Calcium pyrophosphate dihydrate and basic calcium phosphate crystal-induced arthropathies: update on pathogenesis, clinical features, and therapy

Synovial Membrane Is a Major Producer of Extracellular Inorganic Pyrophosphate in Response to Hypoxia

Calcium pyrophosphate dehydrate (CPPD) crystals are found in the synovial fluid of patients with articular chondrocalcinosis or sometimes with osteoarthritis. In inflammatory conditions, the synovial membrane (SM) is subjected to transient hypoxia, especially during movement. CPPD formation is supported by an increase in extracellular inorganic pyrophosphate (ePPi) levels, which are mainly controlled by the transporter Ank and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). We demonstrated previously that transforming growth factor (TGF)-β1 increased ePPi production by inducing Ank and Enpp1 expression in chondrocytes. As the TGF-β1 level raises in synovial fluid under hypoxic conditions, we investigated whether hypoxia may transform SM as a major source of ePPi production. Synovial fibroblasts and SM explants were exposed to 10 ng/mL of TGF-β1 in normoxic or hypoxic (5% O2) culture conditions. Ank and Enpp1 expression were assessed by quantitative PCR, Western blot and immunohistochemistry. ePPi was quantified in culture supernatants. RNA silencing was used to define the respective roles of Ank and Enpp1 in TGF-β1-induced ePPi generation. The molecular mechanisms involved in hypoxia were investigated using an Ank promoter reporter plasmid for transactivation studies, as well as gene overexpression and RNA silencing, the respective role of hypoxia-induced factor (HIF)-1 and HIF-2. Our results showed that TGF-β1 increased Ank, Enpp1, and therefore ePPi production in synovial fibroblasts and SM explants. Ank was the major contributor in ePPi production compared to ENPP1. Hypoxia increased ePPi levels on its own and enhanced the stimulating effect of TGF-β1. Hypoxic conditions enhanced Ank promoter transactivation in an HIF-1-dependent/HIF-2-independent fashion. We demonstrated that under hypoxia, SM is an important contributor to ePPi production in the joint through the induction of Enpp1 and Ank. These findings are of interest as a rationale for the beneficial effect of anti-inflammatory drugs on SM in crystal depositions.

Regenerative inflammation: When immune cells help to re-build tissues

Inflammation is an essential immune response critical for responding to infection, injury and maintenance of tissue homeostasis. Upon injury, regenerative inflammation promotes tissue repair by a timed and coordinated infiltration of diverse cell types and the secretion of growth factors, cytokines and lipids mediators. Remarkably, throughout evolution as well as mammalian development, this type of physiological inflammation is highly associated with immunosuppression. For instance, regenerative inflammation is the consequence of an in situ macrophage polarization resulting in a transition from pro-inflammatory to anti-inflammatory/pro-regenerative response. Immune cells are the first responders upon injury, infiltrating the damaged tissue and initiating a pro-inflammatory response depleting cell debris and necrotic cells. After phagocytosis, macrophages undergo multiple coordinated metabolic and transcriptional changes allowing the transition and dictating the initiation of the regenerative phase. Differences between a highly efficient, complete ad integrum tissue repair, such as, acute skeletal muscle injury, and insufficient regenerative inflammation, as the one developing in Duchenne Muscular Dystrophy (DMD), highlight the importance of a coordinated response orchestrated by immune cells. During regenerative inflammation, these cells interact with others and alter the niche, affecting the character of inflammation itself and, therefore, the progression of tissue repair. Comparing acute muscle injury and chronic inflammation in DMD, we review how the same cells and molecules in different numbers, concentration and timing contribute to very different outcomes. Thus, it is important to understand and identify the distinct functions and secreted molecules of macrophages, and potentially other immune cells, during tissue repair, and the contributors to the macrophage switch leveraging this knowledge in treating diseases.

[Calcific tendinitis]

CLINICAL ISSUE

Calcific tendinitis (TC) is a common-usually self-limiting-musculoskeletal disease, histopathologically characterized by both deposition and subsequent inflammatory breakdown of calcium crystals in tendons. The disease can cause acute, sometimes excruciating pain and restricted movement in the shoulder joint. Furthermore, 10-30% of patients have a complicated course of the disease.

