Bone remodeling and bone matrix quality before and after menopause in healthy women

Effect of hyperoside on osteoporosis in ovariectomized mice through estrogen receptor α/ITG β3 signaling pathway

Osteoporosis is a highly prevalent bone metabolic disease in menopause due to estrogen deficiency. Hyperoside is a main compound in Semen cuscutae. Our team previously reported that Semen cuscutae has anti osteoporosis effect on ovariectomized mice by inhibiting bone resorption of osteoclasts. However, it is still unclear whether hyperoside affects osteoclast differentiation and bone resorption, and whether its anti-osteoporosis effect is related to an estrogen-like effect. This study investigates the potential mechanism of hyperoside's anti-osteoporotic effect by examining its impact on osteoclast differentiation and its relationship with the estrogen receptor. DXA, Micro-CT, TRAP staining, HE, and ELISA were used to assess the impact of hyperoside on OVX-induced osteoporosis. The effect of hyperoside on octeoclast differentiation was evaluated using TRAP activity assay, TRAP staining, F-actin staining. The activation of the estrogen receptor by hyperoside and its relationship with osteoclast differentiation were detected using dual-luciferase reporter assay and estrogen receptor antagonists. Our findings revealed that hyperoside (20-80mg/kg) protect against OVX-induced osteoporosis, including increasing BMD and BMC and improving bone microstructure. Hyperoside inhibited osteoclast differentiation in a concentration dependent manner, whereas estrogen receptor α antagonists reversed its inhibitory effect osteoclast differentiation. Western blot results suggested that hyperoside inhibited TRAP, RANKL, c-Fos and ITG β3 protein expression in osteoclast or femoral bone marrow of ovariectomized mice. Our findings suggest that hyperoside inhibits osteoclast differentiation and protects OVX-induced osteoporosis through the ERα/ITGβ3 signaling pathway.

Interindividual differences contribute to variation in microbiota composition more than hormonal status: A prospective study

AIMS

Ovarian hormone deficiency is one of the main risk factors for osteoporosis and bone fractures in women, and these risks can be mitigated by menopausal hormone therapy. Recent evidence suggests that gut microbiota may link changes in estrogen levels and bone metabolism. This study was conducted to investigate the potential relationship between hormonal and bone changes induced by oophorectomy and subsequent hormonal therapy and shifts in gut microbiota composition.

METHODS

We collected 159 stool and blood samples in several intervals from 58 women, who underwent bilateral oophorectomy. Changes in fecal microbiota were assessed in paired samples collected from each woman before and after oophorectomy or the start of hormone therapy. Bacterial composition was determined by sequencing the 16S rRNA gene on Illumina MiSeq. Blood levels of estradiol, FSH, biomarkers of bone metabolism, and indices of low-grade inflammation were measured using laboratory analytical systems and commercial ELISA. Areal bone mineral density (BMD) of the lumbar spine, proximal femur, and femur neck was measured using dual-energy X-ray absorptiometry.

RESULTS

We found no significant changes in gut microbiota composition 6 months after oophorectomy, despite major changes in hormone levels, BMD, and bone metabolism. A small decrease in bacterial diversity was apparent 18 months after surgery in taxonomy-aware metrics. Hormonal therapy after oophorectomy prevented bone loss but only marginally affected gut microbiota. There were no significant differences in β-diversity related to hormonal status, although several microbes (e.g., Lactococcus lactis) followed estrogen levels. Body mass index (BMI) was the most significantly associated with microbiota variance. Microbiota was not a suitable predictive factor for the state of bone metabolism.

CONCLUSIONS

We conclude that neither the loss of estrogens due to oophorectomy nor their gain due to subsequent hormonal therapy is associated with a specific gut microbiota signature. Sources of variability in microbiota composition are more related to interindividual differences than hormonal status.

Material and nanomechanical properties of bone structural units of cortical and trabecular iliac bone tissues from untreated postmenopausal osteoporotic women

The differences in bone nanomechanical properties between cortical (Ct) and trabecular (Tb) bone remain uncertain, whereas knowing the respective contribution of each compartment is critical to understand the origin of bone strength. Our purpose was to compare bone mechanical and intrinsic properties of Ct and Tb compartments, at the bone structural unit (BSU) level, in iliac bone taken from a homogeneous untreated human population.

