Combined GWAS and single cell transcriptomics uncover the underlying genes and cell types in disorders of gut-brain interaction.

Disorders of gut-brain interaction (DGBIs), formerly known as functional gastrointestinal disorders, are extremely common and historically difficult to manage. This is largely because their cellular and molecular mechanisms have remained poorly understood and understudied. One approach to unravel the molecular underpinnings of complex disorders such as DGBIs is performing genome wide association studies (GWASs). However, due to the heterogenous and non-specific nature of GI symptoms, it has been difficult to accurately classify cases and controls. Thus, to perform reliable studies, we need to access large patient populations which has been difficult to date. Here, we leveraged the UK Biobank (UKBB) database, containing genetic and medical record data of over half a million individuals, to perform GWAS for five DGBI categories: functional chest pain, functional diarrhea, functional dyspepsia, functional dysphagia, and functional fecal incontinence. By applying strict inclusion and exclusion criteria, we resolved patient populations and identified genes significantly associated with each condition. Leveraging multiple human single-cell RNA-sequencing datasets, we found that the disease associated genes were highly expressed in enteric neurons, which innervate and control GI functions. Further expression and association testing-based analyses revealed specific enteric neuron subtypes consistently linked with each DGBI. Furthermore, protein-protein interaction analysis of each of the disease associated genes revealed protein networks specific to each DGBI, including hedgehog signaling for functional chest pain and neuronal function and neurotransmission for functional diarrhea and functional dyspepsia. Finally, through retrospective medical record analysis we found that drugs that inhibit these networks are associated with an increased disease risk, including serine/threonine kinase 32B drugs for functional chest pain, solute carrier organic anion transporter family member 4C1, mitogen-activated protein kinase 6, and dual serine/threonine and tyrosine protein kinase drugs for functional dyspepsia, and serotonin transporter drugs for functional diarrhea. This study presents a robust strategy for uncovering the tissues, cell types, and genes involved in DGBIs, presenting novel predictions of the mechanisms underlying these historically intractable and poorly understood diseases.

Deriving Schwann cells from hPSCs enables disease modeling and drug discovery for diabetic peripheral neuropathy.

Schwann cells (SCs) are the primary glia of the peripheral nervous system. SCs are involved in many debilitating disorders, including diabetic peripheral neuropathy (DPN). Here, we present a strategy for deriving SCs from human pluripotent stem cells (hPSCs) that enables comprehensive studies of SC development, physiology, and disease. hPSC-derived SCs recapitulate the molecular features of primary SCs and are capable of in vitro and in vivo myelination. We established a model of DPN that revealed the selective vulnerability of SCs to high glucose. We performed a high-throughput screen and found that an antidepressant drug, bupropion, counteracts glucotoxicity in SCs. Treatment of hyperglycemic mice with bupropion prevents their sensory dysfunction, SC death, and myelin damage. Further, our retrospective analysis of health records revealed that bupropion treatment is associated with a lower incidence of neuropathy among diabetic patients. These results highlight the power of this approach for identifying therapeutic candidates for DPN.

From Bilateral Periorbital Necrotic Wound to Fungal Brain Abscess: A Complicated Case of COVID-19-Associated Mucormycosis.

COVID-19-associated mucormycosis (CAM) is categorized as rhinocerebral-orbital (RCOM), pulmonary, gastrointestinal, cutaneous, and disseminated mucormycosis. An alarming surge in morbidity and mortality attributed to mucormycosis concurrent with coronavirus disease 2019 (COVID-19) has emerged as a cause for concern during the current outbreak of COVID-19. The global incidence of CAM has been attributed to environmental, host, and iatrogenic factors. Further, Mucorales interacting with epithelial cells followed by endothelium invasion are pivotal in developing mucormycosis in patients with COVID-19. In essence, CAM is an emerging condition that requires increased vigilance in all COVID-19 patients, including those who have recovered. In this case report, we describe a rare case of CAM in a 33-year-old immunocompetent man who developed bilateral periocular pain and a small area of cutaneous necrosis in both medial canthi associated with impaired vision, which progressed into a fungal brain abscess formation in the post-COVID period. Furthermore, this case aims to illustrate the potential underlying risk factors of CAM other than known risk factors, especially in immunocompetent individuals.

Recent Advances on Cell-Based Co-Culture Strategies for Prevascularization in Tissue Engineering.

Currently, the fabrication of a functional vascular network to maintain the viability of engineered tissues is a major bottleneck in the way of developing a more advanced engineered construct. Inspired by vasculogenesis during the embryonic period, the in vitro prevascularization strategies have focused on optimizing communications and interactions of cells, biomaterial and culture conditions to develop a capillary-like network to tackle the aforementioned issue. Many of these studies employ a combination of endothelial lineage cells and supporting cells such as mesenchymal stem cells, fibroblasts, and perivascular cells to create a lumenized endothelial network. These supporting cells are necessary for the stabilization of the newly developed endothelial network. Moreover, to optimize endothelial network development without impairing biomechanical properties of scaffolds or differentiation of target tissue cells, several other factors, including target tissue, endothelial cell origins, the choice of supporting cell, culture condition, incorporated pro-angiogenic factors, and choice of biomaterial must be taken into account. The prevascularization method can also influence the endothelial lineage cell/supporting cell co-culture system to vascularize the bioengineered constructs. This review aims to investigate the recent advances on standard cells used in in vitro prevascularization methods, their co-culture systems, and conditions in which they form an organized and functional vascular network.