STANDARD RADIOLOGICAL METHODS

Imaging-based assessment by X‑ray and ultrasound is required to establish the initial diagnosis and differential diagnosis as well as for follow-up.

METHODOLOGICAL INNOVATIONS

Magnetic resonance imaging (MRI) and, to a lesser degree, computed tomography (CT) complete the imaging work-up for establishing differential diagnoses and detecting complications.

PRACTICAL RECOMMENDATIONS

The combined evaluation of clinical symptoms and imaging findings is crucial to assess prognosis, plan therapy and detect potential complications. This article provides an overview of imaging-based morphology as related to the different stages of TC, relevant complications and potential pitfalls with respect to comorbidities and differential diagnoses.

Imaging of Joints and Bones in Autoinflammation

Autoinflammatory disorders are commonly characterized by seemingly unprovoked systemic inflammation mainly driven by cells and cytokines of the innate immune system. In many disorders on this spectrum, joint and bone involvement may be observed and imaging of these manifestations can provide essential diagnostic information. This review aimed to provide a comprehensive overview of the imaging characteristics for major diseases and disease groups on the autoinflammatory spectrum, including familial Mediterranean fever (FMF), Behçet disease (BD), crystal deposition diseases (including gout), adult-onset Still's disease (AoSD), and syndromatic synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis (CRMO). Herein, we discuss common and distinguishing imaging characteristics, phenotypical overlaps with related diseases, and promising fields of future research.

Calcium Pyrophosphate Dihydrate Deposition Disease in Young Patients: Two Case Reports

Calcium pyrophosphate deposition disease (CPDD) is a type of arthritis caused by the deposition of calcium pyrophosphate crystals, and may present as either acute or chronic arthritis. Development of CPPD crystal deposition disease in young people may be associated with metabolic diseases such as hemochromatosis, hyperparathyroidism, hypomagnesemia, Wilson's disease, hypothyroidism, gout, acromegaly, and X-linked hypophosphatemic rickets. Therefore, investigations for a predisposing metabolic condition are advised in young-onset polyarticular CPPD crystal deposition disease. In this article, we report two young patients who were investigated for recurrent joint pain due to CPPD disease.

Complement activation by cholesterol crystals triggers a subsequent cytokine response

In the host a diverse collection of endogenous danger signals is constantly generated consisting of waste material as protein aggregates or crystalline materials that are recognized and handled by soluble pattern recognition receptors and phagocytic cells of the innate immune system. These signals may under certain circumstances drive processes leading to adverse inflammation. One example is cholesterol crystals (CC) that accumulate in the vessel wall during early phases of atherogenesis and represent an important endogenous danger signal promoting inflammation. CC is recognized by the lectin- and classical pathways of the complement system resulting in activation of C3 and C5 with release of inflammatory mediators like the potent C5a fragment. Complement activation by CC leads to crosstalk with the NLRP3 inflammasome-caspase-1 pathway and production of IL-1β. Neutralization of IL-1β may have beneficial effects on atherosclerosis and a large clinical trial with an IL-1β inhibitor is currently in progress (the CANTOS study). However, upstream inhibition of CC-induced inflammation by using a complement inhibitor may be more efficient in treating atherosclerosis since this will block initiation of inflammation processes before downstream release of cytokines including IL-1β. Another therapeutic candidate can be broad-acting 2-hydroxypropyl-β-cyclodextrin, a compound that targets several mechanisms such as cholesterol efflux, complement gene expression, and the NLRP3 pathway. In summary, emerging evidence show that complement is a key upstream player in the pathophysiology of atherosclerosis and that therapy aiming at inhibiting complement could be effective in controlling atherosclerosis.

