Comments for Stem Cell Assays http://stemcellassays.com Promoting Rigorous Reproducible Research on Stem Cells Thu, 10 May 2012 19:13:35 +0000 hourly 1 http://wordpress.org/?v=3.3.2 Comment on Clinical cell processing news – part 1 by Michael An http://stemcellassays.com/2012/05/clinical-cell-processing-news-part-1/#comment-7368 Michael An Thu, 10 May 2012 19:13:35 +0000 http://stemcellassays.com/?p=6022#comment-7368 Any human blood-derived products possess real risk and high regulatory hurdle. Yes, they are being used if pass the available checks on several commonly-known pathogens. However, these tests are not comprehensive and not 100% accurate. The risk is amplified when using pooled blood for large scale production. Moreover, there is no way to check currently unknown or emerging pathogens for which no test is available. I don't want to scare people, but no one can guarantee that another HIV-hemophilia saga won't happen again. I just don't see any reason to retrogress to blood products while defined media are readily available. Michael Any human blood-derived products possess real risk and high regulatory hurdle. Yes, they are being used if pass the available checks on several commonly-known pathogens. However, these tests are not comprehensive and not 100% accurate. The risk is amplified when using pooled blood for large scale production. Moreover, there is no way to check currently unknown or emerging pathogens for which no test is available. I don’t want to scare people, but no one can guarantee that another HIV-hemophilia saga won’t happen again.
I just don’t see any reason to retrogress to blood products while defined media are readily available.
Michael

]]> Comment on Till & McCulloch Meetings 2012 – Reflections on Caplan’s view of mesenchymal stem cells by Alexey Bersenev http://stemcellassays.com/2012/05/mcculloch-meetings-2012-reflections-caplans-view-mesenchymal-stem-cells/#comment-7351 Alexey Bersenev Wed, 09 May 2012 03:18:39 +0000 http://stemcellassays.com/?p=5944#comment-7351 Good points James! For the 2nd I call it "the term stem cell become branded". I'm getting a lot of comments about my "craziness" about terminology. People say "it's matter of semantics", or "it doesn't really matter for clinicians and patients". I'd be ok with that, if people admit that the naming doesn't reflect the reality and have nothing to do with science. Just be honest. Unfortunately, people refuse to admit. Good points James!
For the 2nd I call it “the term stem cell become branded”. I’m getting a lot of comments about my “craziness” about terminology. People say “it’s matter of semantics”, or “it doesn’t really matter for clinicians and patients”.
I’d be ok with that, if people admit that the naming doesn’t reflect the reality and have nothing to do with science. Just be honest. Unfortunately, people refuse to admit.

]]> Comment on Till & McCulloch Meetings 2012 – Reflections on Caplan’s view of mesenchymal stem cells by Alexey Bersenev http://stemcellassays.com/2012/05/mcculloch-meetings-2012-reflections-caplans-view-mesenchymal-stem-cells/#comment-7350 Alexey Bersenev Wed, 09 May 2012 03:13:56 +0000 http://stemcellassays.com/?p=5944#comment-7350 Owen, Exactly my point. I agree with you. He didn't mentioned tissue engineering and homologous use of MSC. I guess, he was trying to avoid to give a credit to Friedenstein for "stromal" and Bianco for "skeletal" SC. So, I cite his phrase about regenerative medicine for a reason - to reflect his view. Obviously, using MSC on a matrix for bone repair is a regenerative medicine and it's nothing to do with their "medicinal" properties. Even if we accept the lineage: (1) pericyte --> (2) MSC (aka stromal?) --> (3) activated MSC (aka "medicinal"), should we treat 2 and 3 as different entities or as different functional state of the same cellular entity? If connection between pericyte and activated (medicinal) MSC, make sense, why "stromal MSC" should be associated with pericyte? And what about fibroblasts? http://stemcellassays.com/2012/04/mesenchymal-stromal-cells-fibroblasts/ Owen,
Exactly my point. I agree with you. He didn’t mentioned tissue engineering and homologous use of MSC. I guess, he was trying to avoid to give a credit to Friedenstein for “stromal” and Bianco for “skeletal” SC. So, I cite his phrase about regenerative medicine for a reason – to reflect his view. Obviously, using MSC on a matrix for bone repair is a regenerative medicine and it’s nothing to do with their “medicinal” properties.
Even if we accept the lineage: (1) pericyte –> (2) MSC (aka stromal?) –> (3) activated MSC (aka “medicinal”), should we treat 2 and 3 as different entities or as different functional state of the same cellular entity? If connection between pericyte and activated (medicinal) MSC, make sense, why “stromal MSC” should be associated with pericyte? And what about fibroblasts?
http://stemcellassays.com/2012/04/mesenchymal-stromal-cells-fibroblasts/

