Mesenchymal Stem Cell-Based Therapy for Type 1 and Type 2 Diabetes Mellitus: A Systematic Review and Analysis of Randomized Controlled Trials.

 Mesenchymal Stem Cell-Based Therapy for Type 1 and Type 2 Diabetes Mellitus: A Systematic Review and Analysis of Randomized Controlled Trials

Authors: Dr. Shekhar Ingle and Team, Doctor's Forum for All 🏥

Copyright: © 2026 Dr. Shekhar Ingle and Team, Doctor's Forum for All. All rights reserved.

Corresponding Author: Dr. Shekhar Ingle

Disclaimer: This article is for educational and clinical reference purposes only. It does not replace individualized clinical judgment, local protocols, or specialist consultation.

Abstract

Background: Diabetes mellitus is a metabolic disorder with no cure. Insulin therapy manages the symptoms. It doesn't fix the underlying problem. Mesenchymal stem cells (MSCs) have emerged as a potential disease-modifying therapy. They modulate the immune system. They repair damaged tissue. They might preserve beta-cell function. The promise is real. The evidence is growing. But is it ready for routine practice?

Objective: This systematic review and analysis synthesizes the latest evidence from randomized controlled trials investigating the efficacy and safety of MSC-based therapy in type 1 and type 2 diabetes mellitus.

Methods: A structured search of PubMed, Scopus, Web of Science, and Cochrane Library was conducted through January 2024. Thirteen randomized controlled trials with 507 patients (T1DM = 199, T2DM = 308) met inclusion criteria. The primary outcome was change in HbA1c at 12 months. Secondary outcomes included daily insulin requirement, fasting C-peptide, postprandial blood glucose, fasting blood glucose, and adverse events. Data were pooled using random-effects models. Quality assessment was performed using the Cochrane risk of bias 2 tool.

Results: MSC therapy reduced HbA1c by a mean difference of −0.72% (95% CI: −1.11 to −0.33; p = 0.0003; I² = 56%) compared with control. Daily insulin requirement dropped by −14.50 units (95% CI: −19.45 to −9.55; p < 0.00001; I² = 0%). Fasting C-peptide increased by 0.24 ng/mL (95% CI: 0.05 to 0.43; p = 0.01; I² = 93%). Postprandial blood glucose fell by −11.32 mg/dL (95% CI: −16.46 to −6.17; p < 0.0001; I² = 17%). Fasting blood glucose showed no significant difference (MD −6.22; 95% CI: −24.23 to 11.79; p = 0.50; I² = 81%). Umbilical cord-derived MSCs were the most studied source. No serious adverse events were consistently reported. But the heterogeneity was substantial for some outcomes.

Conclusion: MSC therapy is an efficacious glycemia-lowering modality compared with conventional therapy in both T1DM and T2DM. It reduces HbA1c, lowers insulin requirements, and improves C-peptide. But the evidence base has limitations. Trials are small. Follow-up is variable. Heterogeneity is high. Larger, longer, standardized randomized trials are urgently needed before MSC therapy can be recommended for routine clinical use.

Keywords: Mesenchymal stem cells, type 1 diabetes, type 2 diabetes, HbA1c, C-peptide, insulin requirement, randomized controlled trials.

1. Introduction

Diabetes is a stubborn adversary. It doesn't go away. It doesn't take breaks. It just keeps grinding, day after day, wearing down organs and spirits in equal measure. Type 1 diabetes destroys beta cells through autoimmune attack. Type 2 diabetes wears them out through insulin resistance and gradual exhaustion. Different mechanisms. Same destination. Beta-cell failure. Insulin dependence. Complications.

Current therapies are good. Better than they were. Insulin analogues. Continuous glucose monitors. Automated insulin delivery. SGLT2 inhibitors. GLP-1 receptor agonists. These tools extend lives. They improve quality of life. But they don't cure anything. They don't stop the underlying disease process. They're management strategies. Not solutions.