Imaging of Hip Pain: From Radiography to Cross-Sectional Imaging Techniques

Hip pain can have multiple causes, including intra-articular, juxta-articular, and referred pain, mainly from spine or sacroiliac joints. In this review, we discuss the causes of intra-articular hip pain from childhood to adulthood and the role of the appropriate imaging techniques according to clinical suspicion and age of the patient. Stress is put on the findings of radiographs, currently considered the first imaging technique, not only in older people with degenerative disease but also in young people without osteoarthritis. In this case plain radiography allows categorization of the hip as normal or dysplastic or with impingement signs, pincer, cam, or a combination of both.

The inflammasome in liver injury and non-alcoholic fatty liver disease

The liver possesses a strong inflammatory response, as seen experimentally and clinically with liver inflammation due to toxic and metabolic stress, sepsis and ischemia. Initiation of this inflammatory response requires the interaction of two types of extracellular signals which collectively upregulate and activate a cytosolic molecular complex termed the inflammasome. Signal 1 is via activation of pattern recognition receptors, and signal 2 is delivered by diverse stimuli including particulates and adenosine triphosphate. The common end result of inflammasome activation is the activation of the protease caspase-1 with release of active interleukin-1β. The inflammasome is important in a wide range of conditions including alcoholic and non-alcoholic steatohepatitis. Kupffer cells are known to be important, but the consequences of inflammasome activation in other hepatic immune cells have not been well characterized. The inflammasome pathway is also known to be required for a full fibrotic response, as demonstrated by reduced lung, skin and liver fibrosis in inflammasome-deficient mice. Identification of the inflammasome machinery has opened up novel therapeutic avenues by the use of antagonists for Toll-like receptors as well as the adenosine triphosphate receptor P2X7, and the interleukin-1 receptor. There is now great interest in how inflammasome pathways are regulated. The initial challenge is to understand how an acute inflammatory response is sustained. This is a significant issue as the known stimuli result in an acute response that is self-limited to under 24 h. This suggests that there are significant regulators which allow sustained inflammasome activation in conditions such as non-alcoholic steatohepatitis and alcoholic hepatitis.

Inflammasome biology in fibrogenesis

Pathogens and sterile insults both result in an inflammatory response. A significant part of this response is mediated by cytosolic machinery termed as the inflammasome which results in the activation and secretion of the cytokines interleukin-1β (IL-1β) and IL-18. Both of these are known to result in the activation of an acute inflammatory response, resulting in the production of downstream inflammatory cytokines such as tumor necrosis factor (TNF-α), interferon-gamma (IFN-γ), chemotaxis of immune cells, and induction of tissue injury. Surprisingly this very acute inflammatory pathway is also vital for the development of a full fibrogenic response in a number of organs including the lung, liver, and skin. There is evidence for the inflammasome having a direct role on tissue specific matrix producing cells such as the liver stellate cell, and also indirectly through the activation of resident tissue macrophage populations. The inflammasome requires stimulation of two pathways for full activation, and initiating stimuli include Toll-like receptor (TLR) agonists, adenosine triphosphate (ATP), particulates, and oxidative stress. Such a role for an acute inflammatory pathway in fibrosis runs counter to the prevailing association of TGF-β driven anti-inflammatory and pro-fibrotic pathways. This identifies new therapeutic targets which have the potential to simultaneously decrease inflammation, tissue injury and fibrosis. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.

Cartilage biology, pathology, and repair

Osteoarthritis is one of the most common forms of musculoskeletal disease and the most prominent type of arthritis encountered in all countries. Although great efforts have been made to investigate cartilage biology and osteoarthritis pathology, the treatment has lagged behind that of other arthritides, as there is a lack of effective disease-modifying therapies. Numerous approaches for dealing with cartilage degradation have been tried, but enjoyed very little success to develop approved OA treatments with not only symptomatic improvement but also structure-modifying effect. In this review we discuss the most recent findings regarding the regulation of cartilage biology and pathology and highlight their potential therapeutic values.

Molecular mechanisms of cartilage remodelling in osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease that is characterized primarily by progressive breakdown of articular cartilage. The loss of proteoglycans, the mineralization of the extracellular matrix (ECM) and the hypertrophic differentiation of the chondrocytes constitute hallmarks of the disease. The pathogenesis of OA includes several pathways, which in single are very well investigated and partly understood, but in their complex interplay remain mainly unclear. This review summarises recent data on the underlying mechanisms, specifically with respect to cell-matrix interactions and cartilage mineralization. It points out why these findings are of importance for future OA research and for the development of novel therapeutic strategies to treat OA.

