In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging

Chronic traumatic encephalopathy (CTE) is an acquired primary tauopathy with a variety of cognitive, behavioral, and motor symptoms linked to cumulative brain damage sustained from single, episodic, or repetitive traumatic brain injury (TBI). No definitive clinical diagnosis for this condition exists. In this work, we used [F-18]FDDNP PET to detect brain patterns of neuropathology distribution in retired professional American football players with suspected CTE (n = 14) and compared results with those of cognitively intact controls (n = 28) and patients with Alzheimer’s dementia (AD) (n = 24), a disease that has been cognitively associated with CTE. [F-18]FDDNP PET imaging results in the retired players suggested the presence of neuropathological patterns consistent with models of concussion wherein brainstem white matter tracts undergo early axonal damage and cumulative axonal injuries along subcortical, limbic, and cortical brain circuitries supporting mood, emotions, and behavior. This deposition pattern is distinctively different from the progressive pattern of neuropathology [paired helical filament (PHF)-tau and amyloid-β] in AD, which typically begins in the medial temporal lobe progressing along the cortical default mode network, with no or minimal involvement of subcortical structures. This particular [F-18]FDDNP PET imaging pattern in cases of suspected CTE also is primarily consistent with PHF-tau distribution observed at autopsy in subjects with a history of mild TBI and autopsy-confirmed diagnosis of CTE.The consensus statement on concussions from the Fourth International Conference on Concussion in Sports (Zurich 2012) (1) defines acute mild traumatic brain injury (mTBI) or cerebral concussion as a brain injury with a complex pathophysiological process induced by biomechanical forces. Cerebral concussion causes white matter axonal injury due to axonal shearing and stretching (2), typically resulting in the rapid onset of short-lived impairment of neurological function that resolves spontaneously and largely reflects a functional disturbance rather than a structural injury. As such, no abnormality is seen on standard structural neuroimaging determinations (1).A number of early literature reports described a neurodegenerative disease associated with a history of repetitive TBI in retired professional boxers (3, 4), with a prevalence rate of up to 47% among retired professional boxers aged 50 y and older who boxed for more than 10 y (5). Initially named “punch drunk syndrome” (3) and dementia pugilistica (4), this syndrome is now known as chronic traumatic encephalopathy (CTE) in the current literature (6, 7).Compelling autopsy evidence (6–8) and neurobehavioral determinations (9) of retired professional American football athletes indicate that a subgroup develops neurodegenerative and clinical changes typical of CTE, a progressive syndrome distinctively different from Alzheimer’s disease (AD), which is the most common form of dementia in the elderly (10). The connection between multiple concussions and subconcussive head impacts (2) and CTE is compelling, because history of repetitive concussions is the strongest risk factor for development of CTE in numerous contact sports (e.g., American football, rugby, boxing, ice hockey, soccer, and professional wrestling), in war veterans with a history of blast or blunt force TBI, and in conditions where trauma to the head occurs for various reasons (e.g., falls during seizures, head-banging in autistic children, motor vehicle and domestic accidents, domestic violence and abuse) (6, 8, 11–14). As with most neurodegenerative diseases, clinical diagnosis remains elusive due to the lack of specificity of CTE clinical symptomatology criteria, and histopathological examination of brain at autopsy is the most definitive diagnostic modality (6, 8, 11).The novel imaging approaches leading to the in vivo characterization of CTE brain neuropathology premortem (e.g., PET) are complementary to structural imaging modalities [e.g., diffusion tensor imaging MRI (DTI MRI)] and offer a specific and sensitive strategy to facilitate diagnosis of CTE. Neuronal and glial fibrillar hyperphosphorylated microtubule-associated protein tau deposits composed of paired helical filament (PHF)-tau are the primary brain proteinopathy of CTE based on autopsy determinations, and their 3R/4R tau isoform ratio is similar to that of AD (11). Their topographically predictable pattern of distribution was used as a basis for a severity staging system of CTE neuropathology (7), ranging from mild (neuropathology stages I and II) to advanced (neuropathology stages III and IV) (7) (Tables S1 and S2). In addition, more than 80% of analyzed pathologically confirmed CTE cases also show transactive response (TAR) DNA-binding protein of ∼43 kDa (TDP-43) either as inclusions in sparse neurites in cortex, medial temporal lobe structures, and brainstem in CTE neuropathology stages I–III, as widespread neuronal and glial inclusions in severe CTE cases (neuropathology stage IV), or in CTE cases with motor neuron disease (7, 15) (Tables S1 and S2). CTE cases also can exhibit the presence of other fibrillar protein aggregates. McKee et al. (7) and Omalu et al. (8) reported that in autopsy determinations, less than half of all CTE cases and less than one third of “pure” CTE cases show amyloid-β (Aβ) deposits, predominantly as scattered cortical diffuse plaques in low density (Tables S1 and S2). Of note is that subjects with Aβ deposits were significantly older than those without. Moreover, their neuropathology was more severe than that in cases without Aβ deposits and was often combined with α-synuclein deposits (7). As an example, as reported by McKee et al. (7), of 30 CTE cases with at least some cortical Aβ deposits (of 68 confirmed CTE cases), 29 brains were from subjects who died in their seventh decade of life and one from a subject who died in his sixth decade.Subsequent to our preliminary report (16), in this work we use [F-18]FDDNP, an imaging agent for fibrillar insoluble protein aggregates (16–20), and PET imaging with the aim of establishing (i) topographic brain localization of [F-18]FDDNP PET signals indicative of fibrillar neuroaggregates in retired professional American football players with suspected CTE (mTBI group) vs. controls (CTRL); (ii) determination of [F-18]FDDNP PET signal patterns in the mTBI group; (iii) presence of [F-18]FDDNP PET signal as a measure of neuropathology in the brain areas involved in mood disorders related neurocircuits; (iv) correlation of [F-18]FDDNP PET results with neuropathology distributions in confirmed CTE cases; (v) differential patterns of [F-18]FDDNP PET signals, and thus deposition of fibrillar neuroaggregates, in the mTBI group with respect to the AD group; and (vi) preliminary demonstration of differences in [F-18]FDDNP PET signal patterns in mTBI cases with different etiology, i.e., contact-sport–related mTBI in retired professional American football players vs. blast-induced mTBI in war veterans. We further intended to demonstrate that tau (vs. Aβ) specificity of high affinity PET molecular imaging probes may not be a necessary requirement when used in CTE subjects with primary proteinopathy in the form of PHF-tau (8): PET imaging probes potentially sensitive to TDP-43 aggregates and Aβ deposits, which are present in higher densities almost exclusively in older CTE cases with more advanced neuropathology (e.g., stage IV), could better define disease progression based on quantification of differences in regional loads of combined neuropathologies because additional neuropathologies appear in predictable topographical and temporal patterns.     

