Spatial proteogenomics reveals distinct and evolutionarily conserved hepatic macrophage niches.

The liver is the largest solid organ in the body, yet it remains incompletely characterized. Here we present a spatial proteogenomic atlas of the healthy and obese human and murine liver combining single-cell CITE-seq, single-nuclei sequencing, spatial transcriptomics, and spatial proteomics. By integrating these multi-omic datasets, we provide validated strategies to reliably discriminate and localize all hepatic cells, including a population of lipid-associated macrophages (LAMs) at the bile ducts. We then align this atlas across seven species, revealing the conserved program of bona fide Kupffer cells and LAMs. We also uncover the respective spatially resolved cellular niches of these macrophages and the microenvironmental circuits driving their unique transcriptomic identities. We demonstrate that LAMs are induced by local lipid exposure, leading to their induction in steatotic regions of the murine and human liver, while Kupffer cell development crucially depends on their cross-talk with hepatic stellate cells via the evolutionarily conserved ALK1-BMP9/10 axis.

In matters of the heart, (cellular) communication is key.

To maintain cardiac output, the failing heart undergoes significant remodeling. However, the mechanisms regulating this remain unclear. In this issue of Immunity, Zaman et al. and Wong, Mohan, and Kopecky et al. uncover an interaction between resident cardiac macrophages and cardiomyocytes governing this process.

Identification of a Kupffer cell subset capable of reverting the T cell dysfunction induced by hepatocellular priming.

Kupffer cells (KCs) are highly abundant, intravascular, liver-resident macrophages known for their scavenger and phagocytic functions. KCs can also present antigens to CD8+ T cells and promote either tolerance or effector differentiation, but the mechanisms underlying these discrepant outcomes are poorly understood. Here, we used a mouse model of hepatitis B virus (HBV) infection, in which HBV-specific naive CD8+ T cells recognizing hepatocellular antigens are driven into a state of immune dysfunction, to identify a subset of KCs (referred to as KC2) that cross-presents hepatocellular antigens upon interleukin-2 (IL-2) administration, thus improving the antiviral function of T cells. Removing MHC-I from all KCs, including KC2, or selectively depleting KC2 impaired the capacity of IL-2 to revert the T cell dysfunction induced by intrahepatic priming. In summary, by sensing IL-2 and cross-presenting hepatocellular antigens, KC2 overcome the tolerogenic potential of the hepatic microenvironment, suggesting new strategies for boosting hepatic T cell immunity.

Osteopontin characterizes bile duct-associated macrophages and correlates with liver fibrosis severity in primary sclerosing cholangitis.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is an immune-mediated cholestatic liver disease for which pharmacological treatment options are currently unavailable. PSC is strongly associated with colitis and a disruption of the gut-liver axis, and macrophages are involved in the pathogenesis of PSC. However, how gut-liver interactions and specific macrophage populations contribute to PSC is incompletely understood. APPROACH AND RESULTS: We investigated the impact of cholestasis and colitis on the hepatic and colonic microenvironment, and performed an in-depth characterization of hepatic macrophage dynamics and function in models of concomitant cholangitis and colitis. Cholestasis-induced fibrosis was characterized by depletion of resident KCs, and enrichment of monocytes and monocyte-derived macrophages (MoMFs) in the liver. These MoMFs highly express triggering-receptor-expressed-on-myeloid-cells-2 ( Trem2 ) and osteopontin ( Spp1 ), markers assigned to hepatic bile duct-associated macrophages, and were enriched around the portal triad, which was confirmed in human PSC. Colitis induced monocyte/macrophage infiltration in the gut and liver, and enhanced cholestasis-induced MoMF- Trem2 and Spp1 upregulation, yet did not exacerbate liver fibrosis. Bone marrow chimeras showed that knockout of Spp1 in infiltrated MoMFs exacerbates inflammation in vivo and in vitro , while monoclonal antibody-mediated neutralization of SPP1 conferred protection in experimental PSC. In human PSC patients, serum osteopontin levels are elevated compared to control, and significantly increased in advanced stage PSC and might serve as a prognostic biomarker for liver transplant-free survival. CONCLUSIONS: Our data shed light on gut-liver axis perturbations and macrophage dynamics and function in PSC and highlight SPP1/OPN as a prognostic marker and future therapeutic target in PSC.