Developing a pro-angiogenic placenta derived amniochorionic scaffold with two exposed basement membranes as substrates for cultivating endothelial cells.

Decellularized and de-epithelialized placenta membranes have widely been used as scaffolds and grafts in tissue engineering and regenerative medicine. Exceptional pro-angiogenic and biomechanical properties and low immunogenicity have made the amniochorionic membrane a unique substrate which provides an enriched niche for cellular growth. Herein, an optimized combination of enzymatic solutions (based on streptokinase) with mechanical scrapping is used to remove the amniotic epithelium and chorion trophoblastic layer, which resulted in exposing the basement membranes of both sides without their separation and subsequent damages to the in-between spongy layer. Biomechanical and biodegradability properties, endothelial proliferation capacity, and in vivo pro-angiogenic capabilities of the substrate were also evaluated. Histological staining, immunohistochemistry (IHC) staining for collagen IV, and scanning electron microscope demonstrated that the underlying amniotic and chorionic basement membranes remained intact while the epithelial and trophoblastic layers were entirely removed without considerable damage to basement membranes. The biomechanical evaluation showed that the scaffold is suturable. Proliferation assay, real-time polymerase chain reaction for endothelial adhesion molecules, and IHC demonstrated that both side basement membranes could support the growth of endothelial cells without altering endothelial characteristics. The dorsal skinfold chamber animal model indicated that both side basement membranes could promote angiogenesis. This bi-sided substrate with two exposed surfaces for cultivating various cells would have potential applications in the skin, cardiac, vascularized composite allografts, and microvascular tissue engineering.

Iliac Pedicle Wedge Graft as a New Modification for Iliac Osteotomies in Young Adolescents: A Single-blind Randomized Clinical Trial.

BACKGROUND: Iliac osteotomies in adolescent patients may accompany graft related difficulties such as graft absorption and delayed union. A new modification of iliac osteotomies has been proposed to address these difficulties. METHODS: A total of 24 consecutive hip joints in 21 juvenile or adolescent patients who were candidate for salter or triple pelvic osteotomy were included. A modification was performed to harvest a wedged bone graft based on a muscle pedicle of Tensor Fascia Lata and inserted at pelvic osteotomy site instead of a traditional graft technique. The hips were randomized into two groups. The traditional wedge graft was used in group 1, while the new modification was performed in group 2. The primary outcome of this study was duration of union. The secondary outcomes were Center Edge Angle (CE) Angle on pre-operation, immediately post-operation and at the end of follow-up. RESULTS: Both groups were similar statistically regarding their age, gender , estimated blood loss and the duration of follow-up. However, significant differences were found in the time to complete union between the two groups (P=0.03). CE angle decreased in both groups when comparing its last follow-up to its right postoperative values, but the decrease was significant only in group 1(P=0.03). The type of surgery (Salter or TPO) had no significant effect on the average time to union. That shows faster union in pedicle graft group and less coverage loss during follow-up period than conventional graft patients. CONCLUSION: With the modification proposed , the healing at the osteotomy site was faster and the loss of correction, owing to the graft resorption, decreased. Using this pedicle wedge graft technique may improve the results of pelvic osteotomies in adolescent.

Autonomic dysfunction and white matter microstructural changes in drug-naïve patients with Parkinson's disease.

BACKGROUND: Autonomic dysfunction (AD) is one of the non-motor features of Parkinson's disease (PD). Some symptoms tend to occur in the early stages of PD. AD also has a great impact on patient's quality of life. In this study, we aimed to discover the association between AD (Scales for Outcomes in Parkinson's disease-Autonomic, SCOPA-AUT) and microstructural changes in white matter tracts in drug-naïve early PD patients to elucidate the central effects of autonomic nervous system impairments. METHOD: In total, this study included 85 subjects with PD recruited from the Parkinson's Progression Markers Initiative (PPMI) database. Among the 85 PD patients, 38 were in Hoehn & Yahr stage 1 (HY1PD) and 47 were in stage 2 (HY2PD). Diffusion magnetic resonance imaging (DMRI) data were reconstructed in the MNI space using q-space diffeomorphic reconstruction to obtain the spin distribution function. The spin distribution function (SDF) values were used in DMRI connectometry analysis. We investigated through diffusion MRI connectometry the structural correlates of white matter tracts with SCOPA-AUT subscores and total score. RESULTS: Connectometry analysis also revealed positive association with white matter density in bilateral corticospinal tract in HY1PD patients and negative association in genu of corpus callosum (CC) and, bilateral cingulum in both groups. In addition, there were associations between gastrointestinal, sexual, thermoregulatory and urinary items and structural brain connectivity in PD. CONCLUSION: Our study reveals positive correlation, suggesting neural compensations in early PD. Cingulum and CC tracts have well-known roles in PD pathology, compatible with our findings that bring new insights to specific areas of AD and its role in central nervous system (CNS) neurodegeneration, paving the way for using prodromal makers in the diagnosis and treatment of PD.