Among 60 PMMA-embedded transiliac bone biopsies from untreated postmenopausal osteoporotic women (64 ± 7 year-old), >2000 BSUs were analysed by nanoindentation in physiological wet conditions [indentation modulus (elasticity), hardness, dissipated energy], by Fourier transform infrared (FTIRM) and Raman microspectroscopy (mineral and organic characteristics), and by X-ray microradiography (degree of mineralization of bone, DMB). BSUs were categorized based on tissue age, osteonal (Ost) and interstitial (Int) tissues location and bone compartments (Ct and Tb).

Indentation modulus was higher in Ct than in Tb BSUs, both in Ost and Int. dissipated energy was higher in Ct than Tb, in Int BSUs. Hardness was not different between Ct and Tb BSUs. In Ost or Int BSUs, mineral maturity (conversion of non-apatitic into apatitic phosphates) was higher in Ct than in Tb, as well as for collagen maturity (Ost). Mineral content assessed as mineral/matrix (FTIRM and Raman) or as DMB, was lower in Ct than in Tb. Crystallinity (FTIRM) was similar in BSUs from Ct and Tb, and slightly lower in Ct than in Tb when measured by Raman, indicating that the crystal size/perfection was quite similar between Ct and Tb BSUs. The differences found between Ost and Int tissues were much higher than the difference found between Ct and Tb for all those bone material properties. Multiple regression analysis showed that Indentation modulus and dissipated energy were mainly explained by mineral maturity in Ct and by collagen maturity in Tb, and hardness by mineral content in both Ct and Tb.

In conclusion, in untreated human iliac bone, Ct and Tb BSUs exhibit different characteristics. Ct BSUs have higher indentation modulus, dissipated energy (Int), mineral and organic maturities than Tb BSUs, without difference in hardness. Although those differences are relatively small compared to those found between Ost and Int BSUs, they may influence bone strength at macroscale.

The burning maze: The potential value of the human bony labyrinth in estimating sex of calcined remains

Estimating sex from burnt human remains is a challenging task in bioanthropology, mainly due to their high level of alteration and fragmentation. Protected within the petrous part of the temporal bone, the bony labyrinth may be particularly valuable for assessing the sex of burnt remains. This prospective study aims at testing predictive models, already found reliable on unburnt bony labyrinths, to burnt specimens. Six discriminant functions were applied on six bony labyrinths of donated adult cadavers of known sex, before and after outdoor burning experiments. Comparisons between unburnt and burnt measurements were executed using Mann-Whitney U tests while shape and size differences induced by fire exposure were examined through a geometric morphometrics (GM) analysis. Predicted sex on unburnt bony labyrinths was consistent with known sex in five cases while a systematic misclassification for males was highlighted on burnt specimens. Higher values of shrinkage were found in males for two measurements included in the equations. GM analysis revealed significant differences in centroid size among males after calcination. Visualization of mean consensus of both female and male bony labyrinths evidenced a reduction in cochlear size and variations in the width and length of semicircular canals of burnt specimens. This exploratory study seems to confirm that designing sex estimation standards specifically for burnt bony labyrinth may be advisable. Understanding how the burning process could impact its morphology is highly recommended through further experiments on larger samples and in controlled environments.

The Protective Effects of Osteocyte-Derived Extracellular Vesicles Against Alzheimer's Disease Diminished with Aging

Both Alzheimer's disease (AD) and osteoporosis (OP) are common age-associated degenerative diseases and are strongly correlated with clinical epidemiology. However, there is a lack of clear pathological relationship between the brain and bone in the current understanding. Here, it is found that young osteocyte, the most abundant cells in bone, secretes extracellular vesicles (OCY^Young -EVs) to ameliorate cognitive impairment and the pathogenesis of AD in APP/PS1 mice and model cells. These benefits of OCY^Young -EVs are diminished in aged osteocyte-derived EVs (OCY^Aged -EVs). Based on the self-constructed OCY-EVs tracer transgenic mouse models and the in vivo fluorescent imaging system, OCY-EVs have been observed to be transported to the brain under physiological and pathological conditions. In the hippocampal administration of Aβ40 induced young AD model mice, the intramedullary injection of Rab27a-shRNA adenovirus inhibits OCY^Young -EVs secretion from bone and aggravates cognitive impairment. Proteomic quantitative analysis reveals that OCY^Young -EVs, compared to OCY^Aged -EVs, enrich multiple protective factors of AD pathway. The study uncovers the role of OCY-EV as a regulator of brain health, suggesting a novel mechanism in bone-brain communication.

