Background
The study aimed to investigate the physiology, psychophysics, pathology and their relationship in reversible nociceptive nerve degeneration, and the physiology of acute hyperalgesia.
...Methods
We enrolled 15 normal subjects to investigate intraepidermal nerve fibre (IENF) density, contact heat‐evoked potential (CHEP) and thermal thresholds during the capsaicin‐induced skin nerve degeneration–regeneration; and CHEP and thermal thresholds at capsaicin‐induced acute hyperalgesia.
Results
After 2‐week capsaicin treatment, IENF density of skin was markedly reduced with reduced amplitude and prolonged latency of CHEP, and increased warm and heat pain thresholds. The time courses of skin nerve regeneration and reversal of physiology and psychophysics were different: IENF density was still lower at 10 weeks after capsaicin treatment than that at baseline, whereas CHEP amplitude and warm threshold became normalized within 3 weeks after capsaicin treatment. Although CHEP amplitude and IENF density were best correlated in a multiple linear regression model, a one‐phase exponential association model showed better fit than a simple linear one, that is in the regeneration phase, the slope of the regression line between CHEP amplitude and IENF density was steeper in the subgroup with lower IENF densities than in the one with higher IENF densities. During capsaicin‐induced hyperalgesia, recordable rate of CHEP to 43 °C heat stimulation was higher with enhanced CHEP amplitude and pain perception compared to baseline.
Conclusions
There were differential restoration of IENF density, CHEP and thermal thresholds, and changed CHEP–IENF relationships during skin reinnervation. CHEP can be a physiological signature of acute hyperalgesia.
Significance
These observations suggested the relationship between nociceptive nerve terminals and brain responses to thermal stimuli changed during different degree of skin denervation, and CHEP to low‐intensity heat stimulus can reflect the physiology of hyperalgesia.
Gastric cancer is a heterogeneous disease with multiple environmental etiologies and alternative pathways of carcinogenesis. Beyond mutations in TP53, alterations in other genes or pathways account ...for only small subsets of the disease. We performed exome sequencing of 22 gastric cancer samples and identified previously unreported mutated genes and pathway alterations; in particular, we found genes involved in chromatin modification to be commonly mutated. A downstream validation study confirmed frequent inactivating mutations or protein deficiency of ARID1A, which encodes a member of the SWI-SNF chromatin remodeling family, in 83% of gastric cancers with microsatellite instability (MSI), 73% of those with Epstein-Barr virus (EBV) infection and 11% of those that were not infected with EBV and microsatellite stable (MSS). The mutation spectrum for ARID1A differs between molecular subtypes of gastric cancer, and mutation prevalence is negatively associated with mutations in TP53. Clinically, ARID1A alterations were associated with better prognosis in a stage-independent manner. These results reveal the genomic landscape, and highlight the importance of chromatin remodeling, in the molecular taxonomy of gastric cancer.
Piezoelectric biomaterials can generate piezoelectrical charges in response to mechanical activation. These generated charges can directly stimulate bone regeneration by triggering signaling pathway ...that is important for regulating osteogenesis of cells seeded on the materials. On the other hand, mechanical forces applied to the biomaterials play an important role in bone regeneration through the process called mechanotransduction. While mechanical force and electrical charges are both important contributing factors to bone tissue regeneration, they operate through different underlying mechanisms. The utilizations of piezoelectric biomaterials have been explored to serve as self-charged scaffolds which can promote stem cell differentiation and the formation of functional bone tissues. However, it is still not clear how mechanical activation and electrical charge act together on such a scaffold and which factors play more important role in the piezoelectric stimulation to induce osteogenesis. In our study, we found Poly(l-lactic acid) (PLLA)-based piezoelectric scaffolds with higher piezoelectric charges had a more pronounced osteoinductive effect than those with lower charges. This provided a new mechanistic insight that the observed osteoinductive effect of the piezoelectric PLLA scaffolds is likely due to the piezoelectric stimulation they provide, rather than mechanical stimulation alone. Our findings provide a crucial guide for the optimization of piezoelectric material design and usage.