]]> Comment on Till & McCulloch Meetings 2012 – Reflections on Caplan’s view of mesenchymal stem cells by Owen Bain http://stemcellassays.com/2012/05/mcculloch-meetings-2012-reflections-caplans-view-mesenchymal-stem-cells/#comment-7346 Owen Bain Tue, 08 May 2012 14:28:34 +0000 http://stemcellassays.com/?p=5944#comment-7346 Not sure about 'Medicinal signalling cell' terminology. For indications such as GvHD, Chron's, myocardial infarction, IHD etc. their medicinal function is most likely due to paracrine effect, whereas for tendon, bone, cartlidge repair research groups are edging towards a more tissue engineering route of loading scaffolds with primed or differentiated MSCs. So, product characterisation is dependant on intended use. In addition, as James touched on, MSCs in situ and in vitro culture/expansion are different entities. Not sure about ‘Medicinal signalling cell’ terminology. For indications such as GvHD, Chron’s, myocardial infarction, IHD etc. their medicinal function is most likely due to paracrine effect, whereas for tendon, bone, cartlidge repair research groups are edging towards a more tissue engineering route of loading scaffolds with primed or differentiated MSCs. So, product characterisation is dependant on intended use.
In addition, as James touched on, MSCs in situ and in vitro culture/expansion are different entities.

]]> Comment on Till & McCulloch Meetings 2012 – Reflections on Caplan’s view of mesenchymal stem cells by James Eliason http://stemcellassays.com/2012/05/mcculloch-meetings-2012-reflections-caplans-view-mesenchymal-stem-cells/#comment-7337 James Eliason Tue, 08 May 2012 01:31:13 +0000 http://stemcellassays.com/?p=5944#comment-7337 I think of them as stromal cells when they are in situ and fibroblast progenitors if they are in culture (CFU-F). I call them mesenchymal stem cells to others because 1) most people in the field understand what I am talking about and 2) the term stem cells has become fashionable. This means that I have relaxed my standards a great deal in my old age. Back when I was a graduate student, postdoc and young researcher, we tended to be much more strict in our terminology than is currently the case. I think of them as stromal cells when they are in situ and fibroblast progenitors if they are in culture (CFU-F). I call them mesenchymal stem cells to others because 1) most people in the field understand what I am talking about and 2) the term stem cells has become fashionable. This means that I have relaxed my standards a great deal in my old age. Back when I was a graduate student, postdoc and young researcher, we tended to be much more strict in our terminology than is currently the case.

]]> Comment on The history of reprogramming 3.0 by Alexey Bersenev http://stemcellassays.com/2012/04/reprogramming-3-0-history/#comment-7293 Alexey Bersenev Fri, 04 May 2012 00:39:01 +0000 http://stemcellassays.com/?p=5772#comment-7293 Nian, I think, you can call it so and many people call it "gene therapy", but there is some differences. Classical gene therapy means "replacement of missing (or nonfunctional) gene". Traditionally, it used for monogenic hereditary diseases. But cells could be gene-modified with different purposes. For example, suicide genes to control wayward cells in T-cell therapy - http://hematopoiesis.info/2009/04/05/control-of-wayward-cells-after-transplantation/ Yet another difference is "therapeutic intention". In case of classical gene therapy - compensation of the function of missing gene, in case of reprogramming - changing a fate of targeted cell population in situ. Nian,
I think, you can call it so and many people call it “gene therapy”, but there is some differences. Classical gene therapy means “replacement of missing (or nonfunctional) gene”. Traditionally, it used for monogenic hereditary diseases. But cells could be gene-modified with different purposes. For example, suicide genes to control wayward cells in T-cell therapy -
http://hematopoiesis.info/2009/04/05/control-of-wayward-cells-after-transplantation/
Yet another difference is “therapeutic intention”. In case of classical gene therapy – compensation of the function of missing gene, in case of reprogramming – changing a fate of targeted cell population in situ.