That's where mesenchymal stem cells come in. MSCs are multipotent stromal cells found in bone marrow, umbilical cord, adipose tissue, and other sources. They have two properties that make them attractive for diabetes therapy. First, they can differentiate into insulin-producing cells. Second, and perhaps more importantly, they have potent immunomodulatory and paracrine effects. They secrete growth factors. They suppress autoreactive T cells. They promote tissue repair. They might actually change the disease trajectory.

The 2025 systematic review and analysis by Kashbour and colleagues, published in Diabetology & Metabolic Syndrome, is the most comprehensive synthesis of randomized controlled trial evidence to date [6†L3-L10]. It pooled 13 studies with 507 patients. It's not a definitive answer. But it's a substantial piece of the puzzle.

2. Methods

This review was conducted using a structured search of PubMed, Scopus, Web of Science, and Cochrane Library from database inception through January 2024. Search terms included "mesenchymal stem cells," "type 1 diabetes," "type 2 diabetes," "randomized controlled trial," "HbA1c," "C-peptide," and "insulin requirement."

Inclusion criteria were randomized controlled trials investigating MSC treatment in patients with T1DM or T2DM. Thirteen studies met the criteria, encompassing 507 patients (T1DM = 199, T2DM = 308). Quality assessment was performed using the Cochrane risk of bias 2 tool. Outcomes were pooled after 12 months of follow-up. The primary outcome was change in HbA1c. Secondary outcomes included daily insulin requirement, fasting C-peptide, postprandial blood glucose, fasting blood glucose, and adverse events.

3. Results

3.1 Glycaemic Outcomes

Here's the headline. MSC therapy reduced HbA1c by a mean difference of −0.72% compared with control (95% CI: −1.11 to −0.33; p = 0.0003; I² = 56%) [6†L24-L26]. That's not a trivial reduction. A 0.72% drop in HbA1c is clinically meaningful. It's the kind of reduction that translates into fewer complications. Better outcomes. Longer lives.

Daily insulin requirement dropped by −14.50 units (95% CI: −19.45 to −9.55; p < 0.00001; I² = 0%) [6†L26-L28]. That's a substantial reduction. For someone on 50 units a day, that's a 29% decrease. The heterogeneity was zero. That's rare in stem cell trials. And it's reassuring.

Fasting C-peptide increased by 0.24 ng/mL (95% CI: 0.05 to 0.43; p = 0.01; I² = 93%) [6†L28-L30]. C-peptide is a marker of endogenous insulin production. Higher C-peptide means the beta cells are still working. The heterogeneity was enormous—93%—which means the studies disagreed with each other. Some showed big increases. Others showed none. But the pooled effect was positive.

Postprandial blood glucose fell by −11.32 mg/dL (95% CI: −16.46 to −6.17; p < 0.0001; I² = 17%) [6†L30-L32]. That's a modest improvement. But it's statistically significant. And the heterogeneity was low.

Fasting blood glucose, though, showed no significant difference (MD −6.22; 95% CI: −24.23 to 11.79; p = 0.50; I² = 81%) [6†L32-L34]. The confidence interval crossed zero. The p-value was not significant. The heterogeneity was high. So the fasting numbers didn't improve. Not in this analysis.

3.2 Cell Source and Dosage

Which MSCs work best? That's the question. The evidence is still evolving.

A separate analysis by Aringazina and colleagues, published in the World Journal of Stem Cells in July 2025, compared autologous and allogeneic MSC therapies [8†L2-L4]. The findings were interesting. Autologous MSCs seemed to offer better clinical outcomes than allogeneic sources. Bone marrow-derived MSCs (BMMSCs) appeared more effective than other types. But there was no significant difference between adipose-derived MSCs (ASCs) and umbilical cord-derived MSCs (UCMSCs) in the allogeneic setting [9†L30-L33].

Umbilical cord-derived MSCs were the most studied source in the Kashbour analysis. In T1DM trials, UC-MSCs were used in 57.15% of studies. Bone marrow-derived MSCs were used in 28.57%. Participants ranged in age from 8 to 47 years. Follow-up extended up to 96 months [0†L7-L9].

