Hard Calluses Research Articles

Does plantar skin abrasion affect cutaneous mechanosensation?

In humans, plantar cutaneous mechanoreceptors provide critical input signals for postural control during walking and running. Because these receptors are located within the dermis, the mechanical properties of the overlying epidermis likely affect the transmission of external stimuli. Epidermal layers are highly adaptable and can form hard and thick protective calluses, but their effects on plantar sensitivity are currently disputed. Some research has shown no effect of epidermal properties on sensitivity to vibrations, whereas other research suggests that vibration and touch sensitivity diminishes with a thicker and harder epidermis. To address this conflict, we conducted an intervention study where 26 participants underwent a callus abrasion while an age‐matched control group (n = 16) received no treatment. Skin hardness and thickness as well as vibration perception thresholds and touch sensitivity thresholds were collected before and after the intervention. The Callus abrasion significantly decreased skin properties. The intervention group exhibited no change in vibration sensitivity but had significantly better touch sensitivity. We argue that touch sensitivity was impeded by calluses because hard skin disperses the monofilament's standardized pressure used to stimulate the mechanoreceptors over a larger area, decreasing indentation depth and therefore stimulus intensity. However, vibration sensitivity was unaffected because the vibrating probe was adjusted to reach specific indentation depths, and thus stimulus intensity was not affected by skin properties. Since objects underfoot necessarily indent plantar skin during weight‐bearing, calluses should not affect mechanosensation during standing, walking, or running.

Macrophage Colony Stimulating Factor as Predictive Marker of Osteoporosis in T2DM Patients

Background: Diabetes mellitus and osteoporosis are two common medical disorders that are becoming more common as the population ages. T2DM patients have a higher fracture hazard, having a high BMD, which is primarily due to the raise hazard of falling. Macrophage colony-stimulating factor (M-CSF) is one of the hematopoietic growth factor family, and It plays an important function in fracture repair by attracting stem cells to the fracture site and influencing the production of hard calluses by promoting osteoclast genesis. Aims of study: The purpose of this research was to assess the blood level of macrophage colony-stimulating factor in Iraqi osteoporotic patients with and without type 2 diabetes. in addition, that M-CSF may be a predictive marker for osteoporosis in T2DM patients Subjects & Methods: This study was conducted between October 2021 to March 2022 in Medical City of Baghdad Teaching Hospital. The current study included 92 individuals (females and males) aged 40-65 years’ old, 67 of them are patients and 25 as a control. The lumber spine's bone mineral density was determined using dual energy x-ray absorptiometry (DEXA)scan to diagnose these patients. Patients divided into (20) person as T2DM patients, (27) person as osteoporosis patients, and (20) as osteoporosis patients with T2DM Results: The current study showed an important increase in serum M-CSF of osteoporosis patients with and without T2DM groups when compared with control, also, there was no significance increase in M-CSF level in T2DM patients comparing with control. Also, there was an important negative relation between M-CSF and bone mineral density (BMD) In osteoporosis patients, there was a substantial positive connection between M-CSF, FBS, and HbA1C. Conclusions: The current study demonstrated that serum macrophage colony-stimulating factor (M-CSF) levels was significantly elevated in osteoporosis patients with and without T2DM, Therefore, this parameter may be a diagnostic marker for osteoporotic patients. In addition, that diabetic patients may be prone to osteoporosis, and M-CSF may be a predictive biochemical marker for development of osteoporosis in type 2 diabetic patients. Keywords: Macrophage colony-stimulating factor, Osteoporosis, bone mineral density, Type 2 diabetes mellitus.

Calcium-Sensing Receptors in Chondrocytes and Osteoblasts Are Required for Callus Maturation and Fracture Healing in Mice.