Sex Differences in Biological Systems and the Conundrum of Menopause: Potential Commonalities in Post-Menopausal Disease Mechanisms

Sex-specific differences in biology and physiology likely start at the time of conception and progress and mature during the pre-puberty time frame and then during the transitions accompanying puberty. These sex differences are impacted by both genetics and epigenetic alterations during the maturation process, likely for the purpose of preparing for successful reproduction. For females, later in life (~45–50) they undergo another transition leading to a loss of ovarian hormone production at menopause. The reasons for menopause are not clear, but for a subset of females, menopause is accompanied by an increased risk of a number of diseases or conditions that impact a variety of tissues. Most research has mainly focused on the target cells in each of the affected tissues rather than pursue the alternative option that there may be commonalities in the development of these post-menopausal conditions in addition to influences on specific target cells. This review will address some of the potential commonalities presented by an integration of the literature regarding tissue-specific aspects of these post-menopausal conditions and data presented by space flight/microgravity (a condition not anticipated by evolution) that could implicate a loss of a regulatory function of the microvasculature in the risk attached to the affected tissues. Thus, the loss of the integration of the paracrine relationships between endothelial cells of the microvasculature of the tissues affected in the post-menopausal environment could contribute to the risk for post-menopausal diseases/conditions. The validation of this concept could lead to new approaches for interventions to treat post-menopausal conditions, as well as provide new understanding regarding sex-specific biological regulation.

Novel insights into the coupling of osteoclasts and resorption to bone formation

Bone remodeling consists of resorption by osteoclasts (OCs) and formation by osteoblasts (OBs). Precise coordination of these activities is required for the resorbed bone to be replaced with an equal amount of new bone in order to maintain skeletal mass throughout the lifespan. This coordination of remodeling processes is referred to as the "coupling" of resorption to bone formation. In this review, we discuss the essential role for OCs in coupling resorption to bone formation, mechanisms for this coupling, and how coupling becomes less efficient or disrupted in conditions of bone loss. Lastly, we provide perspectives on targeting coupling to treat human bone disease.

Interest of Bone Histomorphometry in Bone Pathophysiology Investigation: Foundation, Present, and Future

Despite the development of non-invasive methods, bone histomorphometry remains the only method to analyze bone at the tissue and cell levels. Quantitative analysis of transiliac bone sections requires strict methodologic conditions but since its foundation more 60 years ago, this methodology has progressed. Our purpose was to review the evolution of bone histomorphometry over the years and its contribution to the knowledge of bone tissue metabolism under normal and pathological conditions and the understanding of the action mechanisms of therapeutic drugs in humans. The two main applications of bone histomorphometry are the diagnosis of bone diseases and research. It is warranted for the diagnosis of mineralization defects as in osteomalacia, of other causes of osteoporosis as bone mastocytosis, or the classification of renal osteodystrophy. Bone biopsies are required in clinical trials to evaluate the safety and mechanism of action of new therapeutic agents and were applied to anti-osteoporotic agents such as bisphosphonates and denosumab, an anti-RANKL, which induces a marked reduction of the bone turnover with a consequent elongation of the mineralization period. In contrast, an increased bone turnover with an extension of the formation site is observed with teriparatide. Romosozumab, an anti-sclerostin, has a dual effect with an early increased formation and reduced resorption. Bone histomorphometric studies allow us to understand the mechanism of coupling between formation and resorption and to evaluate the respective role of bone modeling and remodeling. The adaptation of new image analysis techniques will help bone biopsy analysis in the future.

