Citations

The diaphragm muscle (DIAm) must be able to generate sufficient forces to sustain ventilatory and non‐ventilatory behaviors throughout the lifespan. Age‐related decreases in DIAm fiber cross‐sectional area and specific force, i.e., sarcopenia, may impair the ability to generate transdiaphragmatic pressures (Pdi) necessary to accomplish expulsive, non‐ventilatory behaviors essential for airway clearance. We examined the effects of aging on DIAm function in both male and female mice at 6 and 24 months of age (n=79). Maximum DIAm specific force was 30% lower in old mice (P蠄0.001) and Pdi generated during non‐ventilatory behaviors was ~40% less in old mice (P蠄0.001). No differences in either DIAm force or Pdi were found between males and females. Collectively, these results indicate that DIAm sarcopenia is present in both sexes and significantly affects the ability to generate Pdi needed for airway clearance in old age. Supported by R01‐AG044615, T32‐HL105355, and the Mayo Clinic.

Mono‐and polyunsaturated fats in nuts, such as pistachios (PI), may improve lipoprotein and glycemic status. Overweight persons trend for dyslipidemia and high diabetes risk. The lower limits of PI consumption required for health benefits are unknown. This study determined if PI at bedtime promotes beneficial changes in metabolic status in overweight persons. Overweight subjects (n=22; 55 ± 2 yrs; 90 ± 3.6 kg; BMI 31 ± 1) were randomized to 35.4 g PI self‐administered at bedtime or control (CO; no PI) for 6 weeks. There was no difference in physical activity level between subjects receiving PI and CO. Body weight was not different in PI and CO at wk 0, 1, 2, 4, and 6. HDL cholesterol at wk 0 and 6 in PI was 49.2 ± 3.5 to 50.3 ± 3.0, and CO was 60.8 ± 3.8 and 58.0 ± 2.7 mg/dL, at wk 6 PI had improved slightly relative to CO (P= 0.12). Plasma glucose at wk 0 and 6 in PI was 104.6 ± 2.8 and 99.6 ± 2.6 mg/dL, and CO was 102.0 ± 2.8 and 101.1 ± 2.6 mg/dL, at wk 6 PI had improved slightly relative to CO (P= 0.16). Plasma insulin at wk 0 and 6 in PI was 8.5 ± 1.0 and 8.4 ± 0.9, and CO was 7.2 ± 0.7 to 8.8 ± 0.7 μU/mL, at wk 6 PI had improved slightly relative to CO (P = 0.21). Beneficial changes in HDL, glucose, and insulin probably requires slightly more than 35.4 g/d PI for 6 wks. To increase the probability of metabolic health benefits, nutritionists may wish to encourage levels of daily PI consumption higher than those administered in this study.

Abstract Context The detection and management of concomitant pheochromocytoma (PHEO) and primary aldosteronism (PA) is not well understood. Objective To investigate varying presentations and outcomes of cases with coexisting PHEO and PA to provide an approach to its diagnosis and management. Methods We conducted a retrospective case series of adult patients with concomitant PHEO and PA at Mayo Clinic from 2000-2020 and an additional review of cases before 2000 and from the medical literature. Clinical, biochemical, radiologic, and histologic parameters were measured. Results Fifteen patients (53% men, median age 53 years) were diagnosed with concomitant PHEO and PA. The majority presented with hypertension (13, 87%) and hypokalemia (13, 87%), and 6 (40%) presented with symptoms suggestive of catecholamine excess. All patients who underwent preoperative workup for catecholamine excess (14, 93%) were found to have biochemical levels above the upper limits of normal. Adrenal vein sampling (AVS) was performed in 9 patients (60%), where 5 (56%) were diagnosed with bilateral PA, and 4 (44%) with unilateral PA. Patients underwent either unilateral (12, 80%) or bilateral (3, 20%) adrenalectomy. Biochemical improvement or resolution of catecholamine excess was confirmed in all cases with documented measurements. Recurrence of PHEO was not observed. Six patients (40%) displayed persistent PA postoperatively. Conclusion Concomitant PHEO and PA is a rare but likely underreported condition. Hypertension with or without hypokalemia should prompt evaluation for PA, while any indeterminate adrenal mass should be assessed for PHEO. Coexisting disease warrants consideration of AVS to determine the laterality of PA to ensure appropriate management.

Respiratory failure is one of the most important complications of cervical spinal cord injury. The level of injury critically determines the severity of the complications. We hypothesized that higher cervical contusion injuries will compromise the motor neuron pool and the descending bulbospinal projections, causing greater functional compromise than contusions at lower levels. Unilateral contusion was performed on adult rats at either the C3 or C5 levels vs. laminectomy. No deficit was seen in ventilatory and non‐ventilatory behaviors as assessed by whole body plethysmography or chronic diaphragm electromyography up to 2 weeks. Contusion injuries at either level resulted in similarly sized cavity formation. Phrenic motor neuron loss differed, with C3 contusion causing a 50% loss of phrenic motor neurons, and C5 contusion only 20% loss compared to the contralateral side. The percent of NMJs that were denervated followed a segmental pattern. Following C3 contusion, ventral regions of the diaphragm displayed denervation of ~30% of NMJs compared to 1‐3% in the C5 contusion and laminectomy groups. In contrast, following C5 contusion, denervation was evident only in dorsal regions (~10%). These results show minimal ventilatory impairment following contusion injuries to the mid‐cervical spinal cord that result in phrenic motor neuron loss and evidence of diaphragm muscle denervation. Grant Funding Source : Supported by NIH grant R01 HL096750 and the Mayo Clinic

