Posts Tagged ‘disease’
Gene therapy and glycoside drugs offer new hope for polycystic kidney disease treatment – News-Medical.Net
Researchers have shown that dangerous cysts, which form over time in polycystic kidney disease (PKD), can be prevented by a single normal copy of a defective gene. This means the potential exists that scientists could one day tailor a gene therapy to treat the disease. They also discovered that a type of drug, known as a glycoside, can sidestep the effects of the defective gene in PKD. The discoveries could set the stage for new therapeutic approaches to treating PKD, which affects millions worldwide. The study, partially funded by the National Institutes of Health (NIH), is published in Cell Stem Cell.
Scientists used gene editing and 3-D human cell models known as organoids to study the genetics of PKD, which is a life-threatening, inherited kidney disorder in which a gene defect causes microscopic tubes in the kidneys to expand like water balloons, forming cysts over decades. The cysts can crowd out healthy tissue, leading to kidney function problems and kidney failure. Most people with PKD are born with one healthy gene copy and one defective gene copy in their cells.
Human PKD has been so difficult to study because cysts take years and decades to form. This new platform finally gives us a model to study the genetics of the disease and hopefully start to provide answers to the millions affected by this disease."
Benjamin Freedman, Ph.D., senior study authorat the University of Washington, Seattle
To better understand the genetic reasons cysts form in PKD, Freedman and his colleagues sought to determine if 3-D human mini-kidney organoids with one normal gene copy and one defective copy would form cysts. They grew organoids, which can mimic features of an organ's structure and function, from induced pluripotent stem cells, which can become any kind of cell in the body.
To generate organoids containing clinically relevant mutations, the researchers used a gene editing technique called base editing to create mutations in certain locations on the PKD1 and PKD2 genes in human stem cells. They focused on four types of mutations in these genes that are known to cause PKD by disrupting the production of polycystin protein. Disruptions in two types of the protein polycystin-1 and polycystin-2 are associated with the most severe forms of PKD.
They then compared cells with two gene copy mutations in organoids to cells with only one gene copy mutation. In some cases, they also used gene editing to correct mutations in one of the two gene copies to see how this affected cyst formation. They found organoids with two defective gene copies always produced cysts and those that carried one good gene copy and one bad copy did not form cysts.
"We didn't know if having a gene mutation in only one gene copy is enough to cause PKD, or if a second factor, such as another mutation or acute kidney injury was necessary," Freedman said. "It's unclear what such a trigger would look like, and until now, we haven't had a good experimental model for human PKD."
According to Freedman, the cells with one healthy gene copy make only half the normal amount of polycystin-1 or polycystin-2, but that was sufficient to prevent cysts from developing. He added that the results suggest the need for a second trigger and that preventing that second hit might be able to prevent the disease.
The organoid models also provided the first opportunity to study the effectiveness of a class of drugs known as eukaryotic ribosomal selective glycoside on PKD cyst formation.
"These compounds will only work on single base pair mutations, which are commonly seen in PKD patients," explained Freedman. "They wouldn't be expected to work on any mouse models and didn't work in our previous organoid models of PKD. We needed to create that type of mutation in an experimental model to test the drugs."
Freedman's team found that the drugs could restore the ability of genes to make polycystin, increasing the levels of polycystin-1 to 50% and preventing cysts from forming. Even after cysts had formed, adding the drugs slowed their growth.
Freedman suggested that a next step would be to test existing glycoside drugs in patients. Researchers also could explore the use of gene therapy as a treatment for PKD.
The research was supported by NIH's Nation Center for Advancing Translational Sciences, National Institute of Diabetes and Digestive and Kidney Diseases, and National Institute of General Medical Sciences through awards R01DK117914, UH3TR002158, UH3TR003288, U01DK127553, U01AI176460, U2CTR004867, UC2DK126006, P30DK089507, R21DK128638, and R35GM142902; an Eloxx Pharmaceuticals Award; the Lara Nowak-Macklin Research Fund; and a Washington Research Foundation fellowship.
Source:
Journal reference:
Vishy, C. E.,et al.(2024) Genetics of cystogenesis in base-edited human organoids reveal therapeutic strategies for polycystic kidney disease. Cell Stem Cell. doi.org/10.1016/j.stem.2024.03.005.
Read the original:
Gene therapy and glycoside drugs offer new hope for polycystic kidney disease treatment - News-Medical.Net
ATG or post-transplant cyclophosphamide to prevent GVHD in matched unrelated stem cell transplantation? | Leukemia – Nature.com
Patient characteristics
The baseline characteristics of the study population are presented in Table1. A total of 8764 patients were included, from which 7725 (88%) received rATG, and 1039 (12%) received PTCy as GVHD prophylaxis.