Kupffer Cells Contested as Early Drivers in the Pathogenesis of Primary Sclerosing Cholangitis.

Primary sclerosing cholangitis (PSC) is an idiopathic chronic immune-mediated cholestatic liver disease characterized by fibro-inflammatory bile duct strictures, progressive hepatobiliary fibrosis, and gut-liver axis disruption. The pathophysiology of PSC remains insufficiently characterized, which hampers the development of effective therapies. Hepatic macrophages (MFs) such as Kupffer cells (KCs) are implicated in PSC pathogenesis, but their exact role is unclear. Using the latest markers to discriminate resident KCs (ResKCs) from their monocyte-derived counterparts (MoKCs), and two models of intrahepatic and extrahepatic cholestasis, respectively, this study showed that CLEC4F+TIM4+ ResKCs were depleted after chronic cholestatic liver injury. The infiltrating CLEC4F+TIM4- MoKCs were already enriched during the acute phase of PSC. Transcriptional profiling of hepatic MF subsets during early cholestatic injury indicated that ResKCs were indeed activated and that MoKCs expressed higher levels of pro-inflammatory and proliferative markers compared with those of ResKCs. As indicated in experiments with Clec4fDTR transgenic mice, conditional depletion of KCs, before and during early cholestasis induction, had no effect on the composition of the hepatic myeloid cell pool following injury progression and did not affect disease outcomes. Taken together, these results provide new insights into the heterogeneity of the MF pool during experimental PSC and evidence that depletion of resident and activated KCs during sclerosing cholangitis does not affect disease outcome in mice.

Dimensional assessment on baseline MRI of soft-tissue sarcomas: longest diameter, sum and product of diameters, and volume-which is the best measurement method to predict patients' outcomes?

PURPOSE: The longest diameter (LD) is a strong prognostic factor for patients with soft-tissue sarcoma (STS). Other dimensional assessments, such as the sum of diameters (SoD), product of diameters (PoD), and volume (3D-COG - proposed by the Children Oncology Group), can be rapidly performed; however, their prognostic values have never been compared to LD. Our goal was to investigate their performance in improving patients' prognostication for STS of the lower limbs. METHODS: All consecutive adults managed with curative intent at our sarcoma reference center for a newly diagnosed STS of the lower limbs between 2000 and 2017, with pre-treatment MRI, were included in this retrospective study. Multivariable Cox regression models were trained to predict metastasis-free survival (MFS) in a Training cohort of 66.7% patients based on LD, PoD, SoD, or 3D-COG (and systematically including age, histologic grade, histotype, radiotherapy, chemotherapy, and surgical margins as covariables). The models were then compared on a validation cohort of 33.3% patients using concordance indices (c-index). The same approach was applied for overall survival (OS) and local relapse-free survival (LFS). Measurement reproducibility among three readers was evaluated with an intraclass correlation coefficient (ICC). RESULTS: 382 patients were included in the survival modeling (72/253 [28.5%] metastatic relapses in Training and 36/129 [27.9%] metastatic relapses in Validation). Higher dimensions were associated with lower MFS (multivariable hazard ratio [HR] = 2.44 and P = 0.0018 for LD; HR = 1.88 and P = 0.0009 for PoD, HR = 1.52 and P = 0.0041 for SoD; and HR = 1.08 and P = 0.0195 for 3D-COG). Higher c-indices were obtained with PoD model in Training (c-index = 0.772) and Validation (c-index = 0.688), but they were not significantly higher than those obtained with LD model. None of the measurements was associated with LFS or OS. All measurements demonstrated excellent ICC (> 0.95). CONCLUSION: Regarding its simplicity and good performance, LD appeared as the best metric to incorporate in prognostic models and nomograms for MFS.

Modulating hepatic macrophages with annexin A1 in non-alcoholic steatohepatitis.

