Orbital Kimura disease: maintenance therapy using mycophenolate mofetil.

Kimura disease (KD) is a rare, chronic, inflammatory condition, predominantly found in male patients of Asian ethnicity. It typically presents between 50-60 years of age and usually with bilateral disease. Angiolymphoid hyperplasia with eosinophilia (ALHE) remains the main differential diagnosis, although histological analysis is essential in differentiating from other similarly presenting pathologies. In this case, we present an atypical case of unilateral orbital KD in a middle-aged, Caucasian, male gentleman and no evidence of regional lymphadenopathy along with a literature review of orbital KD and the differential diagnoses, histological features and management modalities available, adding to the sparse literature on the topic. At present, no recognised diagnostic criteria for KD are available, with histopathological analysis through incisional or excisional biopsy being the primary diagnostic method. Complete surgical excision with or without corticosteroid management remains the most common treatment modality although management is shifting to steroid-sparing immunomodulatory therapy. To the best of our knowledge, this is the first case to describe maintenance therapy of KD using mycophenolate mofetil.

Assessment of a Digital Symptom Checker Tool's Accuracy in Suggesting Reproductive Health Conditions: Clinical Vignettes Study.

BACKGROUND: Reproductive health conditions such as endometriosis, uterine fibroids, and polycystic ovary syndrome (PCOS) affect a large proportion of women and people who menstruate worldwide. Prevalence estimates for these conditions range from 5% to 40% of women of reproductive age. Long diagnostic delays, up to 12 years, are common and contribute to health complications and increased health care costs. Symptom checker apps provide users with information and tools to better understand their symptoms and thus have the potential to reduce the time to diagnosis for reproductive health conditions. OBJECTIVE: This study aimed to evaluate the agreement between clinicians and 3 symptom checkers (developed by Flo Health UK Limited) in assessing symptoms of endometriosis, uterine fibroids, and PCOS using vignettes. We also aimed to present a robust example of vignette case creation, review, and classification in the context of predeployment testing and validation of digital health symptom checker tools. METHODS: Independent general practitioners were recruited to create clinical case vignettes of simulated users for the purpose of testing each condition symptom checker; vignettes created for each condition contained a mixture of condition-positive and condition-negative outcomes. A second panel of general practitioners then reviewed, approved, and modified (if necessary) each vignette. A third group of general practitioners reviewed each vignette case and designated a final classification. Vignettes were then entered into the symptom checkers by a fourth, different group of general practitioners. The outcomes of each symptom checker were then compared with the final classification of each vignette to produce accuracy metrics including percent agreement, sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: A total of 24 cases were created per condition. Overall, exact matches between the vignette general practitioner classification and the symptom checker outcome were 83% (n=20) for endometriosis, 83% (n=20) for uterine fibroids, and 88% (n=21) for PCOS. For each symptom checker, sensitivity was reported as 81.8% for endometriosis, 84.6% for uterine fibroids, and 100% for PCOS; specificity was reported as 84.6% for endometriosis, 81.8% for uterine fibroids, and 75% for PCOS; positive predictive value was reported as 81.8% for endometriosis, 84.6% for uterine fibroids, 80% for PCOS; and negative predictive value was reported as 84.6% for endometriosis, 81.8% for uterine fibroids, and 100% for PCOS. CONCLUSIONS: The single-condition symptom checkers have high levels of agreement with general practitioner classification for endometriosis, uterine fibroids, and PCOS. Given long delays in diagnosis for many reproductive health conditions, which lead to increased medical costs and potential health complications for individuals and health care providers, innovative health apps and symptom checkers hold the potential to improve care pathways.

A rare case of orbital inflammation complicated by hemophagocytic lymphohistiocytosis.

