Heterozygous variants in MYH10 associated with neurodevelopmental disorders and congenital anomalies with evidence for primary cilia-dependent defects in Hedgehog signaling.

PURPOSE: Nonmuscle myosin II complexes are master regulators of actin dynamics that play essential roles during embryogenesis with vertebrates possessing 3 nonmuscle myosin II heavy chain genes, MYH9, MYH10, and MYH14. As opposed to MYH9 and MYH14, no recognizable disorder has been associated with MYH10. We sought to define the clinical characteristics and molecular mechanism of a novel autosomal dominant disorder related to MYH10. METHODS: An international collaboration identified the patient cohort. CAS9-mediated knockout cell models were used to explore the mechanism of disease pathogenesis. RESULTS: We identified a cohort of 16 individuals with heterozygous MYH10 variants presenting with a broad spectrum of neurodevelopmental disorders and variable congenital anomalies that affect most organ systems and were recapitulated in animal models of altered MYH10 activity. Variants were typically de novo missense changes with clustering observed in the motor domain. MYH10 knockout cells showed defects in primary ciliogenesis and reduced ciliary length with impaired Hedgehog signaling. MYH10 variant overexpression produced a dominant-negative effect on ciliary length. CONCLUSION: These data presented a novel genetic cause of isolated and syndromic neurodevelopmental disorders related to heterozygous variants in the MYH10 gene with implications for disrupted primary cilia length control and altered Hedgehog signaling in disease pathogenesis.

Frailty and stroke thrombectomy outcomes-an observational cohort study.

INTRODUCTION: Mechanical thrombectomy (MT) can improve outcomes following ischaemic stroke. Patient selection for MT is predominantly based on physiological and imaging parameters. We assessed whether people living with pre-stroke frailty had differing outcomes following MT. METHODS: We included consecutive patients undergoing MT at a UK comprehensive stroke centre. We calculated a cumulative deficits frailty index to identify pre-stroke frailty in those patients presenting directly to the centre. Frailty was defined as an index score ≥ 0.24. We assessed univariable and multivariable association between pre-stroke frailty and stroke outcomes. Our primary outcomes were modified Rankin Scale (mRS) and mortality at 90 days. RESULTS: Of 175 patients who underwent MT (2014-2018), we identified frailty in 49 (28%). Frail and non-frail patients had similar rates of thrombolysis administration, successful recanalization and onset to recanalization times. Those with pre-stroke frailty had higher 24 hour National Institutes of Health Stroke Scale (12(IQR: 8-17) versus 3(IQR: 2-13); P = 0.001); were less likely to be independent (mRS 0-2: 18% versus 61%; P < 0.001) and more likely to die (47% versus 14%; P < 0.001) within 90 days. Adjusting for age, baseline NIHSS and thrombolysis, frailty remained a strong, independent predictor of poor clinical outcome at 90 days (Death OR: 3.12 (95% CI: 1.32-7.4); dependency OR: 3.04 (95%CI: 1.10-8.44). Age was no longer a predictor of outcome when adjusted for frailty. CONCLUSION: Pre-stroke frailty is prevalent in real-world patients eligible for MT and is an important predictor of poor outcomes. Routine assessment of pre-stroke frailty could help decision-making around patient selection for MT.

Disseminated Mucocutaneous Histoplasmosis Diagnosed in the United Kingdom, Presumably as a Result of Recrudescence Decades After Primary Infection Following Immunosuppressive Treatment of Its Mimic, Sarcoidosis: A Multidisciplinary Cautionary Tale.