Non-alcoholic steatohepatitis (NASH) and associated end-stage liver disease is a growing cause of concern throughout the Western world. It constitutes a significant clinical burden for which therapeutic approaches are very limited. Over the last years, considerable attention has therefore been paid to identifying potential therapeutic strategies to reduce this burden. Annexin A1 (AnxA1), a calcium-phospholipid binding protein, has been proposed to be a negative regulator of inflammation in the context of NASH. In a recent publication, Gadipudi, Ramavath, Provera et al. investigated the therapeutic potential of Annexin A1 treatment in preventing the progression of NASH. They demonstrate that treatment of mice with NASH with recombinant human AnxA1 can reduce inflammation and fibrosis without affecting steatosis or metabolic syndrome. This was proposed to be achieved through the modulation of the macrophage populations present in the liver. Here, we discuss the main findings of this work and raise some outstanding questions regarding the possible mechanisms involved and the functions of distinct macrophage populations in NASH.

MRI in differential diagnosis between tuberculous and pyogenic spondylodiscitis.

PURPOSE: The aim of the study was to investigate whether MRI findings together with epidemiological data could help in differentiating between tuberculous and pyogenic spondylodiscitis. METHODS: Clinical records of 260 patients with a suspicion of spondylodiscitis were analysed. Patients were selected using the following inclusion criteria: confirmed diagnosis of spondylodiscitis either from pyogenic bacteria or from Mycobacterium tuberculosis and contrast-enhanced MRI performed before treatment. Clinical data concerning age, sex and country-of-origin were also collected. For each patient, several MRI-features were evaluated by two-expert musculoskeletal radiologists. A chi-squared test and a multiple logistic regression were used to find the best predictors of tuberculous or pyogenic spondylodiscitis. RESULTS: 114 patients were retrospectively enrolled, 30 with tuberculous and 84 with pyogenic spondylodiscitis. We found 18 MRI-features, significantly different between the two groups. Among these, the most strongly associated with tuberculous spondylodiscitis were: heterogeneous vertebral signal on T1w-sequences (Odds Ratio(OR) = 205.759-p < 0.001), presence of epidural abscess (OR = 86.221-p < 0.001), severe vertebral destruction (OR = 10.017-p < 0.001) and absence of epidural phlegmon (OR = 86.221-p < 0.001). Moreover, patients coming from countries with a middle-high prevalence of tuberculosis were more frequently affected by tuberculous spondylodiscitis than others were (OR = 229.136-p < 0.001). The best prediction model demonstrated a correct classification rate of 94.7%. CONCLUSION: To the best of our knowledge this is the largest study comparing MRI-features of tuberculous and pyogenic spondylodiscitis. The above-mentioned MRI-features and epidemiological data are crucial in the differential diagnosis between these two entities, guiding the choice of the appropriate therapy, especially when a pathogen cannot be clearly identified with other modalities.

Ultrasound-guided percutaneous irrigation of calcific tendinopathy outside the rotator cuff: short-term evaluation.

RATIONALE AND OBJECTIVES: While ultrasound-guided percutaneous irrigation for painful calcific tendinopathy (US-PICT) is the treatment of choice for the rotator cuff, there is a lack of knowledge regarding the treatment of this condition with atypical location. The purpose of our study is to assess if US-PICT can be applied safely and successfully in atypical sites, outside of the rotator cuff. MATERIALS AND METHODS: We retrospectively reviewed the US-PICT performed outside the rotator cuff, in the last 5 years in a single institution. A total of 16 patients have been included in this study. We collected the values of the numerical rating scale (NRS) for pain pre- and post-procedure (7 days and 3-month follow-up). Moreover, we assessed the imaging studies available pre- and post-procedure (ultrasound and plain radiography) to assess complications. RESULTS: In all the 16 patients (10F, 6 M; mean age 50.2; range 24-65-year-old), no complications have been observed during and after the procedures. The mean pain NRS before treatment was 8.7 (range 10-6) and dropped to 1.1 (6-0) after 1 week as well after 3 months 1.1 (6-0). The NRS pain reduction from baseline resulted to be statistically significant after 7 days and 3 months (p < 0.001). CONCLUSION: Our results suggest the safety and efficacy of this procedure, underlining the great potential of US-PICT applied even in different atypical locations.