We recently determined the presence of sarcopenia in the diaphragm muscle (DIAm), specifically an age‐related reduction in force and muscle fiber cross‐sectional area, the latter being more pronounced at type IIx and/or IIb DIAm fibers. In limb muscles, age‐related changes at neuromuscular junctions (NMJs) include retraction of presynaptic terminals, disaggregation and fragmentation of the motor end‐plate. However, it is presently not clear whether aging impacts the morphology of DIAm NMJs. Adult male mice (n=14) at 6 and 24 months of age, representing survival rates of 100 and 75%, respectively, were used to examine DIAm NMJ structure, pre‐ and post‐synaptic morphology and overlap as measured in 3D by confocal microscopy (643 NMJs). No age related differences were evident in 2D planar area (mean: 328 µm 2 ) or complexity (i.e., fragmentation) of motor end‐plates. Pre‐ and post‐synaptic volumes were also similar across age groups. Evidence of partial or full denervation was present in ~6% of NMJs in both age groups. Thus, these results indicate that by 24 months of age, DIAm sarcopenia is not associated with evidence of ongoing denervation. Examination of earlier age groups will be necessary to rule out the contribution of NMJ denervation to DIAm sarcopenia given the loss of type IIx and/or IIb fibers by 24 months of age. Grant Funding Source : Supported by R01‐AG044615, T32‐HL105355, and the Mayo Clinic.

Background: Braak and others have proposed that Lewy-type α-synucleinopathy in Parkinson’s disease (PD) may arise from an exogenous pathogen that passes across the gastric mucosa and then is retrogradely transported up the vagus nerve to the medulla. Objective: We tested this hypothesis by immunohistochemically staining, with a method specific for p-serine 129 α-synuclein (pSyn), stomach and vagus nerve tissue from an autopsy series of 111 normal elderly subjects, 33 with incidental Lewy body disease (ILBD) and 53 with PD. Methods: Vagus nerve samples were taken adjacent to the carotid artery in the neck. Stomach samples were taken from the gastric body, midway along the greater curvature. Formalin-fixed paraffin-embedded sections were immunohistochemically stained for pSyn, shown to be highly specific and sensitive for α-synuclein pathology. Results: Median disease duration for the PD group was 13 years. In the vagus nerve none of the 111 normal subjects had pSyn in the vagus, while 12/26 ILBD (46%) and 32/36 PD (89%) subjects were pSyn-positive. In the stomach none of the 102 normal subjects had pSyn while 5/30 (17%) ILBD and 42/52 (81%) of PD subjects were pSyn-positive. Conclusion: As there was no pSyn in the vagus nerve or stomach of subjects without brain pSyn, these results support initiation of pSyn in the brain. The presence of pSyn in the vagus nerve and stomach of a subset of ILBD cases indicates that synucleinopathy within the peripheral nervous system may occur, within a subset of individuals, at preclinical stages of Lewy body disease.

Abstract To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. Significance: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor. This article is highlighted in the In This Issue feature, p. 2355

OBJECTIVES: To characterize the pediatric super-refractory status epilepticus population by describing treatment variability in super-refractory status epilepticus patients and comparing relevant clinical characteristics, including outcomes, between super-refractory status epilepticus, and nonsuper-refractory status epilepticus patients. DESIGN: Retrospective cohort study with prospectively collected data between June 2011 and January 2019. SETTING: Seventeen academic hospitals in the United States. PATIENTS: We included patients 1 month to 21 years old presenting with convulsive refractory status epilepticus. We defined super-refractory status epilepticus as continuous or intermittent seizures lasting greater than or equal to 24 hours following initiation of continuous infusion and divided the cohort into super-refractory status epilepticus and nonsuper-refractory status epilepticus groups. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We identified 281 patients (157 males) with a median age of 4.1 years (1.3–9.5 yr), including 31 super-refractory status epilepticus patients. Compared with nonsuper-refractory status epilepticus group, super-refractory status epilepticus patients had delayed initiation of first nonbenzodiazepine-antiseizure medication (149 min [55–491.5 min] vs 62 min [33.3–120.8 min]; p = 0.030) and of continuous infusion (495 min [177.5–1,255 min] vs 150 min [90–318.5 min]; p = 0.003); prolonged seizure duration (120 hr [58–368 hr] vs 3 hr [1.4–5.9 hr]; p < 0.001) and length of ICU stay (17 d [9.5–40 d] vs [1.8–8.8 d]; p < 0.001); more medical complications (18/31 [58.1%] vs 55/250 [22.2%] patients; p < 0.001); lower return to baseline function (7/31 [22.6%] vs 182/250 [73.4%] patients; p < 0.001); and higher mortality (4/31 [12.9%] vs 5/250 [2%]; p = 0.010). Within the super-refractory status epilepticus group, status epilepticus resolution was attained with a single continuous infusion in 15 of 31 patients (48.4%), two in 10 of 31 (32.3%), and three or more in six of 31 (19.4%). Most super-refractory status epilepticus patients (30/31, 96.8%) received midazolam as first choice. About 17 of 31 patients (54.8%) received additional treatments. CONCLUSIONS: Super-refractory status epilepticus patients had delayed initiation of nonbenzodiazepine antiseizure medication treatment, higher number of medical complications and mortality, and lower return to neurologic baseline than nonsuper-refractory status epilepticus patients, although these associations were not adjusted for potential confounders. Treatment approaches following the first continuous infusion were heterogeneous, reflecting limited information to guide clinical decision-making in super-refractory status epilepticus.