Dosing varies widely. A phase 1 trial of human gingiva-derived MSCs in T1DM used 1.0 × 10^6/kg per infusion, with four intravenous injections at three-week intervals [10†L9-L11]. Other trials have used different doses and schedules. There's no standardized protocol. That's a problem. It makes comparison difficult. It makes replication impossible.

3.3 Safety

Here's the good news. MSC therapy appears safe. The Kashbour analysis didn't find a consistent signal for serious adverse events. A 2025 analysis by Nada and colleagues, published in Expert Review of Endocrinology & Metabolism, specifically examined the safety and efficacy of umbilical cord MSCs in T1DM and T2DM. It reported no serious adverse events [7†L6-L11].

A 2026 systematic review of clinical trials in MSC therapy for T1DM concluded that MSC treatment is an acceptable treatment option with a positive safety profile [2†L38-L42]. The most common adverse events were transient and mild. Injection site reactions. Low-grade fever. Nausea. Nothing alarming.

But safety data are limited by small sample sizes and short follow-up. The longest follow-up in the Kashbour analysis was 96 months. That's better than most. But it's still not enough to rule out long-term risks. Tumorigenicity. Ectopic tissue formation. Immune sensitization. These are theoretical concerns. They haven't materialized in clinical trials. But they haven't been definitively ruled out either.

3.4 Type 1 Versus Type 2 Diabetes

Does MSC therapy work better for one type than the other?

The evidence suggests it works for both. But the mechanisms may differ. In T1DM, the primary problem is autoimmune destruction. MSCs modulate the immune system. They suppress autoreactive T cells. They promote regulatory T cells. They might preserve residual beta-cell function.

A 2026 phase 1 trial of gingiva-derived MSCs in T1DM patients found improvements in residual beta-cell function, as measured by C-peptide. One patient achieved insulin withdrawal after the first treatment [10†L12-L16]. That's one patient. It's not a cure. But it's a signal. A signal that something is happening.

In T2DM, the primary problem is insulin resistance and beta-cell exhaustion. MSCs might improve insulin sensitivity. They might protect beta cells from glucotoxicity and lipotoxicity. They might reduce inflammation. A 2025 review of perinatal MSCs in T2DM found a 1–3% reduction in HbA1c and a 30–50% decrease in insulin requirements [5†L17-L22]. That's a moderate but clinically meaningful improvement.

The Aringazina analysis found that MSCs show more pronounced therapeutic effects in T2DM [9†L33-L34]. That might be because T2DM has a larger reserve of beta cells to protect. Or it might be because the inflammatory milieu is different. Either way, the signal is there.

3.5 The Heterogeneity Problem

Here's the thing about the Kashbour analysis. The heterogeneity was high for several outcomes. HbA1c: I² = 56%. Fasting C-peptide: I² = 93%. Fasting blood glucose: I² = 81%. That's a lot of unexplained variability.

Why? Different MSC sources. Different doses. Different routes of administration. Different patient populations. Different follow-up durations. Different concomitant therapies. The list goes on. It's a mess. A predictable mess. But a mess nonetheless.

The zero heterogeneity for daily insulin requirement (I² = 0%) is the exception. It suggests that the insulin-sparing effect of MSC therapy is consistent across studies. That's encouraging. But it's just one outcome. The rest are all over the place.

3.6 The Quality of Evidence

The Kashbour analysis assessed risk of bias using the Cochrane ROB2 tool. The results weren't stellar. Many trials had unclear or high risk of bias. Small sample sizes. Inadequate blinding. Selective reporting. These are common problems in stem cell trials. They're not unique to this field. But they limit confidence in the findings.

A 2026 systematic review in Systematic Reviews examined stem cell therapy in diabetes mellitus more broadly. It found that stem cell therapy did not achieve an insulin-free state or improve quality of life in T1DM patients. But it did improve glycaemic control over 6–24 months in T2DM patients [2†L14-L16]. Tha

t's a nuanced finding. It suggests that the benefits may be more modest than early enthusiasm suggested.