MRI Diagnosis of Obesity-Related Spinal Epidural Lipomatosis.

A 61-year-old male presented to our hospital complaining of claudication: bilateral leg weakness impeding mobility. Symptoms started after 100 m of walk and recede after several minutes of rest. The patient was obese, with a body mass index (BMI) of 41 kg/m2 and reported a weight gain of about 55 pounds in the last year. Patient's comorbidities were dyslipidemia, hypertension, and antithrombin III deficiency. The patient also suffered from chronic low-back pain recently worsened and cervical pain. Pulses in the lower limbs were present. Neurological examination was also unremarkable.

The role of DXA in sarcopenia.

Sarcopenia is a condition characterized by progressive and generalized reduction in skeletal muscle mass and muscle strength, associated with an increased risk of adverse outcomes (disability, hospitalization, death). The growing attention in the last years, aiming to establish a consensus definition and treatment, reflects the interest of the scientific community toward this complex condition, which has many implications in clinical practice and public health. Dual-energy X-ray absorptiometry (DXA) is the gold-standard technique in the analysis of body composition at molecular level, providing assessment and quantification of fat mass, lean mass and bone mineral content, both in a single body region of interest and at whole-body level. In particular, through the assessment of non-bone lean mass parameters, such as appendicular lean mass adjusted for BMI or height (ALM/BMI and ALM/ht2, respectively), it is possible to discriminate subjects with "physiological" loss of muscle mass from those with "pathological" impoverishment of this compartment, referring to specific cutoff values validated in the literature, but keeping in mind the lack of standardization of DXA measures. In addition, it is useful in treatment planning, estimating resting energy expenditure, and in follow-up, because it allows quantifying with high reproducibility the modifications in BC, distinguishing when the change is biological (deterioration due to a progression of the disease or improvement due to treatment). Due to DXA favorability in terms of accuracy, simplicity, availability, low cost and low radiation exposure, its role in sarcopenia diagnosis is becoming increasingly important, emerging as reference assessment technique in muscle mass evaluation.

Effects of three different testosterone formulations in female-to-male transsexual persons.

INTRODUCTION: Gender dysphoria is characterized by a strong discomfort with the gender assigned at birth and the urge to live as a member of the opposite gender. The acquisition of phenotypic features of the desired gender requires the use of cross-sex hormones. Female-to-male (FtM) transsexual persons are treated with testosterone to induce virilization. AIM: The aim of the study was to assess the effects of three different testosterone formulations on body weight and composition and metabolic and bone parameters. METHODS: Forty-five FtM transsexuals were randomly assigned to receive testoviron depot (i.m.: 100 mg/10 days; n = 15), testosterone gel (50 mg/die; n = 15), and testosterone undecanoate (i.m.: 1,000 mg every 6 weeks for the first 6 weeks and then every 12 weeks, n = 15). FtM individuals were studied before, at week 30, and at week 54 of testosterone treatment. MAIN OUTCOME MEASURES: Anthropometric, metabolic, bone, hematological, and biochemical parameters were evaluated at baseline and after 12 months of treatment. RESULTS: Lean body mass significantly increased and fat mass decreased in all groups. No modifications were reported in fasting insulin and insulin sensitivity index. High-density plasma lipoprotein levels declined significantly and low-density lipoprotein concentrations increased significantly in the three groups. The activated partial thromboplastin time and factor I did not change while prothrombin time significantly increased in all groups. At week 54, all subjects were amenorrheic and time to amenorrhea did not differ between the three groups. Current general life satisfaction was increased in all subjects after 1 year of treatment. CONCLUSIONS: One-year testosterone administration in FtM transsexuals appears to be very safe with no differences among the testosterone formulations used. Our study is preliminary, and the detection of subtle or long-term differences in the effects of the three formulations may require further larger and longer term studies in this and other populations.