We report a rare case of orbital inflammation complicating hemophagocytic lymphohistiocytosis (HLH) patient. HLH is a rare, life-threatening disorder characterized by uncontrolled activation of cytotoxic T lymphocytes, natural killer cells, and macrophages. A 37-year-old man known to have HLH, presented with a left periorbital swelling that was unsuccessfully treated as an orbital cellulitis, with intravenous antibiotics. A computed tomography (CT) scan of the orbits revealed inflammatory changes with no orbital collection or paranasal sinus disease. An orbital biopsy demonstrated lymphoplasmacytic infiltrations admixed with histiocytes. The patient deteriorated and was admitted to the intensive care unit. Ensuing blood results supported a diagnosis of HLH, and the patient responded well to subsequent immunosuppression. This case report highlights the importance of re-considering the diagnosis of orbital cellulitis in treatment resistant cases, particularly in the absence of sinus disease. To our knowledge, this is the third case of orbital inflammation associated with HLH patients.

Lipoid proteinosis; a rare pathology, requiring multidisciplinary input.

A male patient in his early childhood presented to rheumatology with a hoarse voice and recurrent oral and cutaneous ulceration. Serological investigation revealed persistently elevated inflammatory markers. Despite compliance to treatment, flare-ups persisted, prompting the use of further treatment. An airway endoscopy revealed cystic changes to the left vocal cord. Referral to ophthalmology revealed multiple, waxy, skin-coloured, beaded papules on thickened, irregular eyelid margins with distichiasis, in keeping with moniliform blepharosis. Enrolment into the 100 000-genome project helped clinch the diagnosis of lipoid proteinosis. Although this case highlights the diagnostic power of genetics, it also sheds light on the importance of targeted clinical referral. When one considers the typical symptoms and signs of lipoid proteinosis, referral to a centre of rare diseases would have proven effective in not only avoiding polypharmacy but also reducing the psychological burden of several years of uncertainty must have had on our patient.

ChatGPT- versus human-generated answers to frequently asked questions about diabetes: A Turing test-inspired survey among employees of a Danish diabetes center.

Large language models have received enormous attention recently with some studies demonstrating their potential clinical value, despite not being trained specifically for this domain. We aimed to investigate whether ChatGPT, a language model optimized for dialogue, can answer frequently asked questions about diabetes. We conducted a closed e-survey among employees of a large Danish diabetes center. The study design was inspired by the Turing test and non-inferiority trials. Our survey included ten questions with two answers each. One of these was written by a human expert, while the other was generated by ChatGPT. Participants had the task to identify the ChatGPT-generated answer. Data was analyzed at the question-level using logistic regression with robust variance estimation with clustering at participant level. In secondary analyses, we investigated the effect of participant characteristics on the outcome. A 55% non-inferiority margin was pre-defined based on precision simulations and had been published as part of the study protocol before data collection began. Among 311 invited individuals, 183 participated in the survey (59% response rate). 64% had heard of ChatGPT before, and 19% had tried it. Overall, participants could identify ChatGPT-generated answers 59.5% (95% CI: 57.0, 62.0) of the time, which was outside of the non-inferiority zone. Among participant characteristics, previous ChatGPT use had the strongest association with the outcome (odds ratio: 1.52 (1.16, 2.00), p = 0.003). Previous users answered 67.4% (61.7, 72.7) of the questions correctly, versus non-users' 57.6% (54.9, 60.3). Participants could distinguish between ChatGPT-generated and human-written answers somewhat better than flipping a fair coin, which was against our initial hypothesis. Rigorously planned studies are needed to elucidate the risks and benefits of integrating such technologies in routine clinical practice.

Thinning rate over 24 months in ultrathin DSAEK.