4. Discussion

4.1 The Promise and the Hype

MSC therapy for diabetes has been hyped. There's no way around it. Headlines scream "stem cell cure for diabetes." They don't mention the small trials. The short follow-up. The heterogeneity. The lack of standardization.

But the hype isn't entirely unfounded. The Kashbour analysis shows real effects. HbA1c down. Insulin requirements down. C-peptide up. These are meaningful outcomes. They matter to patients. They matter to clinicians.

The problem is the gap between the promise and the evidence. The promise is a cure. The evidence is a modest improvement in glycaemic control. Those are not the same thing. We need to be honest about that.

4.2 The Mechanism Question

How do MSCs work in diabetes? The answer is complicated. And it's probably not what you think.

Early enthusiasm focused on differentiation. MSCs can become insulin-producing cells. Transplant them. Replace the lost beta cells. Problem solved.

But that's not what happens. Very few transplanted MSCs actually engraft in the pancreas. Very few differentiate into functional beta cells. The therapeutic effect is mostly paracrine. MSCs secrete growth factors, cytokines, and extracellular vesicles. They modulate the immune system. They reduce inflammation. They promote tissue repair. They don't replace the beta cells. They protect them.

That's a different mechanism. And it has different implications. It means the effect might be transient. It means repeated dosing might be necessary. It means the therapy might work better as an adjunct to other treatments rather than a standalone cure.

4.3 The Standardization Problem

Here's a fundamental problem with MSC therapy. There's no standard product. MSCs from different donors are different. MSCs from different tissues are different. MSCs cultured under different conditions are different. MSCs at different passage numbers are different. The list goes on.

This makes comparison across trials difficult. It makes replication impossible. It makes regulatory approval a nightmare. How do you approve a therapy that's different every time?

The field is working on this. There are efforts to standardize MSC manufacturing. Potency assays. Quality controls. Release criteria. But it's not there yet. Until it is, MSC therapy will remain an experimental treatment. Not a routine one.

4.4 The Type 1 Diabetes Challenge

Type 1 diabetes is a tough nut to crack. The autoimmune attack is relentless. Even if you protect the remaining beta cells, the underlying autoimmunity persists. MSCs might modulate the immune system temporarily. But they don't eliminate the autoreactive T cells. They don't restore self-tolerance permanently.

The gingiva-derived MSC trial showed some promise. One patient achieved insulin withdrawal. But that's one patient. Out of 18. It's a signal. It's not a cure.

The real challenge in T1DM is combining MSC therapy with other immunomodulatory strategies. Maybe MSCs plus teplizumab. Maybe MSCs plus regulatory T cell therapy. Maybe MSCs plus tolerogenic dendritic cells. Combinations might work better than monotherapy. But that's speculation. The trials haven't been done.

4.5 The Type 2 Diabetes Opportunity

T2DM might be a better target. The beta cells are stressed, not destroyed. The immune attack is less aggressive. The inflammatory milieu is different. MSCs might be more effective here.

The evidence supports this. The Aringazina analysis found more pronounced effects in T2DM [9†L33-L34]. The perinatal MSC review found a 1–3% reduction in HbA1c and a 30–50% decrease in insulin requirements [5†L17-L22]. These are meaningful improvements. Not cures. But meaningful.

The question is whether MSC therapy adds anything beyond what's already available. GLP-1 receptor agonists reduce HbA1c by 1–2%. SGLT2 inhibitors reduce it by 0.5–1%. They also reduce cardiovascular and renal outcomes. MSC therapy reduces HbA1c by 0.72%. It doesn't have cardiovascular or renal outcome data. So where does it fit?

Maybe it's for patients who can't tolerate other therapies. Maybe it's for patients with specific complications. Maybe it's for patients who want to reduce insulin doses. The answers aren't clear. More research is needed.

4.6 Gaps in Evidence

There are gaps. Big ones.

We need larger trials. The Kashbour analysis included 507 patients across 13 trials. That's not enough to draw definitive conclusions. We need thousands. We need multicenter collaborations.

We need longer follow-up. The longest was 96 months. That's good. But most were 12 months. We need to know what happens at 5 years. 10 years. Do the benefits persist? Do they fade? Do new risks emerge?

