Showing posts with label male infertility. Show all posts
Showing posts with label male infertility. Show all posts
Wednesday, April 20, 2011
Sunday, April 17, 2011
Can sperm be grown in a lab dish ? Breakthrough Research suggests it may be possible. this may represent a future solution for men with maturation arrest: article on Nature.
Sperm are very complex cells : they have a head a tail , need to be able to swim and penetrate an egg. Because of this male fertility can be affected by any disease of sperm envelopment. Often we hear about immature sperm or morphologically abnormal sperm.
Researchers have been trying to grow sperm In Vitro for a long time but without success.This work was pioneered by Takehiko Ogawa and colleagues at Yokohama City University. The procedure involves taking biopsies of mouse testes, breaking them up into small pieces, placing them on agarose gel that has been partially soaked with a special medium, and letting them be for two months. If all goes according to plan, the chemicals in the medium would induce the gonadal stem cells to differentiate into mature sperm.
The secret of the success of this research has been to tweak the culture medium over time with different nutrients : it would be too complicated to cover them here.
this is the kind of experiment that is going to be very hard to reproduce by other labs as these guys have been at it for years and , in this type of experiments, the secret is to follow a series of minute details.
Therefore clinical application of this technology (for people) is years away. Another caveat is that in this technology is only valid if you have immature sperm to start with. This is not a technique to make sperms from "scratch". Therefore men who have no immature sperm in their testicles would not be helped with this method. Nevertheless it is a huge leap!
Abstract below:
Link : http://www.nature.com/nature/journal/v471/n7339/full/nature09850.html
Sperm are very complex cells : they have a head a tail , need to be able to swim and penetrate an egg. Because of this male fertility can be affected by any disease of sperm envelopment. Often we hear about immature sperm or morphologically abnormal sperm.
Researchers have been trying to grow sperm In Vitro for a long time but without success.This work was pioneered by Takehiko Ogawa and colleagues at Yokohama City University. The procedure involves taking biopsies of mouse testes, breaking them up into small pieces, placing them on agarose gel that has been partially soaked with a special medium, and letting them be for two months. If all goes according to plan, the chemicals in the medium would induce the gonadal stem cells to differentiate into mature sperm.
The secret of the success of this research has been to tweak the culture medium over time with different nutrients : it would be too complicated to cover them here.
this is the kind of experiment that is going to be very hard to reproduce by other labs as these guys have been at it for years and , in this type of experiments, the secret is to follow a series of minute details.
Therefore clinical application of this technology (for people) is years away. Another caveat is that in this technology is only valid if you have immature sperm to start with. This is not a technique to make sperms from "scratch". Therefore men who have no immature sperm in their testicles would not be helped with this method. Nevertheless it is a huge leap!
Abstract below:
Spermatogenesis is one of the most complex and longest processes of sequential cell proliferation and differentiation in the body, taking more than a month from spermatogonial stem cells, through meiosis, to sperm formation1, 2. The whole process, therefore, has never been reproduced in vitro in mammals3, 4, 5, nor in any other species with a very few exceptions in some particular types of fish6, 7. Here we show that neonatal mouse testes which contain only gonocytes or primitive spermatogonia as germ cells can produce spermatids and sperm in vitro with serum-free culture media. Spermatogenesis was maintained over 2 months in tissue fragments positioned at the gas–liquid interphase. The obtained spermatids and sperm resulted in healthy and reproductively competent offspring through microinsemination. In addition, neonatal testis tissues were cryopreserved and, after thawing, showed complete spermatogenesis in vitro. Our organ culture method could be applicable through further refinements to a variety of mammalian species, which will serve as a platform for future clinical application as well as mechanistic understanding of spermatogenesis. (source : Nature.com)
Link : http://www.nature.com/nature/journal/v471/n7339/full/nature09850.html
Wednesday, April 13, 2011
Does the age of the father have an effect on IVF ?Minimal effect of paternal age on IVF reproduction outcome: study
Interesting review article published on Fertility and Sterility. It is a review of the 10 studies published on the topic, most of them retrospective. the result is a bit surprising as it shows no effect. It is possible that IVF corrects the observed anomalies in sperm production observed wit advancing ageObjective
To summarize the current knowledge about the association between paternal age and assisted reproductive technology (ART) outcomes. In contrast to the extensive investigation of the relationship between maternal age and the success of ART, there are few studies examining the effect of paternal age on ART outcomes.
Design
Systematic review of the literature. By means of a PubMed literature search using the phrases “paternal age”, “male age”, and “assisted reproductive technology”, we identified articles that investigated the role of male age in in vitro reproduction techniques.
Result(s)
The 10 studies included in this review did not show a clear correlation between advanced paternal age and rates of fertilization, implantation, pregnancy, miscarriage, and live birth. Paternal age was not found to affect embryo quality at the cleavage stage (days 2–3). However, a significant decrease in blastocyst embryo formation was associated with increased paternal age, probably reflecting male genomic activation within the embryo. Except for volume, characteristics of semen such as motility, concentration, and morphology did not decrease with age.
Conclusion(s)
There is insufficient evidence to demonstrate an unfavorable effect of paternal age on ART outcomes. Further study with well-defined entry criteria and uniform reporting of outcomes is needed to investigate the subject.
source Fertility and Sterility
Volume 95, Issue 1 , Pages 1-8, January 2011
Tuesday, February 23, 2010
Sperm Fragmentation Assay : is it Useful?