ABSTRACT: Histoplasmosis is a dimorphic fungal infection, which is rare outside endemic pockets in North, Central, and South America, Asia, and Africa. Herein, we describe a woman in her 80s living in the Scottish Borders region of the United Kingdom with a recent diagnosis of granulomatous rosacea, who on receiving escalating immunosuppression for suspected sarcoidosis, and long-standing rheumatoid arthritis developed a striking eruption involving her eyelids along with painful ulceration of the oral and nasal mucosa. Histopathologic examination of the skin and mucosal lesions demonstrated granulomatous inflammation with numerous yeast forms of fungal organisms with morphological characteristics of Histoplasma species. This was confirmed to be H. capsulatum on fungal culture and direct panfungal polymerase chain reaction assay. Although the patient had not left the United Kingdom for more than 20 years, she gave a travel history involving multiple trips to countries where histoplasmosis is known to occur, before that. This case exemplifies the challenges involved in making a diagnosis of histoplasmosis in nonendemic regions for both clinicians and pathologists alike. In this particular patient, the diagnostic difficulties were compounded by the clinicopathological overlap with other cutaneous and systemic granulomatous disorders like granulomatous rosacea and suspected sarcoidosis and also the exceptionally long latency period between the purported historical primary infection and recent recrudescence. We highlight this unusual case to increase an awareness of histoplasmosis, which is very rare in nonendemic regions like the United Kingdom and involves cases acquired during residence in or travel to endemic areas, to ensure its prompt recognition and treatment.

Circulating RNAs as predictive markers for the progression of type 2 diabetes.

Type 2 Diabetes Mellitus (T2DM) is the most prevalent form of diabetes in the USA, thus, the identification of biomarkers that could be used to predict the progression from prediabetes to T2DM would be greatly beneficial. Recently, circulating RNA including microRNAs (miRNAs) present in various body fluids have emerged as potential biomarkers for various health conditions, including T2DM. Whereas studies that examine the changes of miRNA spectra between healthy controls and T2DM individuals have been reported, the goal of this study is to conduct a baseline comparison of prediabetic individuals who either progress to T2DM, or remain prediabetic. Using an advanced small RNA sequencing library construction method that improves the detection of miRNA species, we identified 57 miRNAs that showed significant concentration differences between progressors (progress from prediabetes to T2DM) and non-progressors. Among them, 26 have been previously reported to be associated with T2DM in either body fluids or tissue samples. Some of the miRNAs identified were also affected by obesity. Furthermore, we identified miRNA panels that are able to discriminate progressors from non-progressors. These results suggest that upon further validation these miRNAs may be useful to predict the risk of conversion to T2DM from prediabetes.

Outcomes after Thrombectomy in Belfast: Mothership and Drip-and-Ship in the Real World.

BACKGROUND: Mechanical thrombectomy has revolutionised the treatment of acute ischaemic stroke due to large vessel occlusion. It is well recognised that patients are more likely to benefit when reperfusion happens quickly, however, there is uncertainty as to how best to deliver this service. OBJECTIVES: To compare outcomes of patients in Northern -Ireland who underwent thrombectomy via direct admission to the single endovascular centre (mothership [MS]) with those transferred from primary stroke centres (drip-and-ship [DS]). METHODS: Analysis was conducted on the records of all patients who underwent thrombectomy from January 2014 to December 2017 inclusive. The primary outcome measure was 3 months functional independence (modified Rankin Score [mRS] 0-2). Secondary outcome measures were full recovery (mRS 0) at 3 months, symptomatic intracranial haemorrhage (sICH) rates and mortality rates. RESULTS: Two hundred fourteen patients underwent thrombectomy (MS 124, DS 90). Patients in the MS group were older (median 73 vs. 70 years, p = 0.026), but there was no significant difference in baseline National Institutes of Health Stroke Scale (median 15 MS vs. 16.5 DS, p = 0.162) or thrombolysis rates (41.9% MS vs. 54.4% DS, p = 0.070) between the groups. Time from stroke onset to arrival at thrombectomy centre was shorter in the MS group (median 71 vs. 218 min, p < 0.001) but door to groin puncture time was shorter in the DS group (median 30 vs. 60 min, p < 0.001). There was no significant difference in 3 months functional independence (51.6% MS vs. 62.2% DS, p = 0.123), or in the secondary outcome measures of full recovery (21.8% MS vs. 12.2% DS, p = 0.071), sICH (MS 0.8%, DS 4.4%, p = 0.082) and mortality (MS 24.2%, DS 20.0%, p = 0.468). CONCLUSIONS: Our analysis showed similar outcomes after thrombectomy in the MS and DS groups. For patients potentially eligible for thrombectomy, rapid access to the endovascular centre is essential to optimise both the number of patients treated and the outcomes achieved.

