Integrating EM and Patch-seq data: Synaptic connectivity and target specificity of predicted Sst transcriptomic types

Neural circuit function is shaped both by the cell types that comprise the circuit and the connections between those cell types ¹ . Neural cell types have previously been defined by morphology ^{2, 3} , electrophysiology ^{4, 5} , transcriptomic expression ^6-8 , connectivity ^9-13 , or even a combination of such modalities ^14-16 . More recently, the Patch-seq technique has enabled the characterization of morphology (M), electrophysiology (E), and transcriptomic (T) properties from individual cells ^17-20 . Using this technique, these properties were integrated to define 28, inhibitory multimodal, MET-types in mouse primary visual cortex ²¹ . It is unknown how these MET-types connect within the broader cortical circuitry however. Here we show that we can predict the MET-type identity of inhibitory cells within a large-scale electron microscopy (EM) dataset and these MET-types have distinct ultrastructural features and synapse connectivity patterns. We found that EM Martinotti cells, a well defined morphological cell type ^{22, 23} known to be Somatostatin positive (Sst+) ^{24, 25} , were successfully predicted to belong to Sst+ MET-types. Each identified MET-type had distinct axon myelination patterns and synapsed onto specific excitatory targets. Our results demonstrate that morphological features can be used to link cell type identities across imaging modalities, which enables further comparison of connectivity in relation to transcriptomic or electrophysiological properties. Furthermore, our results show that MET-types have distinct connectivity patterns, supporting the use of MET-types and connectivity to meaningfully define cell types.

Cancer Demographics and Time-to-Care in Belize

BACKGROUND

Belize is a middle-income Caribbean country with poorly described cancer epidemiology and no comprehensive cancer care capacity. In 2018, GO, Inc., a US-based NGO, partnered with the Ministry of Health and the national hospital in Belize City to create the first public oncology clinic in the country. Here, we report demographics from the clinic and describe time intervals to care milestones to allow for public health targeting of gaps.

PATIENTS AND METHODS

Using paper charts and a mobile health platform, we performed a retrospective chart review at the Karl Heusner Memorial Hospital (KHMH) clinic from 2018 to 2022.

RESULTS

During this time period, 465 patients with cancer presented to the clinic. Breast cancer (28%) and cervical cancer (12%) were most common. Most patients (68%) presented with stage 3 or 4 disease and were uninsured (78%) and unemployed (79%). Only 21% of patients ever started curative intent treatment. Median time from patient-reported symptoms to a biopsy or treatment was 130 and 189 days. For the most common cancer, breast, similar times were seen at 140 and 178 days. Time intervals at the clinic: <30 days from initial visit to biopsy (if not previously performed) and <30 days to starting chemotherapy.

CONCLUSION

This study reports the first clinic-based cancer statistics for Belize. Many patients have months between symptom onset and treatment. In this setting, the clinic has built infrastructure allowing for minimal delays in care despite an underserved population. This further affirms the need for infrastructure investment and early detection programs to improve outcomes in Belize.

Updated demographics at the only public oncology clinic in Belize

e18787

Background: Belize is a middle-income Caribbean country without comprehensive cancer care capacity and poorly described cancer epidemiology. In 2020, we reported some of the first cancer demographics from the country. This was made possible by a capacity building partnership with the only public oncology clinic in the country at Karl Heusner Memorial Hospital (KHMH). Here we provide an update on demographic trends at this clinic. Methods: We performed a retrospective chart review of all available patient data at the KHMH clinic from December 2020 to December 2021. This was compared to data from the clinic’s founding in 2018 through its first 12 months. Results: From December 2020 through December 2021, the clinic saw 332 patients, an increase of 141% from the 236 patients seen over the first 12-month period of the clinic. In 2021, 250 (75%) patients had a confirmed pathologic diagnosis of cancer, with 78 (23%) remaining under clinical suspicion. This is in comparison to 63% of patients with a pathologic diagnosis in 2018. H&E staining alone remained the only publicly available pathologic service. Patients were predominantly female (67%) with a median age of 54 (Range: 2-95). The most common histologies (n = 332) were breast (29%), cervical (11%), colorectal (8%), prostate (4%), gastric (4%), and lung (3%). Of patients with histologically confirmed cancer, 221 (66%) were able to be fully staged. Patients predominantly presented with later stage disease (25% Stage III, 34% Stage IV). At the end of 2021, out of all patients tracked longitudinally over the year (n = 332), 24% remained in need of full diagnostic assessment, 34% were on curative treatment (predominantly cytotoxic chemotherapy), 22% were under surveillance, and 18% were receiving palliative chemotherapy or best supportive care due to advanced disease. This is in comparison to 2018, when there was no capacity to administer chemotherapy at KHMH and patients were referred to either private clinics or out of the country. Conclusions: The burden of cancer in Belize is significant and diverse. Compared to 2018, in 2021, the number of patients seen at KHMH increased 141%, as did the percentage of patients with histologically confirmed cancer (120% increase). Chemotherapy treatment was made possible through procurement of a chemotherapeutic stock at KHMH due to key partnerships with the Belizean government, hospital administration, and crucially, the only medical oncologist in the nation. This has led to chemotherapy being available at a public clinic in the country for the first time. Despite this progress, patients continue to present at late stages and many cannot access cancer care due to limited resources, cost, and low public awareness. This further affirms the need for infrastructure investment and early detection programs to improve cancer outcomes in Belize.

