Carboplatin-associated Cranial Neuropathy

A phenotypic screening platform for chronic pain therapeutics using all-optical electrophysiology

ABSTRACT

Chronic pain associated with osteoarthritis (OA) remains an intractable problem with few effective treatment options. New approaches are needed to model the disease biology and to drive discovery of therapeutics. We present an in vitro model of OA pain, where dorsal root ganglion (DRG) sensory neurons were sensitized by a defined mixture of disease-relevant inflammatory mediators, here called Sensitizing PAin Reagent Composition or SPARC. Osteoarthritis-SPARC components showed synergistic or additive effects when applied in combination and induced pain phenotypes in vivo. To measure the effect of OA-SPARC on neural firing in a scalable format, we used a custom system for high throughput all-optical electrophysiology. This system enabled light-based membrane voltage recordings from hundreds of neurons in parallel with single cell and single action potential resolution and a throughput of up to 500,000 neurons per day. A computational framework was developed to construct a multiparameter OA-SPARC neuronal phenotype and to quantitatively assess phenotype reversal by candidate pharmacology. We screened ∼3000 approved drugs and mechanistically focused compounds, yielding data from over 1.2 million individual neurons with detailed assessment of functional OA-SPARC phenotype rescue and orthogonal "off-target" effects. Analysis of confirmed hits revealed diverse potential analgesic mechanisms including ion channel modulators and other mechanisms including MEK inhibitors and tyrosine kinase modulators. Our results suggest that the Raf-MEK-ERK axis in DRG neurons may integrate the inputs from multiple upstream inflammatory mediators found in osteoarthritis patient joints, and MAPK pathway activation in DRG neurons may contribute to chronic pain in patients with osteoarthritis.

Neurofilament light chain as a biomarker of axonal damage in sensory neurons and paclitaxel-induced peripheral neuropathy in patients with ovarian cancer

ABSTRACT

Paclitaxel-induced peripheral neuropathy (PIPN) is a barrier to effective cancer treatment and impacts quality of life among patients with cancer. We used a translational approach to assess the utility of neurofilament light chain (NFL) as a biomarker of PIPN in a human cell model and in patients with ovarian cancer. We measured NFL in medium from human induced pluripotent stem cell-derived sensory neurons (iPSC-SNs) exposed to paclitaxel. Serum NFL (sNFL) levels were quantified in 190 patients with ovarian cancer receiving paclitaxel/carboplatin chemotherapy at baseline and after each of the following 2 or 6 cycles. Adverse outcomes related to PIPN were retrospectively obtained, and Cox regression model was performed with different sNFL cut-offs after first cycle. The apparent elimination half-life of sNFL was estimated in patients who discontinued paclitaxel. Paclitaxel neurotoxicity in iPSC-SNs was accompanied by NFL release in a concentration-dependent manner ( P < 0.001, analysis of variance). Serum NFL levels increased substantially in patients during paclitaxel/carboplatin chemotherapy with considerable interindividual variability. Patients with sNFL >150 pg/mL after first cycle had increased risk to discontinue paclitaxel early (unadjusted HR: 2.47 [95% CI 1.16-5.22], adjusted HR: 2.25 [95% CI: 0.88-5.79]). Similar trends were shown for risk of severe PIPN and paclitaxel dose reduction because of PIPN. The median elimination half-life of sNFL was 43 days (IQR 27-82 days). Neurofilament light chain constitutes an objective biomarker of neurotoxicity in iPSC-SNs and in ovarian cancer patients with high sNFL predicting PIPN-related adverse outcomes. If prospectively validated, NFL can be used to study PIPN and may guide clinical decision making and personalize treatment with paclitaxel.

Neurologic Complications in Patients with Cancer

Neurologic symptoms are commonly seen in patients with cancer and can be among the most challenging to diagnose and manage. It is often difficult to determine if new neurologic symptoms are secondary to direct effects of a malignant lesion, systemic complications of disease, paraneoplastic disorders, or side effects of cancer treatment itself. However, early diagnosis and treatment of each of these conditions can improve patients' quality of life and long-term functional outcomes. In this review, we describe a systematic approach to the diagnosis of new neurologic symptoms in patients with known malignancy. We have categorized the neurologic complications of cancer through a mechanistic approach, with an emphasis on ascertaining underlying pathophysiology to guide treatment choice. This review focuses on the acute neurologic complications of cancer that require hospital admission.

Vocal Fold Motion Impairment Following Chemotherapy Administration: Case Reports and Review of the Literature

OBJECTIVE

Chemotherapy-induced vocal fold motion impairment (CIVFMI) is a rare complication of cancer therapy with potential for airway compromise. The objective of this review is to present 2 new cases of CIVFMI to add to the literature as well as characterize the demographics, symptoms, exam findings, airway complication rates and prognosis of CIVFMI.

METHODS

A search of Pubmed/MEDLINE (1970 to May 1, 2020), Embase (1970 to May 1, 2020), and Cochrane Library using medical study heading (MeSH) terms related to chemotherapy (drug therapy, chemotherapy, vincristine, vinblastine, paclitaxel) and vocal cord motion impairment (vocal cord, cords, vocal folds, immobility, hypomobility) was performed. Exploratory pooling of data without formal meta-analysis was performed.

RESULTS

A preliminary search yielded 148 abstracts, review articles and studies. A total of 23 studies met inclusion criteria. There were 35 total cases presented in the literature, with a mean age of 29.5 (0.4-78). The most common cancer diagnosis was acute lymphoblastic leukemia (n = 15, 42.9%), and the most common agent was vincristine (n = 30, 85.7%). Dysphagia, bilateral CIVFMI, and vocal fold immobility rather than hypomobility were more common in pediatric patients. There were 8 cases of surgical airway intervention, including tracheostomy and posterior cordotomy. The duration of symptoms was 7 to 420 days, and spontaneous resolution was reported in 32 cases.

CONCLUSIONS

CIVFMI has potential for airway complications requiring surgical intervention. Spontaneous resolution after cessation of the offending agent is the most likely outcome. Bilateral CIVFMI, dysphagia and vocal fold immobility are more common in the pediatric population.