Journal of the Peripheral Nervous System最新文献

Background and aims: Small-fibre neuropathy (SFN) is associated with glucose dysregulation, including impaired glucose tolerance (IGT) and type 2 diabetes (T2D). Corneal confocal microscopy (CCM) offers a non-invasive tool to assess corneal nerve damage and dendritic cell density (DCD). In this study, we investigated corneal DCD in patients with SFN and glucose dysregulation, defined as IGT or T2D.

Methods: We enrolled 38 patients with SFN + glucose dysregulation, 51 with SFN + non-glucose dysregulation and 20 healthy controls. All participants underwent neurological examination, neurophysiology and CCM.

Results: Individuals with SFN and glucose dysregulation had higher DCD compared with healthy controls (p = .01), and mature DCD was higher in IGT SFN patients than in T2D patients.

Interpretation: Higher DCD in IGT compared with controls and patients with established T2D may suggest that DCD is a biomarker of early neuropathy.

Background and aims: Hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIG) consists of subcutaneous human immunoglobulin G (IgG) 10% with recombinant human hyaluronidase (rHuPH20) and can be administered at the same dose and interval as intravenous IgG (IVIG). fSCIG recently received US approval as maintenance therapy for adults with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and European approval for adults and children with CIDP after stabilization with IVIG.

Methods: ADVANCE-CIDP 3 (NCT02955355) was an open-label long-term extension of the Phase 3 double-blind randomized placebo-controlled ADVANCE-CIDP 1 study (NCT02549170) that examined fSCIG safety and efficacy as maintenance CIDP therapy. Primary outcomes were safety, tolerability, and immunogenicity. Efficacy was an exploratory outcome.

Results: The study provided 220 patient-years of follow-up data from 85 patients. Median (range) exposure was 33 (0-77) months. Patients received fSCIG every 4 weeks (88.2%) or every 3 weeks (11.8%). Median (range) 4-weekly IgG dose equivalent was 64.0 (28.0-200.0) g. Mean (standard deviation) infusion duration was 135.5 (62.8) minutes. Most adverse events (AEs) were mild or moderate and self-limiting. Of the 1406 AEs, only 48 were severe and 30 were serious. fSCIG-related AEs (n = 798) included infusion site reactions such as pain, redness, and pruritus. Three infusions (0.1%) were reduced in rate, interrupted, or stopped due to intolerability. Relapse occurred in 10 of 77 patients (13.0%); annual relapse rate was 4.5%. An anti-rHuPH20 antibody titer ≥1:160 was detected in 14 of 84 patients (16.7%); patients who tested positive (≥1:160) had similar relapse rates versus those who tested negative (16.7% vs. 12.3%, respectively).

Interpretation: ADVANCE-CIDP 3 demonstrated favorable fSCIG long-term safety and tolerability consistent with its established safety profile, and a low relapse rate, supporting use as maintenance CIDP treatment.

Background and aims: Charcot-Marie-Tooth (CMT) type 1 neuropathies are the most common inherited diseases of the peripheral nervous system. Although more than 100 causative genes have been identified so far, therapeutic options are still missing. We could previously identify that early-onset physical exercise (voluntary wheel running, VWR) dampens peripheral nerve inflammation, improves neuropathological alterations, and clinical outcome in Cx32def mice, a model for CMT1X. We here investigate the clinical and histopathological effect of late-onset exercise in Cx32def mice at an advanced disease stage.

Methods: Nine-month-old Cx32def mice were allowed to run for 4 days/week on a commercially available running wheel for 3 months, with timely limited access to running wheels, representing a running distance of ~2000 m. Control mutants had no access to running wheels. Afterward, mice were investigated by distinct functional tests and by immunohistochemical and electron microscopical techniques.

Results: We found that late-onset physical exercise (late VWR^lim) prevented the robust functional decline in 12-month-old Cx32def mice. This was accompanied by improved neuromuscular innervation of distal muscles and axonal preservation in femoral quadriceps nerves. In contrast to a "pre-symptomatic" start of physical exercise in Cx32def mice, late-onset VWR did not alter nerve inflammation and myelin thickness at 12 months of age.