Evaluation of early postoperative ocular pain after photorefractive keratectomy and corneal crosslinking.

PURPOSE: To evaluate and compare early postoperative pain after photorefractive keratectomy (PRK) and corneal crosslinking (CXL). SETTING: Khatam-al-Anbia Eye Hospital, Mashhad, Iran. DESIGN: Prospective case series. METHODS: The PRK group included patients with simple refractive errors whereas the CXL group included patients with clinical keratoconus. The groups were compared regarding the level of pain based on the visual analogue scale (VAS), verbal rating scale (VRS), and Wong-Baker FACES pain rating scale immediately after surgery, 6 hours postoperatively, and 1, 3, and 7 days postoperatively. The epithelial defect size was measured at 6 hours after surgery and 1 day and 3 days after surgery in both groups. RESULTS: The study comprised 68 patients (34 patients in the PRK group and 34 patients in the CXL group). The epithelial defect size was significantly smaller in the CXL group than in the PRK group (P < .001); however, the amount of pain was significantly higher after CXL than after PRK based on VAS and VRS (P = .04 and P = .019, respectively). In the FACES scaling system, the pain score was also higher in the CXL group than in the PRK group. However, the difference was not statistically significant. No intraoperative or postoperative complications were observed during follow-up. CONCLUSIONS: The epithelial defect healing rate was statistically significantly faster in the CXL group than in the PRK group. However, the level of pain was greater in the CXL group, suggesting that postsurgical pain might be influenced by other factors than the epithelial defect.

Foot scan assessment of metatarsus adductus: A useful adjunct to Bleck's classification.

To determine the severity of metatarsus adductus (MA) comparing with Bleck's classification as a commonly acceptable method for assessing MA, static foot scan has been used. In this cross-sectional descriptive research study, 100 subjects were equally divided into four groups according to Bleck's classification. The feet were scanned and MA severity (MAS) index was measured on the obtained foot scan images. The MAS index was the ratio of the transverse deviation of the forefoot from the lateral border heel line to the width of the ball of the foot. The mean of the MAS index in normal, mild, moderate, and severe MA was 0.02±0.02, 0.1±0.01, 0.159±0.03, and 0.216±0.025, respectively. The difference of MAS index between each group was significant (p<0.001). The mean of MAS index in 4 groups was consistent with Bleck's classification, with a significant increase from normal to severe MA (p<0.05). Since the results of this method are consistent with Bleck's classification and this novel foot scan assessment appears to be more objective than Bleck's classification, the authors recommend this method to be used in examination of patients with MA. However, further studies should be conducted to define interobserver and intraobserver reliability. LEVEL OF EVIDENCE: III.

Inhibition of GABA A receptor improved spatial memory impairment in the local model of demyelination in rat hippocampus.

Cognitive impairment and memory deficit are common features in multiple Sclerosis patients. The mechanism of memory impairment in MS is unknown, but neuroimaging studies suggest that hippocampal demyelination is involved. Here, we investigate the role of GABA A receptor on spatial memory in the local model of hippocampal demyelination. Demyelination was induced in male Wistar rats by bilaterally injection of lysophosphatidylcholine (LPC) 1% into the CA1 region of the hippocampus. The treatment groups were received daily intraventricular injection of bicuculline (0.025, 0.05µg/2µl/animal) or muscimol (0.1, 0.2µg/2µl/animal) 5days after LPC injection. Morris Water Maze was used to evaluate learning and memory in rats. We used Luxol fast blue staining and qPCR to assess demyelination extention and MBP expression level respectively. Immunohistochemistry (IHC) for CD45 and H&E staining were performed to assess inflammatory cells infiltration. Behavioral study revealed that LPC injection in the hippocampus impaired learning and memory function. Animals treated with both doses of bicuculline improved spatial learning and memory function; however, muscimol treatment had no effect. Histological and MBP expression studies confirmed that demylination in LPC group was maximal. Bicuculline treatment significantly reduced demyelination extension and increased the level of MBP expression. H&E and IHC results showed that bicuculline reduced inflammatory cell infiltration in the lesion site. Bicuculline improved learning and memory and decreased demyelination extention in the LPC-induced hippocampal demyelination model. We conclude that disruption of GABAergic homeostasis in hippocampal demyelination context may be involved in memory impairment with the implications for both pathophysiology and therapy.