Overall, the majority of patients were transplanted for acute leukemia (58%), myelodysplastic syndrome (MDS) (19.7%), myeloproliferative neoplasm (MPN) (9.7%) or lymphoma (9%). A high proportion of patients had a low/intermediate Disease Risk Index (DRI, 72.1%), and myeloablative conditioning (MAC) was more frequently performed (53.3%) than reduced intensity conditioning (RIC).
Patients in the rATG group were older, with a median age of 58.6 years (IQR (48.1, 65.4)) vs. 53 years in the PTCy group (IQR 38.6, 62.3) (p<0.01), with a similar proportion of males (57.3% in rATG vs. 58.9% in PTCy, p=0.33), along with a significantly lower use of TBI (14.5% vs. 24.7%, p<0.01) and lower use of MAC (52% vs. 62.3%, p<0.01). Also, the disease relapse index was lower and the year of transplant was more recent in the PTCy group (Table1). The remaining parameters were balanced between the two groups. Median follow up was 2.1 years in both arms. More detailed information is given in Table1.
Univariate outcomes are shown in Figs.1, 2and Table2. The results of the multivariate analyses are summarized in Table3. The P-values and hazard ratios (HR) presented in the following results section are derived from the multivariate analysis.
A NRM; B Overall survival, C Relapse incidence, D Progression-free survival and E GVHD-free relapse-free survival. Cumulative incidences are shown.
A Acute GVHD grades IIIV; B Acute GVHD grades IIIIV, C Chronic GVHD all grades and D Extensive chronic GVHD - Cumulative incidences are shown.
Patients receiving PTCy had a significantly lower NRM as compared to patients receiving rATG (2y incidence: 12.4% vs. 16.1%; HR: 0.72 [95% CI 0.550.94], p=0.016). Similarly, OS and PFS showed a statistically significant and clinically meaningful benefit for PTCy arm, with a higher OS (2y incidence: 73.9% vs. 65.1%; HR: 0.82 [95% CI 0.720.92], p=0.001), and a higher PFS (2y incidence: 64.9% vs. 57.2%; HR: 0.83 [95% CI 0.740.93], p<0.001). RI was lower in the PTCy arm (2y incidence: 22.8% vs. 26.6%; HR: 0.87 [95% CI 0.751.00], p=0.046).
The causes of death are given in Table4. No major differences between the two groups were apparent. Relapse of the underlying malignancy was the most frequent cause of death, accounting for ~50% of total deaths in both arms, followed by NRM causes: infections ~18%, GVHD~16% and other alloSCT-related causes ~8% of total deaths. Secondary malignancies contributed to approximately 1% of total deaths.
Overall chronic GVHD was lower in the PTCy group (2y incidence: PTCy 28.4% vs. rATG 31.4%; HR: 0.77 [95% CI 0.630.95], p=0.012). Extensive chronic GVHD was also reduced in patients receiving PTCy vs. rATG: (2y incidence: 11.9% vs. 13.5%; HR: 0.75 [95% CI 0.620.91], p=0.004).
The incidence of acute GVHD grades II-IV in patients receiving PTCy, compared to those receiving ATG was not statistically significant: (100d incidence: 24.1% vs. 26.5%; HR: 0.85 [95% CI 0.691.04], p=0.11). Similarly, for severe acute GVHD grades IIIIV (100d incidence: 8.7% vs. 9.7%; HR: 0.76 [95% CI 0.551.05], p=0.091).
GRFS was significantly higher in the PTCy arm compared to the rATG arm (2y incidence: 51% vs. 45%; HR: 0.86 [95% CI 0.750.99], p=0.035).
The EBMT Database does not contain data on graft failure/rejection. To get insight into the initial grafts success and any subsequent requirement for additional transplantation procedures, we investigated neutrophil recovery after the first alloSCT as well as the incidence of a second alloSCT. The median incidence of neutrophil recovery at days +30 and +60 in the ATG vs. PTCy groups was: d+30 ATG 96% (IC95% 95.596.4) vs. PTCy 91% (8992.7) and d+60 ATG 97.9% (97.698.2) vs. PTCy 97.4% (96.298.3). The median incidence of a second alloSCT at 2 years was 4.3% (3.84.8) in the ATG group and 3.2% (2.24.6) in the PTCy group.
Continue reading here:
ATG or post-transplant cyclophosphamide to prevent GVHD in matched unrelated stem cell transplantation? | Leukemia - Nature.com