In developing mouse kidneys, orientation of loop of Henle growth is adaptive and guided by long-range cues from medullary collecting ducts.

The path taken by the loop of Henle, from renal cortex to medulla and back, is critical to the ability of the kidney to concentrate urine and recover water. Unlike most developing tubules, which navigate as blind-ended cylinders, the loop of Henle extends as a sharply bent loop, the apex of which leads the double tubes behind it in a 'V' shape. Here, we show that, in normal kidney development, loops of Henle extend towards the centroid of the kidney with an accuracy that increases the longer they extend. Using cultured kidney rudiments, and manipulations that rotate or remove portions of the organ, we show that loop orientation depends on long-range cues from the medulla rather than either the orientation of the parent nephron or local cues in the cortex. The loops appear to be attracted to the most mature branch point of the collecting duct system but, if this is removed, they will head towards the most mature collecting duct branch available to them. Our results demonstrate the adaptive nature of guidance of this unusual example of a growing epithelium, and set the stage for later work devoted to understanding the molecules and mechanisms that underlie it.

Vaterite induced by Lysinibacillus sp. GW-2 strain and its stability.

Studies on the formation and stability of vaterite by bacteria in experimental systems are of great importance for understanding the mechanism by which microbes contribute to carbonate mineralization. In this study, mineralization experiments using Lysinibacillus sp. strain GW-2 were carried out for 72h under shaking conditions and aging experiments using biotic and chemically synthesized vaterite were performed for 60days in distilled water and air. Our results indicate that Lysinibacillus sp. strain GW-2 can induce the formation of vaterite with spherical morphology from an amorphous calcium carbonate precursor. Biogenic vaterite was more stable than chemically synthesized vaterite in distilled water, perhaps due to organic matter secreted by bacteria that enwrapped the vaterite and prevented it from transforming into more stable phases. Infrared spectrophotometry of biogenic and chemically synthesized vaterite confirmed the presence of organic matter in biogenic vaterite.

Management of rheumatoid arthritis in clinical practice using treat-to-target strategy: Where do we stand in the multi-ethnic Malaysia population?

To evaluate the achievement of treat-to-target (T2T) strategy in rheumatoid arthritis (RA) and identify factors associated with failed treatment target in a public rheumatology center. A cross-sectional study was conducted from June 2015 to February 2016. RA patients with disease duration greater than 2 years and under T2T for over a year were invited to the study. Demographic, clinical data, disease activity score of 28 joints (DAS28), and clinical disease activity index (CDAI) were collected in a single routine clinic visit. Treatment target was defined as DAS28 <3.2 or CDAI ≤10. Retrospective chart review was performed to determine reasons of failed treatment target. A total of 371 patients were recruited and 87.1% were female. Mean age and duration of RA were 53.5 years (SD 10.3) and 9.1 years (SD 6.6), respectively. Ethnic distribution was 49% Chinese, 27% Malay, and 24% Indian. T2T was achieved in 81.7% of the cohort. Non-Chinese ethnicity, positive rheumatoid factor, and treatment with three disease modifying anti-rheumatic drugs (DMARDs) were associated with failed treatment target. After controlling for covariates, Malay ethnicity (OR 2.96; 95% CI 1.47-5.96) and treatment with three DMARDs (OR 2.14; 95% CI 1.06-4.35) were associated with failed treatment target. There was no association between age, gender, duration of RA, BMI, smoking status, anti-citrulinated cyclic peptide, and achievement of T2T. The most common reasons of failed treatment target were inability to escalate DMARDs due to side effects (18.8%), lack of biologics fund (15.6%), and persistent disease despite optimum treatment (14.1%). T2T was successfully implemented. Malay patients need aggressive treatment adaptation to achieve optimal outcome.

Real-world clinical experience of biological disease modifying anti-rheumatic drugs in Malaysia rheumatoid arthritis patients.