The LIM and POU homeobox genes ttx-3 and unc-86 act as terminal selectors in distinct cholinergic and serotonergic neuron types.

Transcription factors that drive neuron type-specific terminal differentiation programs in the developing nervous system are often expressed in several distinct neuronal cell types, but to what extent they have similar or distinct activities in individual neuronal cell types is generally not well explored. We investigate this problem using, as a starting point, the C. elegans LIM homeodomain transcription factor ttx-3, which acts as a terminal selector to drive the terminal differentiation program of the cholinergic AIY interneuron class. Using a panel of different terminal differentiation markers, including neurotransmitter synthesizing enzymes, neurotransmitter receptors and neuropeptides, we show that ttx-3 also controls the terminal differentiation program of two additional, distinct neuron types, namely the cholinergic AIA interneurons and the serotonergic NSM neurons. We show that the type of differentiation program that is controlled by ttx-3 in different neuron types is specified by a distinct set of collaborating transcription factors. One of the collaborating transcription factors is the POU homeobox gene unc-86, which collaborates with ttx-3 to determine the identity of the serotonergic NSM neurons. unc-86 in turn operates independently of ttx-3 in the anterior ganglion where it collaborates with the ARID-type transcription factor cfi-1 to determine the cholinergic identity of the IL2 sensory and URA motor neurons. In conclusion, transcription factors operate as terminal selectors in distinct combinations in different neuron types, defining neuron type-specific identity features.

An interstitial deletion within 9p21.3 and extending beyond CDKN2A predisposes to melanoma, neural system tumours and possible haematological malignancies.

Familial atypical multiple mole melanoma syndrome (FAMMM) is characterised by dysplastic naevi, malignant melanoma and pancreatic cancer. Given that large deletions involving CDKN2A (cyclin-dependent kinase inhibitor 2A) account for only 2% of cases, we describe a family that highlights the co-occurrence of both melanoma and neural system tumours to aid clinical recognition and propose a management strategy. A patient with multiple neurofibromas was referred with a provisional diagnosis of neurofibromatosis type 1 (NF1). Prior molecular testing, though, had failed to identify an NF1 mutation by sequencing and multiplex ligation-dependent probe amplification. His family history was significant for multiple in situ/malignant melanomas at young ages and several different cancers reminiscent of an underlying syndrome. A search of the Familial Cancer Database, FaCD Online, highlighted several families with cutaneous melanoma and nervous system tumours who were subsequently identified to have large deletions spanning CDKN2A Although sequencing of CDKN2A and TP53 failed to identify a mutation, a heterozygous CDKN2A deletion was identified by targeted array comparative genomic hybridisation (CGH). Whole-genome oligonucleotide array CGH and SNP analysis identified an interstitial deletion of at least 1.5 Mb within 9p21.3 and spanning approximately 25 genes. Identification of the underlying molecular abnormality permits predictive testing for at-risk relatives. Given the young cancer diagnoses, a surveillance regimen was developed and a clinical team organised for ongoing management so that genetic testing could be offered to both adults and minor children. Surveillance recommendations addressed cancer risks associated with FAMMM, and other cancers exhibited by this family with a large contiguous gene deletion.

Yeast Fex1p Is a Constitutively Expressed Fluoride Channel with Functional Asymmetry of Its Two Homologous Domains.