AIM: To describe the changes in corneal graft thickness following ultrathin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK) comparing pre- and postoperative values over a 24-month period. METHODS: In this retrospective single-center case series, patients who received eye bank-prepared tissues for UT-DSAEK surgery were included. Preoperative and postoperative graft thickness measurements were determined in the eye bank and in clinic using anterior segment optical coherence tomography (AS-OCT) images. Graft thickness measurements and their percentage change between preoperative values and values at 1 day, 1 week and 1, 6, 12, 24 months were calculated. RESULTS: In total, 47 eyes of 47 patients with a mean age of 69 ± 11 years (29 males) were included. Twnty-three patients had Fuchs' endothelial dystrophy (49%) and the remaining 24 had pseudophakic bullous keratopathy (51%). In total, 29/47 eyes underwent UT-DSAEK alone (62%) and 18/47 received combined cataract surgery as a triple procedure (38%). Preoperative donor graft thickness was 92 ± 28 µm. Compared to preoperative values, where graft thickness increased to 194 ± 101.3 µm at 1 day, 151.1 ± 71.4 µm at 1 week, and 108.4 ± 52.5 µm at 1 month. Graft thickness continued to gradually decrease over time until 6 months (91.7 ± 33.6 µm), and then plateaued at 12 months (83.9 ± 25.0 µm), showing minimal changes at 2 years (101.4 ± 37.5 µm). CONCLUSION: Preoperative DSAEK graft thickness measurements as reported by the eye bank are a valid approximation of DSAEK graft thickness at 6 months after surgery and these measurements tend to stabilize over time up to 2 years after surgery.

Personalised Nutritional Recommendations Based on Individual Post-Prandial Glycaemic Responses Improve Glycaemic Metrics and PROMs in Patients with Type 2 Diabetes: A Real-World Assessment.

The recommended first-line therapy in type 2 diabetes (T2D) is lifestyle modification. In many patients, such interventions fail, and disease progresses inexorably to medication requirement. A potential reason for the failure of standard nutritional interventions is the use of generic dietary advice, with no personalisation to account for differences in the effect of food on blood glucose between different individuals. Another is the lack of instant feedback on the impact of dietary modification on glycaemic control, which supports sustained behaviour change. The use of continuous glucose monitoring (CGM) may help address both these shortcomings. We conducted an observational study to explore how personalised nutritional information impacts glycaemic control and patient-reported outcome measures (PROMs) of well-being. Free-living people with T2D eating their normal diet were provided with personalised nutritional recommendations by state-registered nutritionists based on the CGM-enabled analysis of individual post-prandial glycaemic responses (PPGRs). Participants demonstrated considerable inter-individual differences in PPGRs, reductions in post-prandial incremental area under the curve (iAUC) and daytime AUC, and improvements in energy levels, ability to concentrate, and other PROMs. These results suggest a role for personalised nutritional recommendations based on individual-level understanding of PPGRs in the non-pharmaceutical management of T2D.

Quality of condition suggestions and urgency advice provided by the Ada symptom assessment app evaluated with vignettes optimised for Australia.

When people face a health problem, they often first ask, 'Is there an app for that?'. We investigated the quality of advice provided by the Ada symptom assessment application to address the question, 'How do I know the app on my phone is safe and provides good advice?'. The app was tested with 48 independently created vignettes developed for a previous study, including 18 specifically developed for the Australian setting, using an independently developed methodology to evaluate the accuracy of condition suggestions and urgency advice. The correct condition was listed first in 65% of vignettes, and in the Top 3 results in 83% of vignettes. The urgency advice in the app exactly matched the gold standard 63% of vignettes. The app's accuracy of condition suggestion and urgency advice is higher than that of the best-performing symptom assessment app reported in a previous study (61%, 77% and 52% for conditions suggested in the Top 1, Top 3 and exactly matching urgency advice respectively). These results are relevant to the application of symptom assessment in primary and community health, where medical quality and safety should determine app choice.

Algorithm Change Protocols in the Regulation of Adaptive Machine Learning-Based Medical Devices.