Breast cancer characteristics and time to chemotherapy initiation in Belize

e18643

Background: Breast cancer is the most common cancer in low and middle-income countries. Belize, a middle-income country in the Caribbean with significant inequality, lacks a national screening program and has limited treatment capacity. There are no studies describing breast cancer characteristics in Belize in the available literature. We collected data from the sole public oncology clinic in the country, established in 2018 at Karl Heusner Memorial Hospital (KHMH), to describe the characteristics of breast cancer patients and establish baseline measurements of time to chemotherapy initiation for the curative intent treatment population; the aim being to identify potential areas for quality improvement. Methods: We performed a retrospective chart review of available patient data from December 2020 to December 2021. We examined the time from a patient’s initial visit at KHMH until chemotherapy initiation (TCI) in the neoadjuvant setting with patients stratified by stage. Significant outliers (predominantly patients with misclassified data or those with private access to physicians and therapeutics) were excluded. Results: The clinic provided care for 80 patients with biopsy-proven breast cancer between December 2020 to December 2021. Patients were 97% female with a median age of 55 (Range: 34-81). For stageable patients (n=75), 33% presented with clinically localized disease, 49% with locally advanced, and 17% with recurrent or metastatic disease. Of the 51 patients on chemotherapy, 57% were receiving preoperative treatment, 31% were on adjuvant therapy, and 12% on palliative therapy. Patients not on therapy (n=29) at KHMH were either in surveillance, referred to a private cancer center, or deceased. Neoadjuvant TCI was calculated for 21 patients after the removal of outliers (n=5). The majority of these patients arrived at their initial clinic visit with a biopsy-proven diagnosis. Mean TCI for early stage disease was 49 days (n=7, 95% CI [9, 89]) and locally advanced disease was 36 days (n=14, 95% CI [12, 61]). Aggregate mean TCI was 40 days (n=21, 95% CI [19, 62]). Conclusions: In Belize, breast cancer affects younger women and patients present with later stages of disease than in high-income countries; however, time to chemotherapy initiation in a small sample of neoadjuvant patients at the Belizean clinic was comparable. Given the inherent limitations of small samples of data, additional investigation is needed to support these findings, as well as to delineate patient barriers to access and potential for improvements in clinic follow-up. Nevertheless, indications of a robust TCI call for further characterization of this newly established cancer clinic and its practices.

LB0006 SARILUMAB IN PATIENTS WITH RELAPSING POLYMYALGIA RHEUMATICA: A PHASE 3, MULTICENTER, RANDOMIZED, DOUBLE BLIND, PLACEBO CONTROLLED TRIAL (SAPHYR)

Background

Interleukin-6 (IL-6) is elevated in patients with active polymyalgia rheumatica (PMR) and is associated with disease activity, relapse and severity. Clinical trials with IL-6 receptor (IL-6R) inhibitors in PMR showed higher remission rates and reduced glucocorticoid (GC) use vs GC alone.1-4

Objectives

The SAPHYR study (NCT03600818) assessed the efficacy and safety of sarilumab (SAR), a fully human anti IL-6Rα monoclonal antibody, with a 14 week (wk) GC taper in patients with steroid resistant active PMR who flared on ≥7.5 mg/day prednisone or equivalent.

