Stroke Recovery in Rats after 24-Hour-Delayed Intramuscular Neurotrophin-3 Infusion.

OBJECTIVE: Neurotrophin-3 (NT3) plays a key role in the development and function of locomotor circuits including descending serotonergic and corticospinal tract axons and afferents from muscle and skin. We have previously shown that gene therapy delivery of human NT3 into affected forelimb muscles improves sensorimotor recovery after stroke in adult and elderly rats. Here, to move toward the clinic, we tested the hypothesis that intramuscular infusion of NT3 protein could improve sensorimotor recovery after stroke. METHODS: Rats received unilateral ischemic stroke in sensorimotor cortex. To simulate a clinically feasible time to treatment, 24 hours later rats were randomized to receive NT3 or vehicle by infusion into affected triceps brachii for 4 weeks using implanted catheters and minipumps. RESULTS: Radiolabeled NT3 crossed from the bloodstream into the brain and spinal cord in rodents with or without strokes. NT3 increased the accuracy of forelimb placement during walking on a horizontal ladder and increased use of the affected arm for lateral support during rearing. NT3 also reversed sensory impairment of the affected wrist. Functional magnetic resonance imaging during stimulation of the affected wrist showed spontaneous recovery of peri-infarct blood oxygenation level-dependent signal that NT3 did not further enhance. Rather, NT3 induced neuroplasticity of the spared corticospinal and serotonergic pathways. INTERPRETATION: Our results show that delayed, peripheral infusion of NT3 can improve sensorimotor function after ischemic stroke. Phase I and II clinical trials of NT3 (for constipation and neuropathy) have shown that peripheral high doses are safe and well tolerated, which paves the way for NT3 as a therapy for stroke. ANN NEUROL 2019;85:32-46.

Staging FDG PET-CT changes management in patients with gastric adenocarcinoma who are eligible for radical treatment.

AIM: 18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is valuable in the management of patients with oesophageal cancer, but a role in gastric cancer staging is debated. Our aim was to review the role of FDG PET-CT in a large gastric cancer cohort in a tertiary UK centre. METHODS: We retrospectively reviewed data from 330 patients presenting with gastric adenocarcinoma between March 2014 and December 2016 of whom 105 underwent pre-treatment staging FDG PET-CT scans. FDG PET-CT scans were graded qualitatively and quantitatively (SUVmax) and compared with staging diagnostic CT and operative pathology results (n = 30) in those undergoing resection. RESULTS: Of the 105 patients (74 M, median age 73 years) 86% of primary tumours were metabolically active (uptake greater than normal stomach) on FDG PET-CT [41/44 (93%) of the intestinal histological subtype (SUVmax 14.1 ± 1.3) compared to 36/46 (78%) of non-intestinal types (SUVmax 9.0 ± 0.9), p = 0.005]. FDG PET-CT upstaged nodal or metastastic staging of 20 patients (19%; 13 intestinal, 6 non-intestinal, 1 not reported), with 17 showing distant metastases not evident on other imaging. On histological analysis, available in 30 patients, FDG PET-CT showed low sensitivity (40%) but higher specificity (73%) for nodal involvement. CONCLUSION: FDG PET-CT provides new information in a clinically useful proportion of patients, which leads to changes in treatment strategy, most frequently by detecting previously unidentified metastases, particularly in those with intestinal-type tumours.

Large-scale chondroitin sulfate proteoglycan digestion with chondroitinase gene therapy leads to reduced pathology and modulates macrophage phenotype following spinal cord contusion injury.

Chondroitin sulfate proteoglycans (CSPGs) inhibit repair following spinal cord injury. Here we use mammalian-compatible engineered chondroitinase ABC (ChABC) delivered via lentiviral vector (LV-ChABC) to explore the consequences of large-scale CSPG digestion for spinal cord repair. We demonstrate significantly reduced secondary injury pathology in adult rats following spinal contusion injury and LV-ChABC treatment, with reduced cavitation and enhanced preservation of spinal neurons and axons at 12 weeks postinjury, compared with control (LV-GFP)-treated animals. To understand these neuroprotective effects, we investigated early inflammatory changes following LV-ChABC treatment. Increased expression of the phagocytic macrophage marker CD68 at 3 d postinjury was followed by increased CD206 expression at 2 weeks, indicating that large-scale CSPG digestion can alter macrophage phenotype to favor alternatively activated M2 macrophages. Accordingly, ChABC treatment in vitro induced a significant increase in CD206 expression in unpolarized monocytes stimulated with conditioned medium from spinal-injured tissue explants. LV-ChABC also promoted the remodelling of specific CSPGs as well as enhanced vascularity, which was closely associated with CD206-positive macrophages. Neuroprotective effects of LV-ChABC corresponded with improved sensorimotor function, evident as early as 1 week postinjury, a time point when increased neuronal survival correlated with reduced apoptosis. Improved function was maintained into chronic injury stages, where improved axonal conduction and increased serotonergic innervation were also observed. Thus, we demonstrate that ChABC gene therapy can modulate secondary injury processes, with neuroprotective effects that lead to long-term improved functional outcome and reveal novel mechanistic evidence that modulation of macrophage phenotype may underlie these effects.

Amyloid precursor protein (APP) contributes to pathology in the SOD1(G93A) mouse model of amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS), the progressive loss of motor neurons is accompanied by extensive muscle denervation, resulting in paralysis and ultimately death. Upregulation of amyloid beta (A4) precursor protein (APP) in muscle fibres coincides with symptom onset in both sporadic ALS patients and the SOD1(G93A) mouse model of familial ALS. We have further characterized this response in SOD1(G93A) mice and also revealed elevated levels of ß-amyloid (Aß) peptides in the SOD1(G93A) spinal cord, which were predominantly localized within motor neurons and their surrounding glial cells. We therefore examined the effect of genetic ablation of APP on disease progression in SOD1(G93A) mice, which significantly improved multiple disease parameters, including innervation, motor function, muscle contractile characteristics, motor unit and motor neuron survival. These results therefore strongly suggest that APP actively contributes to SOD1(G93A)-mediated pathology. Together with observations from ALS cases, this study indicates that APP may contribute to human ALS pathology.