Osteoarthritis affects millions of people worldwide but current treatments using analgesics or anti-inflammatory drugs only alleviate symptoms of this disease. Here, we present an injectable, ...biodegradable piezoelectric hydrogel, made of short electrospun poly-L-lactic acid nanofibers embedded inside a collagen matrix, which can be injected into the joints and self-produce localized electrical cues under ultrasound activation to drive cartilage healing. In vitro, data shows that the piezoelectric hydrogel with ultrasound can enhance cell migration and induce stem cells to secrete TGF-β1, which promotes chondrogenesis. In vivo, the rabbits with osteochondral critical-size defects receiving the ultrasound-activated piezoelectric hydrogel show increased subchondral bone formation, improved hyaline-cartilage structure, and good mechanical properties, close to healthy native cartilage. This piezoelectric hydrogel is not only useful for cartilage healing but also potentially applicable to other tissue regeneration, offering a significant impact on the field of regenerative tissue engineering.
Aims
Sensory nerve degeneration and consequent abnormal sensations are the earliest and most prevalent manifestations of familial amyloid polyneuropathy (FAP) due to amyloidogenic transthyretin ...(TTR). FAP is a relentlessly progressive degenerative disease of the peripheral nervous system. However, there is a lack of mouse models to replicate the early neuropathic manifestations of FAP.
Methods
We established human TTR knock‐in mice by replacing one allele of the mouse Ttr locus with human wild‐type TTR (hTTRwt) or human TTR with the A97S mutation (hTTRA97S). Given the late onset of neuropathic manifestations in A97S‐FAP, we investigated nerve pathology, physiology, and behavioural tests in these mice at two age points: the adult group (8 – 56 weeks) and the ageing group (> 104 weeks).
Results
In the adult group, nerve profiles, neurophysiology and behaviour were similar between hTTRwt and hTTRA97S mice. By contrast, ageing hTTRA97S mice showed small fibre neuropathy with decreased intraepidermal nerve fibre density and behavioural signs of mechanical allodynia. Furthermore, significant reductions in sural nerve myelinated nerve fibre density and sensory nerve action potential amplitudes in these mice indicated degeneration of large sensory fibres. The unaffected motor nerve physiology replicated the early symptoms of FAP patients, that is, sensory nerves were more vulnerable to mutant TTR than motor nerves.
Conclusions
These results demonstrate that the hTTRA97S mouse model develops sensory nerve pathology and corresponding physiology mimicking A97S‐FAP and provides a platform to develop new therapies for the early stage of A97S‐FAP.
Familial amyloid polyneuropathy (FAP) due to amyloidogenic transthyretin (TTR) is often associated with impairment of thermonociceptive functions. This study investigated skin innervation and its ...clinical significance in genetically defined FAP due to a hot-spot Ala97Ser TTR mutation (Ala97Ser).
Skin biopsies were performed on the distal leg of patients with Ala97Ser, and intraepidermal nerve fiber (IENF) densities were quantified.
There were 19 unrelated patients with Ala97Ser manifesting a late-onset (59.47 +/- 5.70 years) generalized neuropathy with disabling motor, sensory, and autonomic symptoms. Against a background of a slowly progressive course, 7 patients (36.8%) exhibited additional rapid declines in neurologic deficits, which were associated with elevation of the protein content in the CSF (p < 0.001). The IENF density was markedly reduced in Ala97Ser patients compared to age- and gender-matched controls (0.99 +/- 1.11 vs 8.31 +/- 2.87 fibers/mm, p < 0.001). Skin denervation was present in all patients and was lower in patients with a higher disability grade (0.17 +/- 0.26 vs 1.37 +/- 1.16 fibers/mm, p = 0.003). Albuminocytologic dissociation in the CSF was observed in 14 patients (73.7%), and the IENF density was negatively correlated with the CSF protein concentration (p = 0.015).
Skin denervation was common in Ala97Ser, and degeneration of cutaneous nerve terminals was correlated with the severity of clinical phenotypes and the level of CSF protein.
More than 32.5 million American adults suffer from osteoarthritis, and current treatments including pain medicines and anti-inflammatory drugs only alleviate symptoms but do not cure the disease. ...Here, we have demonstrated that a biodegradable piezoelectric poly(L-lactic acid) (PLLA) nanofiber scaffold under applied force or joint load could act as a battery-less electrical stimulator to promote chondrogenesis and cartilage regeneration. The PLLA scaffold under applied force or joint load generated a controllable piezoelectric charge, which promoted extracellular protein adsorption, facilitated cell migration or recruitment, induced endogenous TGF-β via calcium signaling pathway, and improved chondrogenesis and cartilage regeneration both in vitro and in vivo. Rabbits with critical-sized osteochondral defects receiving the piezoelectric scaffold and exercise treatment experienced hyaline-cartilage regeneration and completely healed cartilage with abundant chondrocytes and type II collagen after 1 to 2 months of exercise (2 to 3 months after surgery including 1 month of recovery before exercise), whereas rabbits treated with nonpiezoelectric scaffold and exercise treatment had unfilled defect and limited healing. The approach of combining biodegradable piezoelectric tissue scaffolds with controlled mechanical activation (via physical exercise) may therefore be useful for the treatment of osteoarthritis and is potentially applicable to regenerating other injured tissues.