The sterile inflammatory response

The acute inflammatory response is a double-edged sword. On the one hand, it plays a key role in initial host defense, particularly against many infections. On the other hand, its aim is imprecise, and as a consequence, when it is drawn into battle, it can cause collateral damage in tissues. In situations where the inciting stimulus is sterile, the cost-benefit ratio may be high; because of this, sterile inflammation underlies the pathogenesis of a number of diseases. Although there have been major advances in our understanding of how microbes trigger inflammation, much less has been learned about this process in sterile situations. This review focuses on a subset of the many sterile stimuli that can induce inflammation-specifically dead cells and a variety of irritant particles, including crystals, minerals, and protein aggregates. Although this subset of stimuli is structurally very diverse and might appear to be unrelated, there is accumulating evidence that the innate immune system may recognize them in similar ways and stimulate the sterile inflammatory response via common pathways. Here we review established and emerging data about these responses.

Familial hypocalciuric hypercalcemia revealed by chondrocalcinosis

BACKGROUND

Calcium pyrophosphate dihydrate crystal deposition disease (CPPD-CDD) has been associated to hypercalcemia. Familial hypocalciuric hypercalcemia (FHH) is a rare but important consideration in the differential diagnosis of hypercalcemia. This autosomal dominantly inherited condition is characterized by elevated plasma calcium levels, relative or absolute hypocalciuria, and normal to moderately elevated plasma PTH level. The disease is caused by inactivating mutations in the calcium-sensing receptor gene.

CASE REPORT

We describe a 77-year-old Italian man with arthritis secondary to CPPD-CDD and hypercalcemia. Clinical and biochemical data (s-Ca: 2.94 mmol/L; PTH: 5.9 pmol/L; 24 h urinary calcium: 69.6 mg; calcium/creatinine clearance: 0.004) suggested the diagnosis of FHH. Mild hypocalciuric hypercalcemia was also found in five of seven relatives confirming the diagnosis, of these one showed chondrocalcinosis.

CONCLUSIONS

It is important to screen for FHH using fractional urinary excretion of calcium in subjects with CPPD-CDD associated to hypercalcemia, this approach may prevent unnecessary parathyroidectomy.

Articular gout and suspected pseudogout in a Basilisk lizard (Basilicus plumifrons)

A 9-yr-old male Basilisk lizard (Basilicus plumifrons) with a history of painful and limited mobility for approximately 4 mo, which had seemed to be more pronounced in the front limbs, was presented for necropsy. The animal had exhibited moderate weight loss and anorexia before euthanasia. Postmortem examination revealed yellow-to-white, soft-to-semifirm nodules within the periarticular fascia and musculature of the left and right shoulder joints, hip joints, and stifle joints. Several other joints, including the left and right tarsi, left and right elbow joints, and the left carpus had calcified, white material present on the articular surfaces. Histopathologic evaluation of representative sections of all organs and the joints confirmed tophaceous articular gout and articular pseudogout. The differentiation between articular gout and pseudogout was based on histologic appearance, histochemical staining for calcium, and birefringence under polarized light.

Advances in understanding calcium-containing crystal disease

PURPOSE OF REVIEW

Calcium pyrophosphate dihydrate and basic calcium phosphate crystals are the two most common calcium-containing crystals involved in rheumatic diseases. Recent literature concerning their role in the pathogenesis of osteoarthritis is reviewed.

RECENT FINDINGS

In some instances, these calcium crystals might worsen osteoarthritis cartilage destruction. Laboratory investigations have identified determinants of cartilage calcification, especially a better characterization of matrix vesicle content and a better understanding of the regulation of inorganic pyrophosphate and phosphate concentration. In-vitro studies have highlighted new pathogenic mechanisms of calcium crystal-induced cell activation. Several intracellular signalling pathways are activated by calcium crystals. Recent studies suggested the implication of the inflammasome complex and a pivotal role for IL-1 in pseudogout attacks and chondrocyte apoptosis in basic calcium phosphate crystal-related arthropathies.