Methods

Patients were randomized (1:1) to 52 wks of treatment with SAR 200 mg every 2 wks (Q2W) + 14 wk GC tapered regimen (SAR arm) OR placebo Q2W + 52 wk GC tapered regimen (comparator arm). The primary endpoint was the proportion of patients achieving sustained remission at wk 52, defined as disease remission by wk 12, absence of disease flare, CRP normalization from wks 12 to 52 and adherence to the per protocol GC taper from wks 12 to 52.

Results

The study was terminated early due to protracted recruitment timelines during the COVID-19 pandemic, resulting in 118 of the intended 280 patients recruited between Oct 2018 and Jul 2020, and 117 were treated (SAR n=59, comparator n=58). The demographics were balanced; patients were primarily female, Caucasian, and a median age of ~70 years (Table 1). Overall, 78 patients completed the treatment (SAR n=42; comparator n=36). Primary reasons for treatment discontinuation were adverse events (AEs; SAR n=7, comparator n=4) and lack of efficacy (SAR n=4, comparator n=9). Sustained remission rate was significantly higher in the SAR arm vs the comparator arm (28.3% vs 10.3%; P=0.0193). Results of a sensitivity analysis excluding CRP from the sustained remission definition was consistent with the primary analysis (31.7% vs 13.8%; P=0.0280). All sustained remission components favored SAR (Figure 1). Patients in the SAR arm were 44% less likely to have a flare after achieving clinical remission vs the comparator arm (16.7% vs 29.3%; HR 0.56; 95% CI 0.35–0.90; P=0.0158). The comparator arm required more additional GCs vs the SAR arm, mainly due to PMR flare (median difference in actual and expected cumulative dose 199.5 mg vs 0.0 mg; P=0.0189). The cumulative GC toxicity index scores numerically favored SAR but the difference was not statistically significant. PMR activity scores improved in the SAR arm vs the comparator arm (LS mean -15.57 vs -10.27, nominal P=0.0002). Patient reported outcomes (eg, physical and mental health component scores, disability index, etc) favored SAR (Figure 1). Incidence of treatment-emergent AEs (TEAEs) was numerically higher in the SAR arm vs the comparator arm (94.9% vs 84.5%) and included neutropenia (15.3%) and arthralgia (15.3%) in the SAR arm, and insomnia (15.5%) in the comparator arm. Conversely, the frequency of serious AEs was higher in the comparator arm vs the SAR arm (20.7% vs 13.6%). No deaths were reported.

Table 1.

Demographics and baseline characteristics

ParameterSAR + 14 wk GC taperPlacebo + 52 wk GC taper(n=60)(n=58)Age, median years (range)69 (51–88)70 (52–88)Sex (female), n (%)45 (75.0)37 (63.8)Race, n (%) Caucasian50 (83.3)48 (82.8) Asian1 (1.7)2 (3.4) Not reported9 (15.0)8 (13.8)PMR duration (diagnosis date to baseline),* median days (range)292 (78–3992)310 (66–2784)Any prior disease modifying anti rheumatic drugs, n (%) Methotrexate5 (8.3)10 (17.2) Leflunomide2 (3.3)1 (1.7) Azathioprine01 (1.7) Hydroxychloroquine1 (1.7)1 (1.7) Adalimumab1 (1.7)0 Tocilizumab01 (1.7)CRP (mg/L), median (range)6.8 (0.5–38.2)5.7 (0.1–62.3)Erythrocyte sedimentation rate (mm/h), median (range)25.0 (2.0–115.0)22.0 (5.0–85.0)

*SAR n = 54; comparator n= 50.

Conclusion

SAR + 14 wk GC taper demonstrated significant efficacy vs the comparator arm in steroid refractory PMR patients, including clinically meaningful improvement in quality of life. Safety was consistent with the known safety profile of SAR.

References

[1]Mori 2016;

[2]Akiyama 2020;

[3]Lally 2016,

[4]Devauchelle Pensec 2015

Acknowledgements

Medical writing support was provided by Vijay Kadasi of Sanofi and funded by Sanofi.