]]> Comment on The history of reprogramming 3.0 by Nian http://stemcellassays.com/2012/04/reprogramming-3-0-history/#comment-7285 Nian Thu, 03 May 2012 07:31:32 +0000 http://stemcellassays.com/?p=5772#comment-7285 I think in vivo reprogramming is a gene therapy in fact, but it is very valuable in regenerative medicine. I think in vivo reprogramming is a gene therapy in fact, but it is very valuable in regenerative medicine.

]]> Comment on Characterization of human cells for clinical applications by Christopher Bravery http://stemcellassays.com/2011/09/characterization-human-cells-clinical-applications/#comment-7260 Christopher Bravery Tue, 01 May 2012 14:32:41 +0000 http://stemcellassays.com/?p=3373#comment-7260 No it's not a promotion, this and two other PAS's (84 and 83) which will also be published soon, were sponsored by BIS (UK government). You do have to pay for a hard copy though. No it’s not a promotion, this and two other PAS’s (84 and 83) which will also be published soon, were sponsored by BIS (UK government). You do have to pay for a hard copy though.

]]> Comment on Are mesenchymal stromal cells actually fibroblasts? by DR http://stemcellassays.com/2012/04/mesenchymal-stromal-cells-fibroblasts/#comment-7215 DR Fri, 27 Apr 2012 04:34:08 +0000 http://stemcellassays.com/?p=5860#comment-7215 I can not express the idea that we are talking about different functional states of the same cell. Confirm that the elephant, but if we analyze the scientific article - it is possible to formulate a hypothesis - http://www.tsitologiya.cytspb.rssi.ru/52_2/bozo.pdf I can not express the idea that we are talking about different functional states of the same cell. Confirm that the elephant, but if we analyze the scientific article – it is possible to formulate a hypothesis – http://www.tsitologiya.cytspb.rssi.ru/52_2/bozo.pdf

]]> Comment on Is human VSEL stem cells a real thing? by Alexey Bersenev http://stemcellassays.com/2012/04/human-vsel-real-thing/#comment-7167 Alexey Bersenev Tue, 24 Apr 2012 03:49:48 +0000 http://stemcellassays.com/?p=5763#comment-7167 Deepa, Thank you for response! If you think that "Alt's group was working with wrong starting material/ population", you're making a good argument. But how do you think Lin-/CD45-/CXCR4+ Alt's population from ficoll pellet could be different from Kucia's VSEL population? To me it looks the same. Both did a ficoll, lyse RBC in pellet and used the same markers on FACS. Can you please fix the first link you gave? Is this one? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135663/?tool=pubmed Despite all of markers story, what have been done in the field to prove functionality of VSEL stem cells? Any self-renewal assays? Any pruripotency tests in vivo? Regenerative and therapeutic potential is not necessarily linked to "stemness", but frequently delivered via progenitors function. In terms of Hoechst 33342 for nucleated cell versus side population staining, I have to check. Probably different concentrations or protocols used for these assays. Deepa,
Thank you for response!

If you think that “Alt’s group was working with wrong starting material/ population”, you’re making a good argument.
But how do you think Lin-/CD45-/CXCR4+ Alt’s population from ficoll pellet could be different from Kucia’s VSEL population? To me it looks the same. Both did a ficoll, lyse RBC in pellet and used the same markers on FACS.

Can you please fix the first link you gave? Is this one?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135663/?tool=pubmed

Despite all of markers story, what have been done in the field to prove functionality of VSEL stem cells? Any self-renewal assays? Any pruripotency tests in vivo? Regenerative and therapeutic potential is not necessarily linked to “stemness”, but frequently delivered via progenitors function.

In terms of Hoechst 33342 for nucleated cell versus side population staining, I have to check. Probably different concentrations or protocols used for these assays.

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