One of the greatest strengths of artificial intelligence (AI) and machine learning (ML) approaches in health care is that their performance can be continually improved based on updates from automated learning from data. However, health care ML models are currently essentially regulated under provisions that were developed for an earlier age of slowly updated medical devices-requiring major documentation reshape and revalidation with every major update of the model generated by the ML algorithm. This creates minor problems for models that will be retrained and updated only occasionally, but major problems for models that will learn from data in real time or near real time. Regulators have announced action plans for fundamental changes in regulatory approaches. In this Viewpoint, we examine the current regulatory frameworks and developments in this domain. The status quo and recent developments are reviewed, and we argue that these innovative approaches to health care need matching innovative approaches to regulation and that these approaches will bring benefits for patients. International perspectives from the World Health Organization, and the Food and Drug Administration's proposed approach, based around oversight of tool developers' quality management systems and defined algorithm change protocols, offer a much-needed paradigm shift, and strive for a balanced approach to enabling rapid improvements in health care through AI innovation while simultaneously ensuring patient safety. The draft European Union (EU) regulatory framework indicates similar approaches, but no detail has yet been provided on how algorithm change protocols will be implemented in the EU. We argue that detail must be provided, and we describe how this could be done in a manner that would allow the full benefits of AI/ML-based innovation for EU patients and health care systems to be realized.

Rebubbling rate in preloaded versus surgeon prepared DSAEK.

PURPOSE: To compare the clinical outcomes of eye bank preloaded Descemet stripping automated endothelial keratoplasty (DSAEK) grafts and surgeon prepared. METHODS: In this retrospective study, the data were obtained from two groups (a) surgeon cut DSAEK where tissue was prepared by the surgeon immediately before surgery, and (b) preloaded DSAEK tissue shipped to the surgeon after preparation by the eye bank. Standard DSAEK preparations using Moria microkeratome with single pass method were performed. For the tissues prepared by the eye banks, they were preloaded in an iGlide device and shipped in transport media. Standard DSAEK surgery using bimanual pull-through technique was performed for all the grafts. Air was used as a tamponade. Main outcome measures included best corrected visual acuity (BCVA) and rebubbling rate. RESULT: Out of 107 eyes of 101 patients that underwent DSAEK surgery, 33 tissues were prepared by the surgeon (sc-DSAEK), while 74 were prepared by the eye bank (pl-DSAEK). sc-DSAEK showed a rebubbling rate of 9.1%, compared to the 16.2% for the preloaded DSAEK (p = 0.11). There was no statistical difference in postoperative BCVA between the two groups. Logistic regression analysis showed no association between detachment rate and cataract surgery, graft preparation method, graft diameter and reason for graft. CONCLUSION: Preloaded grafts have similar rebubbling rate and visual acuity achieved compared with surgeon prepared grafts.

Altered supraspinal motor networks in survivors of poliomyelitis: A cortico-muscular coherence study.

OBJECTIVE: Poliomyelitis results in changes to the anterior horn cell. The full extent of cortical network changes in the motor physiology of polio survivors has not been established. Our aim was to investigate how focal degeneration of the lower motor neurons (LMN) in infancy/childhood affects motor network connectivity in adult survivors of polio. METHODS: Surface electroencephalography (EEG) and electromyography (EMG) were recorded during an isometric pincer grip task in 25 patients and 11 healthy controls. Spectral signal analysis of cortico-muscular (EEG-EMG) coherence (CMC) was used to identify the cortical regions that are functionally synchronous and connected to the periphery during the pincer grip task. RESULTS: A pattern of CMC was noted in polio survivors that was not present in healthy individuals. Significant CMC in low gamma frequency bands (30-47 Hz) was observed in frontal and parietal regions. CONCLUSION: These findings imply a differential engagement of cortical networks in polio survivors that extends beyond the motor cortex and suggest a disease-related functional reorganisation of the cortical motor network. SIGNIFICANCE: This research has implications for other similar LMN conditions, including spinal muscular atrophy (SMA). CMC has potential in future clinical trials as a biomarker of altered function in motor networks in post-polio syndrome, SMA, and other related conditions.

Clinical outcomes of pre-loaded ultra-thin DSAEK and pre-loaded DMEK.

