Morphological study of cartilage cell death in patients affected by osteoarthritis and chondrocalcinosis

The role of chondrocyte death in the pathogenesis of osteoarthritis (OA) has been largely discussed in literature, but its relative contribution is difficult to assess (1). Chondrocyte death, be it apoptotic, necrotic or chondroptotic, has been clearly documented in OA and a certain correlation between the degree of cartilage damage and chondrocyte apoptosis has been demonstrated (2;3). Conversely, the relationship between the different types of cell death and chondrocalcinosis (CC) is still little known, as well as the presence and role of chondroptotic cells. The aim of this research was to compare chondrocyte behavior in the cartilage of osteoarthritic and chondrocalcinotic knees, evaluating the different types of cell death by means of optical and electron microscopy. During total knee replacement surgeries, cartilage specimens of femoral condyle have been withdrawn and their transversal semithin sections, stained with toluidine blue and alizarin solutions, have been investigated by optical microscopy. From the same samples, thin sections were obtained for transmission electron microscopy to evaluate, at high magnification, the specific ultrastructural features of different types of cell death. Cartilage specimens from both conditions revealed a thickness reduction of superficial layer and a high number of empty lacunae in the middle layer. Calcium pyrophosphate crystals appeared in the samples of patients affected by CC. In osteoarthritic cartilage, numerous chondrocytes revealed necrotic features, whereas, in chondrocalcinotic tissue, the middle zone was characterized by morphological patterns suggestive of chondroptosis, such as chromatin condensation mostly localized at the nuclear periphery, mitochondria alterations, a marked increase in endoplasmic reticulum, the presence of a diffuse autophagic component and the extrusion of cellular material into the lacunae. In conclusion, a different distribution of cell death types seems to characterize the intermediate layers of cartilage specimens from patients affected by CC compared to OA

An ultrastructural study of Sertoli cells inside alginate microcapsules

Sertoli cells (SeC) are the main components of the blood-testis barrier, are essential for spermatogenesis and are long known for their ability to secrete trophic, anti-inflammatory and immunomodulatory factors [1]. For these reasons, SeC have been encapsulated in sodium alginate microcapsules and then used to create an ectopic immune-privileged environment to prolong survival of co-transplanted cells or modulate the immune responses [2]. Encapsulation has represented an improvement for the use of SeC. In fact, it has been reported that inside the microcapsules SeC (SeC-MC) act as a “micro-biofactory” and drug delivery system. By secreting immunomodulatory and trophic factors once injected into the peritoneal cavity of dystrophic mice [3], they can ameliorate muscle morphology and function. Since the manipulation of the microcapsules is rather complicated, we performed for the first time, an ultrastructure study on SeC-MC. The good cell morphology, along with viability of organellar compartment, was demonstrated

Melatonin prevents mitochondrial dysfunctions and death in differentiated skeletal muscle cells

Oxidative stress increase induces cellular damage and apoptosis activation, a mechanism believed to represent a final common pathway correlated to sarcopenia and many skeletal muscle disorders. The goal of this study is to evaluate if melatonin, a ROS scavenger molecule, is able to counteract or modulate myotube death. Here, differentiated C2C12 skeletal muscle cells have been treated with melatonin before chemicals known to induce apoptotic death and oxidative stress, and its effect has been investigated by means of morpho-functional analyses. Ultrastructural observations show melatonin protection against triggers by the reducing of membrane blebbing, chromatin condensation, myonuclei loss and in situ DNA cleavage. Moreover, melatonin is able to prevent mitochondrial dysfunctions which occur in myotubes exposed to the trigger alone. These findings demonstrate melatonin ability in preventing apoptotic cell death in skeletal muscle fibers in vitro, suggesting for this molecule a potential therapeutic role in the treatment of various muscle disorders

Morphological study of cartilage cell death in patients affected by osteoarthritis and chondrocalcinosis.