SUMMARY

Animal models of osteoarthritis and in-vitro studies using calcium pyrophosphate dihydrate and basic calcium phosphate crystals will improve our knowledge of these common crystals and could suggest new targets for drugs, as these common diseases are 'orphan' with respect to therapy.

Calcific constrictive pericarditis with refractory hypokalemia in a patient with Gitelman's syndrome

Calcific constrictive pericarditis can be idiopathic or associated with radiation therapy, surgery, infection, or autoimmune disorders. Gitelman's syndrome is a distal renal tubular defect involving the thiazide-sensitive luminal sodium chloride cotransporter and has been associated with nephrolithiasis and chondrocalcinosis. There has not been any case of calcific constrictive pericarditis reported so far in association with Gitelman's syndrome. We have reported a male patient with persistent hypokalemia and refractory ascites diagnosed with calcific constrictive pericarditis and Gitelman's syndrome.

Synthesis and Structural and Magnetic Characterization of {[(phen)2Ni]2(μ-P2O7)}·27H2O and {[(phen)2Mn]2(μ-P2O7)}·13H2O: Rare Examples of Coordination Complexes with the Pyrophosphate Ligand

The reaction in water of M(II) [M = Ni or Mn] with 1,10-phenanthroline (phen) and sodium pyrophosphate (Na4P2O7) in a 2:4:1 stoichiometry resulted in the crystallization of dinuclear complexes featuring the heretofore rare bridging pyrophosphate. Single-crystal X-ray diffraction studies revealed the complexes to be {[(phen)2Ni]2(micro-P2O7)} . 27H2O (1) and {[(phen)2Mn]2(micro-P2O7)} . 13H2O (2) where the asymmetric M(phen)2 units are bridged by bis-bidentate pyrophosphate, each metal ion exhibiting a distorted octahedral geometry. The bridging pyrophosphate places adjacent metal centers at 5.031 A in 1 and 4.700 A in 2, and its conformation also gives rise to an intramolecular pi-pi interaction between two adjacent phen ligands. Intermolecular pi-pi interactions between phen ligands from adjacent dinuclear complexes create an ornate 3D network in 1, whereas a 2D sheet results in 2. The hydrophilic nature of the pyrophosphate ligand leads to heavy hydration with the potential solvent-accessible area for 1 and 2 accounting for 45.7% and 26.4% of their unit cell volumes, respectively. Variable-temperature magnetic susceptibility measurements on polycrystalline samples of 1 and 2 revealed net weak intramolecular antiferromagnetic coupling between metal centers in both compounds with J = -3.77 cm(-1) in 1 and J = -0.88 cm(-1) in 2, the Hamiltonian being defined as H = -JSA.SB. The ability of the bis-bidentate pyrophosphate to mediate magnetic interactions between divalent first row transition metal ions is discussed bearing in mind the number and nature of the interacting magnetic orbitals.

Recurrent acute low back pain secondary to lumbar epidural calcification

INTRODUCTION

Epidural calcification is a rare cause of back pain, and spontaneous epidural calcification has not been reported previously.

CASE REPORT

We describe a patient with acute low back pain and signs of lumbar nerve root compression due to epidural calcification, as demonstrated by CT-scan and MRI. Radiological signs of spondylodiscitis led to a search for an infectious cause, which was negative, and her symptoms responded rapidly to NSAID treatment alone. Her symptoms recurred 18 months later, and further imaging studies again revealed epidural calcification, but with a changed distribution. Her symptoms were relieved once more by NSAID treatment alone.

DISCUSSION

We propose that epidural calcification secondary to aseptic spondylodiscitis is the main cause of acute back pain in this patient. A possible mechanism may be the pro-inflammatory effects of calcium pyrophosphate or hydroxyapatite crystal deposition within the epidural space.