It's just an additional test that may give additional insight . Like many test in infertility it delivers results in relative terms i.e one may have a REDUCED chance of fertility if the test is abnormal (as opposed to all or nothing) . Having said so most still decide to use their own sperm even if the test is abnormal and take their (albeit reduced) chances . This is the reason why i do not use the test as much because i don't offer it to people who under no circumstances would use donor sperm . For others the test helps as it may offer some insight in why a cycle did not work. so if you go for he route of donor sperm at least you know that you made the decision based on scientific evidence as opposed of trial and error. A couple of scientific articles below.
It's just an additional test that may give additional insight . Like many test in infertility it delivers results in relative terms i.e one may have a REDUCED chance of fertility if the test is abnormal (as opposed to all or nothing) . Having said so most still decide to use their own sperm even if the test is abnormal and take their (albeit reduced) chances . This is the reason why i do not use the test as much because i don't offer it to people who under no circumstances would use donor sperm . For others the test helps as it may offer some insight in why a cycle did not work. so if you go for he route of donor sperm at least you know that you made the decision based on scientific evidence as opposed of trial and error. A couple of scientific articles below.
Reprod Biomed Online. 2010 Jan;20(1):114-124. Epub 2009 Nov 10.
Sperm chromatin structure assay and classical semen parameters: systematic review.
Castilla JA, Zamora S, Gonzalvo MC, Luna Del Castillo JD, Roldan-Nofuentes JA, Clavero A, Björndahl L, Martínez L.
Reproduction Unit, Hospital 'Virgen de las Nieves', E-18014 Granada, Spain; Sperm Bank CEIFER, Granada, Spain.
The present study is based on a PubMed search and compares the clinical validity of classical semen parameters (CSP) and the sperm chromatin structure assay (SCSA) in different clinical contexts. The PubMed database was searched using keywords on the sperm diagnostic test for pregnancy in three clinical scenarios: (i) couples attempting to conceive; (ii) couples who had been attempting to conceive for 12months without success; and (iii) couples treated with intrauterine insemination (IUI). There was a considerable heterogeneity among the studies included. For couples attempting to conceive following a SCSA that produced an abnormal result, the likelihood of male factor infertility ranged from a pre-test value of 7.5% to a post-test value of 32.1% [95% confidence interval (CI) 15.7-54.5], while after CSP with an abnormal result, the post-test probability was 17.3% (95% CI 11.8-24.5). For a pre-test prevalence of male factor infertility of 50%, the post-test probability of male factor infertility after an abnormal test is very similar for both SCSA and CSP. In couples treated with IUI, the clinical validity of SCSA is higher than that of sperm morphology alone, but not enough to introduce SCSA as a test in male infertility work-up. Copyright © 2009 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
Toxicol Appl Pharmacol. 2005 Sep 1;207(2 Suppl):532-7.
Environmental toxicants cause sperm DNA fragmentation as detected by the Sperm Chromatin Structure Assay (SCSA).
Evenson DP, Wixon R.
HCLD, Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA. scsa@brookings.net
Studies over the past two decades have clearly shown that reproductive toxicants cause sperm DNA fragmentation. This DNA fragmentation can usually be detected prior to observing alterations of metaphase chromosomes in embryos. Thus, Sperm Chromatin Structure Assay (SCSA)-detected DNA damage is viewed as the molecular precursor to later gross chromosome damage observed under the light microscope. SCSA measurements of animal or human sperm consist of first obtaining a fresh or flash frozen neat semen sample in LN2 or dry ice. Samples are then sent to a SCSA diagnostic laboratory where the samples are thawed, diluted to approximately 1-2 x 106 sperm/ml, treated for 30 s with a pH 1.2 detergent buffer and then stained with acridine orange (AO). The low pH partially denatures DNA at the sites of DNA strand breaks and the AO-ssDNA fluoresces red while the AO-dsDNA fluoresces green. Flow cytometry measurements of 5000 sperm/sample provide statistically robust data on the ratio of red to green sperm, the extent of the DNA fragmentation and the standard deviations of measures. Numerous experiments on rodents treated with reproductive toxicants clearly showed that SCSA measures are highly dose responsive and have a very low CV. Different agents that act on germ cells at various stages of development usually showed sperm DNA fragmentation when that germ cell fraction arrived in the epididymis or ejaculate. Some of these treated samples were capable of successful in vitro fertilization but with frequent embryo failure. A 2-year longitudinal study of men living a valley town with a reported abnormal level of infertility and spontaneous miscarriages and also a seasonal atmospheric smog pollution, showed, for the first time, that SCSA measurements of human sperm DNA fragmentation were detectable and correlated with dosage of air pollution while the classical semen measures were not correlated. Also, young men spraying pesticides without protective gear are at an increased risk for elevated sperm DNA fragmentation. Extensive DNA fragmentation probably cannot be repaired by the egg and the spontaneous abortion rate is approximately 2x higher if a man has more than 30% of sperm showing DNA fragmentation. DNA fragmentation is an excellent marker for exposure to potential reproductive toxicants and a diagnostic/prognostic tool for potential male infertility.
Subscribe to:
Posts (Atom)