Disclosure of Interests

Bhaskar Dasgupta Consultant of: Sanofi, Roche Chugai, Speakers bureau: Roche Chugai, Cipla, Grant/research support from: Sanofi, Roche, Abbvie, Sebastian Unizony Consultant of: Sanofi, Kiniksa, Janssen, Grant/research support from: Genentech, Kenneth J Warrington Paid instructor for: Chemocentryx, Grant/research support from: Eli Lilly, Kiniksa, GSK, Jennifer Sloane Lazar Employee of: Sanofi, Angeliki Giannelou Shareholder of: Regeneron, Employee of: Regeneron, Chad Nivens Shareholder of: Regeneron, Employee of: Regeneron, Bolanle Akinlade Shareholder of: Regeneron, Employee of: Regeneron, Wanling Wong Employee of: Sanofi, Yong Lin Employee of: Sanofi, Frank Buttgereit Consultant of: Sanofi, Horizon Pharma, Roche, Galapagos, Abbvie, Novartis, Grant/research support from: Sanofi, Horizon Pharma, Roche, Galapagos, Abbvie, Novartis, Valerie Devauchelle-Pensec: None declared, Andrea Rubbert-Roth Consultant of: Sanofi, Speakers bureau: Sanofi, Roche, Robert Spiera Consultant of: Sanofi, GSK, Novartis, Chemocentryx, Roche-Genetech, Abbvie, Vera, Grant/research support from: GSK, Chemocentryx, Corbus, Inflarx, Boehringer Ingelheim

Modeling radiative and non-radiative pathways at both the Franck-Condon and Herzberg-Teller approximation level

Here, we present a concise model that can predict the photoluminescent properties of a given compound from first principles, both within and beyond the Franck-Condon approximation. The formalism required to compute fluorescence, Internal Conversion (IC), and Inter-System Crossing (ISC) is discussed. The IC mechanism, in particular, is a difficult pathway to compute due to difficulties associated with the computation of required bosonic configurations and non-adiabatic coupling elements. Here, we offer a discussion and breakdown on how to model these pathways at the Density Functional Theory (DFT) level with respect to its computational implementation, strengths, and current limitations. The model is then used to compute the photoluminescent quantum yield (PLQY) of a number of small but important compounds: anthracene, tetracene, pentacene, diketo-pyrrolo-pyrrole (DPP), and Perylene Diimide (PDI) within a polarizable continuum model. Rate constants for fluorescence, IC, and ISC compare well for the most part with respect to experiment, despite triplet energies being overestimated to a degree. The resulting PLQYs are promising with respect to the level of theory being DFT. While we obtained a positive result for PDI within the Franck-Condon limit, the other systems require a second order correction. Recomputing quantum yields with Herzberg-Teller terms yields PLQYs of 0.19, 0.08, 0.04, 0.70, and 0.99 for anthracene, tetracene, pentacene, DPP, and PDI, respectively. Based on these results, we are confident that the presented methodology is sound with respect to the level of quantum chemistry and presents an important stepping stone in the search for a tool to predict the properties of larger coupled systems.

Long-term loss to follow-up in the TREAT Asia HIV Observational Database (TAHOD)

OBJECTIVES

With earlier antiretroviral therapy (ART) initiation, time spent in HIV care is expected to increase. We aimed to investigate loss to follow-up (LTFU) in Asian patients who remained in care 5 years after ART initiation.

METHODS

Long-term LTFU was defined as LTFU occurring after 5 years on ART. LTFU was defined as (1) patients not seen in the previous 12 months; and (2) patients not seen in the previous 6 months. Factors associated with LTFU were analysed using competing risk regression.

RESULTS

Under the 12-month definition, the LTFU rate was 2.0 per 100 person-years (PY) [95% confidence interval (CI) 1.8-2.2 among 4889 patients included in the study. LTFU was associated with age > 50 years [sub-hazard ratio (SHR) 1.64; 95% CI 1.17-2.31] compared with 31-40 years, viral load ≥ 1000 copies/mL (SHR 1.86; 95% CI 1.16-2.97) compared with viral load < 1000 copies/mL, and hepatitis C coinfection (SHR 1.48; 95% CI 1.06-2.05). LTFU was less likely to occur in females, in individuals with higher CD4 counts, in those with self-reported adherence ≥ 95%, and in those living in high-income countries. The 6-month LTFU definition produced an incidence rate of 3.2 per 100 PY (95% CI 2.9-3.4 and had similar associations but with greater risks of LTFU for ART initiation in later years (2006-2009: SHR 2.38; 95% CI 1.93-2.94; and 2010-2011: SHR 4.26; 95% CI 3.17-5.73) compared with 2003-2005.

CONCLUSIONS

The long-term LTFU rate in our cohort was low, with older age being associated with LTFU. The increased risk of LTFU with later years of ART initiation in the 6-month analysis, but not the 12-month analysis, implies that there was a possible move towards longer HIV clinic scheduling in Asia.