Abstract
Mosaicism refers to the presence of two or more populations of genetically distinct cells within an individual, all of which originate from a single zygote. Previous literature estimated the ...percentage of parental mosaicism ranged from 0.33 to 25.9%. In this study, parents whose children had previously been diagnosed with developmental disorders with an apparent de novo variant were recruited. Peripheral blood, buccal and semen samples were collected from these parents if available for the detection of potential parental mosaicism using droplet digital PCR, complemented with the method of blocker displacement amplification. Among the 20 families being analyzed, we report four families with parental mosaicism (4/20, 20%). Two families have maternal gonosomal mosaicism (
EYA1
and
EBF3
) and one family has paternal gonadal mosaicism (
CHD7
) with a pathogenic/ likely pathogenic variant. One family has a paternal gonosomal mosaicism with a variant of uncertain significance (
FLNC
) with high clinical relevance. The detectable variant allele frequency in our cohort ranged from 8.7–35.9%, limit of detection 0.08–0.16% based on our in-house
EBF3
assay. Detecting parental mosaicism not only informs family with a more accurate recurrence risk, but also facilitates medical teams to create appropriate plans for pregnancy and delivery, offering the most suitable care.
•Regenerative engineering has been recently proposed to regenerate skeletal tissue.•Regenerative small molecules play a vital role in bone regenerative engineering.•Numerous small molecules have been ...recently discovered for bone regeneration.•Polymeric scaffolds play an important role to delivery small molecules in vivo.
Stimulation of bone regeneration using growth factors is a promising approach for musculoskeletal regenerative engineering. However, common limitations with protein growth factors, such as high manufacturing costs, protein instability, contamination issues, and unwanted immunogenic responses of the host reduce potential clinical applications. New strategies for bone regeneration that involve inexpensive and stable small molecules can obviate these problems and have a significant impact on the treatment of skeletal injury and diseases. Over the past decade, a large number of small molecules with the potential of regenerating skeletal tissue have been reported in the literature. Here, we review this literature, paying specific attention to the prospects for small molecule-based bone-regenerative engineering. We also review the preclinical study of small molecules associated with bone regeneration.
Plants perceive microbial invaders using pattern recognition receptors that recognize microbe-associated molecular patterns. In this study, we identified RESPONSIVENESS TO BOTRYTIS ...POLYGALACTURONASES1 (RBPG1), an Arabidopsis (Arabidopsis thaliana) leucine-rich repeat receptor-like protein, AtRLP42, that recognizes fungal endopolygalacturonases (PGs) and acts as a novel microbe-associated molecular pattern receptor. RBPG1 recognizes several PGs from the plant pathogen Botrytis cinerea as well as one from the saprotroph Aspergillus niger. Infiltration of B. cinerea PGs into Arabidopsis accession Columbia induced a necrotic response, whereas accession Brno (Br-0) showed no symptoms. A map-based cloning strategy, combined with comparative and functional genomics, led to the identification of the Columbia RBPG1 gene and showed that this gene is essential for the responsiveness of Arabidopsis to the PGs. Transformation of RBPG1 into accession Br-0 resulted in a gain of PG responsiveness. Transgenic Br-0 plants expressing RBPG1 were equally susceptible as the recipient Br-0 to the necrotroph B. cinerea and to the biotroph Hyaloperonospora arabidopsidis. Pretreating leaves of the transgenic plants with a PG resulted in increased resistance to H. arabidopsidis. Coimmunopredpitation experiments demonstrated that RBPG1 and PG form a complex in Nicotiana benthamiana, which also involves the Arabidopsis leucine-rich repeat receptor-like protein SOBIR1 (for SUPPRESSOR OF BIR1). sobirl mutant plants did not induce necrosis in response to PGs and were compromised in PG-induced resistance to H. arabidopsidis.
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