OBJECTIVE: To compare clinical outcomes and complications between pre-loaded ultra-thin Descemet stripping automated endothelialkeratoplasty (pl-UT-DSAEK) and pre-loaded Descemet membrane endothelial keratoplasty (pl-DMEK). METHODS AND ANALYSIS: Comparative study in patients with endothelial dysfunction associated with Fuchs endothelial corneal dystrophy and pseudophakic bullous keratopathy who underwent pl-UT-DSAEK or pl-DMEK transplants. For both groups, the tissues were pre-loaded at the Fondazione Banca degli Occhi del Veneto (Venice, Italy) and shipped to The Royal Liverpool University Hospital (Liverpool, UK). Best corrected visual acuity (BCVA) and re-bubbling rates were the main outcome measures. RESULTS: 56 eyes of 56 patients were included. 31 received pl-UT-DSAEK and 25 received pl-DMEK. At 12 months, BCVA (LogMAR) was significantly better for pl-DMEK (0.17±0.20 LogMAR) compared with pl-UT-DSAEK (0.37±0.37 LogMAR, p<0.01). The percentage of people that achieved ≥20/30 was significantly higher in the pl-DMEK group. The rate of re-bubbling, however, was significantly higher for pl-DMEK (44.0%) than for Pl-UT-DSAEK (12.9%), p<0.01. CONCLUSION: Pl-DMEK offers better BCVA than pl-UT-DSAEK. The higher re-bubbling rate associated with pre-loaded DMEK is of concern.

AI in Cardiac Imaging: A UK-Based Perspective on Addressing the Ethical, Social, and Political Challenges.

Imaging and cardiology are the healthcare domains which have seen the greatest number of FDA approvals for novel data-driven technologies, such as artificial intelligence, in recent years. The increasing use of such data-driven technologies in healthcare is presenting a series of important challenges to healthcare practitioners, policymakers, and patients. In this paper, we review ten ethical, social, and political challenges raised by these technologies. These range from relatively pragmatic concerns about data acquisition to potentially more abstract issues around how these technologies will impact the relationships between practitioners and their patients, and between healthcare providers themselves. We describe what is being done in the United Kingdom to identify the principles that should guide AI development for health applications, as well as more recent efforts to convert adherence to these principles into more practical policy. We also consider the approaches being taken by healthcare organizations and regulators in the European Union, the United States, and other countries. Finally, we discuss ways by which researchers and frontline clinicians, in cardiac imaging and more broadly, can ensure that these technologies are acceptable to their patients.

Leukemic blasts program bone marrow adipocytes to generate a protumoral microenvironment.

Despite currently available therapies, most patients diagnosed with acute myeloid leukemia (AML) die of their disease. Tumor-host interactions are critical for the survival and proliferation of cancer cells; accordingly, we hypothesize that specific targeting of the tumor microenvironment may constitute an alternative or additional strategy to conventional tumor-directed chemotherapy. Because adipocytes have been shown to promote breast and prostate cancer proliferation, and because the bone marrow adipose tissue accounts for up to 70% of bone marrow volume in adult humans, we examined the adipocyte-leukemia cell interactions to determine if they are essential for the growth and survival of AML. Using in vivo and in vitro models of AML, we show that bone marrow adipocytes from the tumor microenvironment support the survival and proliferation of malignant cells from patients with AML. We show that AML blasts alter metabolic processes in adipocytes to induce phosphorylation of hormone-sensitive lipase and consequently activate lipolysis, which then enables the transfer of fatty acids from adipocytes to AML blasts. In addition, we report that fatty acid binding protein-4 (FABP4) messenger RNA is upregulated in adipocytes and AML when in coculture. FABP4 inhibition using FABP4 short hairpin RNA knockdown or a small molecule inhibitor prevents AML proliferation on adipocytes. Moreover, knockdown of FABP4 increases survival in Hoxa9/Meis1-driven AML model. Finally, knockdown of carnitine palmitoyltransferase IA in an AML patient-derived xenograft model improves survival. Here, we report the first description of AML programming bone marrow adipocytes to generate a protumoral microenvironment.

Effect of tissue inhibitor of metalloproteinases 3 on DLK1 shedding in cultured human pre-adipocytes and implications for adipose tissue remodelling.

