Microstructural analysis of bony alterations in a historic case of actinomycosis.

OBJECTIVE: Actinomycosis infection of bone is rare and its diagnosis challenging. Here, we aim to identify and verify its microstructural features and the potential value for differential diagnosis. MATERIALS: We investigated the dry preparation of the lumbar vertebrae and pelvic ring of a purported case of actinomycosis documented by a post-mortem examination in 1891. METHODS: Macroscopic inspection, conventional radiology, µCT, 3D reconstruction, and histological examination were employed. RESULTS: All approaches revealed new periosteal bone deposition with increased vascularisation of the os coxa, vertebrae, and sacrum. The µCT revealed cortical loss underneath the new bone formation; the 3D reconstruction and histological examination revealed plexiform bone and granular structures. CONCLUSIONS: The plexiform bone is the result of reactive rapid growth and remodelling processes, and is consistent with pathomorphological findings summarised in the autopsy report (soft tissue abscesses and formation of fistulas caused by "Actinomycosis intestine et ossis ilei sin."). SIGNIFICANCE: This is the first case of a historically documented case of actinomycosis infection investigated by µCT and histology. Different degrees of tissue damage and inflammatory reaction in form of plexiform bone, which has not been reported previously, was identified. LIMITATIONS: The noted bone tissue modifications are not solely pathognomic of actinomycosis; they characterise other diseases, as well. Histological evaluation is not appropriate for identifying the aetiology of the granular structures observed here; but clinically such aggregations appear in tissue affected by actinomycosis. SUGGESTIONS FOR FURTHER RESEARCH: Histochemical and molecular-genetic analyses are obligatory to affirm the diagnosis based on micromorphological features.

Cathepsin S controls adipocytic and osteoblastic differentiation, bone turnover, and bone microarchitecture.

Cathepsin S is a cysteine protease that controls adipocyte differentiation and has been implicated in vascular and metabolic complications of obesity. Considering the inverse relation of osteoblasts and adipocytes and their mutual precursor cell, we hypothesized that cathepsin S may also affect osteoblast differentiation and bone remodeling. Thus, the fat and bone phenotypes of young (3 months old) and aged (12 or 18 months old) cathepsin S knock-out (KO) and wild-type (WT) mice were determined. Cathepsin S KO mice had a normal body weight at both ages investigated, even though the amount of subscapular and gonadal fat pads was reduced by 20%. Further, cathepsin S deficiency impaired adipocyte formation (-38%, p<0.001), which was accompanied by a lower expression of adipocyte-related genes and a reduction in serum leptin, IL-6 and CCL2 (p<0.001). Micro-CT analysis revealed an unchanged trabecular bone volume fraction and density, while tissue mineral density was significantly lower in cathepsin S KO mice at both ages. Aged KO mice further had a lower cortical bone mass (-2.3%, p<0.05). At the microarchitectural level, cathepsin S KO mice had thinner trabeculae (-8.3%), but a better connected trabecular network (+24%). Serum levels of the bone formation marker type 1 procollagen amino-terminal-propeptide and osteocalcin were both 2-3-fold higher in cathepsin S KO mice as was the mineralized surface. Consistently, osteogenic differentiation was increased 2-fold along with an increased expression of osteoblast-specific genes. Interestingly, serum levels of C-terminal telopeptide of type I collagen were also higher (+43%) in cathepsin S KO mice as were histological osteoclast parameters and ex vivo osteoclast differentiation. Thus, cathepsin S deficiency alters the balance between adipocyte and osteoblast differentiation, increases bone turnover, and changes bone microarchitecture. Therefore, bone and fat metabolisms should be monitored when using cathepsin S inhibitors clinically.

Bone and cellular immune system of multiparous sows are insensitive to ovariectomy and nutritive calcium shortage.

Research in osteoporosis, which is a complex systemic disease, demands suitable large animal models. In pigs, most research has been done in growing minipigs, which probably are not ideal models for postmenopausal osteoporosis. Therefore, our aim was to analyze the effects of ovariectomy (OVX) and nutritive calcium shortage on multiparous Large White sows. 32 animals were randomly assigned to 4 groups in a cross design with OVX vs. sham and physiological calcium supplementation (0.75% calcium) vs. dietary calcium shortage (0.3% calcium). The observation period was 10 months with blood sampling every 2 months for hematological, immunological, and biochemical bone marker measurements. At the termination of the experiment, animals were sacrificed. Samples of trabecular bone of distal radius, proximal tibia, and sixth lumbar vertebra were subjected to micro-computed tomography imaging and ashed afterwards. Dual X-ray absorptiometry scans of the proximal femora were performed with prepared bones being placed in a water bath for mimicking soft tissue. Analyses of bone marker and cytokine profile kinetics, distribution of leukocyte subpopulations, and morphometrical and densitometrical analyses showed no evidence of any impact of OVX or calcium shortage. In conclusion, the skeleton of adult sows of a conventional breed is seemingly protected from effects of OVX and calcium shortage.

Differential diagnosis on ancient skeletal remains: conventional methods and novel application of the BSE-mode in SEM on a skull tumor of the early Bronze Age.

Tumor-like lesions on skeletal remains put relatively high demands on paleopathological diagnostic methods. In addition to conventional anthropological determination and non-invasive methods of macroscopical description and radiodiagnostic examination, bony lesions can be analyzed more accurately, but also more elaborately by light microscopy of invasive section preparations. In this study an irregular new bone formation on the excavated skull of a juvenile individual was also investigated by scanning electron microscopy (SEM). A cut-out block of the lesion was first observed in the secondary electron-mode (SE-mode), and then methylmethacrylate-embedded ground and polished sections were for the first time also evaluated in the back-scattered electron-mode (BSE-mode). Thereby, new insights into the bone structure and the development of this tumor-like lesion could be obtained which led to the diagnosis of a meningioma.

Cancellous bone structure in the growing and aging lumbar spine in a historic Nubian population.

There is abundant data on cancellous bone in the aging human spine, but little relating to the growing vertebral cancellous bone in childhood an adolescence. The purpose of this study was to map vertebral cancellous bone in a growth and age series of historic skeletal samples and to make comparisons with data published on recent material. Lumbar vertebral bodies were collected from 65 skeletons (0-60 years) from a medieval Nubian population. Ethnohistoric information was collected to interpret conditions that might have influenced bone structure and metabolism. The cancellous bone was studied three dimensionally, using stereophotography and scanning electron microscopy and morphometrically by performing a semiautomatic structural analysis on digitized backscattered electron images of polymethacrylate-embedded material. The cancellous bone structure in the children consisted mainly of a densely packed, uniform network of small rodlike trabeculae. The greatest bone volume fraction with small, more platelike trabeculae was observed during adolescence. In young adults, larger platelike trabeculae were present in the central zone and smaller trabeculae in the superior and inferior zones, as described for modern skeletal material. Structural changes associated with aging were observed much sooner than in modern man. by the estimated age of approximately 50-60 years, the predominant architectural elements were slender rarified rods in both sexes. The ethnohistorical data suggest that this was essentially a black African population of physically active peasants, not likely to suffer Vitamin D insufficiency or deficient calcium intake. Thus an earlier onset of the biological age changes in cancellous bone found in modern populations was probably relevant.