Transpedicular Contrast-enhanced CT-guided biopsy of the body and dens of the axis avoiding the trans-oral approach: Technical report and literature review.

This technical report illustrates the technique to perform computed tomography (CT)-guided bone biopsies in the body and dens of the axis (C2 vertebra) through a posterior transpedicular approach with the use of preoperative contrast-enhanced scans to highlight the course of the vertebral artery. The technique is presented through two exemplification cases: a pediatric patient with osteoblastoma and secondary aneurysmal bone cyst and one adult patient with melanoma metastasis. This case highlights the potential of the CT-guided posterolateral/transpedicular approach for performing safe and effective biopsies in the body and dens of C2, even in pediatric patients.

Image-Guided Minimally Invasive Treatment Options for Degenerative Lumbar Spine Disease: A Practical Overview of Current Possibilities.

Lumbar back pain is one of the main causes of disability around the world. Most patients will complain of back pain at least once in their lifetime. The degenerative spine is considered the main cause and is extremely common in the elderly population. Consequently, treatment-related costs are a major burden to the healthcare system in developed and undeveloped countries. After the failure of conservative treatments or to avoid daily chronic drug intake, invasive treatments should be suggested. In a world where many patients reject surgery and prefer minimally invasive procedures, interventional radiology is pivotal in pain management and could represent a bridge between medical therapy and surgical treatment. We herein report the different image-guided procedures that can be used to manage degenerative spine-related low back pain. Particularly, we will focus on indications, different techniques, and treatment outcomes reported in the literature. This literature review focuses on the different minimally invasive percutaneous treatments currently available, underlining the central role of radiologists having the capability to use high-end imaging technology for diagnosis and subsequent treatment, allowing a global approach, reducing unnecessary surgeries and prolonged pain-reliever drug intake with their consequent related complications, improving patients' quality of life, and reducing the economic burden.

Percutaneous CT-Guided Bone Biopsies: Indications, Feasibility and Diagnostic Yield in the Different Skeletal Sites-From the Skull to the Toe.

CT-guided bone biopsies are currently the diagnostic tool of choice for histopathological (and microbiological) diagnoses of skeletal lesions. Several research works have well-demonstrated their safety and feasibility in almost all skeletal regions. This comprehensive review article aims at summarizing the general concepts in regard to bone biopsy procedures, current clinical indications, the feasibility and the diagnostic yield in different skeletal sites, particularly in the most delicate and difficult-to-reach ones. The choice of the correct imaging guidance and factors affecting the diagnostic rate, as well as possible complications, will also be discussed. Since the diagnostic yield, technical difficulties, and complications risk of a CT-guided bone biopsy significantly vary depending on the different skeletal sites, subdivided analyses of different anatomical sites are provided. The information included in the current review article may be useful for clinicians assisting patients with possible bone neoplasms, as well as radiologists involved in the imaging diagnoses of skeletal lesions and/or in performing bone biopsies.

Could Spinal Epidural Lipomatosis Be the Hallmark of Metabolic Syndrome on the Spine? A Literature Review with Emphasis on Etiology.

Spinal epidural lipomatosis is defined by an excessive amount of epidural fat in the spinal canal, usually in the lumbosacral tract: a well-known cause of lumbar pain and spinal stenosis with a possible wide range of neurological symptoms. Recent research data reveal that, nowadays, obesity has become the main cause of spinal epidural lipomatosis. Moreover, this condition was recently recognized as a previously unknown manifestation of metabolic syndrome. Radiological studies (CT and MRI) are the only tools that are able to diagnose the disease non-invasively. Indeed, radiologists play a key role in disease recognition, with subsequent possible implications on patients' systemic health assessments. Despite its clinical importance, the condition is still underreported and neglected. The current literature review summarizes all the main etiologies of spinal epidural lipomatosis, particularly regarding its linkage with metabolic syndrome. An overview of disease characteristics from diagnosis to treatment strategies is also provided.

