This research paper presents a study protocol for an exploratory clinical trial evaluating the safety and potential efficacy of autologous peripheral blood mononuclear cell (PBMNC)-loaded injectable cell scaffold (ICS-001) for angiogenic therapy in chronic limb-threatening ischaemia (CLTI). CLTI, the advanced stage of peripheral artery disease, presents significant therapeutic challenges.

Angiogenic therapy using ICS-001 with PBMNCs—a novel approach designed to enhance local cell retention and promote neovascularisation—will be explored. The study will address the pathophysiology of CLTI, the limitations of current treatments and the rationale for cell-based therapies, alongside the clinical trial design for evaluating the safety and efficacy of ICS-001. We hypothesise that ICS-001 will improve ulcer healing and reduce ischaemic rest pain in patients with CLTI. This paper outlines the methodology, including patient selection, CD34⁺ cell mobilisation, scaffold preparation, injection protocols, clinical assessments, data collection and safety monitoring. The anticipated results, discussion and conclusion will offer insight into the clinical significance and potential impact of ICS-001 as a pioneering angiogenic therapy for CLTI.

The institutional review boards of all participating hospitals approved this study protocol (latest version V.6.0, 5 June 2025). Final data will be made publicly available. A report detailing the study results will be submitted for publication in an appropriate peer-reviewed journal.

Data are available on reasonable request. Technical appendix, statistical code is available by contacting the corresponding author. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) licence, which permits others to distribute, remix, adapt, build on this work non-commercially, and licence their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

jRCT2052230115, Japan Registry of Clinical Trials.

Post-COVID-19 conditions (PCC) may include pulmonary sequelae, fatigue and other symptoms, but its mechanisms are not fully elucidated.

This study investigated the correlation between fatigue and the presence of pulmonary abnormalities in PCC patients with respiratory involvement 6–12 months after hospitalisation.

Cross-sectional study.

A tertiary hospital in Brazil.

315 patients, aged ≥18 years, were considered eligible based on SARS-CoV-2 infection confirmed by reverse transcription-PCR.

Pulmonary function tests (PFT), cardiopulmonary exercise tests (CPET), chest CT and hand grip were performed. The following scales were applied: Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale, Euroqol 5 Dimensions quality of life (EQ-5D) and Hospital Anxiety and Depression Scale (HADS). Participants were divided between the fatigue group (FACIT-F≤30) and the non-fatigue group (FACIT-F>30). For the statistical analysis, the primary outcome was the difference in the diffusing capacity of the lungs for carbon monoxide (DLCO) between groups. Considered secondary outcomes were differences in PFT, CPET, chest CT, hand grip, EQ-5D and HADS.

The fatigue group had 81 patients (25.7%) against 234 (74.3%). PFT and CPET showed no significant difference in DLCO and oxygen consumption peak values between groups. The fatigue group had a lower workload (mean 55.3±21.3 watts vs 66.5±23.2 watts, p=0.003), higher breathing reserve (median 41.9% (33.8–52.5) vs 37.7% (28.9–47.1), p=0.028) and lower prevalence of ground glass opacity (60.8% vs 77.7%, p=0.003) and reticulation (36.7% vs 54.9%, p=0.005) in chest CT. The fatigue group had higher anxiety (57% vs 24%, p

Fatigue in patients with PCC 6–12 months after hospitalisation is relatively common and had weak correlation with pulmonary disorders. Our results suggested fatigue could be strongly related with peripheral disorders such as reduced musculoskeletal strength or psychosocial limitations.