Diazinon exposure reduces bone mineral density in adult and immature rats: A histomorphometric and radiographic study

Diazinon has been widely used as a domestic and agricultural pesticide. This study examined the effects of diazinon on bone mineral density (BMD) of mature and immature rats. For this purpose, 24 adult Wistar rats (male; 8 weeks old) were initially divided into four groups (n = 6). Corn oil was used as the control while diazinon at 15, 30, and 45 mg/kg in corn oil was given to mature rats via gavage per day. Since these dosages were lethal for the immature rats, 12 immature Wistar rats (male; 4 weeks old) (n = 6) were gavaged with corn oil as control and 5 mg/kg of diazinon in corn oil. The animals were sacrificed on day 28 with their left femur bones removed for histomorphometric studies. BMD was measured in the right femur, using standardized radiographs in the femoral head, femoral neck, greater trochanter, and shaft. The Image J Program was used for measuring the bone lamellae and epiphyseal growth plates. The results of this study for the first time revealed that diazinon reduced BMD in both adults and immature rats. Diazinon exposure was associated with diminished trabecular and cortical bone density. Correspondingly, our results indicated that in immature rats, DZN led to the reduction in the epiphyseal growth plate width, both in the proliferation and hypertrophic zones. These results suggested that diazinon might be associated with impaired bone longitudinal growth as well as bone metabolism in adults.

Potential Role of Perilacunar Remodeling in the Progression of Osteoporosis and Implications on Age-Related Decline in Fracture Resistance of Bone

PURPOSE OF REVIEW

We took an interdisciplinary view to examine the potential contribution of perilacunar/canalicular remodeling to declines in bone fracture resistance related to age or progression of osteoporosis.

RECENT FINDINGS

Perilacunar remodeling is most prominent as a result of lactation; recent advances further elucidate the molecular players involved and their effect on bone material properties. Of these, vitamin D and calcitonin could be active during aging or osteoporosis. Menopause-related hormonal changes or osteoporosis therapies affect bone material properties and mechanical behavior. However, investigations of lacunar size or osteocyte TRAP activity with age or osteoporosis do not provide clear evidence for or against perilacunar remodeling. While the occurrence and potential role of perilacunar remodeling in aging and osteoporosis progression are largely under-investigated, widespread changes in bone matrix composition in OVX models and following osteoporosis therapies imply osteocytic maintenance of bone matrix. Perilacunar remodeling-induced changes in bone porosity, bone matrix composition, and bone adaptation could have significant implications for bone fracture resistance.

Duration-Dependent Increase of Human Bone Matrix Mineralization in Long-Term Bisphosphonate Users with Atypical Femur Fracture

Bisphosphonates (BPs) are the most widely used drugs for the treatment of osteoporosis but prolonged use of BPs might increase the risk of atypical femur fracture (AFF). There are only a few studies that address the bone material quality in patients on long-term BP treatment with or without AFFs. We analyzed 52 trans-iliac bone biopsies from patients on long-term BP therapy with (n = 26) and without (n = 26) AFF. At the microscopic level, the degree of mineralization of bone (DMB) was assessed on whole bone by X-ray digitized microradiography while microhardness by Vickers microindentation, and bone matrix characteristics by Fourier transform infrared microspectroscopy (FTIRM) (mineral/organic ratio, mineral maturity and crystallinity, and collagen maturity) were measured at random focal areas. The AFF patients were treated longer than non-AFF patients (9.7 ± 3.3 years versus 7.9 ± 2.7 years). As expected, bone remodeling was low in both groups, without difference between them. The AFF group had significantly higher DMB in cortical bone (+2.9%, p = .001), which remained so after adjusting for treatment duration (p = .007), and showed a trend in cancellous bone (+1.6%, p = .05). Consistent with higher DMB, heterogeneity index (HI) was lower in the AFF than in the non-AFF group, illustrating lower heterogeneity of mineralization in the AFF group. A significant positive correlation between the duration of treatment and DMB in cortical bone was found in AFF, and not in the non-AFF group. Microhardness and bone matrix characteristics were similar between groups. We conclude that the AFF group had a duration-dependent increase in DMB leading to a significantly higher DMB than the non-AFF. Because BPs have high affinity to bone mineral and lining the walls of the osteocyte lacunae, the accumulation of matrix-bound BPs in AFF could lead to inhibition of the osteocyte cytoskeleton blunting their response to mechanical strains, a hypothesis to be further investigated. © 2021 American Society for Bone and Mineral Research (ASBMR).

