside has the capability to counteract the negative effects of glucocorticoids on bone cells and prevents steroid-induced osteonecrosis. Additionally, it exhibits multifaceted anti-inflammatory actions, notably through the inhibition of tumor necrosis factor-alpha and interleukin-6 expression, while enhancing the expression of interleukin-10. This publication presents a comprehensive review of the literature on the impact of salidroside on various aspects of bone tissue metabolism, emphasizing its potential role in the prevention and treatment of osteoporosis and other diseases affecting bone physiology.

Rhodiola rosea, a perennial herb from the Crassulaceae family, contains the bioactive compound salidroside, recognized as an adaptogen with significant therapeutic potential for bone metabolism. Salidroside promotes osteoblast proliferation and differentiation by activating critical signaling pathways, including bone morphogenetic protein-2 and adenosine monophosphate-activated protein kinase, essential for bone formation and growth. It enhances osteogenic activity by increasing alkaline phosphatase activity and mineralization markers, while upregulating key transcription factors such as runt-related transcription factor 2 and osterix. Additionally, salidroside facilitates angiogenesis via the hypoxia-inducible factor 1-alpha and vascular endothelial growth factor pathway, crucial for coupling bone formation with vascular support. Its antioxidant properties offer protection against bone loss by reducing oxidative stress and promoting osteogenic differentiation through the nuclear factor erythroid 2–related factor 2 pathway. Salidroside's ability to counteract the negative effects of glucocorticoids on bone cells and prevent steroid-induced osteonecrosis, along with its anti-inflammatory properties, enhances its potential in treating conditions like osteoarthritis. These attributes underscore its multifaceted role in bone metabolism. This article reviews the literature, including in vitro and in vivo studies primarily on rodent models, demonstrating salidroside's efficacy in mitigating bone loss, preserving bone microarchitecture, and accelerating fracture healing. Future research directions to explore salidroside’s applications in bone-related diseases are also highlighted.

The flow of substances between the blood and the central nervous system is precisely regulated by the blood–brain barrier (BBB). Its disruption due to unbalanced blood glucose levels (hyper- and hypoglycemia) occurring in metabolic disorders, such as type 2 diabetes, can lead to neuroinflammation, and increase the risk of developing neurodegenerative diseases. One of the most studied natural anti-diabetic, anti-inflammatory, and neuroprotective compounds is resveratrol (RSV). It activates sirtuin 1 (SIRT1), a key metabolism regulator dependent on cell energy status. The aim of this study was to assess the astrocyte SIRT1 response to neuroinflammation and subsequent RSV treatment, depending on systemic glycemia. For this purpose, we used an optimized in vitro model of the BBB consisting of endothelial cells and astrocytes, representing microvascular and brain compartments (MC and BC), in different glycemic backgrounds. Astrocyte-secreted SIRT1 reached the highest concentration in hypo-, the lowest in normo-, and the lowest in hyperglycemic backgrounds. Lipopolysaccharide (LPS)-induced neuroinflammation caused a substantial decrease in SIRT1 in all glycemic backgrounds, as observed earliest in hyperglycemia. RSV partially counterbalanced the effect of LPS on SIRT1 secretion, most remarkably in normoglycemia. Our results suggest that abnormal glycemic states have a worse prognosis for RSV-therapy effectiveness compared to normoglycemia.

There is a profound dependence of cell behaviour on the stiffness of its microenvironment. To gain a better understanding of the regulation of cellular differentiation by mechanical cues, we investigated the influence of matrix stiffness (E = 1.46 kPa and E = 26.12 kPa) on differentiated osteogenic cell lineage of bone marrow stem cells (BM‐MSCs) and bone‐derived cells (BDCs) using flexible collagen‐coated polyacrylamide substrates. Differentiation potential was determined by measuring alkaline phosphatase activity, expression of osteoblast‐specific markers including alkaline phosphatase, osteocalcin, Runx2 and collagen type I, as well as assessment of mineralisation (Alizarin Red S staining). We found that osteogenic differentiation can be regulated by the rigidity of the substrate, which may depend on the commitment in multi‐ or uni‐potent targeting cells. Osteogenic differentiation of BM‐MSCs was enhanced on a stiff substrate compared to a soft one, whereas BDCs osteogenic differentiation did not vary depending on the substrate stiffness. The data help in understanding the role of the external mechanical determinants in stem cell differentiation, and can also be useful in translational approach in functional tissue engineering.