Clinical manifestations and pathogenesis of hydroxyapatite crystal deposition in juvenile dermatomyositis

Pathologic deposition of mineral in the form of bone-like hydroxyapatite is a frequent occurrence in juvenile dermatomyositis (JDM) and other connective tissue diseases. Although the sizes of the mineral crystals in JDM are similar to those in bone, there is much more mineral in the deposits than there is in bone. Bone matrix proteins also accumulate associated with the deposits. The reasons for the formation of these deposits are not known. It is our hypothesis that persistent inflammation is a component of JDM and other hydroxyapatite deposition diseases. Other contributing factors are genetic, environmental, and physical chemical. This paper discusses the influence of inflammation on the deposition of hydroxyapatite, with emphasis on the clinical and environmental factors that may facilitate the formation of calcific deposits in JDM.

Photobiomodulation of Pain and Inflammation in Microcrystalline Arthropathies: Experimental and Clinical Results

OBJECTIVE

This article presents the results of laser therapy in crystal (hydroxyapatite, calcium pyrophosphate, and urates) deposition-induced arthritis in rats and the clinical applications in humans.

BACKGROUND DATA

Microcrystalline arthropathies are prevalent among geriatric patients, who are more vulnerable to the side effects of drugs. The effectiveness of laser therapy for pain relief, free of side effects, has been reported in painful conditions.

METHODS

Two milligrams of each of the above-mentioned crystals was injected in both joints of the back limbs in three groups of rats; these groups were then treated with laser irradiation. Three other groups received no treatment after the injections. We determined the plasmatic levels of inflammatory markers (fibrinogen, prostaglandin E2, and TNF(alpha)), tissues (prostaglandin E(2)) and conducted anatomopathological studies. Twenty-five patients with acute gout arthritis were randomized into two groups and treated over 5 days: group A, diclofenac 75 mg orally, twice a day; and group B, laser irradiation once a day. Forty-nine patients with knee chronic pyrophosphate arthropathy were randomized into two groups and treated over 21 days; group A, diclofenac 50 mg orally, twice a day; and group B, laser irradiation once a day. Thirty patients with shoulder chronic hydroxyapatite arthropathy were randomized into two groups and treated over 21 days; group A, diclofenac 50 mg orally, twice a day; and group B, laser irradiation once a day.

RESULTS

Fibrinogen, prostaglandin E(2), and TNF(alpha) concentrations in the rats injected with crystals and treated with laser decreased significantly as compared with the groups injected with crystals without treatment. Both laser therapy and diclofenac achieved rapid pain relief in patients with acute gouty arthritis without significant differences in efficacy. Laser therapy was more effective than diclofenac in patients with chronic pyrophosphate arthropathy and in patients with chronic apatite deposition disease.

CONCLUSION

Laser therapy represents an effective treatment in the therapeutic arsenal of microcrystalline arthropathies.

Sclerochoroidal calcification associated with Gitelman syndrome and calcium pyrophosphate dihydrate deposition

Sclerochoroidal calcification is an uncommon condition. Metabolic evaluation and clinical examination are important to exclude associated systemic conditions such as the Bartter and Gitelman syndromes. It has been suggested that the lesions seen in sclerochoroidal calcification are calcium pyrophosphate dihydrate crystals. This report describes the first documented case in the UK of sclerochoroidal calcification associated with Gitelman syndrome and calcium pyrophosphate dihydrate deposition.

Rapid multifocal chondrolysis after liver transplantation in four patients

BACKGROUND

Favourable clinical outcomes achieved with liver transplantation may be jeopardised by corticosteroid-induced osteoarticular complications, such as osteoporosis or aseptic osteonecrosis.

CASE REPORT

A previously unreported joint complication in liver transplant recipients is described.

METHODS

Retrospective study of liver transplant recipients in whom destructive joint disease developed, identified among 330 symptomatic patients out of a total of 1260 managed over a 15 year period (November 1984-January 2000) in a university based liver transplantation centre.

RESULTS

In four patients (23-56 years), rapid chondrolysis developed 2-12 years after transplantation in more than three weightbearing or non-weightbearing joints free of radiological features of avascular osteonecrosis, evidence of infection, or defined inflammatory arthritis. Pathological examination of five hip joints and one knee joint found no evidence of infection or inflammation. Six joint replacement procedures were performed successfully in three patients.