The effect of biologic disease modifying anti-rheumatic drugs (bDMARDs) in treating rheumatoid arthritis (RA) in real-world clinical practice remains unknown in Southeast Asia. We aimed to assess the efficacy and safety of bDMARDs among Malaysian RA patients treated in routine clinical practice. A retrospective medical chart review of RA patients from 11 government hospitals were conducted from January 2003 to January 2014. A standardized questionnaire was used to abstract patient's demographic, clinical and treatment data. Level of disease activity was measured by DAS28 collected at baseline, 3, 6 and 12 months. Three hundred and one patients were available for analysis, mean age 41 (SD, 10.8) years, mean RA duration 12.3 (SD, 6.9) years and 98% had history of two or more conventional-synthetic DMARDs. There were 467 bDMARD courses prescribed with mean bDMARDs duration use of 12.9 months (SD 14.7). Tumour necrosis factor alpha inhibitors were the most common prescribed bDMARDs (77.1%), followed by Tocilizumab (14.6%) and Rituximab (8.4%). We observed significant improvement in mean DAS28 values from baseline to 3, 6 and 12 months (p < 0.001). Overall, 16.9% achieved DAS28 remission at 6 months. A third (35.6%) of patients reported adverse events, three commonest being infections (46.5%), allergy (22.9%) and laboratory abnormalities (12.9%). 3.7% of our patients had tuberculosis. Biologic DMARDs were effective in treating RA in real-world practice in Malaysia, despite a lower remission rate compared to developed countries. Except for higher rates of tuberculosis, the AEs were similar to the published reports.

Node retraction during patterning of the urinary collecting duct system.

This report presents a novel mechanism for remodelling a branched epithelial tree. The mouse renal collecting duct develops by growth and repeated branching of an initially unbranched ureteric bud: this mechanism initially produces an almost fractal form with young branches connected to the centre of the kidney via a sequence of nodes (branch points) distributed widely throughout the developing organ. The collecting ducts of a mature kidney have a different form: from the nephrons in the renal cortex, long, straight lengths of collecting duct run almost parallel to one another through the renal medulla, and open together to the renal pelvis. Here we present time-lapse studies of E11.5 kidneys growing in culture: after about 5 days, the collecting duct trees show evidence of 'node retraction', in which the node of a 'Y'-shaped branch moves downwards, shortening the stalk of the 'Y', lengthening its arms and narrowing their divergence angle so that the 'Y' becomes a 'V'. Computer simulation suggests that node retraction can transform a spread tree, like that of an early kidney, into one with long, almost-parallel medullary rays similar to those seen in a mature real kidney.

A self-avoidance mechanism in patterning of the urinary collecting duct tree.

BACKGROUND: Glandular organs require the development of a correctly patterned epithelial tree. These arise by iterative branching: early branches have a stereotyped anatomy, while subsequent branching is more flexible, branches spacing out to avoid entanglement. Previous studies have suggested different genetic programs are responsible for these two classes of branches. RESULTS: Here, working with the urinary collecting duct tree of mouse kidneys, we show that the transition from the initial, stereotyped, wide branching to narrower later branching is independent from previous branching events but depends instead on the proximity of other branch tips. A simple computer model suggests that a repelling molecule secreted by branches can in principle generate a well-spaced tree that switches automatically from wide initial branch angles to narrower subsequent ones, and that co-cultured trees would distort their normal shapes rather than colliding. We confirm this collision-avoidance experimentally using organ cultures, and identify BMP7 as the repelling molecule. CONCLUSIONS: We propose that self-avoidance, an intrinsically error-correcting mechanism, may be an important patterning mechanism in collecting duct branching, operating along with already-known mesenchyme-derived paracrine factors.

Engineering kidneys from simple cell suspensions: an exercise in self-organization.

Increasing numbers of people approaching and living with end-stage renal disease and failure of the supply of transplantable kidneys to keep pace has created an urgent need for alternative sources of new organs. One possibility is tissue engineering of new organs from stem cells. Adult kidneys are arguably too large and anatomically complex for direct construction, but engineering immature kidneys, transplanting them, and allowing them to mature within the host may be more feasible. In this review, we describe a technique that begins with a suspension of renogenic stem cells and promotes these cells' self-organization into organ rudiments very similar to foetal kidneys, with a collecting duct tree, nephrons, corticomedullary zonation and extended loops of Henle. The engineered rudiments vascularize when transplanted to appropriate vessel-rich sites in bird eggs or adult animals, and show preliminary evidence for physiological function. We hope that this approach might one day be the basis of a clinically useful technique for renal replacement therapy.

An improved method of renal tissue engineering, by combining renal dissociation and reaggregation with a low-volume culture technique, results in development of engineered kidneys complete with loops of Henle.