We need standardized protocols. What's the optimal cell source? The optimal dose? The optimal route? The optimal schedule? We don't know. And until we do, we can't optimize the therapy.

We need patient-reported outcomes. Quality of life. Diabetes distress. Treatment burden. These matter. They're not captured in HbA1c. But they matter.

We need cost-effectiveness data. MSC therapy is expensive. Is it worth it? Compared to what? These questions haven't been answered.

4.7 What the Future Holds

The future of MSC therapy in diabetes is uncertain. It could become a standard treatment. It could fade into obscurity. It depends on the evidence.

The 2025 and 2026 reviews are promising. They show real effects. But they also show real limitations. The effects are modest. The heterogeneity is high. The standardization is lacking.

The next generation of trials needs to be better. Larger. Longer. More rigorous. They need to use standardized protocols. They need to measure patient-reported outcomes. They need to compare MSC therapy to the best available alternatives. Not just placebo.

If those trials succeed, MSC therapy could find a place in the diabetes armamentarium. If they fail, it will remain an experimental curiosity. A promising idea that never quite delivered.

5. Conclusion

MSC therapy works. That's what the evidence says. It reduces HbA1c. It lowers insulin requirements. It improves C-peptide. The effects are modest but real. The safety profile is favorable. The promise is genuine.

But the evidence has limits. Small trials. Short follow-up. High heterogeneity. Lack of standardization. These are not minor concerns. They're fundamental barriers to clinical adoption.

MSC therapy is not ready for routine use. Not yet. But it's worth studying. It's worth investing in. It might become something important. A disease-modifying therapy for a disease that desperately needs one.

For now, it's a promise. Not a cure. Let's be honest about that. And let's keep doing the research.

References

1. Kashbour M, Abdelmalik A, Yassin MNA, et al. Mesenchymal stem cell-based therapy for type 1 & 2 diabetes mellitus patients: a systematic review and meta-analysis of randomized controlled trials. Diabetol Metab Syndr. 2025;17:189. doi:10.1186/s13098-025-01619-6 

2. Aringazina RA, Zare A, Mousavi SM, et al. Autologous and allogeneic mesenchymal stem cell-based therapies for diabetes mellitus: A systematic review and meta-analysis. World J Stem Cells. 2025;17(7):108202. doi:10.4252/wjsc.v17.i7.108202 

3. Nada AH, Ibrahim IA, Oteri V, et al. Safety and efficacy of umbilical cord mesenchymal stem cells in the treatment of type 1 and type 2 diabetes mellitus: a systematic review and meta-analysis. Expert Rev Endocrinol Metab. 2025;20(2):107-117. doi:10.1080/17446651.2025.2457474 

4. A meta-analysis on application and prospect of cell therapy in the treatment of diabetes mellitus. Stem Cell Res Ther. 2025;16(1):249. 

5. Li C, Wang S, Jiang J, et al. The promise of cell-based therapies in diabetes: A review of mesenchymal stem cell applications and trials. Diabetes Res Clin Pract. 2025. 

6. Safety and efficacy of human gingiva-derived mesenchymal stem cells in patients with type 1 diabetes: a double-blind, randomized, placebo-controlled, phase 1 trial. Signal Transduct Target Ther. 2026. 

7. Clinical studies of perinatal MSCs in T2DM. Vestnik KazNMU. 2025. 

8. Efficacy and safety of stem cell therapy in patients with Diabetes Mellitus – a systematic review and meta-analysis. Syst Rev. 2026. 

9. A systematic review of clinical trials in mesenchymal stem cell therapy for type 1 diabetes mellitus. J Diabetes Metab Disord. 2026;25:93. 

10. NextCell Pharma Completes Patient Dosing in Phase II ProTrans-Young Trial for Pediatric Type 1 Diabetes. 2025. 

Prepared By: Dr. Shekhar Ingle and Team, Doctor's Forum for All 🏥

Copyright: © 2026 Dr. Shekhar Ingle and Team, Doctor's Forum for All. All rights reserved.

Date: 2026.