The role of chondrocyte death in the pathogenesis of osteoarthritis (OA) has been largely discussed in literature, but its relative contribution is difficult to assess (1). Chondrocyte death, be it apoptotic, necrotic or chondroptotic, has been clearly documented in OA and a certain correlation between the degree of cartilage damage and chondrocyte apoptosis has been demonstrated (2;3). Conversely, the relationship between the different types of cell death and chondrocalcinosis (CC) is still little known, as well as the presence and role of chondroptotic cells. The aim of this research was to compare chondrocyte behavior in the cartilage of osteoarthritic and chondrocalcinotic knees, evaluating the different types of cell death by means of optical and electron microscopy. During total knee replacement surgeries, cartilage specimens of femoral condyle have been withdrawn and their transversal semithin sections, stained with toluidine blue and alizarin solutions, have been investigated by optical microscopy. From the same samples, thin sections were obtained for transmission electron microscopy to evaluate, at high magnification, the specific ultrastructural features of different types of cell death. Cartilage specimens from both conditions revealed a thickness reduction of superficial layer and a high number of empty lacunae in the middle layer. Calcium pyrophosphate crystals appeared in the samples of patients affected by CC. In osteoarthritic cartilage, numerous chondrocytes revealed necrotic features, whereas, in chondrocalcinotic tissue, the middle zone was characterized by morphological patterns suggestive of chondroptosis, such as chromatin condensation mostly localized at the nuclear periphery, mitochondria alterations, a marked increase in endoplasmic reticulum, the presence of a diffuse autophagic component and the extrusion of cellular material into the lacunae. In conclusion, a different distribution of cell death types seems to characterize the intermediate layers of cartilage specimens from patients affected by CC compared to OA

Chondroptotic chondrocytes in the loaded area of chondrocalcinotic cartilage: A clinical proposal?

none9noNo abstractmixedCurzi D.; Fardetti F.; Beccarini A.; Salucci S.; Burini D.; Gesi M.; Calvisi V.; Falcieri E.; Gobbi P.Curzi D.; Fardetti F.; Beccarini A.; Salucci S.; Burini D.; Gesi M.; Calvisi V.; Falcieri E.; Gobbi P

Hip Labral Morphological Changes in Patients with Femoroacetabular Impingement Speed Up the Onset of Early Osteoarthritis

: Over the last decade, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early hip osteoarthritis (OA). The aim of this study was to compare the ultrastructure and tissue composition of the hip labrum in healthy and pathological conditions, as FAI and OA, to provide understanding of structural changes which might be helpful in the future to design targeted therapies and improve treatment indications. We analyzed labral tissue samples from five healthy multi-organ donors (MCDs) (median age, 38 years), five FAI patients (median age, 37 years) and five late-stage OA patients undergoing total hip replacement (median age, 56 years). We evaluated morpho-functional by histology and transmission electron microscopy. Extracellular matrix (ECM) structure changes were similar in specimens from FAI compared to those from patients with OA (more severe in the latter) showing disorganization of collagen fibers and increased proteoglycan content. In FAI and in OA nuclei the chromatin was condensed, organelle degenerated and cytoplasm vacuolized. Areas of calcification were mainly observed in FAI and OA labrum, as well as apoptotic-like features. We showed that labral tissue of patients with FAI had similar pathological alterations of tissue obtained from OA patients, suggesting that FAI patients might have high susceptibility to develop OA

Morphological and ultrastructural analysis of normal, injured and osteoarthritic human knee menisci

The human meniscus plays a crucial role for transmission and distribution of load across the knee, as well as shock absorption, joint stability, lubrication, and congruity. The aim of this study was to compare the complex geometry, and unique ultrastructure and tissue composition of the meniscus in healthy (control) and pathological conditions to provide understanding of structural changes that could be helpful in the future design of targetted therapies and improvement of treatment indications. We analyzed meniscus samples collected from 3 healthy multi-organ donors (median age, 66 years), 5 patients with traumatic meniscal tear (median age, 41 years) and 3 patients undergoing total knee replacement (TKR) for end-stage osteoarthritis (OA) (median age, 72 years). We evaluated the extracellular matrix (ECM) organization, the appearance and distribution of areas of calcification, and modifications of cellular organization and structure by electron microscopy and histology. The ECM structure was similar in specimens from traumatic meniscus tears compared to those from patients with late-stage OA, showing disorganization of collagen fibers and increased proteoglycan content. Cells of healthy menisci showed mainly diffuse chromatin and well preserved organelles. Both in traumatic and in OA menisci, we observed increased chromatin condensation, organelle degeneration, and cytoplasmic vacuolization, a portion of which contained markers of autophagic vacuoles. Areas of calcification were also observed in both traumatic and OA menisci, as well as apoptotic-like features that were particularly prominent in traumatic meniscal tear samples. We conclude that meniscal tissue from patients with traumatic meniscal injury demonstrate pathological alterations characteristic of tissue from older patients undergoing TKR, suggesting that they have high susceptibility to develop OA