BACKGROUND: Tissue engineering of functional kidney tissue is an important goal for clinical restoration of renal function in patients damaged by infectious, toxicological, or genetic disease. One promising approach is the use of the self-organizing abilities of embryonic kidney cells to arrange themselves, from a simply reaggregated cell suspension, into engineered organs similar to fetal kidneys. The previous state-of-the-art method for this results in the formation of a branched collecting duct tree, immature nephrons (S-shaped bodies) beside and connected to it, and supportive stroma. It does not, though, result in the significant formation of morphologically detectable loops of Henle - anatomical features of the nephron that are critical to physiological function. METHODS: We have combined the best existing technique for renal tissue engineering from cell suspensions with a low-volume culture technique that allows intact kidney rudiments to make loops of Henle to test whether engineered kidneys can produce these loops. RESULTS: The result is the formation of loops of Henle in engineered cultured 'fetal kidneys', very similar in both morphology and in number to those formed by intact organ rudiments. CONCLUSION: This brings the engineering technique one important step closer to production of a fully realistic organ.

Genome-Wide Characterization of a Highly Penetrant Form of Hyperlipoprotein(a)emia Associated With Genetically Elevated Cardiovascular Risk.

BACKGROUND: Lp(a) (lipoprotein [a]) is a highly atherogenic lipoprotein strongly associated with coronary artery disease (CAD). Lp(a) concentrations are chiefly determined genetically. Investigation of large pedigrees with extreme Lp(a) using modern whole-genome approaches may unravel the genetic determinants underpinning this pathological phenotype. METHODS: A large family characterized by high Lp(a) and increased CAD incidence was recruited by cascade screening. Plasma lipids, lipoproteins, and apolipoproteins concentrations, as well as the size of apo(a) isoforms, were determined enzymatically by high-resolution mass spectrometry and Western blot, respectively. Whole-exome sequencing was performed to search for rare defects in modifier genes. Genetic risk scores (GRS) for Lp(a) and CAD were calculated and their discriminative power was assessed. RESULTS: Seventeen individuals displayed extreme Lp(a) levels including 6 with CAD. Whole-exome sequencing showed no hint for genetic defects outside the LPA locus. The extreme Lp(a) phenotype segregated with the presence of a short apo(a) isoform containing 21 Kringle IV domains. This allele was characterized by the presence of three rare strongly Lp(a) increasing single nucleotide polymorphisms and a significantly increased load of oxidized phospholipids per Lp(a) particle. An Lp(a) GRS consisting of 48 single nucleotide polymorphisms that represent 2001 genome-wide significant LPA single nucleotide polymorphisms, efficiently captured the hyper-Lp(a) phenotype and discriminated affected and nonaffected individuals with great accuracy. The genome-wide GRS for CAD, encompassing 6.6 million single nucleotide polymorphisms, was very high for most family members (>97.5 percentile of the reference population), but this observation was no longer valid when the contribution of the LPA locus was omitted. CONCLUSIONS: High-Lp(a) phenotypes can be successfully captured using the Lp(a) GRS even among closely related family members. In hyper-Lp(a) individuals, LPA can be a major locus driving a very high CAD GRS. This underpins the large contribution of the LPA locus to the cardiovascular genetic risk in families.

Prophylactic gonadectomy in 46 XY females; why, where and when?

OBJECTIVES: We compared cases of phenotypic female patients who presented with male karyotype and underwent prophylactic gonadectomy. CASE PRESENTATION: Five patients with female phenotypes presented in early adulthood with primary amenorrhoea with varying degrees of puberty. One was tall with breast development. Another was very short with clitoromegaly and multiple co-morbidities. The other three had no secondary sexual characteristics. They were examined, after which hormonal profile, karyotyping, ultrasound examination and magnetic resonance imaging were done to assess the site of gonads. Gonadectomy was performed once their 46 XY karyotype was confirmed. Results of histopathological examination of their gonads ranged from dysgenetic gonads to having testicular tissues and malignancy. CONCLUSION: Female patients with 46 XY karyotypes require prophylactic gonadectomy performed at different timings depending on diagnosis due to the malignancy risk. Pre-operative assessment is essential to locate the gonads prior to surgery.

Clinically compatible advances in blood-derived endothelial progenitor cell isolation and reprogramming for translational applications.