Calcium and its putative receptor (CaSR) control skeletal development by pacing chondrocyte differentiation and mediating osteoblast (OB) function during endochondral bone formation-an essential process recapitulated during fracture repair. Here, we delineated the role of the CaSR in mediating transition of callus chondrocytes into the OB lineage and subsequent bone formation at fracture sites and explored targeting CaSRs pharmacologically to enhance fracture repair. In chondrocytes cultured from soft calluses at a closed, unfixed fracture site, extracellular [Ca2+ ] and the allosteric CaSR agonist (NPS-R568) promoted terminal differentiation of resident cells and the attainment of an osteoblastic phenotype. Knockout (KO) of the Casr gene in chondrocytes lengthened the chondrogenic phase of fracture repair by increasing cell proliferation in soft calluses but retarded subsequent osteogenic activity in hard calluses. Tracing growth plate (GP) and callus chondrocytes that express Rosa26-tdTomato showed reduced chondrocyte transition into OBs (by >80%) in the spongiosa of the metaphysis and in hard calluses. In addition, KO of the Casr gene specifically in mature OBs suppressed osteogenic activity and mineralizing function in bony calluses. Importantly, in experiments using PTH (1-34) to enhance fracture healing, co-injection of NPS-R568 not only normalized the hypercalcemic side effects of intermittent PTH (1-34) treatment in mice but also produced synergistic osteoanabolic effects in calluses. These data indicate a functional role of CaSR in mediating chondrogenesis and osteogenesis in the fracture callus and the potential of CaSR agonism to facilitate fracture repair. © 2019 American Society for Bone and Mineral Research.

Increased Bone Turnover and Possible Accelerated Fracture Healing in a Murine Model With an Increased Circulating C-Type Natriuretic Peptide.

Recent studies have revealed that C-type natriuretic peptide (CNP) is a potent stimulator of endochondral bone growth. Nevertheless, the effect of CNP on bone turnover has not yet been well studied. To elucidate this issue, we investigated the bone phenotype of a mouse model with elevated plasma CNP concentrations (SAP-CNP-Tg mice) in the present study. Microcomputed tomography (CT) analysis revealed less bone in femurs, but not in lumber vertebrae, of young adult SAP-CNP-Tg mice than that of wild-type mice. Bone histomorphometry of the tibiae from 8-week-old SAP-CNP-Tg mice showed enhanced osteoblastic and osteoclastic activities, in accordance with elevated serum levels of osteocalcin and tartrate-resistant acid phosphatase-5b, respectively. Next we performed an open and stabilized femoral fracture using 8-week-old SAP-CNP-Tg mice and compared the healing process with age-matched wild-type mice. An immunohistochemical study revealed that CNP and its receptors, natriuretic peptide receptor-B and natriuretic peptide clearance receptor, are expressed in hard calluses of wild-type mice, suggesting a possible role of CNP/natriuretic peptide receptor-B signaling in fracture repair, especially in bone remodeling stage. On micro-CT analysis, a rapid decrease in callus volume was observed in SAP-CNP-Tg mice, followed by a generation of significantly higher new bone volume with a tendency of increased bone strength. In addition, a micro-CT analysis also showed that bone remodeling was accelerated in SAP-CNP-Tg mice, which was also evident from increased serum osteocalcin and tartrate-resistant acid phosphatase-5b levels in SAP-CNP-Tg mice at the remodeling stage of fracture repair. These results indicate that CNP activates bone turnover and remodeling in vivo and possibly accelerates fracture healing in our mouse model.

Matrix Metalloproteinase–Driven Endochondral Fracture Union Proceeds Independently of Osteoclast Activity

As new insights into the complexities of endochondral fracture repair emerge, the temporal role of osteoclast activity remains ambiguous. With numerous antiresorptive agents available to treat bone disease, understanding their impact on bone repair is vital. Further, in light of recent work suggesting osteoclast activity may not be necessary during early endochondral fracture union, we hypothesize instead a pivotal role of matrix metalloproteinase (MMP) secreting cells in driving this process. Although the role of MMPs in fracture healing has been examined, no directly comparative experiments exist. We examined a number of antiresorptive treatments to either block osteoclast activity, including the potent bisphosphonates zoledronic acid (ZA) and clodronate (CLOD), which work via differing mechanisms, or antagonize osteoclastogenesis with recombinant OPG (HuOPG-Fc), comparing these directly to an inhibitor of MMP activity (MMI270). Endochondral ossification to union occurred normally in all antiresorptive groups. In contrast, MMP inhibition greatly impaired endochondral union, significantly delaying cartilage callus removal. MMP inhibition also produced smaller, denser hard calluses. Hard callus remodeling was, as expected, delayed with ZA, CLOD, and OPG treatment at 4 and 6 weeks, resulting in larger, more mineralized calluses at 6 weeks. As a result of reduced hard callus turnover, bone formation was reduced with antiresorptive agents at these time points. These results confirm that the achievement of endochondral fracture union occurs independently of osteoclast activity. Alternatively, MMP secretion by invading cells is obligatory to endochondral union. This study provides new insight into cellular contributions to bone repair and may abate concerns regarding antiresorptive therapies impeding initial fracture union.