CONCLUSION

Clinicians managing liver transplant recipients, and perhaps recipients of other organs, should be aware that rapid chondrolysis may develop. The pathogenesis of this rare complication is unclear.

4 T MRI of chondrocalcinosis in combination with three-dimensional CT, radiography, and arthroscopy: a report of three cases

OBJECTIVE

To describe 4 T MRI techniques in imaging chondrocalcinosis within the knee and examine the results together with those demonstrated using three-dimensional (3D) computed tomography, conventional radiography, and arthroscopy.

DESIGN AND PATIENTS

From a larger clinical imaging study of early osteoarthritis, knee arthroscopy patients were imaged using high-field MRI and high-resolution 3D CT prior to their surgery. Retrospective review of the imaging data diagnosed three patients with chondrocalcinosis. Fat-suppressed 3D spoiled gradient (3D SPGR) and two-dimensional fat-suppressed fast spin echo (FSE) imaging was performed at 4 T. The MR images, multi-planar reformatted CT (MPR-CT) and maximum intensity projection CT (MIP-CT) images, and radiographs were examined by a musculoskeletal radiologist for the presence and location of chondrocalcinosis. The findings from arthroscopy were also included.

RESULTS

MRI showed 16 sites of punctate hypointense regions from 18 articular surfaces and five of six menisci with similar signal characteristics. Both meniscal chondrocalcinosis and meniscal tears were clearly visible using the 3D SPGR sequence. Only three sites were demonstrated to have calcification using MPR-CT and MIP-CT revealed an additional three. In articular cartilage surfaces showing surface disruption, arthroscopy demonstrated 11 sites with crystal deposition. Arthroscopy also revealed five menisci with calcification present.

CONCLUSION

Our preliminary findings suggest that imaging chondrocalcinosis using spoiled gradient 4 T MRI is superior and complementary to the other imaging modalities in the detection of crystal deposition in both articular cartilage and menisci.

“Nanobacterium sanguineum” – Is it a new life-form in search of human ailment or commensal: Overview of its transmissibility and chemical means of intervention

Morphological, cultural, and immuno-histochemical characteristics of "Nanobacterium sanguineum" (NB) described in the literature are reviewed. NB is reported to be a motile, Gram negative organism that divides by binary fission within a calcium-coated slimy shell; this yeast-like shell replicates by budding. It measures between 20 and 200 nm with a unique structure containing 16S ribosomal RNA. NB has been observed by electron microscopy in coronary artery plaques (CAD) and in kidney stones (KS) found in renal diseases. On the basis of supportive literature, we suggest that NB is not only present in the human body but also has auxiliary association with human ailments without a specific etiological role; anti-NB antibody has been detected in subjects with calcified lesions and inflammation in diverse ailments including choriodecidual inflammation in pregnancy, ovarian cancers, arthritis and even Alzheimer's disease. More recent report on the detection and vertical transmission of NB antigen and anti-NB antibody in HIV-infected mothers supports the view that NB might be an important opportunistic infective agent contributing to HIV pathology; we note that the presence of viable and transmitting NB was not studied and suggest further studies to establish vertical transmission of NB in HIV-infected persons. On the basis of the foregoing we suggest that NB possibly exacerbates human ailments and raise the question: Is NB a new life-form in search of human ailment or a commensal organism? Recognizing the presence of NB in the human body, we discuss clinical trials, reported in the literature relevant to its eradication, with a rectal suppository containing very high amounts of disodium EDTA and tetracycline. We suggest that tetracycline in this formulation acted in combination with EDTA, more as a chelating agent than an antibiotic; oxytetracycline- a non-chelating form of tetracycline-does not inhibit or kill NB. Evaluation of anti-NB effect of orally administrable and potentially safer as well as therapeutically more acceptable chelating agent -ascorbic acid, acting alone or in combination with antibiotics-that eradicates another slime forming bacterium - Pseudomonas aeruginosa - in children with cystic fibrosis, is suggested.