Fluoride is a ubiquitous environmental toxin with which all biological species must cope. A recently discovered family of fluoride export (FEX) proteins protects organisms from fluoride toxicity by removing it from the cell. We show here that FEX proteins in Saccharomyces cerevisiae function as ion channels that are selective for fluoride over chloride and that these proteins are constitutively expressed at the yeast plasma membrane. Continuous expression is in contrast to many other toxin exporters in yeast, and this, along with the fact that two nearly duplicate proteins are encoded in the yeast genome, suggests that the threat posed by fluoride ions is frequent and detrimental. Structurally, eukaryotic FEX proteins consist of two homologous four-transmembrane helix domains folded into an antiparallel dimer, where the orientation of the two domains is fixed by a single transmembrane linker helix. Using phylogenetic sequence conservation as a guide, we have identified several functionally important residues. There is substantial functional asymmetry in the effect of mutation at corresponding sites in the two domains. Specifically, mutations to residues in the C-terminal domain proved significantly more detrimental to function than did similar mutations in the N-terminal domain. Our data suggest particular residues that may be important to anion specificity, most notably the necessity of a positive charge near the end of TMH1 in the C-terminal domain. It is possible that a cationic charge at this location may create an electrostatic well for fluoride ions entering the channel from the cytoplasm.

Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins.

Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, (18)F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions.

Transplanted bone marrow mononuclear cells and MSCs impart clinical benefit to children with osteogenesis imperfecta through different mechanisms.

Transplantation of whole bone marrow (BMT) as well as ex vivo-expanded mesenchymal stromal cells (MSCs) leads to striking clinical benefits in children with osteogenesis imperfecta (OI); however, the underlying mechanism of these cell therapies has not been elucidated. Here, we show that non-(plastic)-adherent bone marrow cells (NABMCs) are more potent osteoprogenitors than MSCs in mice. Translating these findings to the clinic, a T cell-depleted marrow mononuclear cell boost (> 99.99% NABMC) given to children with OI who had previously undergone BMT resulted in marked growth acceleration in a subset of patients, unambiguously indicating the therapeutic potential of bone marrow cells for these patients. Then, in a murine model of OI, we demonstrated that as the donor NABMCs differentiate to osteoblasts, they contribute normal collagen to the bone matrix. In contrast, MSCs do not substantially engraft in bone, but secrete a soluble mediator that indirectly stimulates growth, data which provide the underlying mechanism of our prior clinical trial of MSC therapy for children with OI. Collectively, our data indicate that both NABMCs and MSCs constitute effective cell therapy for OI, but exert their clinical impact by different, complementary mechanisms. The study is registered at www.clinicaltrials.gov as NCT00187018.

Dendritic cell PAR1-S1P3 signalling couples coagulation and inflammation.

Defining critical points of modulation across heterogeneous clinical syndromes may provide insight into new therapeutic approaches. Coagulation initiated by the cytokine-receptor family member known as tissue factor is a hallmark of systemic inflammatory response syndromes in bacterial sepsis and viral haemorrhagic fevers, and anticoagulants can be effective in severe sepsis with disseminated intravascular coagulation. The precise mechanism coupling coagulation and inflammation remains unresolved. Here we show that protease-activated receptor 1 (PAR1) signalling sustains a lethal inflammatory response that can be interrupted by inhibition of either thrombin or PAR1 signalling. The sphingosine 1-phosphate (S1P) axis is a downstream component of PAR1 signalling, and by combining chemical and genetic probes for S1P receptor 3 (S1P3) we show a critical role for dendritic cell PAR1-S1P3 cross-talk in regulating amplification of inflammation in sepsis syndrome. Conversely, dendritic cells sustain escalated systemic coagulation and are the primary hub at which coagulation and inflammation intersect within the lymphatic compartment. Loss of dendritic cell PAR1-S1P3 signalling sequesters dendritic cells and inflammation into draining lymph nodes, and attenuates dissemination of interleukin-1beta to the lungs. Thus, activation of dendritic cells by coagulation in the lymphatics emerges as a previously unknown mechanism that promotes systemic inflammation and lethality in decompensated innate immune responses.