Bariatric Surgery as a Bridge to Facilitate Renal Transplantation in Patients with End-Stage Renal Disease.

PURPOSE: Renal transplantation (RT) is not recommended above BMI 40 kg/m2 as post-operative risks (delayed graft function, wound complications) are increased. Bariatric surgery (BS) results in sustained long-term weight loss. However, renal failure (RF) patients are theoretically higher risk candidates. We aim to investigate the safety of BS in patients with RF and the effect of BS on access to renal transplantation. METHODS: We reviewed data from 31 patients with RF referred for BS between 2013 and 2021. We compared the outcomes of patients with RF who underwent BS to those who were referred but did not undergo BS. Controls matched for age/BMI/comorbidity (MC) but without RF were used for comparison. RESULTS: Of 31 patients referred, 19 proceeded with BS (68% female, median age 52 years, BMI 46.2 ± 4.9 kg/m2) and 12 did not (58% female, median age 58, mean BMI 41.5 ± 4.1). Excess body weight loss (EBWL) was 71.2% ± 20.2% at 2 years in RF patients versus 66.0% ± 28.0% in MC patients. In the operated group, 11/19 (58%) patients reached their treatment target (six transplanted, five placed on waiting list) versus 3/12 (25%) in unoperated patients (three transplanted). There was no difference in perioperative complications between RF and MC groups. Long-term, there were seven deaths amongst RF patients (two operated, five unoperated), none amongst the MC group. CONCLUSION: BS in patients with RF increased access to RT and was safe and effective. We therefore recommend consideration of BS in patients with obesity and RF in specialised units.

Current margin practice and effect on re-excision rates following the publication of the SSO-ASTRO consensus and ABS consensus guidelines: a national prospective study of 2858 women undergoing breast-conserving therapy in the UK and Ireland.

INTRODUCTION: There is variation in margin policy for breast conserving therapy (BCT) in the UK and Ireland. In response to the Society of Surgical Oncology and American Society for Radiation Oncology (SSO-ASTRO) margin consensus ('no ink on tumour' for invasive and 2 mm for ductal carcinoma in situ [DCIS]) and the Association of Breast Surgery (ABS) consensus (1 mm for invasive and DCIS), we report on current margin practice and unit infrastructure in the UK and Ireland and describe how these factors impact on re-excision rates. METHODS: A trainee collaborative-led multicentre prospective study was conducted in the UK and Ireland between 1st February and 31st May 2016. Data were collected on consecutive BCT patients and on local infrastructure and policies. RESULTS: A total of 79 sites participated in the data collection (75% screening units; average 372 cancers annually, range 70-900). For DCIS, 53.2% of units accept 1 mm and 38% accept 2-mm margins. For invasive disease 77.2% accept 1 mm and 13.9% accept 'no ink on tumour'. A total of 2858 patients underwent BCT with a mean re-excision rate of 17.2% across units (range 0-41%). The re-excision rate would be reduced to 15% if all units applied SSO-ASTRO guidelines and to 14.8% if all units followed ABS guidelines. Of those who required re-operation, 65% had disease present at margin. CONCLUSION: There continues to be large variation in margin policy and re-excision rates across units. Altering margin policies to follow either SSO-ASTRO or ABS guidelines would result in a modest reduction in the national re-excision rate. Most re-excisions are for involved margins rather than close margins.

Chondroitinase ABC promotes plasticity of spinal reflexes following peripheral nerve injury.

Peripheral nerve transection, even with optimal repair, can result in an extensive disruption of central connectivity, which can lead to long-lasting impairments in motor and sensory function. We hypothesised that removal of spinal cord chondroitin sulphate proteoglycans (CSPGs) would promote plasticity in the spinal cord, allowing compensation for inaccurate peripheral reinnervation. In adult rats, the median and radial nerves were cut and repaired, either correctly (median to median and radial to radial), or incorrectly (median to radial and vice versa). This produced two levels of inaccuracy of peripheral reinnervation. Whole nerve recordings from a third brachial plexus nerve, the ulnar, were made during median or radial nerve stimulation. Low and high threshold reflexes were characterised in uninjured animals and a clear difference in the pattern of ulnar response to flexor (median) or extensor (radial) stimulation was established. This included the phenomenon of wind-up, where repetitive median nerve stimulation at supramaximal C-fibre threshold leads to a progressive increase in the number of spikes recorded. To achieve digestion of CSPGs a lentiviral vector expressing ChABC was delivered to the spinal cord via intraspinal injection. Following ChABC treatment, we found several indicators of reorganisation of central connections. Firstly, we found that the amplitude of a low threshold, polysynaptic reflex could be increased after nerve injury, only following treatment with ChABC. Secondly, wind-up of motor responses in the ulnar nerve to supramaximal stimulation of afferents in the median nerve, which collapses after nerve injury (to ~25% of uninjured value), could be restored by ChABC after correct repair (to ~90% of uninjured value). Thirdly, wind-up in ulnar motor axons to stimulation of radial nerve afferents, which is minimal in the uninjured state, becomes significantly stronger after nerve injury and ChABC treatment (a 10 fold increase). We propose that application of a plasticity-promoting treatment to the spinal cord allows the amplification of adaptive changes in response to inaccurate wiring in the periphery.