Immature osteoblastic cells express the pro-α2(XI) collagen gene during bone formation in vitro and in vivo

Type XI collagen is predominantly found in cartilage. However, expression of the pro-α2(XI) collagen gene (COL11A2) has recently been detected in various non-cartilaginous tissues. We identified the differentiation stage at which COL11A2 was expressed in cultured fetal rat calvarial (FRC) cells and in rat femoral fracture calluses in order to investigate the involvement of COL11A2 during bone formation in vitro and in vivo. We also studied the alternative splicing of exons 6–8 in FRC cells and fracture calluses. In FRC cells, mineralized nodules stained with von Kossa stain were observed from day 9 after confluence. COL11A2 was highly expressed on days 0 and 5, but the expression levels were rapidly decreased on day 9 by Northern blot analysis. During rat femoral fracture repair, intramembranous ossification proceeded and newly formed woven bone was observed on the cortex on day 7 after fracture. In situ hybridization showed that COL11A2 signals were detected in osteoblastic cells in the newly formed woven bone. According to the maturation and remodeling of the woven bone into the trabecular bone, the distribution of the signal for COL11A2 mRNA was limited to the superficial osteoblastic cells of the newly formed trabecular bone. These results demonstrated that COL11A2 was expressed in relatively immature osteoblastic cells during bone formation in vitro and in vivo. RT-PCR showed that the shortest band corresponding to mRNA lacking exons 6–8 was clearly detected when using RNA from soft calluses. In contrast, the largest band corresponding to mRNA with exons 6–8 was predominant when using RNA from FRC cells or from hard calluses on days 7 and 14. These results indicate that the splicing pattern of exons 6–8 in osteoblastic cells is different from the pattern in chondrocytes.

Optimization of callus culture and shoot multiplication ofAsparagus densiflorus

The effects of different growth regulators on induction and growth of callus ofAsparagus densiflorus cv. Sprengeri were studied. Calluses grew more rapidly on Murashige and Skoog basal medium supplemented with 5.4 μM p-chlorophenoxyacetic acid (pCPA) and 4.4 μM 6-benzylaminopurine (BA) (medium 1) as compared to the same medium with 11.3 μM 2,4-dichlorophenoxyacetic acid (2,4-d) and 4.6 μM kinetin (medium 2). Calluses on medium 1 were soft and friable, whereas, compact, hard calluses originated on medium 2. Different concentrations and combinations of BA and/or kinetin were also used to study their effects on shoot regeneration. Kinetin was found to be less effective than BA in the initiation of shoots (1.8 shoots/callus). High numbers of shoots were produced in the presence of 0.4 μM BA alone (3.3 shoots/callus). The addition of ancymidol (5 μM) in MS with 0.4 μM BA enhanced multiplication of shoots (9.8 shoots/explant) and also produced well-developed crowns.

Callus induction and shoot regeneration in Sempervivum tectorum

Leaf and shoot explants of Sempervivum tectorum L., taken from 14- and 30-day-old plants germinated in vitro, have been studied by using Murashige-Skoog and White basal media with cytokinins (benzyladenine, kinetin) and auxins (indoleacetic acid, naphthaleneacetic acid, indolebutyric acid) in various concentrations. Explants taken from 14-day-old plants died but 30-day-old leaves and shoots produced yellow and soft, as well as green and hard calluses on Murashige-Skoog medium with 4.4–8.8 μM benzyladenine and 0.57 μM indoleacetic acid. Shoot organogenesis was induced from green, hard callus in a medium with 2.2 μM benzyladenine plus either 1.1 μM indoleacetic acid or 2.5 μM indolebutyric acid. Whole plants were grown on Murashige-Skoog medium without plant growth regulators. On the other hand, White medium was not suitable for raising Sempervivum tectorum in vitro.