BACKGROUND: Metabolically unhealthy obesity is associated with adipose tissue inflammation and increased risk of type 2 diabetes. Dysfunctional adipose tissue remodelling has been implicated in development of metabolically unhealthy obesity, but the pathogenesis remains poorly characterised. We hypothesised that in health, tissue inhibitor of metalloproteinases 3 (TIMP3) modulates adipose tissue remodelling by regulating extracellular matrix turnover and shedding of the adipogenic regulator DLK1, but that in adipose tissue inflammation it might drive development of metabolically unhealthy obesity. METHODS: Primary pre-adipocyte and in-vitro-differentiated adipocyte cultures were established from abdominal subcutaneous adipose tissue donated by healthy women undergoing breast reconstruction. Cells were seeded onto collagen I, and subsequently treated with differentiation medium or tumour necrosis factor (TNF) alpha (50 ng/mL). Adenoviral transduction allowed TIMP3 overexpression. Media and lysates were collected for quantitative RT-PCR, and immunoblot and hydroxyproline release assays. Statistical analysis was performed with t testing or ANOVA. FINDINGS: Induction of differentiation in human pre-adipocytes reduced TIMP3 mRNA levels by 75% (n=3, p<0·0001). Hydroxyproline release by differentiating pre-adipocytes was 2·3 times greater than that by control-treated cells (mean 5·66 µg/mL [SD 0·77] vs 2·45 [0·36], p<0·0001) indicating greater collagen I degradation. TNF alpha reduced TIMP3 mRNA levels by 66% in in-vitro-differentiated adipocytes (n=3, p<0·0001); reduced TIMP3 expression was confirmed by western blot. Shedding of soluble DLK1 (sDLK1) by pre-adipocytes was increased by TNF alpha and by overexpression of adenovirally delivered TIMP3 compared with control conditions, as confirmed by immunoblot (n=3). Addition of recombinant human sDLK1 (500 pM) to pre-adipocyte cultures reduced adipogenesis, as assessed by oil red O staining (n=2). INTERPRETATION: We have shown that TIMP3 is downregulated in adipogenesis, and by inflammatory signals in adipocytes. Furthermore, TIMP3 modulates sDLK1 shedding and collagen I degradation. TIMP3 is known to inhibit ADAM17 (DLK1 sheddase) and MMP14 (implicated in extracellular matrix turnover). TIMP3 might therefore integrate inflammatory signals with adipose remodelling. Subversion of remodelling pathways by chronic adipose inflammation might lead to maladaptive adipose expansion and metabolically unhealthy obesity. FUNDING: British Heart Foundation, Diabetes Research and Wellness Foundation Open Funding 2011.

The role of metalloproteinases and their tissue inhibitors in adipose tissue remodelling and whole-body lipid distribution: a cross-sectional clinical study.

BACKGROUND: Metabolically unhealthy obesity is associated with insulin resistance. Dysfunctional adipose tissue remodelling might explain features of this disorder, such as chronic white adipose tissue inflammation, adipocyte hypertrophy, and ectopic lipid deposition. Metalloproteinases and their tissue inhibitors (TIMPs) have been implicated in human adipose tissue remodelling. In a cross-sectional study, we investigated the association of adipose metalloproteinase and TIMP expression with whole-body lipid distribution and insulin resistance. METHODS: Healthy women undergoing elective surgery donated fasting blood samples (for calculation of homoeostasis model assessment of insulin resistance [HOMA2-IR], the primary outcome). At operation 2 cm(3) biopsy samples of subcutaneous and visceral adipose tissue were obtained. 1 cm(3) was fixed, paraffin-embedded, and stained for adipocyte size quantification, and RNA was extracted from the remaining tissue for quantitative RT-PCR analysis. The women also underwent whole-body MRI for analysis of fat distribution. FINDINGS: 26 women were recruited (mean age 50·3 years, SD 13·1) into five body-mass index categories (18·5-24·9 kg/m(2) [n=12, 46·1%], 25-29·9 [n=6, 23·1%], 30-34·9 [n=3, 11·5%], 35-39·9 [n=3, 11·5%], >40 [n=2, 7·8%]). Mean fasting glucose was 5·29 mmol/L (SD 0·66), mean fasting insulin 71·29 pmol/L (47·72), and mean HOMA2-IR 1·35 (0·91). HOMA2-IR correlated with body-mass index (r=0·73, p<0·0001), subcutaneous and visceral adipose tissue volumes (r=0·94 and r=0·87, respectively; both p<0·0001), and hepatic fat fraction (r=0·57, p=0·013). Visceral adipose tissue MMP14 expression correlated strongly with hepatic fat fraction (r=0·944, p<0·0001), HOMA2-IR (r=0·74, p=0·01), and visceral adipose tissue volume (r=0·74, p=0·036). Subcutaneous adipose tissue TIMP3 expression correlated with subcutaneous adipocyte area (r=0·72, p=0·029), but not with HOMA2-IR (r=-0·53, p=0·062). INTERPRETATION: The results suggest that metalloproteinases and TIMPs regulate adipose tissue remodelling and distribution. MMP14 has been implicated in collagen turnover in pre-adipocyte differentiation, whereas TIMP3 may modulate the shedding of DLK1, a regulator of adipogenesis. In our concurrent in-vitro study, we have shown that human adipocytes express metalloproteinases and TIMPs, and that their expression varies with inflammatory stimulation. These proteins might therefore integrate inflammatory signals with dysregulated adipose remodelling in metabolically unhealthy obesity. FUNDING: British Heart Foundation, Diabetes Research & Wellness Foundation Open Funding 2011.