Interpretation: We conclude that VWR has robust beneficial effects on nerve function in Cx32def mice, even when applied at a progressed disease stage. These results have important translational implications, suggesting that physical exercise might be an effective treatment option for CMT1 patients, even when disease symptoms have already progressed.

Background and aims: Peripheral neuropathy (PN) is a common neurological condition in elderly adults. Vitamin D deficiency has been associated with diabetic and chemotherapy-induced neuropathy, but its role in idiopathic PN, in which no underlying cause of neuropathy can be identified, has not been investigated.

Methods: Two hundred thirty patients with idiopathic PN enrolled in the Peripheral Neuropathy Research Registry (PNRR) at Johns Hopkins University School of Medicine had vitamin D testing information on record. Linear and logistic regressions were used to investigate the relationship between absolute vitamin D level or vitamin D insufficiency (<20 ng/mL) and both the severity of neuropathy as measured by the reduced total neuropathy score (TNSr) and severity of neuropathic pain.

Results: Sixteen (7%) patients were vitamin D insufficient (<20 ng/mL). Controlling for factors known to correlate with severity of neuropathy, there was no correlation between absolute vitamin D levels and TNSr (correlation coefficient 0.01, 95% CI -0.03 to 0.07, p = .59) and no association between vitamin D insufficiency and TNSr (correlation coefficient 0.3, 95% CI -2.8 to 3.4, p = .86). Vitamin D insufficiency was not associated with the presence of neuropathic pain (OR 4.1, 95% CI 0.6-26.0, p = .13), and there was no correlation between vitamin D levels and pain score (correlation coefficient 0.01, 95% CI -0.02 to 0.03, p = .59).

Interpretation: In a single-center cohort of patients with idiopathic PN, there was no correlation between vitamin D levels and the severity of neuropathy or neuropathic pain.

The prevalence of chronic polyneuropathy will increase due to the aging population, and therefore, it becomes ever so important to optimize the diagnostic process. However, it is uncertain which blood tests are required and when nerve conduction studies (NCS) should be done in the workup of chronic polyneuropathy. We aimed to investigate the methodology used to develop national polyneuropathy guidelines and to provide an overview and strength of evidence of the recommendations. We searched PubMed and websites of national neurological associations as listed on the website of the World Federation of Neurology to identify national guidelines pertaining to the workup of chronic polyneuropathy by neurologists in an outpatient clinic setting. We identified three national guidelines in the United States and seven national guidelines in Denmark, France, Germany, the Netherlands, Norway, Spain, and Turkey. The methodology used to develop the guidelines differed greatly. All guidelines recommend a series of blood tests. Some guidelines advise to conduct NCS in all patients, while other guidelines advise to conduct NCS when certain symptoms are present. There is variation in recommendations about the extensiveness of NCS, but all mention measuring the sural nerve and the motor peroneal nerve. The evidence for the recommendations is graded as low. Despite some overlap, there are disparities between guidelines regarding the workup that is advised to do in patients with chronic polyneuropathy. It remains unclear which combination of blood tests are to be strongly recommended. Furthermore, it is undetermined whether NCS are always necessary.

Background and aims: Chemotherapy-induced peripheral neurotoxicity (CIPN), with paraesthesia, numbness, dysesthesia and neuropathic pain ranks among the most common dose-limiting toxicity of several widely used anticancer drugs. Recent studies revealed the microvascular angiogenesis as a new important actor, beside peripheral neurons, in the neurotoxicity and neuropathic pain development and chronicisation. The aim of this work is to elucidate the role of vascular alterations in CIPN.

Methods: We evaluated the severity of CIPN with neurophysiological, behavioural and neuropathological analysis together with the microvascular network in central and peripheral nervous systems of rats in order to correlate the features of the CIPN and the vascular abnormalities. The vascular network was quantitatively evaluated through synchrotron radiation-based X-ray phase-contrast micro-tomography imaging, measuring four specific parameters: vascular density, vessel diameter, vessel tortuosity and branching.