The promise of using induced pluripotent stem cells (iPSCs) for cellular therapies has been hampered by the lack of easily isolatable and well characterized source cells whose genomes have undergone minimal changes during their processing. Blood-derived late-outgrowth endothelial progenitor cells (EPCs) are used for disease modeling and have potential therapeutic uses including cell transplantation and the translation of induced pluripotent stem cell (iPSC) derivatives. However, the current isolation of EPCs has been inconsistent and requires at least 40-80 mL of blood, limiting their wider use. In addition, previous EPC reprogramming methods precluded the translation of EPC-derived iPSCs to the clinic. Here a series of clinically-compatible advances in the isolation and reprogramming of EPCs is presented, including a reduction of blood sampling volumes to 10 mL and use of highly efficient RNA-based reprogramming methods together with autologous human serum, resulting in clinically relevant iPSCs carrying minimal copy number variations (CNVs) compared to their parent line.

Increased complement activation is a distinctive feature of severe SARS-CoV-2 infection.

Complement activation has been implicated in the pathogenesis of severe SARS-CoV-2 infection. However, it remains to be determined whether increased complement activation is a broad indicator of critical illness (and thus, no different in COVID-19). It is also unclear which pathways are contributing to complement activation in COVID-19, and, if complement activation is associated with certain features of severe SARS-CoV-2 infection, such as endothelial injury and hypercoagulability. To address these questions, we investigated complement activation in the plasma from patients with COVID-19 prospectively enrolled at two tertiary care centers. We compared our patients to two non-COVID cohorts: (a) patients hospitalized with influenza, and (b) patients admitted to the intensive care unit (ICU) with acute respiratory failure requiring invasive mechanical ventilation (IMV). We demonstrate that circulating markers of complement activation (i.e., sC5b-9) are elevated in patients with COVID-19 compared to those with influenza and to patients with non-COVID-19 respiratory failure. Further, the results facilitate distinguishing those who are at higher risk of worse outcomes such as requiring ICU admission, or IMV. Moreover, the results indicate enhanced activation of the alternative complement pathway is most prevalent in patients with severe COVID-19 and is associated with markers of endothelial injury (i.e., Ang2) as well as hypercoagulability (i.e., thrombomodulin and von Willebrand factor). Our findings identify complement activation to be a distinctive feature of COVID-19, and provide specific targets that may be utilized for risk prognostication, drug discovery and personalized clinical trials.

A neutrophil activation signature predicts critical illness and mortality in COVID-19.

Pathologic immune hyperactivation is emerging as a key feature of critical illness in COVID-19, but the mechanisms involved remain poorly understood. We carried out proteomic profiling of plasma from cross-sectional and longitudinal cohorts of hospitalized patients with COVID-19 and analyzed clinical data from our health system database of more than 3300 patients. Using a machine learning algorithm, we identified a prominent signature of neutrophil activation, including resistin, lipocalin-2, hepatocyte growth factor, interleukin-8, and granulocyte colony-stimulating factor, which were the strongest predictors of critical illness. Evidence of neutrophil activation was present on the first day of hospitalization in patients who would only later require transfer to the intensive care unit, thus preceding the onset of critical illness and predicting increased mortality. In the health system database, early elevations in developing and mature neutrophil counts also predicted higher mortality rates. Altogether, these data suggest a central role for neutrophil activation in the pathogenesis of severe COVID-19 and identify molecular markers that distinguish patients at risk of future clinical decompensation.

Delayed production of neutralizing antibodies correlates with fatal COVID-19.

Recent studies have provided insights into innate and adaptive immune dynamics in coronavirus disease 2019 (COVID-19). However, the exact features of antibody responses that govern COVID-19 disease outcomes remain unclear. In this study, we analyzed humoral immune responses in 229 patients with asymptomatic, mild, moderate and severe COVID-19 over time to probe the nature of antibody responses in disease severity and mortality. We observed a correlation between anti-spike (S) immunoglobulin G (IgG) levels, length of hospitalization and clinical parameters associated with worse clinical progression. Although high anti-S IgG levels correlated with worse disease severity, such correlation was time dependent. Deceased patients did not have higher overall humoral response than discharged patients. However, they mounted a robust, yet delayed, response, measured by anti-S, anti-receptor-binding domain IgG and neutralizing antibody (NAb) levels compared to survivors. Delayed seroconversion kinetics correlated with impaired viral control in deceased patients. Finally, although sera from 85% of patients displayed some neutralization capacity during their disease course, NAb generation before 14 d of disease onset emerged as a key factor for recovery. These data indicate that COVID-19 mortality does not correlate with the cross-sectional antiviral antibody levels per se but, rather, with the delayed kinetics of NAb production.