Ultrasound-Guided Percutaneous Bone Biopsy: Feasibility, Diagnostic Yield and Technical Notes.

While nowadays, CT-guided bone biopsy represents the gold standard tool for histopathological and microbiological diagnosis of skeletal lesions, the role of US-guided bone biopsy has not yet been fully explored. US-guided biopsy offers several advantages, such as the absence of ionizing radiation, fast acquisition time, as well as good intra-lesional echo, and structural and vascular characterization. Despite that, a consensus in regard to its applications in bone neoplasms has not been established. Indeed CT-guided technique (or fluoroscopic ones) still represents the standard choice in clinical practice. This review article aims to review the literature data about US-guided bone biopsy, underlying clinical-radiological indications, advantages of the procedure and future perspectives. Bone lesions taking the best advantages of the US-guided biopsy are osteolytic, determining the erosion of the overlying bone cortex and/or with an extraosseous soft-tissue component. Indeed, osteolytic lesions with extra-skeletal soft-tissue involvement represent a clear indication for US-guided biopsy. Moreover, even lytic bone lesions with cortical thinning and/or cortical disruption, especially located in the extremities or pelvis, can be safely sampled with US guidance with very good diagnostic yield. US-guided bone biopsy is proven to be fast, effective and safe. Additionally, it offers real-time needle evaluation, an advantage when compared to CT-guided bone biopsy. In the current clinical settings, it seems relevant to select the exact eligibility criteria for this imaging guidance since the effectiveness can vary depending on the type of lesion and body site involved.

The New Ice Age of Musculoskeletal Intervention: Role of Percutaneous Cryoablation in Bone and Soft Tissue Tumors.

In the rapidly evolving field of interventional oncology, minimally invasive methods, including CT-guided cryoablation, play an increasingly important role in tumor treatment, notably in bone and soft tissue cancers. Cryoablation works using compressed gas-filled probes to freeze tumor cells to temperatures below -20 °C, exploiting the Joule-Thompson effect. This cooling causes cell destruction by forming intracellular ice crystals and disrupting blood flow through endothelial cell damage, leading to local ischemia and devascularization. Coupling this with CT technology enables precise tumor targeting, preserving healthy surrounding tissues and decreasing postoperative complications. This review reports the most important literature on CT-guided cryoablation's application in musculoskeletal oncology, including sarcoma, bone metastases, and bone and soft tissue benign primary tumors, reporting on the success rate, recurrence rate, complications, and technical aspects to maximize success for cryoablation in the musculoskeletal system.

Limitations of PLX3397 as a microglial investigational tool: peripheral and off-target effects dictate the response to inflammation.

Microglia, the resident macrophages of the central nervous system (CNS), play a critical role in CNS homeostasis and neuroinflammation. Pexidartinib (PLX3397), a colony-stimulating factor 1 (CSF1) receptor inhibitor, is widely used to deplete microglia, offering flexible options for both long-term depletion and highly versatile depletion-repopulation cycles. However, the potential impact of PLX3397 on peripheral (immune) cells remains controversial. Until now, the microglia-specificity of this type of compounds has not been thoroughly evaluated, particularly in the context of peripherally derived neuroinflammation. Our study addresses this gap by examining the effects of PLX3397 on immune cells in the brain, liver, circulation and bone marrow, both in homeostasis and systemic inflammation models. Intriguingly, we demonstrate that PLX3397 treatment not only influences the levels of tissue-resident macrophages, but also affects circulating and bone marrow immune cells beyond the mononuclear phagocyte system (MPS). These alterations in peripheral immune cells disrupt the response to systemic inflammation, consequently impacting the phenotype irrespective of microglial depletion. Furthermore, we observed that a lower dose of PLX3397, which does not deplete microglia, demonstrates similar (non-)MPS effects, both in the periphery and the brain, but fails to fully replicate the peripheral alterations seen in the higher doses, questioning lower doses as a 'peripheral control' strategy. Overall, our data highlight the need for caution when interpreting studies employing this compound, as it may not be suitable for specific investigation of microglial function in the presence of systemic inflammation.