Results: Rats exposed to paclitaxel and affected by a severe painful sensory axonopathy showed an increased vascular density (putative sprouting angiogenesis) in the crucial districts of the central (somatosensory cortex and lumbar spinal cord) and peripheral nervous system (lumbar dorsal root ganglia). In addition, the complexity of the vascular network and the size of neo-formed vessels were significantly decreased in specific regions. On the other hand, less significant changes were observed in rats exposed to cisplatin, affected by a painless peripheral neuropathy, suggesting a specific involvement of neo-angiogenesis in the development of severe neurotoxicity and neuropathic pain.

Interpretations: These new ground-breaking results can shed light on new pathogenetic mechanisms and potential novel therapeutic approaches for painful-CIPN.

Aim: Obesity is a major risk factor for diabetic peripheral neuropathy (DPN) in type 2 diabetes (T2D). This study investigated the effect of glucose lowering medication associated with weight change on DPN.

Methods: Participants with T2D were grouped based on whether their glucose lowering medications were associated with weight gain (WG) or weight loss (WL). They underwent clinical, metabolic testing and assessment of neuropathic symptoms, vibration perception threshold (VPT), sudomotor function and corneal confocal microscopy (CCM) at baseline and follow-up between 4 and 7 years.

Results: Of 76 participants, 69.7% were on glucose lowering medication associated with WG, and 30.3% were on glucose lowering medication associated with WL. At baseline, participants in the WG group had a significantly longer duration of diabetes (p < .01), higher douleur neuropathique en 4 (DN4) score (p < .0001) and VPT (p = .01) compared with those in the WL group. Over a 56-month period, participants in the WG group showed no significant change in body weight (p = .11), HbA1c (p = .18), triglycerides (p = .42), DN4 (p = .11), VPT (p = .15) or Sudoscan (p = .43), but showed a decline in corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fiber length (CNFL) (p < .0001). Participants in the WL group showed a reduction in weight (p = .01) and triglycerides (p < .05), no change in DN4 (p = .30), VPT (p = .31) or Sudoscan (p = .17) and a decline in the corneal nerve branch density (p < .01).

Conclusions: Participants treated with glucose lowering medication associated with weight gain had worse neuropathy and greater loss of corneal nerves during follow-up, compared to patients treated with medication associated with weight loss.

Background and aims: Porphyrias are inherited metabolic disorders caused by mutations in genes encoding enzymes involved in the heme biosynthetic pathway, leading to the accumulation of heme precursors. Acute hepatic porphyrias (AHP), including acute intermittent porphyria (AIP), can present with predominant peripheral neurological manifestations, often leading to a misdiagnosis as Guillain-Barré syndrome.

Methods: We report a case of AIP initially presenting as a peripheral neuropathy mimicking Parsonage-Turner syndrome (neuralgic amyotrophy, NA). Clinical and electrophysiological evaluations were conducted, including nerve conduction studies and needle electromyography (EMG).

Results: A 41-year-old woman presented with burning pain and electric shock-like sensations in the shoulders and trunk, alongside asymmetrical motor weakness in the upper limbs affecting arm abduction and finger extension. Electrophysiological evaluation revealed involvement of the superior trunk of the brachial plexus and the posterior interosseous nerve. Initially diagnosed with NA, she showed significant improvement in proximal strength over nine months but relapsed at fourteen months with severe finger extension weakness. Concurrent severe abdominal pain with constipation led to the identification of elevated urinary porphobilinogen (PBG) and delta-aminolevulinic acid (ALA) levels, confirming AHP and specifically AIP via genetic and biochemical testing. The patient received hemin and givosiran infusions, resulting in decreased ALA levels, improvement of motor weakness, and no further attacks.

Interpretation: This case underscores the need to consider AIP in the differential diagnosis of acute neuropathies like NA, especially when accompanied by abdominal pain and severe constipation. Early recognition and appropriate testing for PBG and ALA can prevent misdiagnosis and enable targeted treatment.