Loss-of-function mutations in Notch receptors in cutaneous and lung squamous cell carcinoma.

Squamous cell carcinomas (SCCs) are one of the most frequent forms of human malignancy, but, other than TP53 mutations, few causative somatic aberrations have been identified. We identified NOTCH1 or NOTCH2 mutations in ~75% of cutaneous SCCs and in a lesser fraction of lung SCCs, defining a spectrum for the most prevalent tumor suppressor specific to these epithelial malignancies. Notch receptors normally transduce signals in response to ligands on neighboring cells, regulating metazoan lineage selection and developmental patterning. Our findings therefore illustrate a central role for disruption of microenvironmental communication in cancer progression. NOTCH aberrations include frameshift and nonsense mutations leading to receptor truncations as well as point substitutions in key functional domains that abrogate signaling in cell-based assays. Oncogenic gain-of-function mutations in NOTCH1 commonly occur in human T-cell lymphoblastic leukemia/lymphoma and B-cell chronic lymphocytic leukemia. The bifunctional role of Notch in human cancer thus emphasizes the context dependency of signaling outcomes and suggests that targeted inhibition of the Notch pathway may induce squamous epithelial malignancies.

Macrophage mediated mesoscale brain mechanical homeostasis mechanically imaged via optical tweezers and Brillouin microscopy in vivo.

Tissues are active materials where epithelial turnover, immune surveillance, and remodeling of stromal cells such as macrophages all regulate form and function. Scattering modalities such as Brillouin microscopy (BM) can non-invasively access mechanical signatures at GHz. However, our traditional understanding of tissue material properties is derived mainly from modalities which probe mechanical properties at different frequencies. Thus, reconciling measurements amongst these modalities remains an active area. Here, we compare optical tweezer active microrheology (OT-AMR) and Brillouin microscopy (BM) to longitudinally map brain development in the larval zebrafish. We determine that each measurement is able to detect a mechanical signature linked to functional units of the brain. We demonstrate that the corrected BM-Longitudinal modulus using a density factor correlates well with OT-AMR storage modulus at lower frequencies. We also show that the brain tissue mechanical properties are dependent on both the neuronal architecture and the presence of macrophages. Moreover, the BM technique is able to delineate the contributions to mechanical properties of the macrophage from that due to colony stimulating factor 1 receptor (CSF1R) mediated stromal remodeling. Here, our data suggest that macrophage remodeling is instrumental in the maintenance of tissue mechanical homeostasis during development. Moreover, the strong agreement between the OT-AM and BM further demonstrates that scattering-based technique is sensitive to both large and minute structural modification in vivo.

Serine protease inhibition reduces post-ischemic granulocyte recruitment in mouse intestine.

Proteases and proteinase-activated receptor (PAR) activation are involved in several intestinal inflammatory conditions. We hypothesized that serine proteases and PAR activation could also modulate the intestinal injury induced by ischemia-reperfusion (I-R). C57Bl/6 mice were subjected to 90 minutes of intestinal ischemia followed or not by reperfusion. Sham-operated animals served as controls. After ischemia, plasma and tissue serine protease activity levels were increased compared to the activity measured in plasma and tissues from sham-operated mice. This increase was maintained or further enhanced after 2 and 5 hours of reperfusion, respectively. Trypsin (25 kDa) was detected in tissues both after ischemia and 2 hours of reperfusion. Treatment with FUT-175 (10 mg/kg), a potent serine protease inhibitor, increased survival after I-R, inhibited tissue protease activity, and significantly decreased intestinal myeloperoxidase (MPO) activity and chemokine and adhesion molecule expression. We investigated whether serine proteases modulate granulocyte recruitment by a PAR-dependent mechanism. MPO levels and adhesion molecule expression were significantly reduced in I-R groups pre-treated with the PAR(1) antagonist SCH-79797 (5 mg/kg) and in Par(2)(-/-)mice, compared, respectively, to vehicle-treated group and wild-type littermates. Thus, increased proteolytic activity and PAR activation play a pathogenic role in intestinal I-R injury. Inhibition of PAR-activating serine proteases could be beneficial to reduce post-ischemic intestinal inflammation.