The air liquid-interface, a skin microenvironment, promotes growth of melanoma cells, but not their apoptosis and invasion, through activation of mitogen-activated protein kinase.

The air-liquid interface (ALI) is a common microenvironment of the skin, but it is unknown whether the ALI affects melanoma cell behaviors. Using a collagen gel invasion assay, immunohistochemistry, and Western blots, here we show that melanoma cell proliferation in cultures with an ALI is higher than melanoma cell proliferation in submerged cultures. Bromodeoxyuridine (BrdU) uptake, an indicator of cell proliferation, of melanoma cells at the ALI was about 3 times that of submerged cells, while ALI and submerged melanoma cells had similar levels of single-stranded DNA (a marker of apoptosis). The ALI enhanced the expression of Raf-1, MEK-1 and pERK-1/2 components of the mitogen-activated protein kinase (MAPK) cascade, in cells more than the submerged condition did. The increases in BrdU uptake and pERK-1/2 expression promoted by ALI was abolished by the MEK inhibitor, PD-98059. ALI-treated and submerged melanoma cells did not infiltrate into the collagen gel, and they showed no significant difference in the expression of the invasion- and motility-related molecules, matrix metalloproteinase-1 and -9, laminin 5, and filamin A. Our data indicate that the ALI, a skin microenvironment, accelerates the growth, but not the apoptosis or invasion, of melanoma cells through MAPK activation.

Delayed diagnosis of Ewing's sarcoma in a young patient presented with left knee monoarthritis.

A 19-year-old girl presented to the rheumatology clinic for left knee monoarthritis for the past 4 months. She also had constitutional symptoms with significant weight loss. On physical examination, she appeared cachexic, her left knee was swollen and tender. MRI of the left knee showed a soft tissue swelling extending into the knee joint. Left knee synovial fluid showed small round cells. Histopathology results were compatible with Ewing's sarcoma. Due to the delay in seeking medical advice, she succumbed to the disease 1 week after the diagnosis was made. Soft tissue/bone tumour causes monoarthritis is not common. A careful history taking, physical examination and investigations should be done in order to identify a sinister cause of monoarthritis such as Ewing's sarcoma. Early treatment should be initiated to ensure a better outcome.

Macrophage activation syndrome as an initial presentation of systemic lupus erythematosus with sensorineural hearing loss in a young male patient.

An 18-year-old male adolescent presented with prolonged high spiking temperature, photosensitive rash, oral ulcers and reduced hearing bilaterally of recent onset. Examination revealed malar rash, vasculitis rash over bilateral palms and soles, oral and buccal ulcers, palpable posterior auricular and inguinal lymph nodes, and reduced hearing bilaterally. His further investigations noted pancytopaenia, elevated transaminases, hyperferritinaemia, low C3 and C4 levels, positive antinuclear antibody, double-stranded DNA and direct Coombs test, while bone marrow aspiration revealed active phagocytic activity suggestive of hemophagocytic syndrome. We made a diagnosis of systemic lupus erythematosus with macrophage activation syndrome. We treated him with pulse intravenous methylprednisolone and his condition improved drastically. Temperature resolved on the next day after intravenous methylprednisolone; bilateral sensorineural hearing loss improved to near-normal hearing after treatment. He remained well during follow-up with a tapering dose of prednisolone.

Life-threatening complications of Henoch-Schönlein purpura: diffuse alveolar haemorrhage, venous thrombosis and bowel ischaemia.

Henoch-Schönlein purpura (HSP) is a common systemic vasculitis occurring in children. Making a diagnosis of HSP is often straightforward, managing its complications can be difficult. Diffuse alveolar haemorrhage (DAH), bowel ischaemia and venous thrombosis are rare complications of this disorder. We present a case of a 15-year-old teenage girl presenting with typical purpuric rash of HSP, developed DAH, bowel ischaemia and venous thrombosis. She was successfully treated with pulse methylprednisolone, intravenous Ig and intravenous cyclophosphamide.