High resolution 3D structures of mineralized tissues in health and disease

A thorough knowledge of the structures of healthy mineralized tissues, such as bone or cartilage, is key to understanding the pathological changes occurring during disease. Such knowledge enables the underlying mechanisms that are responsible for pathology to be pinpointed. One high-resolution 3D method in particular - focused ion beam-scanning electron microscopy (FIB-SEM) - has fundamentally changed our understanding of healthy vertebrate mineralized tissues. FIB-SEM can be used to study demineralized matrix, the hydrated components of tissue (including cells) using cryo-fixation and even untreated mineralized tissue. The latter requires minimal sample preparation, making it possible to study enough samples to carry out studies capable of detecting statistically significant differences - a pre-requisite for the study of pathological tissues. Here, we present an imaging and characterization strategy for tissue structures at different length scales, describe new insights obtained on healthy mineralized tissues using FIB-SEM, and suggest future research directions for both healthy and diseased mineralized tissues.

Age related changes of rib cortical bone matrix and the application to forensic age-at-death estimation

Forensic anthropology includes, amongst other applications, the positive identification of unknown human skeletal remains. The first step in this process is an assessment of the biological profile, that is: sex, age, stature and ancestry. In forensic contexts, age estimation is one of the main challenges in the process of identification. Recently established admissibility criteria are driving researchers towards standardisation of methodological procedures. Despite these changes, experience still plays a central role in anthropological examinations. In order to avoid this issue, age estimation procedures (i) must be presented to the scientific community and published in peer reviewed journals, (ii) accurately explained in terms of procedure and (iii) present clear information about the accuracy of the estimation and possible error rates. In order to fulfil all these requirements, a number of methods based on physiological processes which result in biochemical changes in various tissue structures at the molecular level, such as modifications in DNA-methylation and telomere shortening, racemization of proteins and stable isotopes analysis, have been developed. The current work proposes a new systematic approach in age estimation based on tracing physicochemical and mechanical degeneration of the rib cortical bone matrix. This study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create equations that would produce the best 'estimates of age at death' vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R² = 0.863 and mean absolute error of 4.64 years. The present method meets all the admissibility criteria previously described. Furthermore, the method is experience-independent and as such can be performed without previous expert knowledge of forensic anthropology and human anatomy.

Intrinsic properties of osteomalacia bone evaluated by nanoindentation and FTIRM analysis

Osteomalacia is a pathological bone condition consisting in a deficient primary mineralization of the matrix, leading to an accumulation of osteoid tissue and reduced bone mechanical strength. The amounts, properties and organization of bone constituents at tissue level, are known to influence its mechanical properties. It is then important to investigate the relationship between mechanical behavior and tissue composition at this scale in order to provide a better understanding of bone fragility mechanisms associates with this pathology. Our purpose was to analyze the links between ultra-structural properties and the mechanical behavior of this pathological bone tissue (osteomalacia) at tissue level (mineral and osteoid separately, or global). Four bone biopsies were taken from patients with osteomalacia, and subsequently embedded, sectioned, and polished. Then nanoindentation tests were performed to determine local elastic modulus E, contact hardness Hc and true hardness H for both mineralized and organic bone phases and for the global bone. The creep of the bone was also studied using a special indentation procedure in order to assess visco-elasto-plastic (creep) bone behavior. This allowed a detailed study of the rheological models adapted to the bone and to calculate the parameters associated to a Burgers model. Ultra-structural parameters were measured by Fourier Transform InfraRed Microspectroscopy (FTIRM) on the same position as the indents. The use of rheological models confirmed a significant contribution from the organic phase on the viscous character of bone tissue. The elastic E and the elasto-plastic H_c deformation were correlated to both collagen maturity and Mineral/Matrix. The pure plastic deformation H was only correlated to the mineral phase. Our data show that mineral phase greatly affects mechanical variables (moduli and viscosities) and that organic phase (as illustrated in osteoid tissue) may play an important role in the creep behavior of bone. In conclusion, this study brings mechanical and physicochemical values for osteoid and mineral phases.