Integrated Care Models for Long Coronavirus Disease.

Professional or governmental agencies and organizations have developed guidelines to define the problem and evaluate and manage patients with Post-Acute Sequelae of SARS CoV-2 (PASC). Multidisciplinary models largely exist in academic centers and larger cities; however, most care for PASC patients is provided by the primary care providers. The American Academy of Physical Medicine and Rehabilitation has been in the forefront in releasing consensus statements as a part of the long COVID collaborative.

Organ specific microenvironmental MR1 expression in cutaneous melanoma.

The microenvironment is an important regulator of intertumoral trafficking and activity of immune cells. Understanding how the immune system can be tailored to maintain anti-tumor killing responses in metastatic disease remains an important goal. Thus, immune mediated eradication of metastasis requires the consideration of organ specific microenvironmental cues. Using a xenograft model of melanoma metastasis in adult zebrafish, we perturbed the dynamic balance between the infiltrating immune cells in the metastatic setting using a suite of different transgenic zebrafish. We employed intravital imaging coupled with metabolism imaging (FLIM) to visualize and map the organ specific metabolism with near simultaneity in multiple metastatic lesions. Of all the MHC complexes examined for brain and skeletal metastases, we determined that there is an organ specific expression of mhc1uba (human ortholog, MR1) for both the melanoma cells and the resident and infiltrating immune cells. Specifically, immune clusters did not express mhc1uba in brain metastatic lesions in immune competent fish. Finally, the differential immune response drove organ specific metabolism where tumor glycolysis was increased in brain metastases compared to skeletal and parental lines as measured using fluorescence lifetime imaging microscopy (FLIM). As MR1 belongs to the MHC class I molecules and is a target of immunotherapeutic drugs, we believe that our data presents an opportunity to understand the relationship between organ specific tumor metabolism and drug efficacy in the metastatic setting.

YAP localization mediates mechanical adaptation of human cancer cells during extravasation in vivo.

Biophysical profiling of primary tumors has revealed that individual tumor cells fall along a highly heterogeneous continuum of mechanical phenotypes. One idea is that a subset of tumor cells is "softer" to facilitate detachment and escape from the primary site, a step required to initiate metastasis. However, it has also been postulated that cells must be able to deform and generate sufficient force to exit into distant sites. Here, we aimed to dissect the mechanical changes that occur during extravasation and organ colonization. Using multiplexed methods of intravital microscopy and optical tweezer based active microrheology, we obtained longitudinal images and mechanical profiles of cells during organ colonization in vivo. We determined that cells were softer, more liquid like upon exit of the vasculature but stiffened and became more solid like once in the new organ microenvironment. We also determined that a YAP mediated mechanogenotype influenced the global dissemination in our in vivo and in vitro models and that reducing mechanical heterogeneity could reduce extravasation. Moreover, our high throughput analysis of mechanical phenotypes of patient samples revealed that this mechanics was in part regulated by the external hydrodynamic forces that the cancer cells experienced within capillary mimetics. Our findings indicate that disseminated cancer cells can keep mutating with a continuum landscape of mechano-phenotypes, governed by the YAP-mediated mechanosensing of hydrodynamic flow.

Proteinase-activated receptor 2 modulates neuroinflammation in experimental autoimmune encephalomyelitis and multiple sclerosis.