Genetic expression of extracellular matrix proteins correlates with histologic changes during fracture repair.

We characterized gene expression in the reparative callus that formed after fracture of the rat femur. The callus was divided into regions of bone formation (hard callus) and cartilage formation (soft callus), and gene expression was examined separately in each region. Expression of extracellular matrix protein genes varied with the progression of repair and differed between hard and soft calluses. Messenger ribonucleic acids (mRNAs) for osteonectin, alkaline phosphatase, and type I procollagen were detected in the hard callus at maximal levels during endochondral ossification and bone remodeling (day 15) and at 50% maximal levels during intramembranous bone formation (day 7). Messenger RNAs for these proteins in the soft callus were detected at low levels during chondrogenesis (day 9) but increased to 80% of maximal levels with chondrocyte hypertrophy and mineralization of the cartilage matrix (day 13). Messenger RNAs for type II procollagen and proteoglycan core protein were detected at maximal levels in the soft callus during chondrogenesis (day 9). Osteocalcin gene expression was detected in the hard callus during endochondral ossification and remodeling but not during intramembranous bone formation or at any time in the soft callus. Osteonectin mRNA was detected in both the hard and soft callus throughout the entire course of fracture repair. Expression of cartilage and bone-related genes correlated with the temporal sequence of histologic changes, suggesting transcriptional regulation of gene expression during repair. Differences in gene expression between hard and soft callus and in each of these regions as repair progressed suggest local regulation of gene expression during cell differentiation and matrix synthesis.

Somatic Embryogenesis and Plant Regeneration in Hyoscyamus niger

Culture of segments of leaves, petioles, and stems and of germinated seeds and whole ovaries enclosing unpollinated ovules of Hyoscyamus niger in a medium containg 2, 4-dichlorophen-oxyacetic acid caused massive growth of calluses. In cultured germinated seeds and ovaries, calluses were formed from the hypocotyl and placenta, respectively. Leaf and stem explants generally gave rise to hard, white, and compact calluses. Upon transfer of these calluses to an auxin-free medium they regenerated roots or buds but showed no further signs of morphogenesis. Calluses formed on petioles, germinated seeds, and ovaries were a mixture of the white, compact and brown, friable types. Subsequent morphogenesis of the friable calluses in a medium lacking auxin was characterized by the formation of somatic embryos whose pattern of development was similar to that of zygotic embryos.

SOMATIC EMBRYOGENESIS AND PLANT REGENERATION IN HYOSCYAMUS NIGER

Culture of segments of leaves, petioles, and stems and of germinated seeds and whole ovaries enclosing unpollinated ovules of Hyoscyamus niger in a medium containg 2, 4‐dichlorophen‐oxyacetic acid caused massive growth of calluses. In cultured germinated seeds and ovaries, calluses were formed from the hypocotyl and placenta, respectively. Leaf and stem explants generally gave rise to hard, white, and compact calluses. Upon transfer of these calluses to an auxin‐free medium they regenerated roots or buds but showed no further signs of morphogenesis. Calluses formed on petioles, germinated seeds, and ovaries were a mixture of the white, compact and brown, friable types. Subsequent morphogenesis of the friable calluses in a medium lacking auxin was characterized by the formation of somatic embryos whose pattern of development was similar to that of zygotic embryos.

Effects of kinetin and gibberellin a3 on callus growth and organ formation inLimnophila chinensis tissue culture

The action of exogenously applied hormones in the induction of morphogenesis inLimnophila chinensis (Osb.) Merr. tissue culture has been demonstrated. Stem expiants were grown on Murashige and Skoog’s medium containing various levels of kinetin, gibberellic acid and indole-3-acetic acid. Formation of roots, shoots (normal or abnormal), plantlets and friable, hard or nodulated calluses depended largely on the hormone levels used. The formation of normal shoots and roots were stimulated by treatment with kinetin. GA3 treatment stimulated the bud differentiation but inhibited the root initiation. A combination of kinetin and GA3 gave variable results.