Deciphering the Relevance of Bone ECM Signaling

Bone mineral density, a bone matrix parameter frequently used to predict fracture risk, is not the only one to affect bone fragility. Other factors, including the extracellular matrix (ECM) composition and microarchitecture, are of paramount relevance in this process. The bone ECM is a noncellular three-dimensional structure secreted by cells into the extracellular space, which comprises inorganic and organic compounds. The main inorganic components of the ECM are calcium-deficient apatite and trace elements, while the organic ECM consists of collagen type I and noncollagenous proteins. Bone ECM dynamically interacts with osteoblasts and osteoclasts to regulate the formation of new bone during regeneration. Thus, the composition and structure of inorganic and organic bone matrix may directly affect bone quality. Moreover, proteins that compose ECM, beyond their structural role have other crucial biological functions, thanks to their ability to bind multiple interacting partners like other ECM proteins, growth factors, signal receptors and adhesion molecules. Thus, ECM proteins provide a complex network of biochemical and physiological signals. Herein, we summarize different ECM factors that are essential to bone strength besides, discussing how these parameters are altered in pathological conditions related with bone fragility.

Lack of periosteal apposition in the head and neck of femur after menopause in Chinese women with high risk for hip fractures - A cross-sectional study with QCT

In elderly subjects and in particular in those with osteoporosis the evidence on age related volume changes of the hip is still very limited. Even less is known about bone changes of the femoral head. The aim of this study is to explore associations of bone size of the femoral head and neck with age in postmenopausal women with very high risk of hip fracture and to investigate associations of femoral head and neck bone mineral density. MIAF (medical image analysis framework)-Femur was used for the analysis of CT datasets from 319 females with acute hip fractures age 50 to 98. Integral BMD and volume of the head and neck were assessed. The femoral head was divided into four quadrants to address differential vBMD and volume responses of its superior, inferior, posterior and anterior parts. Areal BMD (aBMD) of femoral neck was also obtained. In this population of postmenopausal women we did not observe age-related changes in bone volume of the femoral head or neck between ages 50 and 98 years. Integral vBMD in the head in the 90-98 year group was 48.0 mg/cm³ lower than that in 50-59 year group, which accounts for nearly 30% decrease in vBMD with 40 years increase. Age-related vBMD changes in the head quadrants were similar to that in total. With age, the trend line correlation coefficients for vBMD in quadrants were relatively small, but significant (p < 0.001) for all. The femoral head integral vBMD correlates well with neck vBMD and FN aBMD. FN aBMD explained 45% of head integral vBMD variance (p < 0.0001). Elderly women had relative preservation of femoral head and neck bone volume from 50 yrs. over four decades but markedly lower integral vBMD of proximal femur. The findings of our study call in question about the concept of bone expansion with aging even in elderly age.

A Clinical Perspective on Advanced Developments in Bone Biopsy Assessment in Rare Bone Disorders

Introduction: Bone biopsies have been obtained for many centuries and are one of the oldest known medical procedures in history. Despite the introduction of new noninvasive radiographic imaging techniques and genetic analyses, bone biopsies are still valuable in the diagnosis of bone diseases. Advanced techniques for the assessment of bone quality in bone biopsies, which have emerged during the last decades, allows in-depth tissue analyses beyond structural changes visible in bone histology. In this review, we give an overview of the application and advantages of the advanced techniques for the analysis of bone biopsies in the clinical setting of various rare metabolic bone diseases. Method: A systematic literature search on rare metabolic bone diseases and analyzing techniques of bone biopsies was performed in PubMed up to 2019 week 34. Results: Advanced techniques for the analysis of bone biopsies were described for rare metabolic bone disorders including Paget's disease of bone, osteogenesis imperfecta, fibrous dysplasia, Fibrodysplasia ossificans progressiva, PLS3 X-linked osteoporosis, Loeys-Diets syndrome, osteopetrosis, Erdheim-Chester disease, and Cherubism. A variety of advanced available analytical techniques were identified that may help to provide additional detail on cellular, structural, and compositional characteristics in rare bone diseases complementing classical histopathology. Discussion: To date, these techniques have only been used in research and not in daily clinical practice. Clinical application of bone quality assessment techniques depends upon several aspects such as availability of the technique in hospitals, the existence of reference data, and a cooperative network of researchers and clinicians. The evaluation of rare metabolic bone disorders requires a repertoire of different methods, owing to their distinct bone tissue characteristics. The broader use of bone material obtained from biopsies could provide much more information about pathophysiology or treatment options and establish bone biopsies as a valuable tool in rare metabolic bone diseases.