Non-viral gene therapy that targets motor neurons in vivo.

A major challenge in neurological gene therapy is safe delivery of transgenes to sufficient cell numbers from the circulation or periphery. This is particularly difficult for diseases involving spinal cord motor neurons such as amyotrophic lateral sclerosis (ALS). We have examined the feasibility of non-viral gene delivery to spinal motor neurons from intraperitoneal injections of plasmids carried by "immunogene" nanoparticles targeted for axonal retrograde transport using antibodies. PEGylated polyethylenimine (PEI-PEG12) as DNA carrier was conjugated to an antibody (MLR2) to the neurotrophin receptor p75 (p75NTR). We used a plasmid (pVIVO2) designed for in vivo gene delivery that produces minimal immune responses, has improved nuclear entry into post mitotic cells and also expresses green fluorescent protein (GFP). MLR2-PEI-PEG12 carried pVIVO2 and was specific for mouse motor neurons in mixed cultures containing astrocytes. While only 8% of motor neurons expressed GFP 72 h post transfection in vitro, when the immunogene was given intraperitonealy to neonatal C57BL/6J mice, GFP specific motor neuron expression was observed in 25.4% of lumbar, 18.3% of thoracic and 17.0% of cervical motor neurons, 72 h post transfection. PEI-PEG12 carrying pVIVO2 by itself did not transfect motor neurons in vivo, demonstrating the need for specificity via the p75NTR antibody MLR2. This is the first time that specific transfection of spinal motor neurons has been achieved from peripheral delivery of plasmid DNA as part of a non-viral gene delivery agent. These results stress the specificity and feasibility of immunogene delivery targeted for p75NTR expressing motor neurons, but suggests that further improvements are required to increase the transfection efficiency of motor neurons in vivo.

Transcriptional diversity during lineage commitment of human blood progenitors.

Blood cells derive from hematopoietic stem cells through stepwise fating events. To characterize gene expression programs driving lineage choice, we sequenced RNA from eight primary human hematopoietic progenitor populations representing the major myeloid commitment stages and the main lymphoid stage. We identified extensive cell type-specific expression changes: 6711 genes and 10,724 transcripts, enriched in non-protein-coding elements at early stages of differentiation. In addition, we found 7881 novel splice junctions and 2301 differentially used alternative splicing events, enriched in genes involved in regulatory processes. We demonstrated experimentally cell-specific isoform usage, identifying nuclear factor I/B (NFIB) as a regulator of megakaryocyte maturation-the platelet precursor. Our data highlight the complexity of fating events in closely related progenitor populations, the understanding of which is essential for the advancement of transplantation and regenerative medicine.