The proteinase-activated receptors (PARs) are widely recognized for their modulatory properties of inflammation and neurodegeneration. We investigated the role of PAR2 in the pathogenesis of multiple sclerosis (MS) in humans and experimental autoimmune encephalomyelitis (EAE) in mice. PAR2 expression was increased on astrocytes and infiltrating macrophages in human MS and murine EAE central nervous system (CNS) white matter (P < 0.05). Macrophages and astrocytes from PAR2 wild-type (WT) and knockout (KO) mice exhibited differential immune gene expression with PAR2 KO macrophages showing significantly higher interleukin 10 production after lipopolysaccharide stimulation (P < 0.001). PAR2 activation in macrophages resulted in the release of soluble oligodendrocyte cytotoxins (P < 0.01). Myelin oligodendrocyte glycoprotein-induced EAE caused more severe inflammatory gene expression in the CNS of PAR2 WT animals (P < 0.05), together with enhanced T cell proliferation and interferon gamma production (P < 0.05), compared with KO littermates. Indeed, PAR2 WT animals showed markedly greater microglial activation and T lymphocyte infiltration accompanied by worsened demyelination and axonal injury in the CNS compared with their PAR2 KO littermates. Enhanced neuropathological changes were associated with a more severe progressive relapsing disease phenotype (P < 0.001) in WT animals. These findings reveal previously unreported pathogenic interactions between CNS PAR2 expression and neuroinflammation with ensuing demyelination and axonal injury.

Evolving patient selection and clinical benefit criteria for sapropterin dihydrochloride (Kuvan®) treatment of PKU patients.

PURPOSE: To understand current patient selection, dosing, and response criteria used for sapropterin dihydrochloride (sapropterin, Kuvan®) to treat phenylketonuria (PKU). METHODS: Results of a 2010 survey of twenty-nine academic medical centers are reported to describe practice patterns in comparison to results of a survey done in 2008 and to what is reported in the literature. RESULTS/CONCLUSIONS: In addition to reduction in blood phenylalanine (Phe) levels, clinicians report using broader disease-management approaches when evaluating clinical benefit of sapropterin, including consideration of increased Phe tolerance and behavioral changes. Similar approaches are reported in the literature.

Association of 1,25-dihydroxyvitamin D levels with physical performance and thigh muscle cross-sectional area in chronic kidney disease stage 3 and 4.

BACKGROUND: Declines in 1,25-dihydroxyvitamin D (1,25(OH)2D) levels and physical functioning follow the course of chronic kidney disease (CKD). Although the molecular actions of vitamin D in skeletal muscle are well known, and muscle weakness and atrophy are observed in vitamin D-deficient states, there is little information regarding vitamin D and muscle function and size in CKD. OBJECTIVE: To examine associations of vitamin D with physical performance (PF) and muscle size. DESIGN: Cross-sectional. SETTING: CKD clinic. SUBJECTS: Twenty-six patients (61 ± 13 years, 92% men) with CKD stage 3 or 4. MAIN OUTCOME MEASURES: Gait speed, 6-minute walk, sit-to-stand time, 1-legged balance, and thigh muscle cross-sectional area (MCSA), measured by magnetic resonance imaging (MRI). RESULTS: Overall, 73% were 25-hydroxyvitamin D (25(OH)D) deficient (n = 10) or insufficient (n = 9) (Kidney Disease Outcomes Quality Initiative guidelines). 25(OH)D level was associated with normal gait speed only (r = 0.41, P = .04). Normal and fast gait speed, the distance walked in 6 minutes, and sit-to-stand time were best explained by 1,25(OH)2D and body mass index (P < .05 for all) and 1-legged stand by 1,25(OH)2D (r = 0.40, P < .05) only. There were no associations of age, estimated glomerular filtration rate (eGFR), intact parathyroid hormone (iPTH), or albumin with any PF measures. MCSA was associated with eGFR (r = 0.54, P < .01) only. Variance in MCSA was best explained by a model containing 1,25(OH)2D, plasma Ca²âº, and daily physical activity (by accelerometry) (P < .05 for all). Once these variables were in the model, there was no contribution of eGFR. CONCLUSION: These results suggest that 1,25(OH)2D is a determinant of PF and muscle size in patients with stage 3 and 4 CKD.