A Phase II Study of the Efficacy and Safety of Chloroquine in Combination With Taxanes in the Treatment of Patients With Advanced or Metastatic Anthracycline-refractory Breast Cancer

IntroductionChemotherapy eliminates most of the cancer cells except those with potential for self-renewal and tumor initiation, called cancer stem cells (CSCs). Chloroquine, through bioinformatics, was found to be a potential agent to target CSCs. We designed a phase II trial to test the efficacy and safety of chloroquine in combination with taxane or taxane-like chemotherapy agents in patients with advanced or metastatic breast cancer who are refractory to anthracycline-based chemotherapy.Patients and MethodsFemale patients ≥ 18 years of age who had received prior anthracycline chemotherapy were enrolled in this study. Chloroquine 250 mg was given daily orally with either docetaxel or paclitaxel or nab-paclitaxel or ixabepilone every 3 weeks. The maximum number of 3-week cycles allowed was 6. The primary efficacy endpoint was the objective response rate (ORR). The secondary efficacy endpoints included progression-free survival (PFS) and safety analysis.ResultsThirty-eight patients were enrolled in the study, and 31 patients were evaluated for response. The median age was 54.1 years (range, 31.7-78.1 years). The ORR was 45.16% (95% confidence interval [CI], 29.2%-62.2%), which was higher than the expected ORR of 30% (P = .03). Patients were followed for a median of 25.4 months and experienced a median PFS of 12.4 months (95% CI, 4.9-24.6 months) and a median OS of 25.4 months (95% CI, 13.7-83.5 months). The combination was well-tolerated, with only 13.15% of patients experiencing grade ≥ 3 adverse events.ConclusionA combination of chloroquine with taxane or taxane-like chemotherapy was efficacious in patients with locally advanced or metastatic breast cancer with prior anthracycline-based chemotherapy.     

Outcomes of Stage I and II Breast Cancer with Nodal Micrometastases Treated with Mastectomy without Axillary Therapy

Breast Cancer Research and Treatment - Studies that report equivalent oncologic outcomes of sentinel lymph node biopsy (SLNB) alone versus axillary lymph node dissection (ALND) for T1-2N1mi breast...     

Cutaneous squamous cell carcinoma in two pediatric lung transplant patients on prolonged voriconazole treatment

Oral voriconazole is commonly used for treatment and prophylaxis of invasive fungal disease post‐LTx. Development of cutaneous SCC has been described in adult LTx recipients, although it is extremely rare in children. We describe two Caucasian children who developed cutaneous SCC beyond three yr post‐LTx. Both developed severe photosensitivity, actinic keratosis and required curative surgical excision of the cutaneous SCC lesions. Neither patient developed metastatic lesions nor had allograft dysfunction as a result of the SCC or the change in medical treatments. The effect of voriconazole on the development of malignant skin lesions is discussed and a recommendation on dermatologic surveillance, preventive measures against phototoxicity and early treatment of SCC are provided.